Beyond The Sprues

Modelling => Ideas & Inspiration => Land => : Jeffry Fontaine September 23, 2012, 02:24:52 AM

: Churchill Tank
: Jeffry Fontaine September 23, 2012, 02:24:52 AM
(http://a.modellversium.de/galerie/bilder/0/0/8/10008-tumb.jpg) (http://www.modellversium.de/galerie/6-militaer-ww2/10008-churchill-ark-tamiya.html)

Click on thumbnail or image to view article

Churchill ARK Armoured Ramp Carrier built by Erich Rauthe and based on the Tamiya kit (http://www.modellversium.de/galerie/6-militaer-ww2/10008-churchill-ark-tamiya.html)
: Re: Churchill Tank
: raafif September 23, 2012, 04:36:09 AM
nice model !

        The Churchill is much neglected in whif & other areas -- love to see a decent SPG version :P  _______ brain in gear, maybe a line-drawing coming .....


: Re: Churchill Tank
: ChernayaAkula September 23, 2012, 02:17:55 PM
Nice indeed!  :)

        The Churchill is much neglected in whif & other areas <...>

Agreed!  :) SPG sounds interesting.
Someone (apophenia, maybe?) did a Churchill (or Black Prince?) with an updated Centurion turret that looked really cool.  8)
: Re: Churchill Tank
: Weaver September 24, 2012, 04:04:08 AM
I always hated building them for wargaming because of all the little wheels.... On the other hand though, that does make them a good candidate for scaleorama because you can re-scale, say, a 1/35th one to 1/72nd and the plethora of small wheels looks more convincing for a HUGE vehicle than a few big ones. The tiny escape hatches become decent-sized doors when scaleorama'd too.
: Re: Churchill Tank
: Feldmarschall Zod September 24, 2012, 05:38:39 AM
When I get home,I will have to see if a StuG III fighting compartment will fit onto a Churchill hull. Make it into some sort of SP artillery,a bunker buster.
: Re: Churchill Tank
: jcf September 24, 2012, 07:08:28 AM
Henk of Holland's Churchill page:

http://henk.fox3000.com/churchill.htm (http://henk.fox3000.com/churchill.htm)


The oh so lovely A22D 3" self-propelled:
http://arcaneafvs.com/a22d_churchill_gun_carrier.html (http://arcaneafvs.com/a22d_churchill_gun_carrier.html)
(http://arcaneafvs.com/a22/a22_guncarrier__001.jpg)

I think a Stugified Churchill would bear some resemblance to the A39 Tortoise.

 :icon_fsm:
: Re: Churchill Tank
: raafif September 24, 2012, 08:01:17 AM

I think a Stugified Churchill would bear some resemblance to the A39 Tortoise.



yep I have the Tortoise kit & may do it as a possible "end-of-line" Churchill SPG development but I want to do a Churchill Heavy-SPG as it may have emerged in say early 1944  ((also a Matilda SPG)).

(http://i148.photobucket.com/albums/s34/hobgrot/1122B.jpg)

When I saw the remains of that A22D 3" at Bovvy in 2000, it was a very sad wreck with most of the left hull missing :icon_crap:
: Re: Churchill Tank
: dy031101 September 30, 2012, 10:26:15 AM
 ;D
: Re: Churchill Tank
: GTX_Admin September 30, 2012, 07:30:24 PM
 :)
: Re: Churchill Tank
: Jeffry Fontaine October 01, 2012, 04:32:48 AM
How about improving on the sponsons and making them stick out a bit further for a weapons station that could fit a gunner and weapon in the prone position firing a small caliber infantry support gun (47mm or 37mm) or a machine gun (15mm Besa or .303" Browning)?  It would be perfect for a post WW1 early thirties tank development before the doctrine on how to best use these weapons was was fully established. 
: Re: Churchill Tank
: Rickshaw October 01, 2012, 09:25:08 PM
How about improving on the sponsons and making them stick out a bit further for a weapons station that could fit a gunner and weapon in the prone position firing a small caliber infantry support gun (47mm or 37mm) or a machine gun (15mm Besa or .303" Browning)?  It would be perfect for a post WW1 early thirties tank development before the doctrine on how to bust use these weapons was was fully established.

The original prototype for what became the Churchill had that, with MGs in the sponsons.  They were removed because they weakened the armour and were difficult to manufacture.
: Re: Churchill Tank
: Volkodav July 28, 2013, 10:56:00 AM
The Australian developed 25 pounder tank gun used as a CS gun for the Churchill to instead of the 95mm CS, later replaced by a CS version of the L9 165mm demolition gun.  The 95mm is developed with a longer barrel, increasing performance and negating the need for a counter weight on the barrel.
: Re: Churchill Tank
: Volkodav November 26, 2013, 07:49:58 PM
What would be the minimum mods required to fit a RR Meteor engine and either a 17lbr or 77mm HV to a Churchill?  Not looking for a Black Prince type redesign but rather something that could have been done to the MkVII to make it more competitive in 44-45 and incidentally something that would be comparatively easy to model on the Basis of the original Tamiya Churchill Crocodile I have in my stash.

I assume an increase in hull width and a larger diameter turret ring but should be able to get away with the existing length.  Maybe some extra armour.
: Re: Churchill Tank
: dy031101 November 26, 2013, 09:28:46 PM
For mounting a 17 pounder...... two words: Black Prince.
: Re: Churchill Tank
: Volkodav November 26, 2013, 09:48:08 PM
Ah huh but not looking for a Black Prince, looking for minimal change to the chassis but must have the Meteor and its 600bhp
: Re: Churchill Tank
: dy031101 November 27, 2013, 10:52:47 AM
Ah huh but not looking for a Black Prince, looking for minimal change to the chassis but must have the Meteor and its 600bhp

Hum...... maybe you can try a French-style oscillating turret then......
: Re: Churchill Tank
: Volkodav November 27, 2013, 11:01:23 AM
Hadn't thought of that, it would work!

What the history of the oscillating turret, I know it was first prototyped for a cancelled late 40s MBT but was the concept around for an escaping French designer / engineer to offer it to the Brits in 1940?

No thinking Churchill Mk VII with a raised engine deck and oscillating turret with a 17pdr, would probably look at a larger bustle though, one that permits the autoloader to be topped up from under armour.
: Re: Churchill Tank
: buzzbomb November 27, 2013, 12:58:36 PM
As another thought, totally without looking at the detail.. what about popping an Achilles Tank Destroyer open topped Turret with the 17pdr on it.. I cannot see that the ring size of that and the MkVII Churchy would be too much different.
 
: Re: Churchill Tank
: jcf November 28, 2013, 01:43:53 AM
Churchill: 54.25"

M10/Achilles: 69"
: Re: Churchill Tank
: Feldmarschall Zod November 28, 2013, 02:34:43 AM
Accurate Armour has a Churchill dozer conversion armed with a 165 mm demolition gun for the Tamiya kit. Also includes a decal sheet.

http://www.accurate-armour.com/ShowProduct.cfm?manufacturer=0&category=66&subcategory=39&product=2361 (http://www.accurate-armour.com/ShowProduct.cfm?manufacturer=0&category=66&subcategory=39&product=2361)
: Re: Churchill Tank
: Volkodav November 28, 2013, 09:50:58 AM
Churchill: 54.25"

M10/Achilles: 69"

Ok 14.75" difference, over a foot!
374.65mm - 10.71mm in 1/35 that is a big plug to increase width and probably an extra road wheel for length, back in Black Prince territory.

Another option I just thought of is raise the hull and have sponsons over the tracks.  Alternatively move the trunnions mounts forward, or the trunnions themselves back onto the breach with a counter weight on an integrated loading tray and have a counter balancing bustle.

Comet had a 64" turret ring, 247.65mm difference, 7.1mm in 1/35 still a lot to fudge.  Messing with the hull height or trunnions looks the most promising.
: Re: Churchill Tank
: Volkodav November 28, 2013, 09:55:36 AM
Accurate Armour has a Churchill dozer conversion armed with a 165 mm demolition gun for the Tamiya kit. Also includes a decal sheet.

[url]http://www.accurate-armour.com/ShowProduct.cfm?manufacturer=0&category=66&subcategory=39&product=2361[/url] ([url]http://www.accurate-armour.com/ShowProduct.cfm?manufacturer=0&category=66&subcategory=39&product=2361[/url])


Interesting, I wonder if a 25pdr adapted with a one piece round would fit in a standard MkVII turret?  APDS and HE would be pretty effective and probably better than the 75mm while still not in 17pdr or 76mm territory.
: Re: Churchill Tank
: Volkodav November 28, 2013, 10:56:17 AM
Another thought, the Cromwell based Charioteer had a two man turret with a 20pdr, could a similar turret have been developed for the Churchill in WWII for the 17pdr?
: Re: Churchill Tank
: buzzbomb November 28, 2013, 12:55:22 PM
Another thought, the Cromwell based Charioteer had a two man turret with a 20pdr, could a similar turret have been developed for the Churchill in WWII for the 17pdr?


Same sort of thing was done with the Centurion to produce the Conway, bung a larger turret on the basic hull
(http://arcaneafvs.com/fv4004_5/conway5.jpg)

Your thoughts around the 25pdr appear sound.. look at the Bishop mounting on a Valentine, which was much smaller than a Churchill, albeit non rotating.

Again around the Conway project.. you could do something like this
(http://arcaneafvs.com/fv4004_5/fv4005e.jpg)
: Re: Churchill Tank
: Jeffry Fontaine November 28, 2013, 01:33:45 PM
Churchill could really benefit from a sloped front glacis plate and get rid of that shot trap.
: Re: Churchill Tank
: Rickshaw November 28, 2013, 02:35:14 PM
Another thought, the Cromwell based Charioteer had a two man turret with a 20pdr, could a similar turret have been developed for the Churchill in WWII for the 17pdr?

It could have been done but the question would have been, "why?"

The Churchill was developed as an infantry tank and was not intended to engage other tanks so a gun which fired a good sized HE round and had a secondary AT round with reasonable penetration was what was required and the 75mm did that rather well.

Infantry tanks were originally not even intended to have cannons but rather MGs and were intended just to engage strong points and keep the enemy's heads down while the infantry followed up the creeping barrage.   It was soon realised that with the proliferation of AT guns a HE thrower was required to engage and destroy the ones which the artillery barrage had missed.    I refer you back to the military ethos article I posted for you in the scenarios forum.
: Re: Churchill Tank
: Feldmarschall Zod November 28, 2013, 06:45:45 PM
Accurate Armour has a Churchill dozer conversion armed with a 165 mm demolition gun for the Tamiya kit. Also includes a decal sheet.

[url]http://www.accurate-armour.com/ShowProduct.cfm?manufacturer=0&category=66&subcategory=39&product=2361[/url] ([url]http://www.accurate-armour.com/ShowProduct.cfm?manufacturer=0&category=66&subcategory=39&product=2361[/url])


Interesting, I wonder if a 25pdr adapted with a one piece round would fit in a standard MkVII turret?  APDS and HE would be pretty effective and probably better than the 75mm while still not in 17pdr or 76mm territory.

I can see a 25 pdr in a Churchill turret.
: Re: Churchill Tank
: Feldmarschall Zod November 28, 2013, 06:56:51 PM
Another thought, the Cromwell based Charioteer had a two man turret with a 20pdr, could a similar turret have been developed for the Churchill in WWII for the 17pdr?

It could have been done but the question would have been, "why?"

The Churchill was developed as an infantry tank and was not intended to engage other tanks so a gun which fired a good sized HE round and had a secondary AT round with reasonable penetration was what was required and the 75mm did that rather well.

Infantry tanks were originally not even intended to have cannons but rather MGs and were intended just to engage strong points and keep the enemy's heads down while the infantry followed up the creeping barrage.   It was soon realised that with the proliferation of AT guns a HE thrower was required to engage and destroy the ones which the artillery barrage had missed.    I refer you back to the military ethos article I posted for you in the scenarios forum.
I know the Churchill and Sherman were not supposed to engage enemy tanks per doctrine. But how many times in combat do the enemy forces adhere to the official doctrine of the other side?
I see both sides of the conversation. One hand,you need something with a main gun with great AP performance is enemy tanks. But yet,you also need a tank that has a main gun that has great HE performance.
: Re: Churchill Tank
: Volkodav November 28, 2013, 07:20:07 PM
Looking outside the square for a counter for the Tiger I, the Churchill had the armour but could have done with an improved gun and engine.  The Churchill was one of the most common UK tanks in Europe post D Day so a minimum change version able to kill a Tiger would have been a useful addition, if not at troop level then definitely at squadron level, similar to the way Sherman Fireflies re-enforced regular Sherman units and the later Conqueror did for Centurion units.

The first Tiger I knocked out, actually immobilised and abandoned by its crew, was taken out by a Churchill in North Africa.  This Tiger, is I believe the running model Bovington has today.

The thinking behind the 25pdr was the set up in the Sentinel ACII but that was based on the short barrelled mountain gun version, I imaging a Churchill would have the full length or even a longer barrel.  For a slugging match with a Tiger the 17pdr or 77mm HV would be preferable, maybe an arrangement where the majority of Churchills have 25pdr and are supported buy 17pdr models at a ratio or 3:2 in each troop.  With the 25pdr being the standard gun the crappy 95mm could be discontinued.
: Re: Churchill Tank
: Rickshaw November 28, 2013, 10:44:22 PM
Another thought, the Cromwell based Charioteer had a two man turret with a 20pdr, could a similar turret have been developed for the Churchill in WWII for the 17pdr?

It could have been done but the question would have been, "why?"

The Churchill was developed as an infantry tank and was not intended to engage other tanks so a gun which fired a good sized HE round and had a secondary AT round with reasonable penetration was what was required and the 75mm did that rather well.

Infantry tanks were originally not even intended to have cannons but rather MGs and were intended just to engage strong points and keep the enemy's heads down while the infantry followed up the creeping barrage.   It was soon realised that with the proliferation of AT guns a HE thrower was required to engage and destroy the ones which the artillery barrage had missed.    I refer you back to the military ethos article I posted for you in the scenarios forum.
I know the Churchill and Sherman were not supposed to engage enemy tanks per doctrine. But how many times in combat do the enemy forces adhere to the official doctrine of the other side?
I see both sides of the conversation. One hand,you need something with a main gun with great AP performance is enemy tanks. But yet,you also need a tank that has a main gun that has great HE performance.

Hence the creation of the "Universal Tank" and by extension the MBT concept which did away with the Heavy Tank.

While it's easy to be dismissive of this sort of artificial division of responsibilities, always remember, all major combatants did it to some degree or other in the early years of mechanised development (primarily, I suspect 'cause they copied the British "Purple Primer" training pamphlet on Mechanised Warfare (even Gudrian did it as well!).
: Re: Churchill Tank
: Rickshaw November 28, 2013, 10:59:24 PM
Looking outside the square for a counter for the Tiger I, the Churchill had the armour but could have done with an improved gun and engine.  The Churchill was one of the most common UK tanks in Europe post D Day so a minimum change version able to kill a Tiger would have been a useful addition, if not at troop level then definitely at squadron level, similar to the way Sherman Fireflies re-enforced regular Sherman units and the later Conqueror did for Centurion units.

The first Tiger I knocked out, actually immobilised and abandoned by its crew, was taken out by a Churchill in North Africa.  This Tiger, is I believe the running model Bovington has today.


Actually, the first Tiger I knocked out by a Western Ally was by a 6 Pdr AT gun in Tunisia.  However, that Tiger I was then recovered by the Germans.  I heartily recommend David Fletcher's book on The Tiger Tank: a British perspective" (I think that's the title) it contains all the intelligence reports which were filed about the Tiger by British Military Intelligence.  Makes fascinating reading and explains the reasons why there is so much "fog" in wartime.

The thinking behind the 25pdr was the set up in the Sentinel ACII but that was based on the short barrelled mountain gun version,


I doubt it.  The 25Pdr used in the Sentinel was a standard length barrel. 

(http://lib.rus.ec/i/99/257899/pic_7.jpg)
: Re: Churchill Tank
: Old Wombat November 29, 2013, 01:39:57 AM
THAT's what I forgot to put on my Airfix wishlist!

1/35 AC Sentinel family (I, II & IV)

:o

Guy
: Re: Churchill Tank
: dy031101 November 29, 2013, 12:11:26 PM
I can see a 25 pdr in a Churchill turret.

Wikipedia claims that a HEAT round was under development but was not pursued further due to the wider introduction of the 17 pounder.

How much more potent would a 25-pounder-armed Churchill be made by HEAT ammunitions against hostile armours compared to, for the sake of argument, the 17 pounder??
: Re: Churchill Tank
: Rickshaw November 29, 2013, 04:27:06 PM
I just realised that's a drawing of the ACI not the ACIII.

Here is a picture of the ACIII, showing the 25pdr barrel length:

(http://upload.wikimedia.org/wikipedia/commons/6/6f/AC3_tank_%28AWM_101155%29.jpg)
: Re: Churchill Tank
: Rickshaw November 29, 2013, 04:34:57 PM
I can see a 25 pdr in a Churchill turret.


Wikipedia claims that a HEAT round was under development but was not pursued further due to the wider introduction of the 17 pounder.

How much more potent would a 25-pounder-armed Churchill be made by HEAT ammunitions against hostile armours compared to, for the sake of argument, the 17 pounder??


It wouldn't have been.  HEAT's armour penetration is more dependent on the diameter of the cone, than the weight of the explosive backing it.  A ~89mm WWII HEAT round such as the 25 Pdr would have penetrated about 90mm of armour at zero degrees incidence, at all ranges where as a 17 Pdr penetration varies upon round (APCBC versus APDS) and range.

Armour Piercing, Capped, Ballistic Capped (APCBC) ammunition could penetrate 130 mm of armour at 500 metres and 119 mm at 1000 m at a 30-degree angle. Armour-piercing discarding sabot (APDS) could penetrate 204 mm of armour at 500 m and 185 mm at 1000 m at a 30-degree angle,

[Source (http://en.wikipedia.org/wiki/Ordnance_QF_17-pounder)]

Of course all armour penetration figures should be taken with a grain of salt when no methodology or hardness figures are provided.
: Re: Churchill Tank
: tankmodeler December 01, 2013, 10:25:03 AM
The difference in the turret ring diameters is teh real problem in upgunning the Churchill past the Brit 75mm.

However, you can use the solution the Israeli's did for the M50 and M51 Shermans, i.e. push the gun trunnions forward enough to permit the proper recoil. And, because we know the 69" sherman and 64" Comet could handle the 17 pdr, we also know how much ahead of the existing trunion point the new one would have to be. Adding an extension to the front of the turret, looking kinda like the way the Valentine IX, X and XI turets did it would also offer a chance to provide an angled front to the new turret casting and possibly the sides as well, increasig crew room to handle the new gun.

Exchanging the old engines for a newer Meteor would be problematic with the size of the engine bay. That said, if you were prepared to live with not being able to shoot directly behind, you could add an angled bevel gearbox between the Meteor and the Merrit Brown transmission and then mount the meteor nose down so that the part of the engine sits over the tranny and then the bevel box drives the power down into the tranny, which has it's input located on top and not on the front face. You'd end up with a big hump in the back edge of the engine deck, but maybe it could be done. It would make for an interesting story, anyway!  :)

Paul
: Re: Churchill Tank
: Volkodav December 01, 2013, 01:31:39 PM
 ;) Yes thankyou, that would be the trick, now the question is could the UK have produced such a vehicle in numbers ready for Normandy?  I for one believe so and now we have the UK fielding a much more reliable and versatile counter to the Tiger I.

Thankyou again.
: Re: Churchill Tank
: dy031101 December 01, 2013, 03:17:07 PM
However, you can use the solution the Israeli's did for the M50 and M51 Shermans, i.e. push the gun trunnions forward enough to permit the proper recoil. And, because we know the 69" sherman and 64" Comet could handle the 17 pdr, we also know how much ahead of the existing trunion point the new one would have to be. Adding an extension to the front of the turret, looking kinda like the way the Valentine IX, X and XI turets did it would also offer a chance to provide an angled front to the new turret casting and possibly the sides as well, increasig crew room to handle the new gun.

Any idea on how the gun elevation and depression would be affected with this setup?
: Re: Churchill Tank
: Rickshaw December 01, 2013, 04:14:51 PM
;) Yes thankyou, that would be the trick, now the question is could the UK have produced such a vehicle in numbers ready for Normandy?  I for one believe so and now we have the UK fielding a much more reliable and versatile counter to the Tiger I.

Thankyou again.

Well, they remanufactured most Churchills which had been produced (about 2,000) starting in IIRC late 1943-early 1944.  It took them about 12 months, from memory.  At that point, they had been contemplating discontinuing production but the vehicles success in North Africa and Italy had convinced them to persevere with it.  They also started producing new marks - the Mk.VI and VIII and IIX and IX.   The quality of production had been low, the gearboxes were crap and the engines bad in most of the early marks.  Funny thing was the Churchills which were sent out (Mk.III and IV), all outperformed the other tanks, so they can't have been that bad.

If you were contemplating upgunning them, that would be the point to do it.   Thing was, Tigers were rarely encountered in combat (Whittman's effort not withstanding).  Most died either because of aircraft attack or breakdown.
: Re: Churchill Tank
: Volkodav December 01, 2013, 05:13:17 PM
On the basis of the Tiger being encountered in North Africa in 1942 it would have made sense to develop a counter to it prior to in invasions of Italy and France as it could be assumed that they would be encountered more often.  It was fortunate that the Tigers and Panthers were not as reliable, or as easy to manufacture as they could have been.
: Re: Churchill Tank
: tankmodeler December 02, 2013, 03:17:30 AM
Any idea on how the gun elevation and depression would be affected with this setup?
Well, it would reduce the elevation and depression compared to what would be available in a tank designed for it from the start, however, would it be reduced too much? No way to know, really. You have set an actual trunnion position (and not my completely fabricated sketch) and then do the sums. Certainly the Russian vehicles from the T-54 on have had significantly less elevation and deression than their Western opposites and Western armies have _always_ thought that a flaw. Russian/Soviet armies, however, have thought the benefits more important than that flaw. It's all a matter of perspective and needs.

Paul
: Re: Churchill Tank
: tankmodeler December 02, 2013, 03:28:07 AM
;) Yes thankyou, that would be the trick, now the question is could the UK have produced such a vehicle in numbers ready for Normandy?
No, they could not. That's a flat out fact.

The UK could barely provide enough Fireflies for 1 vehicle in 4 in combat units and that really wasn't enough and it only involved relatively minor changes to the Sherman turret and innards. Doing what the Israelis did to make the M50 to the Churchill turret would have been significantly more work than the Firefly conversion and then to add the massive rebuild of the arse end to add the Meteor (if it was even possible)? No, there simply wasn't enough time.

One also have to examine the Churchill as a basis for such a conversion. If you could get the top speed up to 25 or so MPH, then, yeah, it might be worth it, but the rebuild time/cost would have been immense for each vehicle. And, frankly, the suspension probably wasn't up to moving that vehicle much faster over broken ground. The small wheel system really isn't good for speed over undulating terrain.

Then you have to imagine how it would be used. If it was to provide an armoured suport for infantry against German tanks, it could have been useful and would not have needed the engine upgrade. In that role, it might be worthwhile. However, of course, the tank destroyers were used in that role with success when required, so I'm not sure the need was really there. What was needed was a cruiser with a 17 pdr and the Comet and Firefly adequately filled that niche.

Remember, the needs of the attacker are always different than those of the defender and an upgunned Churchill would have been best as an infantry defender, but would not have been good as an attacker. And, in the final analysis, attacking is what the Allies were doing for the entire last year of the war, individual defensive actions notwithstanding.

Paul
: Re: Churchill Tank
: dy031101 December 02, 2013, 03:55:19 AM
Exchanging the old engines for a newer Meteor would be problematic with the size of the engine bay. That said, if you were prepared to live with not being able to shoot directly behind, you could add an angled bevel gearbox between the Meteor and the Merrit Brown transmission and then mount the meteor nose down so that the part of the engine sits over the tranny and then the bevel box drives the power down into the tranny, which has it's input located on top and not on the front face. You'd end up with a big hump in the back edge of the engine deck, but maybe it could be done. It would make for an interesting story, anyway!  :)

If the "hump" should be deemed undesirable, what would have been the alternative?

(I found that Meteor has a two-third size variant called Meteorite available...... and then that the Meteorite has only 285 bhp at 2000 rpm......  Ireland was said to have experimented with re-engining the Churchill with Merlins salvaged from their Seafire.  Was it unsuccessful for the same reason as taking Meteor would have produced that "hump"?)
: Re: Churchill Tank
: dy031101 December 02, 2013, 04:23:52 AM
I mistakenly believed that I failed to save a copy on my hard drive:

(http://i.imgur.com/YVpS9oa.jpg)
(http://i.imgur.com/OTydgpJ.jpg)

I still either never knew or have forgotten who the author is though.
: Re: Churchill Tank
: buzzbomb December 02, 2013, 05:49:50 AM
I like that.. nice and subtle.. works for me
: Re: Churchill Tank
: tankmodeler December 02, 2013, 06:52:47 AM
If the "hump" should be deemed undesirable, what would have been the alternative?
With the Meteor? Nothing really. If you could get your hands on some Ford GAA engines in the M4A3 that might be shorter, but it was also only 450 HP so the tank would be much less powerful but still better than the normal Churchill. You might be able to fit that if you lengthened the hull, but that's not a mod, that's a new tank. The problem is that the location of the drive sprocket sets the limit on what can fit into the arse end of the Churchill. And, like most Brit tanks built in WW II, they were designed with very little room to expand the design. I mean, by the time they were designing the Churchill (and the Ram, as it turns out) the Brits wre not only asking for 54" turret rings (which was better than the ring for the 2 pdr tanks) but also turning _down_ requests to go to the same 69" that the US was putting in the Sherman as not only currently unnecessary, but not likely to _ever_ be necessary.

Which then meant that even the brand new Comet could not fit a full sized 17 pdr, it had to use the somewhat derated 77mm gun because the 64" turret ring could not take the recoil like the Sherman could. All because of a continuing lack of vision by the British tank design authorities. They never, right up to the Centurion, could see past the end of the exact tank they were working on. It was bloody criminal, to be sure.

(I found that Meteor has a two-third size variant called Meteorite available...... and then that the Meteorite has only 285 bhp at 2000 rpm......

That's less than the normal 300 hp of the Churchill, so you're not helping.  :)

Ireland was said to have experimented with re-engining the Churchill with Merlins salvaged from their Seafire.  Was it unsuccessful for the same reason as taking Meteor would have produced that "hump"?)
At least those problems plus the fact that the Merlins run at much higher horsepowers for much shorter times. They are not set up to produce lower HP for longer periods. In essence, you need to design a new engine around the same displacement and size, which of course, brings you back to the Meteor, 'cause that's exactly what that was.

Paul
: Re: Churchill Tank
: Volkodav December 02, 2013, 07:43:40 AM
Thanks, interesting discussion.  I have read that part of the issue was military intelligence reported that both the Tiger and Panther were highly specialized vehicles and would only be available in very limited numbers and as such there was no need to develop a counter to them.  This led to official resistance to even the development and production of the Firefly.  As history shows they were wrong and losses were much higher as a result.

I imagine had the allies been away of the number of Tigers and Panthers that would be encountered in Normandy we would have seen the deployment of effective counter earlier and in much greater numbers.
: Re: Churchill Tank
: dy031101 December 02, 2013, 08:05:39 AM
If you could get your hands on some Ford GAA engines in the M4A3 that might be shorter, but it was also only 450 HP so the tank would be much less powerful but still better than the normal Churchill.

I'd be content even if a new engine would only result in better reliability, and if it wouldn't require major modifications like what you mentioned.

That's less than the normal 300 hp of the Churchill, so you're not helping.  :)

Of course not- I mentioned the Meteorite in a way intended to show that it is not what I'm looking for.  ???

===========================================================================

As for up-gunning the Churchill...... I think I'll still go back to the idea that 25-pounder is the way to go.  Its "success" with Sentinel AC3 at least gives me hope that it might be less of a headache to put into a Churchill, and it was likely a better infantry support gun than the 77mm HV until Summer 1944 anyway.
: Re: Churchill Tank
: tankmodeler December 02, 2013, 08:55:54 AM
Of course not- I mentioned the Meteorite in a way intended to show that it is not what I'm looking for.  ???
I know, I'm just poking fun.

As for up-gunning the Churchill...... I think I'll still go back to the idea that 25-pounder is the way to go.  Its "success" with Sentinel AC3 at least gives me hope that it might be less of a headache to put into a Churchill,

Yes, it would be a lot easier. Depending upon whether you want to assume there was a new recoil mechanism developed for the tank mounting, if you don't, you need to add an armoured box for the 25 pdr recoil mechanism that wold normally stick well out of the turret.
and it was likely a better infantry support gun than the 77mm HV until Summer 1944 anyway.
The 25 pdr would always be a better infantry support weapon than the 77mm/17 pdr. The 77mm is a pretty bad infantry support weapon, the HE round was crap. The 84mm HE round of the 25 pdr would have been a great boon to the infantry as would the wide range of ammo available to the 25 pdr.

Paul
: Re: Churchill Tank
: Volkodav December 02, 2013, 09:08:09 AM
If you had a Troop structure with 3x25pdr (battle tank section) and 2x17pdr (over watch / AT section) you would be doing ok.  The ideal would probably be to have such a setup for heavy (Churchill) medium (Sherman) and cruiser (Centur) regiments.

On the 25pdr option I believe the setup in the Sentinel ACIII had a modified recoil system.
: Re: Churchill Tank
: Rickshaw December 02, 2013, 09:16:12 AM
Which then meant that even the brand new Comet could not fit a full sized 17 pdr, it had to use the somewhat derated 77mm gun because the 64" turret ring could not take the recoil like the Sherman could. All because of a continuing lack of vision by the British tank design authorities. They never, right up to the Centurion, could see past the end of the exact tank they were working on. It was bloody criminal, to be sure.

It is always easier to condemn than to understand.  This is one reason why I like Fletcher's books over most of the others which have been written about British tank development in WWII.    I also suppose it all depends on whom you refer to as "the authorities".   The Centurion was the first tank that the Ordnance Department had full authority over and obviously they had been listening and absorbing what they had been told 'cause didn't they come up with a cracker!   Before that, first the Tank design board and then industry actually had first and second say and the Army only last on how tanks should be designed.  It makes one rather suspect that if the Army had, had sole control from the start they might have gotten something better sooner.

The 77mm gun was actually a completely different gun to the 17Pdr, you realise and not "derated" at all?   It actually had it's roots in a private venture Vickers 75mm design, dating back to about 1941-2 IIRC.  It went through several evolutions before finally being adopted as the 77mm.

One of the interesting things to emerge from the use of the Churchill's use in NW Europe was that despite it's supposed handicaps of a lack of speed and poor suspension in the final month of WWII, Churchill units in the final drive into Northern Germany actually advanced further and faster than their medium or even cruiser equipped counterparts.   While they might not have been speedsters, what they could do was keep on fighting and advancing when they encountered opposition whereas the other tanks had to stop and try and outflank rather than go in, head on.

The key to their mobility was always their superior gearbox, which was carried over into the Centurion design.    Funnily enough, the gearbox in both the Churchill and the Tiger had common roots, in British heavy vehicle designs.   Yet the Tiger's version was actually less manoeuvrable.
: Re: Churchill Tank
: tankmodeler December 02, 2013, 09:27:53 AM

It is always easier to condemn than to understand.  This is one reason why I like Fletcher's books over most of the others which have been written about British tank development in WWII.
Me, too. The Great Tank Scandel is a ringing indictment of the Tank Board and British industry. As you say, only when the Army got the say in their own vehicles did something really useful actually arise, the Centurion.

It makes one rather suspect that if the Army had, had sole control from the start they might have gotten something better sooner.
I suspect so, even if it was something that the Government and industry didn't want to build for them.

The 77mm gun was actually a completely different gun to the 17Pdr, you realise and not "derated" at all?

Indeed, however, with a lower amount of propellant in the case, it's performance was marginally less than that of the 17 pdr, hence my term derated, but yes, your clarification was good for those who didn't know the history of the 77mm. It has long been a hoary old story that the 77mm was nothing but a 17 pdr cut down with a smaller amount of propellant.

Paul
: Re: Churchill Tank
: Rickshaw December 02, 2013, 10:05:06 AM
Ah huh but not looking for a Black Prince, looking for minimal change to the chassis but must have the Meteor and its 600bhp

Black Prince was what was required to get a Meteor into a Churchill chassis.   However, Black Prince was underpowered, even with a Meteor, unreliable and basically a dead end.  This is made very clear from the trials report that Fletcher reprints in the back of "Mr. Churchill's Tank" (well worth reading if you want the the history of Churchill tank development). 

What you want is a standard, Mk.VIII Churchill armed with a 25 pdr gun.  That is IMHO quite doable with relative minor modifications to the turret shape and it's internals (ammunition stowage, etc).   You'd end up with a marginally better HE round but at the expense of AT capability.   You'd need a new gun essentially with only the tube and breech being retained from the field gun.  It would need a new recoil system and a new mounting and associated sights, etc.  All possible but if you want it available for use in mid-1944, you'd more than likely have to start about 18 months earlier, at the latest, to develop the mounting and the fixed case ammunition.

It would not be much use against Germany heavy Panzers IMO.

: Re: Churchill Tank
: Volkodav December 02, 2013, 10:23:51 AM
The Black Prince used the same Bedford flat 12 as the Churchill, the Meteor was considered during the design phase but never fitted or planned to be fitted to the Black Prince.
 
: Re: Churchill Tank
: tankmodeler December 02, 2013, 10:57:50 AM
What you want is a standard, Mk.VIII Churchill armed with a 25 pdr gun.
And if you are going that way, why go away from the Churchill VIII, which was a Churchill VII (with slightly modified turret) with the standard Brit 95mm howitzer in the turret, and was used for close support? The extra range of the 25 pdr couldn't really be used in the Churchill turret and the 95mm had an even better HE round than the 25 pdr.

Paul
: Re: Churchill Tank
: dy031101 December 02, 2013, 11:53:48 AM
And if you are going that way, why go away from the Churchill VIII, which was a Churchill VII (with slightly modified turret) with the standard Brit 95mm howitzer in the turret, and was used for close support? The extra range of the 25 pdr couldn't really be used in the Churchill turret and the 95mm had an even better HE round than the 25 pdr.

The 25-pounder wasn't the best anti-tank gun with the Allies, but it was decent enough if you want a bigger punch against armours than the short 75mm while still having good HE.

Or give the 95mm some kind of HEAT ammo.
: Re: Churchill Tank
: Volkodav December 02, 2013, 12:35:23 PM
I always found it interesting that the main criticism on the 95mm was its lack of accuracy, range and velocity; all things that could potentially be fixed by a longer barrel, yet the barrel always appears to have been fitted with a counterweight.  You would think that a longer barrels would be the ideal fix
: Re: Churchill Tank
: PR19_Kit December 02, 2013, 01:52:44 PM
I know naff all about tanks, but I DO know about 25 pdrs. (I was a BSM in the CCF and we had a 25 pdr for our troop back in the late 50s and early 60s.)

As you mention above you'd need fixed case ammo to use in a tank turret, using the rounds and the bag charges would have been far too chaotic in the close confines of a turret I'm sure. But would you have to use different sets of rounds with different charges or would you dispense with the variable charge capability in tank use? And if so which charge would you use? Presumably Chaarge 3 Super as it gave the greatest velocity?
: Re: Churchill Tank
: Volkodav December 02, 2013, 05:12:08 PM
Ah huh! Found it!
http://www.mheaust.com.au/Aust/Research/Sentinel/sentinelmk.htm (http://www.mheaust.com.au/Aust/Research/Sentinel/sentinelmk.htm)

"The 25 pounder was mounted in the turret with a coaxial 0.303 Vickers water cooled machine gun. The AC3 was of similar dimensions to the AC1 and used the same 137cm (54 inch) turret ring, this in particular meant that the AC3 turret was somewhat cramped particularly for the loader who had to be careful to keep out of the recoil path of the gun. To swing the larger turret the 40 volt electrical traverse motor of the AC1 was replaced by a 110 volt motor. Stowage was provided for 120 rounds of ammunition, 60 High Explosive/Smoke shells and 60 of the shorter 9kg (20 lb) Armour Piercing shot, and 2500 rounds for the coaxial Vickers, stored in 250 round boxes. As the 25 pounder used 2 part ammunition 120 cartridges were to be carried consisting of charge 3 and charge Super. Despite the two part ammunition and the cramped turret the rate of fire showed that the tank was far from unusable, in tests with the commander assisting the loader by ramming the projectile the crew were able to fire 8 rounds in 73 seconds. The tank mounting of the 25 pounder proved to be excellent, unlike the towed version multiple rounds could be fired without having to relay the gun on the target."

Looks like I was right and wrong, I will blame approaching old age
: Re: Churchill Tank
: PR19_Kit December 02, 2013, 06:32:54 PM
Very interesting.

So they did use 2 part ammo, I'm surprised but one advantage would have been there was no shell casing to get rid of, at least for short periods. They'd have to clean out the breech after 10-15 rounds I'd have thought because the charge bags left some residue behind, even if not that much. And Charge 3 and Charge Super makes sense if you're targeting other armour most of the time.

I bet their ears hurt after a few rounds of Super!  :o We took our gun to Larkhill after I'd found its barrel was still certified and I'd spent WEEKS persuading our CO and our parent company at the Oxford Uni OTC, and fired off maybe half a dozen rounds. I got to fire the 2nd one (they fired the first one via a lanyard!) and chose an APDS shot, shooting against a Comet target with Charge Super. It was LOUD, but I did hit it!  :)
: Re: Churchill Tank
: Volkodav December 02, 2013, 06:55:57 PM
What did the APDS do to the Comet?
: Re: Churchill Tank
: tankmodeler December 02, 2013, 08:22:13 PM
There was an APDS round for the 25 pdr????
: Re: Churchill Tank
: PR19_Kit December 02, 2013, 09:06:41 PM
Made a damn great hole in the side.  :)

I think that's what it's called, the one with four curved bits that fit round a centre core, and then they fly off when the round comes out of the barrel. There were thin wire spring things that held them in place while you loaded it and they had VERY sharp ends if you weren't careful.

Could it have been a post-war development, as they provided the ammunition for our shoot from Larkhill.
: Re: Churchill Tank
: tankmodeler December 03, 2013, 09:02:28 AM
I think that's what it's called, the one with four curved bits that fit round a centre core, and then they fly off when the round comes out of the barrel.

Well, that's APDS, for sure.
 
Could it have been a post-war development, as they provided the ammunition for our shoot from Larkhill.
It might have beeen an experimental round as I've taken a look through several books and I see no reference to any production APDS rounds for the 25 pdr either during or after the war. Certainly, after 1945 there would be no realistic expectations of using the 25 pdr in the AT role and the muzzle velocity of the 25 pdr, even on super charge wasn't really that great to make the use of a complicated APDS round make a lot of sense.

Paul
: Re: Churchill Tank
: PR19_Kit December 03, 2013, 04:24:47 PM
Perhaps the Larkhill guys reckoned our gun was expendible if it all went wrong? Which means I would have been expendible too as I was No 3 on the gun!  :( :o

Mind you, an APDS round didn't have any explosive aboard so there wasn't much to go wrong. Is there a site anywhere that says what sort of ammo was normally used in a 25 pdr?
: Re: Churchill Tank
: Rickshaw December 03, 2013, 05:32:01 PM
I think you'll find they carried 120 rounds - 120 shells and 120 cases. The 25 Pdr fired with a shell case to provide obturation. It didn't rely on purely bagged charges. Each round was in a "semi-fixed" form, with the shell placed in its top. Each case came with sufficient charge bags for Charge 2 pre-loaded. The loader would remove the shell ram that up the bore and either remove or add bags to give the correct combination before ramming the case into the breech.

This image appears to be giving some difficulty when trying to insert it to the post so I'll just provide the URL.  It shows several 25 Pdr rounds displayed.

http://upload.wikimedia.org/wikipedia/commons/c/c0/QF_25_pounder_Ammunition-001.jpg (http://upload.wikimedia.org/wikipedia/commons/c/c0/QF_25_pounder_Ammunition-001.jpg)

This mean you'd have spare charge bags rattling around in the turret with the possibility of split bags with spilt powder. Which is generally not a good idea.

I'm not aware of an APDS round for the 25 Pdr, only an AP round (not sure if its AP, APC or APCBC, I suspect the latter).

If tanks were to mount 25 Pdrs in large numbers, I can see a fixed round being developed, with AP with permanent supercharge bags in the shell case. You might see some bright spark developing an APDS round for the 25 Pdr. but as has been noted, it wouldn't have been of much value (and may have caused problems with the muzzle brake which was developed to cope with Super Charge rounds).
: Re: Churchill Tank
: Volkodav December 03, 2013, 06:12:23 PM
Would a tank mounted 25pdr have needed a muzzle break even with super charge? The ACIII was said to be a good gun platform with the gun not needing to be relayed between shots, I imagine the significantly heavier Churchill would have been even better.
: Re: Churchill Tank
: Rickshaw December 03, 2013, 08:09:27 PM
Muzzle brakes are used to relieve recoil stresses on the mounting by directing gases to the rear of the gun.  Those ports on the sides are actually angled rearwards.  Without a muzzle brake you have to either beef up the mount, provide a longer recoil travel or simply wear the fact that the mounting will have a shorter life.   

Now, you don't want to increase the recoil travel - the turret is already very cramped.  If you beef up the mount, that again consumes internal turret space.   So you need to alleviate the recoil, either by mounting more or larger recuperators.  The British tended to mount more, rather than larger ones.  If you ever get to Puckapunyal and the RAC museum, you'll see a sectioned Centurion turret used as a crew trainer.  What is surprising is how short the recoil travel is on the 20 Pdr.  There are four, short but prominent recuperators to absorb all that recoil, two above and two below.

So, yes, you could get rid of the muzzle brake if you wanted to but as in anything there are trade offs.  APDS can be fired from guns with muzzle brakes, the 17 Pdr had one.  It's just that there is a known problem with the petals of the sabot fouling muzzle brakes.   So, perhaps a single baffle one instead of the double baffle?

The Germans were BTW by war's end experimenting with fixed guns - letting the armoured vehicle's mass and suspension absorb the recoil, however that was out of desperation to speed up manufacturing time by simplifying the vehicle and saving materials, particularly oil but were only starting to think about actually putting them in Panzerjaeger vehicles when the war ended.  After the war no one except the Soviets really paid much attention to it as an idea and even they abandoned it after a few experiments.
: Re: Churchill Tank
: tankmodeler December 03, 2013, 08:24:34 PM
only an AP round (not sure if its AP, APC or APCBC, I suspect the latter).
No, the only production AP round was a simple shot design, the black one in your photo. No cap or balistic cap round was ever fielded.

Which is why I find the concept of an APDS round difficult to fathom.

In a tank mounting, I would expect all of the ammo to be of one charge so there would be no spare charge bags in the turret. The mounting really can't elevate enough to change the range significantly even with higher chargers, so why bother. If using the gun as artillery (as was done with alomst all tanks at one time or another) you could mount the tank on a berm to get the elevation you wanted and then suppply with normal 25 pdr variable charge rounds.

Paul
: Re: Churchill Tank
: PR19_Kit December 04, 2013, 05:41:56 AM
How odd, I don't recall the brass charge casings either.

We had dummy charges in our limber of course, NO chance they'd let a bunch of schoolkids loose with real live cordite! IIRC they were just cotton, or sort of burlap bags, with the 'charge' inside and they had different numbers on them determining which charge they were, 1, 2, 3 or Super. I think Charge 3 was larger than the other ones as well and the Super was a small bag added after a Charge 3 was loaded.

Would that black AP round have bits that fell off after it was fired, something like a wad used with a muzzle loaded rifle?

I'm still in touch with the No.1 on our gun (he was best man at my first wedding  :)) and I'll ask him what he can remember of the live firing trials we did at Larkhill.
: Re: Churchill Tank
: Rickshaw December 04, 2013, 07:50:26 AM
You sure it was a 25 Pdr, Kit and not a 18 Pdr?  ;D

The bags would have been cotton.  You should have been using brass cases 'cause otherwise there wouldn't have been sufficient obturation (sealing) from the sliding breech block alone.  Nor was the 25 Pdr equipped IIRC with an exploder tube (a mini-breech on the side where an over-sized shotgun like small brass case was inserted.  This is what was actually "fired" when it was used on larger guns.  It in turn exploded the main charge, in the main breech).

25 Pounder (http://www.youtube.com/watch?v=F8pgPjgmb-o#ws) has some good scenes, particularly about 1:28 of the loading sequence on the 25 Pdr.  You see the breech being opened, the shell being rammed, then the case being inserted and the breech closed and the round fired.

: Re: Churchill Tank
: PR19_Kit December 06, 2013, 02:33:02 AM
What a terrific vid, brought back loads of memories. :)

The guns in the vid were exactly like the one I served on, even down to the dial sight poking up above the blast shield for indirect firing. I see what you mean about the brass charge casings, but that wasn't like the propellant bags we had, at least not at school. They may have used them when we took the gun to Larkhill but they wouldn't let us load the gun there, presumably as they were using live rounds.

I got in touch with my old No. 1 but he was no good at all as he said all he could remember was painting the darn ting time after time! :)

I suspect they had different procedures for Cadet Forces just BECAUSE we were Cadets and we were issued with 'drill rounds' and stuff for our exercises, but for our Larkhill shoot we may have caught them on the hop as the 25 pdr wasn't in general service with the Army by then. In fact the BSM at Larkhill said we may have got the only 25 pdr with current barrel certificate at that time. I think it was Easter 1961 when we took it to Larkhill BTW.
: Re: Churchill Tank
: Volkodav December 09, 2013, 06:45:52 PM
Just had a thought for a completely off the wall Wiff for the Churchill.  The original concept that led to the Churchill was to have had sponson mounted guns so why not have a multi gun infantry support tank with a 17pdr on one side and a 25pdr on the other and a twin 20mm AA turret.  The sponson guns would fire forward only and be aimed by turning the whole vehicle but would be able to be elevated and depressed with loading being done from within the hull.
: Re: Churchill Tank
: Rickshaw December 10, 2013, 09:07:23 AM
Just had a thought for a completely off the wall Wiff for the Churchill.  The original concept that led to the Churchill was to have had sponson mounted guns so why not have a multi gun infantry support tank with a 17pdr on one side and a 25pdr on the other and a twin 20mm AA turret.  The sponson guns would fire forward only and be aimed by turning the whole vehicle but would be able to be elevated and depressed with loading being done from within the hull.

Unnecessarily complicated.  Sponson gun positions are an induced weakness in the hull armour, which is why navies abandoned their use.  They complicate manufacture and they also increase the height of the vehicle to larger than a sitting position (to allow the gunner to aim the gun).   Also, because of their low position, and the narrowness of most European roads/lanes they wouldn't be able to be brought to bear.  You need a low vehicle but not one that is too low.  Different weapon calibres in the one vehicle introduce all sorts of problems with ammunition stowage and fighting the vehicle.  You also need a really good gearbox to give you the finesse required to aim a gun in azimuth.   As the experience with the M3 Medium showed, hull mounted guns also limit what sort of firing position you can take up.
: Re: Churchill Tank
: ChernayaAkula December 10, 2013, 09:43:19 AM
Good points, but who said whiffs had to be practical?  :icon_beer:
: Re: Churchill Tank
: Old Wombat December 10, 2013, 11:53:03 AM
Well, this seemed to start off as a thread on practical ways of up-gunning of the Churchill. ???

But, then, I guess, sometimes you've just got to go with the motto of the School of the Rule of Cool. 8)

SI SPECTAT BONUM, FACIAT!
(If it looks good, do it!)


:)

Guy
: Re: Churchill Tank
: Volkodav December 10, 2013, 07:20:34 PM
Just had a thought for a completely off the wall Wiff for the Churchill.  The original concept that led to the Churchill was to have had sponson mounted guns so why not have a multi gun infantry support tank with a 17pdr on one side and a 25pdr on the other and a twin 20mm AA turret.  The sponson guns would fire forward only and be aimed by turning the whole vehicle but would be able to be elevated and depressed with loading being done from within the hull.

Unnecessarily complicated.  Sponson gun positions are an induced weakness in the hull armour, which is why navies abandoned their use.  They complicate manufacture and they also increase the height of the vehicle to larger than a sitting position (to allow the gunner to aim the gun).   Also, because of their low position, and the narrowness of most European roads/lanes they wouldn't be able to be brought to bear.  You need a low vehicle but not one that is too low.  Different weapon calibres in the one vehicle introduce all sorts of problems with ammunition stowage and fighting the vehicle.  You also need a really good gearbox to give you the finesse required to aim a gun in azimuth.   As the experience with the M3 Medium showed, hull mounted guns also limit what sort of firing position you can take up.

Umm....I did say "completely off the wall"
: Re: Churchill Tank
: Volkodav December 10, 2013, 07:28:58 PM
on a more serious note I am toying with an Australian production version of the Churchill, initially with a 6pdr and intended to be exported to the UK but with Japans entry into the war they were retained in country and when a CS version was required instead of acquiring or manufacturing 95mm the 25pdr, already in service with the ACIII, was used.  When intelligence indicated that Japan was looking t licence produce the Tiger I it was decided to up gun but the Sentinel and the Churchill.

What would be needed that didn't exist at the time was the facility to manufacture rolled armour, the lack of this capability was why the Sentinel had cast armour, could be that the capability was introduced but still limited therefore the Sentinels still used cast while the Churchills use rolled and welded.
: Re: Churchill Tank
: Rickshaw December 11, 2013, 08:20:09 AM
I'd suggest in that case a Churchill with a cast hull.  The turret was already cast so why not go with the technology which was already known and the industry that was already in existence?  It would be easier to produce as there would be no need for frames nor riveting.   Make it in sections and bolt them together.  You could also eliminate the hull glacis "step", which would improve it's ballistic shape.

Alternatively, perhaps a cast version of the Valentine (ie the Valiant, although that was by all accounts a dog)?  It is of a comparable size to the Sentinel and would use similar production facilities.

While I think we had the technical knowhow to build a large rolling plant it would have been wasted as tank production wouldn't have been great enough to sustain it and as we weren't building large warships, it wouldn't have been necessary.  Casting OTOH had uses in other industries so expanding that industry would have been logical.

Australia bought at war's end over 200 Churchills but they were never issued and ended up being scrapped with the arrival of the Centurions.  They were IIRC a mix of Mk.IX and Mk.X so we obviously were prepared to either import or manufacture 95mm ammunition.
: Re: Churchill Tank
: Volkodav December 11, 2013, 09:23:54 AM
The Churchills arrived post war and were used by 1Armd Regt until the Centurions were delivered.  What I was thinking was much earlier production locally to support the British war effort possibly using infrastructure built during the 1920s as part of a local cruiser build.  The UK would have requested Australia build these vehicles for them with work on the production facilities beginning before the design was finalized.  Maybe the Matilda could have been produced first.  Japans entry to the war would have precipitated the retention of the vehicles for the mechanization of the Australian Militia.

I like the idea of a cast Churchill  but it would be a big job to model.  I will keep it in mind though.
: Re: Churchill Tank
: tankmodeler December 11, 2013, 11:09:56 AM
Good points, but who said whiffs had to be practical?  :icon_beer:
Well, no-one, of course, but the resulting model becomes much easier to believe if it doesn't violate known physical limitations.

You can build a Churchilll with little tiny wings and call it a flying tank, if you want to, but it'll never be convincing no matter how well it may be built or painted.

For me a wiff (unless purposefully whimsical) has to be eminantly practical to allow the viewer to suspend disbelief and focus on the model.

Paul
: Re: Churchill Tank
: Rickshaw December 11, 2013, 02:53:54 PM
The Churchills arrived post war and were used by 1Armd Regt until the Centurions were delivered.  What I was thinking was much earlier production locally to support the British war effort possibly using infrastructure built during the 1920s as part of a local cruiser build.  The UK would have requested Australia build these vehicles for them with work on the production facilities beginning before the design was finalized.  Maybe the Matilda could have been produced first.  Japans entry to the war would have precipitated the retention of the vehicles for the mechanization of the Australian Militia.

I was wrong, there were 510 ordered of which only 51 were delivered.  While issued to 1 Armoured Regiment, they weren't used much and they remain largely a mystery.  I've always assumed they were kept in storage and M3 mediums were used instead.  M3 Mediums and Matildas lasted into the early-mid 1950s in the Militia.  I remember seeing film of Hunter River Valley Lancers parading with M3 Mediums in ~1954.

I like the idea of a cast Churchill  but it would be a big job to model.  I will keep it in mind though.
A judicial use of putty would give the impression of casting.  Eliminate the bow glacis "step" and not bother with a bow MG.  That would be sufficient IMO.  I still think Valentines would be more likely, given the time frame.   A cast one would end up looking similar to the Valiant.
: Re: Churchill Tank
: GTX_Admin December 11, 2013, 02:55:18 PM
Keeping the ARA Churchills in service and modifying them into a variety of other roles could prove interesting.
: Re: Churchill Tank
: Old Wombat December 11, 2013, 05:06:50 PM
Keeping the ARA Churchills in survive and modifying them into a variety of other roles could prove interesting.

Fire support in Vietnam, either standard with a M163 20mm Vulcan turret or widened with a M-42 twin bofors turret? ;)

:)

Guy

(Actually, make that an M-19 turret - turret ring diameters; 54.25" (Churchill), 60" (M-19 GMC), 73" (M-42 SPAAG))
: Re: Churchill Tank
: Volkodav December 11, 2013, 10:39:29 PM
On the valentines I skipped them (primarily because I don't like them) because Canada was already lined up to build them so it could be justified opting for a different vehicle to be built in Australia.  Could be argued Canada was ready earlier so got the earlier design where Australia was slower off the mark so got the then current Churchill instead.

On the updated Churchills I remember reading that the AVRE versions had their Petard mortar replaced post war with a L9 165mm demolition gun, now that would have been one hell of a CS weapon   >:D
: Re: Churchill Tank
: GTX_Admin December 12, 2013, 04:23:33 AM
Some info on ARA Churchills:

http://www.mheaust.com.au/Aust/Research/Churchill/Chill.htm (http://www.mheaust.com.au/Aust/Research/Churchill/Chill.htm)
: Re: Churchill Tank
: Rickshaw December 12, 2013, 10:58:44 AM
On the valentines I skipped them (primarily because I don't like them) because Canada was already lined up to build them so it could be justified opting for a different vehicle to be built in Australia.  Could be argued Canada was ready earlier so got the earlier design where Australia was slower off the mark so got the then current Churchill instead.

On the updated Churchills I remember reading that the AVRE versions had their Petard mortar replaced post war with a L9 165mm demolition gun, now that would have been one hell of a CS weapon   >:D

Particularly if a SPLINTEX round was developed for it.  As one after-action report from Vietnam dryly noted about the use of 20 Pdr SPLINTEX, "SPLITNEX does wonders for enemy constipation...", I can just imagine what 165mm would be like...  ;)

By all accounts the 165mm HESH was impressive as well.
: Re: Churchill Tank
: tankmodeler December 12, 2013, 11:30:32 AM
(Actually, make that an M-19 turret - turret ring diameters; 54.25" (Churchill), 60" (M-19 GMC), 73" (M-42 SPAAG))
Well, no, I'm afraid. The M24 Chaffee had a turret ring of 60", the turret on the M19 was virtually identical to that of the M42, i.e. approx. 73".
: Re: Churchill Tank
: tankmodeler December 12, 2013, 11:39:22 AM
I like the idea of a cast Churchill  but it would be a big job to model.  I will keep it in mind though.
A judicial use of putty would give the impression of casting.  Eliminate the bow glacis "step" and not bother with a bow MG.  That would be sufficient IMO.  I still think Valentines would be more likely, given the time frame.   A cast one would end up looking similar to the Valiant.
Canada did cast significant portions of the Valentine, the turret and the front of the hull and did so for reasons similar to those given above, we had access to casting facilites and not really to rolled plate facilities.

Making a cast hull Churchill really wouldn't be terribly difficult but would involve making some changes to how things like the suspension was integrated in the hull sponsons. If you could convince the Brits to eliminate the step in the front plate and the bow gunner, you really could improve the vehicle's proteaction. Casting the sponsons  would also allow the armour thickness to be locally tailored to increase protection over the crew compartment and maybe to introduce some sloped surfaces not unlike the sponsons of the French FCM.

If they had access to American 75mm guns, it might also have been possible to make an indiginous Churchill NA 75 wiout all the hassle the British team went through trying to shoehorn the US gun into the Brit turret. They could make changes as needed.

Actually, that's not a bad WHIF combination, a cast hull Churchilll, made in Oz with a US 75mm M3 gun with an M34A1 mantlet and a reshaped turret to manage it all. The turret could look like a combination of the Mk IV and the Sherman turret.

Paul
: Re: Churchill Tank
: Old Wombat December 12, 2013, 01:12:03 PM
(Actually, make that an M-19 turret - turret ring diameters; 54.25" (Churchill), 60" (M-19 GMC), 73" (M-42 SPAAG))
Well, no, I'm afraid. The M24 Chaffee had a turret ring of 60", the turret on the M19 was virtually identical to that of the M42, i.e. approx. 73".

Well, I'm not an expert & I had trouble finding consistent sources on turret ring diameters (one had the turret ring of the M-19 at 85") but all said that the M-19 turret had to be modified to fit the larger turret ring (73") when fitted to the M-42 Duster.

Eventually I found 2 sources that agreed on 60" for the turret ring of the M-19 & I went with that. The accompanying photo's also seemed to show a significantly smaller turret ring on the M-19 (with the rest of the turret being pretty-much identical) surrounded externally by a ring of ready-use ammunition racks.

:)

Guy
: Re: Churchill Tank
: Rickshaw December 12, 2013, 01:36:00 PM
I could imagine a cast hull for a Churchill being assembled from several pieces, bolted and/or welded together.  Bow, centre, rear of the central hull are separate and the side sponsons as a single piece, to which the suspension was attached, above and below.  That would in turn be covered in pieces of mild, rolled steel to prevent ingestion of vegetation and earth.   The British were, by war's end making extensive use of combined cast and rolled armour elements (turret walls were cast and the turret roof welded on).  I don't see why that couldn't have been arrived at earlier, with perhaps a central section of the hull roof, where the turret ring was being rolled and welded on.  This would speed and ease production considerably.

As to choice of gun, it would more than likely start with 2 Pdr an a mix of 3in How. Quickly replaced down under with 25 Pdr as the emphasis changed from AT to infantry support.  I agree that the Mk.IV would be more than likely the best shape to start with.  75mm was an imported calibre, I'm not aware of any 75mm production facilities but I'll check the official history this evening to make sure.
: Re: Churchill Tank
: tankmodeler December 13, 2013, 10:59:53 AM
(Actually, make that an M-19 turret - turret ring diameters; 54.25" (Churchill), 60" (M-19 GMC), 73" (M-42 SPAAG))
Well, no, I'm afraid. The M24 Chaffee had a turret ring of 60", the turret on the M19 was virtually identical to that of the M42, i.e. approx. 73".

Well, I'm not an expert & I had trouble finding consistent sources on turret ring diameters (one had the turret ring of the M-19 at 85") but all said that the M-19 turret had to be modified to fit the larger turret ring (73") when fitted to the M-42 Duster.

Eventually I found 2 sources that agreed on 60" for the turret ring of the M-19 & I went with that. The accompanying photo's also seemed to show a significantly smaller turret ring on the M-19 (with the rest of the turret being pretty-much identical) surrounded externally by a ring of ready-use ammunition racks.

Well, I'm afraid those sources are incorrect. The M19 and the M42 both used the M4 gun mount (I have the manuals for both vehicles), which was the entire turret. The M19 used the M4 and the M42 used the M4E1 variant. There were obvious differences, of course, but nothing major, otherwise the mount number would have been different. You can tell from photos that the arrangement of guns and crew in the turret were identical and a reduction of a foot in the diameter of the turrets simply whould not permit them to be laid out the same. A crew of 4 only barely fin in it as it was.

Paul
: Re: Churchill Tank
: tankmodeler December 13, 2013, 11:06:54 AM
75mm was an imported calibre, I'm not aware of any 75mm production facilities but I'll check the official history this evening to make sure.
Well, by late 43 the brits were makine and using 75mm guns based on their own 6 pdr that use the standard American 75mm ammo.

My thought was that it was an Aussie vehicle and the Aussies didn't have the capability of making either the 6 pdr or the 25 pdr, so they might just have imported the American guns and fitted them to their cast Churchill. They did import American components for the Sentinel, which was also largely cast.

Sounds like I have a possible whiff brewing...

Paul
: Re: Churchill Tank
: Rickshaw December 13, 2013, 11:38:27 AM
Australia produced 2 Pdr, 6 Pdr, 25 Pdr, 5.5in guns.  75mm was an "odd" calibre and we never produced ammunition for it (despite using it in the M3 Medium and the 75mm Pack How.) as far as as I am aware.  This is why we've seen an emphasis in this thread on the 25 Pdr.  It was in production, as was it's ammunition.

I look forward to your model.
: Re: Churchill Tank
: tankmodeler December 13, 2013, 08:44:11 PM
Interesting! I knew you guys made 2 pdrs, but did not know about the larger calibres. The 25 pdr makes much more sense, then. A 25 pdr in an all cast (and bolted together) Churchill it shall be, then!

As my daughter says "Challenge accepted!"  :)  :)

Paul
: Re: Churchill Tank
: Volkodav December 13, 2013, 09:02:36 PM
I believe we also manufactured the 4" Mk XVI Naval DP gun in Australia but that is getting silly when discussion the Churchill, unless of course it is a casemate TD 8)
: Re: Churchill Tank
: Rickshaw December 13, 2013, 10:44:06 PM
Interesting! I knew you guys made 2 pdrs, but did not know about the larger calibres. The 25 pdr makes much more sense, then. A 25 pdr in an all cast (and bolted together) Churchill it shall be, then!

As my daughter says "Challenge accepted!"  :)  :)

Paul

We knew about them but they didn't fit into our Orbat.  We had limited production facilities, so had to rationalise what we produced to what we really needed.  We didn't use 75mm guns to any great extent so didn't produce any.  Now, in Whiffdom, you could say we did.  Just rationalise it as being a calibre we adopted from say, one of the commercial Vickers guns or even the French in WWI (which is where the US Army's M2/M3 tank guns came from).   ;)
: Re: Churchill Tank
: tankmodeler December 15, 2013, 08:58:59 AM
We didn't use 75mm guns to any great extent so didn't produce any.  Now, in Whiffdom, you could say we did.  Just rationalise it...
Or, I could go the other way...

The ingenious Aussies, having access to 25 pdrs and ammo, took the initiative when putting the 25 pdr into their home made Churchill and lengthened the 25 pdr's tube a little, adding about 12" to the length and taking full advantage of the increased muzzle velocity to increase the armour penetration power of the 25 pdr's AP rounds while not sacrificing the performance of the HE and smoke rounds. The new recoil mechanism needed for the turret mount could easily absorb the higher recoil, but the increase in velocity and bore pressure wasn't enough to compromise the existing 25 pdr ammo.

Cast Churchillls were supplied with 75 rounds of what was called 87mm ammo to distinguish the fixed tank ammo from the separate loading 25 pdr artillery ammo, but both the shells and the cartridges were the same for both types. 87mm AP rounds were the equivalent of the standard AP shot married to the super-charged casing and the HE round was the equivalent of the 25 pdr's HE round married to a casing filled with the artillery Charge 1. There being no need for extended range for the tank gun, fixed cartridges with different charges were not procured.

Late in the war, the Austrialian ordnance industry developed a APCBC round, but given the poor quality of the Japanese armour, this was not proceeded with.

Howzat??  :)  :)

Paul
: Re: Churchill Tank
: Volkodav December 15, 2013, 05:19:53 PM
 ;D loving it, keep up the great ideas
: Re: Churchill Tank
: Rickshaw December 15, 2013, 06:00:52 PM
Howzat??  :)  :)

Excellent.  That's the ticket.  Excellent reasoning there and it covers most bases.  Not sure whether that small a lengthening would have an overally dramatic improvement in penetration, though.  A better round would definitely help plus a bigger charge to drive it.  Unfortunately you can't increase the case length without increasing the chamber size, which leads to an altogether new gun and of course you need a reason to justify such developments which the Japanese just don't supply...
: Re: Churchill Tank
: Volkodav December 15, 2013, 08:53:19 PM
You could actually see such a vehicle forming the core of a post war RAAC, or at least the CMF / Militia side of things.  Maybe a regiment or reinforced squadron deployed in support of 3 RAR in Korea.  Another idea I have had as a 44-45 option for the 2nd AIF or even a 1946 job would have been deployment of Australian or ANZAC Corps to China to fight the Japanese rather than the Borneo campaign.
: Re: Churchill Tank
: tankmodeler December 15, 2013, 10:52:19 PM
Not sure whether that small a lengthening would have an overally dramatic improvement in penetration, though.
Absolutely, the point is to get as much as possible from the existing rounds and breech without making changes the ripple outward any further. Such a lengthened barrel wouldn't give _much_ of an increase, but might as well get as much as you can while you are already designing a new recoil mechanism for the tank.

The 25 pdr had a muzzle vel of 600 M/s on super charge and a penetration of 61mm at 30 deg at 500 yds. The short M2 75 had a MV of 588m/s and the M3 had one of 619 m/s. The M3 was 2 feet longer than the M2 (an increase in length of 9 calibers) and increased the MV by just over 5% adding 16mm to the penetration. Adding a foot to the 25 pdr barrel adds just over 3 calibres and uses the same ammo as the 75mm field gun and the M2 tank gun so lets suppose we can add 9 calibres to the 25 pdr without chaning the ammo or the tube wall thickness. That actually allows us to add over 2 1/2 feet to the tube length! Lets say the Aussies weren't soooo sure of their calculations and added just 2 feet and as a consequence they got just under 5% increase in MV to 628 M/s increasing the penetration of the shot round from 61 mm to a quite respectible 79mm at 500 yds.

The Japanese never fielded a tank with more than 3" of armour during the war so the 87mm gun worked out just fine and many Japanese targets struck with the 87mm shot simply collapsed structurally under the massive impact. If need be, an APCBC and a hollow charge round (actually designed in Canada) were on the shelf if the Japanese fielded a better tank. For its short term of service after the war, these rounds were introduced. One can only imagine what an APDS or HESH round might have been like given the large bore of the 25 pdr! A HESH round would have been more effective than a similar round in the 20 pdr.

Paul
: Re: Churchill Tank
: tankmodeler December 15, 2013, 10:54:55 PM
Oh, and I've already started to glue together the bits of the Tamiya Churchill VII to convert it into a cast vehicle. And I have an old Tamiya 25 pdr which will give up its tube to this project.  :)

Piccies to follow once there is something to show for it.
: Re: Churchill Tank
: Volkodav June 18, 2014, 08:54:32 PM
I wonder if the 77mm HV would fit, or a 25 pdr
: Re: Churchill Tank
: dy031101 June 18, 2014, 10:29:32 PM
I wonder if the 77mm HV would fit, or a 25 pdr


Please check older entries of this thread for inspiration.  ;)

=============================================================

How much room is inside of the largest Churchill turret compared to KV-1?

(http://i.imgur.com/IT7MwQp.jpg)

I'm thinking of using a Soviet-designed U-11 122mm howitzer to up-gun the Churchill (in a similar vein as Logan Hartke's close support Sherman evolution)......

I like the idea of the KV-9, but after all the attrition and being replaced on the production line by the IS, there probably wouldn't be that many KV-1s left for conversion; the IS can mount the long-barreled 122mm field gun derivative, so U-11 is likely pointless to it; I kinda want to do a heavy tank in keeping with KV's heavy tank theme, and of the remaining WWII Allied AFV types I either do not remember or do not recognize anything of the sort other than the Churchill......

Just some crude ideas for now- I found someone on the internet claiming that the turret ring diameter of the KV-1 (of which AFAIK the KV-9 is a derivative with that tank howitzer) is 1580mm, which seems to me still larger than the Churchill's turret ring size of 1378mm, so I'm kinda trying to move the trunnion forward (but then I don't know where exactly the stock Churchill 75mm's trunnion is)......

Any suggestions on how I should proceed from there?
: Re: Churchill Tank
: tankmodeler June 22, 2014, 12:39:28 AM
The trunnions are just inside the front face of the turret.
: Re: Churchill Tank
: dy031101 June 22, 2014, 12:57:46 PM
The trunnions are just inside the front face of the turret.

Sounds like I won't have to move the trunnion very far......
: Re: Churchill Tank
: tankmodeler June 22, 2014, 09:12:10 PM
The trunnions are just inside the front face of the turret.

Sounds like I won't have to move the trunnion very far......
Add a 10-12" bulge out the front of the turret and you should be in the same relative position. The KV2 had a much larger bulge and external access to the trunnions as well.
: Re: Churchill Tank
: dy031101 July 04, 2014, 04:40:49 AM
It would seem that Israel in its early struggles against its neighbours had a myriad of different armoured vehicles such as Patton, Centurion, and different models of Shermans.  They seemed to have done fine even while resulting logistical complication lasted.

That's absolutely true, but none of those vehicles were as much trouble to maintain as the Churchill. Also, the only British tank of the group, the Centurion was much loved by the Israelis and certainly the best of the three, but that was only after the Israelis replaced the engine and transmission with American ones. The Israeli comments on the Meteor engine are not...flattering.

Again, as you note, they did what they could to standardize the types they had. They standardized on the HVSS and Cummins engine for all their myriad of Sherman variants. They replaced the guns on early Centurions and the M48s with the L7 105mm, gave them both the engine from the M60 (which they had just started using), and gave both the Centurion and M48 the same Allison transmission.

So...... what could be done to make retaining the Churchill as painless as possble?

I'm at this point expecting it to be engine and transmission...... would there be more?

I don't suppose sharing engine with the Sherman is feasible, and an earlier intellectual exercise by others seem to suggest that Meteor would be too builky...... what Cold War era tank engine might be viable?
: Re: Churchill Tank
: Logan Hartke July 04, 2014, 06:09:08 AM
As I understand it, it was mainly the suspension that was the source of most of the tank's maintenance needs. It was that very suspension and layout that helped give it the agility that it was renowned for. The engine and gearbox weren't as reliable as those on the Sherman, but they weren't as bad as those on the German heavies.

I think the answer to operating the Churchill as painlessly as possible is to simply use it in a role that suits it.

When you needed an assault tank in challenging terrain, the Churchill had no rival. Try to force it on a 100 mile road march, use it for patrolling, send it up against an armored threat, or use it in the exploitation role and you're going to be sorely disappointed. Similarly, if you are forced to retreat, you'll be leaving broken down tanks on the side of the road, as they had to do at Seoul in 1951.

(http://blog.joins.com/usr/f/ab/fabiano/1206/4fe0fb1339ef3.jpg)

Therein lies the problem. The Churchill was overspecialized. Britain retained a few after WWII for specialist roles, but discarded most of them. The Sherman, Comet, and Centurion were versatile. They had the speed to operate in the exploitation role. They had a big enough turret ring to mount a 17 pdr gun or better.

By comparison, the Churchill had two main strong points: its agility in tough terrain and its armor. After WWII, its armor wasn't good enough to stop enemy anti-tank weapons and its agility alone wasn't enough to make up for its many limitations. That's one main reason why it didn't see much use after WWII.

(http://northirishhorse.net/articles-2/Jordan/Churchill-Jordan.jpg)

As the saying goes, though, "beggars can't be choosers" and there were many countries in the postwar period that would take whatever they got. Had it been called upon to do so, the Churchill could have been upgraded in various ways to continue to serve. They'd need to be well cared for, but that can be said of many tank types.

At this point, though, we're covering old ground. You, me, and rickshaw discussed much of this in 2010 on the What If forum thread on the Churchill. (http://www.whatifmodelers.com/index.php/topic,17296.msg424498.html#msg424498)

Cheers,

Logan
: Re: Churchill Tank
: tankmodeler July 04, 2014, 06:27:52 AM
So...... what could be done to make retaining the Churchill as painless as possble?
Later production batches of the "light" Churchills and the Mk VII "heavy" Churchill were not as bad in terms of maintenance. The engines were generally reliable and once the bugs were worked out of the tranny, it was as well.

I'm at this point expecting it to be engine and transmission...... would there be more?
One issue that was never really resolved was the suspension. They strengthened it so it seldom broke, but the many small units always required too much maintenance and there is no replacing them with a different design.

I don't suppose sharing engine with the Sherman is feasible
Actually, sharing an engine with a Sherman might be, as long as you are talking about the Ford GAA from the M4A3 and M26. It would be similar in size to the Bedfords and up to 550 hp, a useful increase from the Bedford's 350 or so. Once you get into the 1960s, you can replace the GAA with a commercial diesel of even higher HP in a similar-sized package that probably includes a new or modified tranny. It would need a new engine deck, but that's nothing as the M50s and M51s showed.

Paul
: Re: Churchill Tank
: Rickshaw July 04, 2014, 08:45:41 AM
As I understand it, it was mainly the suspension that was the source of most of the tank's maintenance needs. It was that very suspension and layout that helped give it the agility that it was renowned for. The engine and gearbox weren't as reliable as those on the Sherman, but they weren't as bad as those on the German heavies.

Well, the Merrit-Browne gearboxes were the best in the world and developed versions continue to this day in use in the Challenger MBT and were the ancestors of most heavy synchromesh gearboxes.  Even the German ZF gearboxes of the German Heavies relied heavily on the same technology (something which came as a person surprise to me when I read it in Fletcher's "Tiger!" book).  The suspension was reliable, as were the engines.   It may appear over complex to our eyes but for the period it was fairly standard fair.  One only has to look at the comparable pre-war German heavies to see that.   I've seen British Army training films which showed just how agile a Churchill was compared to the other tanks of the period and you'd be surprised what a well trained driver could do with them and what sort of slopes they could climb.  There were scenes in one such film of the various tanks undertaking an obstacle course for comparison and the Churchill powered through whereas all others were slowed or stopped.

I think the answer to operating the Churchill as painlessly as possible is to simply use it in a role that suits it.

Which is exactly what I proposed.   A specialist role with a specialist tank to fulfil it.

When you needed an assault tank in challenging terrain, the Churchill had no rival. Try to force it on a 100 mile road march, use it for patrolling, send it up against an armored threat, or use it in the exploitation role and you're going to be sorely disappointed. Similarly, if you are forced to retreat, you'll be leaving broken down tanks on the side of the road, as they had to do at Seoul in 1951.

Well, the Churchills sent to Korea were unfortunately somewhat elderly and had not been maintained to their peak since the end of the war, Logan.  A better example would be the British advance into Germany in 1945 where advances of over 100 miles were the norm, withh few breakdowns and where the tanks were used as general support tanks.

Therein lies the problem. The Churchill was overspecialized. Britain retained a few after WWII for specialist roles, but discarded most of them. The Sherman, Comet, and Centurion were versatile. They had the speed to operate in the exploitation role. They had a big enough turret ring to mount a 17 pdr gun or better.

By comparison, the Churchill had two main strong points: its agility in tough terrain and its armor. After WWII, its armor wasn't good enough to stop enemy anti-tank weapons and its agility alone wasn't enough to make up for its many limitations. That's one main reason why it didn't see much use after WWII.

I agree, however I am not suggesting the use of the Churchill as anything other than what it was designed for.  Yes, the British moved towards a "Universal Tank" as Montgomery called it.  So did the US Army after WWII - the artificial division between tanks and tank destroyers was done away with in exactly the same way the artificial division between Infantry and Cruiser tanks was.  The Centurion was a good half-way house between the two.  It's interesting they chose the Churchill's gearbox to propel it, though.

: Re: Churchill Tank
: tankmodeler July 04, 2014, 09:02:17 AM
Well, the Merrit-Browne gearboxes were the best in the world and developed versions continue to this day in use in the Challenger MBT
True, but the initial units in Churchills were terrible for reliability. Later production batch units were much, much better.
It's interesting they chose the Churchill's gearbox to propel it, though.
The Merrit-Browne design, yes, but not the Churchill's actual unit. The Cent was much, much too heavy for the actual Churchill units (52 vs 39 t).

According to "Mr. Churchill's tank" the suspension, once strengthened in the reworked and later production vehicles, was reliable as long as it was well cared for, which took a lot of preventative maintenance.

Paul
: Re: Churchill Tank
: Logan Hartke July 04, 2014, 11:57:04 AM
A gearbox does not a reliable tank make. Besides, just because something is the technological basis for a later development doesn't make it inherently reliable. The V-2 rocket was the ancestor to the Saturn V, one of the most reliable rocket designs in the history of spaceflight, and I don't need to tell you how reliable the V-2 was...

(http://i380.photobucket.com/albums/oo243/SGM_ret/Churchill%20Mk%20III/Gearbox%20Compartment/TrannyCompartment_zps5bbc671e.jpg)

In Italy, the 21st Tank Brigade (12th RTR, 48 RTR, 145 RAC) operated a mix of Churchills and Shermans in operations together. From late 1944 to early 1945 the Brigade was involved in assaulting the Gothic Line. During those operations, the losses were 52 Churchill, 29 Shermans, 4 Stuarts of which 15 Churchill and 21 Shermans were recovered in salvageable condition and repaired. The disparity between the Churchill and Sherman write off figures can be explained by the fact that the former were used primarily as assault tanks and the latter as support tanks.

In maintenance the Brigade workshops used:
While the Churchill gearbox seems to be the least troublesome component on the Churchill, it still falls well short of the Sherman for reliability. During that time, they didn't need a single replacement Sherman transmission.

(http://2.bp.blogspot.com/-oeqrnyx6fvo/T1YFcA-ZCxI/AAAAAAAAJ5M/m7U643yU0Fc/s1600/assembly%2Bdrive%2Bunit%2Bm4%2Bsherman%2B%25288%2529.jpg)

I hope this example puts the matter to rest. If we can't evaluate the Churchill as it existed in 1943, 1944, 1945, or 1951, I have to ask at what point we can evaluate its reliability? The Shermans used in Korea were likewise well worn, some even having been used as monuments before being reactivated and sent to Korea, but they served reliably throughout the conflict.

As for the Churchill's role as an assault tank, it was well suited for the role, certainly, but I'd argue that it was no better suited than the Sherman Jumbo. You see, while envisaged as an assault tank, the Sherman Jumbo ended up not being used in that role exclusively. It was the versatility of the Sherman that we've been discussing that permitted the use of the Sherman Jumbo in ways that would not have been wise or economical for the Churchill VII to perform.

(http://3.bp.blogspot.com/-snUDFjc_y40/U9_uOZ3iwcI/AAAAAAAAjik/LEkCy2D8R_w/s1600/0_d7ac2_3d6ca96b_orig.jpg)

You see, you're looking for a Churchill-sized hole in the US Army for the tank to fill and—because of the way the US Army was organized at the time—no such hole of any size existed at the time. US Shermans operated in two primary formations during WWII, Armored Divisions and independent tank battalions. The Churchill didn't have the speed to operate in US Armored Divisions given their role of exploitation. The Jumbo, however, could keep up—and did. In fact, the Third Army assigned more than half of its allotted Jumbos to Armored Divisions.

Now, I imagine your proposal is to equip some US independent tank battalions with the Churchill, operating in the role of infantry support tank as it did in the British Army. There are two main issues with this. First of all, US independent tank battalions were not permanently assigned to infantry divisions. Some were shuffled around to different sectors of the front, supporting different infantry divisions, airborne divisions, cavalry squadrons, etc. Even if we ignore the logistical problem of trying to follow around a half-dozen Churchill battalions in US Armies, you still have the problem of different infantry division commanders having to adapt to operating with an entirely unfamiliar tank type. You mentioned the US Army eliminating the artificial division between tank destroyers and tanks after WWII? They had enough trouble with US commanders when they'd swap an M10 Wolverine unit for an M4 Sherman unit, and those were vehicles with VERY similar capabilities. Now try to swap an M10 unit for a Churchill unit. It would be a complete culture shock. You'd have the division commander asking the Churchill commanders to perform missions they were entirely unsuited for, or vice versa. I'd hate to show up to support a division with M18 Hellcats when the infantry commander was used to Churchills. It's hard to think of "tanks" that were more dissimilar in WWII.

(http://img.xooimage.com/files94/0/c/a/mmum_get_jpeg-3aa29f3.jpg)

Furthermore, the Jumbo never equipped any full battalion. It always operated with normal Shermans. The most Jumbos received by any single battalion is 15 tanks, about on quarter of its medium tank strength. This was no problem with the Jumbo since they could use the same tracks, bogies, engines, transmissions, etc. as any standard M4A3. You could not do any of these things with a Churchill.

If, on the other hand, you try to equip an entire US battalion with them, you run out of Churchills pretty quickly. You need 59 Shermans for a US tank battalion, and that's not counting attrition, combat losses, etc. They only made 1,600 A22Fs total. You use up about 4% of the total production run for every battalion you wish to outfit...no losses. Jumbos served in 13 different independent US Army tank battalions in the ETO, primarily used to lead assaults, lead tank columns, etc. If you tried to replace all the Shermans in those battalions alone with heavy Churchills, you use up half the A22F production run. The US deployed 35 independent medium tank battalions in support of the 42 infantry divisions that served in France and Germany. Replace all the Shermans in those battalions and you use up every A22F built, again, no replacements, none left for the Commonwealth.

(http://modelhobby.eu/wp-content/uploads/2011/11/post-78-1185720352.jpg)

If you try to operate them in penny packet fashion, as the US did with the Jumbo, then you run into all the problems with the logistics and maintenance at the lower level. A typical number of Jumbos in a battalion was 5. Give a US tank battalion 5 Churchills and see how much fun they have operating them alongside 50 Shermans and 17 Stuarts.

So, I reiterate, the Churchill VII could not have performed the role of the Sherman Jumbo in WWII. It wasn't versatile enough to serve in the variety of roles performed by the Jumbo. Mechanically, it prevented interoperability with the US tank battalions in small numbers like the Sherman Jumbo did. On the other hand, it wasn't numerous enough to completely replace the Sherman in anything but a very small number of US independent tank battalions. Even then, it would complicate the US ability to swap battalions between divisions as necessary risking even greater danger to the units operating the Churchill, the infantry they'd be supporting, and even other battalions that may be called upon to replace them.

(http://3.bp.blogspot.com/-iAU4E10evaQ/TVkCC-bEyZI/AAAAAAAADgc/YJZJRtvsavQ/s1600/file017.bmp)

I think the only reasonable scenario for the replacement of standard Sherman gun tanks in US Army service with Churchill VIIs on any scale is in Italy. If you replaced the Shermans that served with the independent tank battalions in Italy, you'd probably at least get an even break for the trouble. Italy was already the red-headed stepchild of the US Army logistical branch, never getting the good equipment like 76mm-armed Shermans, M36 tank destroyers, or Jumbos in any numbers. So, the armor would be a pure upgrade and the armament wouldn't be any worse. Further still, the Sherman couldn't make good use of its greater speed in Italy and the "mountain goat" nature of the Churchill would serve it well.

Finally, you're not talking about 35 battalions in that scenario. You're really just looking at 751st, 752nd, 755th, 757th, 758th, and 760th battalions. That's still over 350 tanks, 100 more tanks than the total number of Jumbos built and over a fifth of all A22Fs produced, but a lot fewer tanks that would be required in France and Germany. Alternatively, you could just keep all the Shermans and just replace the light tank companies in the independent tank battalions in Italy with Churchills. That allows you to basically cut out an unnecessary tank type (the M5 Stuart) that nobody's really going to miss and still gain the advantages of the Churchill. It also means that you only need six companies of Churchills, or about 100 tanks. Even with the necessary replacements, it's still a relatively reasonable number. Given how closely US forces in Italy operated with British forces and how rarely they got new equipment anyway, this relatively uncommon tank wouldn't be too much of a headache in Italy.

That's about the only plausible scenario I see for gun-armed Churchills in US Army service in any numbers in WWII.

Cheers,

Logan
: Re: Churchill Tank
: dy031101 July 05, 2014, 12:37:01 AM
Once you get into the 1960s, you can replace the GAA with a commercial diesel of even higher HP in a similar-sized package that probably includes a new or modified tranny. It would need a new engine deck, but that's nothing as the M50s and M51s showed.

How about Cummins VT8-460?  I know it was fitted to A1 and A4 instead of A3 but as an aftermarket engine, so I don't know if engine size was a consideration for the Super Sherman.

(You know, I have an awful sense of scale and therefore need to constantly ask size-related questions  ;D)

Come to think about it, M36 during the Yugoslav Civil War were re-engined with one used on the T-55, too...... granted, I'm not necessarily limiting my options to the afore-mentioned two- they just so happened to have been used in a Sherman or Sherman derivative (which I intent the upgraded Churchill to serve alongside).  Your mention of a commercial diesel seems like plenties to choose from.  :)
: Re: Churchill Tank
: tankmodeler July 05, 2014, 02:33:41 AM
I have no idea what commercial diesels would fit in any of these tanks. I have no knowledge of them whatsoever, just an understadning that a couple of countries replaced Sherman sized engines with diesels at around that time so something, somewhere would likely fit the bill. :)

Paul
: Re: Churchill Tank
: Rickshaw July 06, 2014, 09:40:50 PM
Logan, thats a comprehensive rebuttal.  I wasn't aware that the Jumbo was not used in separate battalions and instead shared out in penny packets.
: Re: Churchill Tank
: Logan Hartke July 06, 2014, 10:00:06 PM
Yep. Here's a breakdown as compiled by someone far smarter than me (Chad Lares):

Tank units in the ETO with Jumbos on hand (the assignment of units to armies is as of mid December). This listing appears to account for all units issued with the Jumbo.

First Army

3rd AD 6 (16 Dec)
5th AD 3 (19 Dec)
70th TkBn 4 (11 Feb)
743rd TkBn 15 (14 Oct, 3 lost as of 3 Dec)
745th TkBn 15 (14 Oct), 1 (15 Dec)
746th TkBn 6 (14 Oct), 15 (9 Nov), 5 (21 Dec)
774th TkBn 10 (16 Dec)

The 70th Tank Battalion’s tanks were in very poor condition in mid December. Unit diaries note that they were all “original issue” and worn out. Thus it appears that the Jumbos assigned to the 70th Tank Battalion may have been from some of the last available. These units account for about 37 in mid December and a total of 22 were lost to 28 January. That total of 59 is very similar to the 54 on hand and en route as of 3 December. It is likely that all 40-odd of the remaining 105 allocated to the First Army were utilized as replacements and to equip the 70th Tank Battalion.

Third Army

4th AD 20 (22 Dec)
6th AD 11 (29 Dec, this may include the 5 reported en route on 3 December)
10th AD 5 (22 Nov)
702nd Tk Bn 5 (22 Nov), 5 (29 Jan)
712th Tk Bn 5 (22 Nov), 1 (11 Feb)
735th Tk Bn 5 (22 Nov), 2 (12 Feb)
737th Tk Bn 15 (22 Nov), 5 (15 Dec), 3 (29 Jan)
761st Tk Bn 5 (22 Nov)

The available reports tend to indicate that this is a fairly accurate picture of all the Jumbos assigned to the Third Army. By mid December some 68 may be accounted for including 7 that had been lost. This closely matches the 59 on hand and 5 en route count for 3 December. It may also be concluded that 10 were probably withdrawn from the 737th Tank Battalion prior to 15 December and were assigned to the 4th (or less likely 6th) AD. The remaining 30-odd allocated to the Third Army were probably utilized as replacements in these units during 1945.

Ninth Army

709th Tk Bn 1 (19 Dec)
747th Tk Bn 5 (27 Nov, plus 10 en route)
778th Tk Bn 4 (27 Jan)

This appears to account for only 20 of the 36 on hand or en route as of 3 December. Three had been lost to that date and another was lost between 21-28 December. The remaining 12 or 13 may have been issued later (likely to the 709th Tk Bn), may have been issued to other units (possibly the 3rd AD), or they may have been retained as replacements. It appears probable that the remaining 24 of the 60 allocated to the Ninth Army were never in fact shipped, given the strategic situation in mid December, the losses sustained to date, and the reduction in the number shipped from 254 to 250.

It does not appear as if the 2nd, 7th-14th, 16th, or 20th Armored Divisions were ever issued Jumbos.


(http://militarymashup.com/mmu_get_jpeg.php?14abd72a310a440fd49c2fa8e09d2d184)

This explains why almost all pictures of the Jumbo show it in "mixed company" and you almost never see multiple Jumbos in the same picture. That's just not how they were used. They were often used to lead a column of Shermans whenever they were on a road march because they could shrug off a hit from a Pak 40. It's no coincidence that "Cobra King" was the first tank into Bastogne. It was leading the way for a reason. Because this was happening all across the ETO from late 1944 until the end of the war, with the Jumbo serving in at least 13 different independent tank battalions and 5 different armored divisions, the Jumbo was a real force multiplier in a way 250 Churchills never could have been.

Again, about the worst thing that you can say about the Jumbo is that they didn't build enough of them.

Cheers,

Logan
: Re: Churchill Tank
: Volkodav January 04, 2015, 12:16:12 AM
As I have been laid up for the last several weeks I have been reading a fair bit and watching a few documentaries (mostly on You Tube) and a fair bit of it has been on tanks. 

Something that keeps coming up is the comparative unreliability of British tanks and how everyone preferred Shermans, until the shooting started.  I had no idea how many Shermans were lost, or that some battalions / regiment suffered 500% plus vehicle casualties between D-day and VE Day.  I had heard the story that it took four or five Shermans to kill a single Panther or Tiger with often with the loss of some Shermans but didn't realise that it was actually a deliberate tactic to sacrifice tanks to get a single vehicle into a position, where if it was lucky it could kill the Panzer from the rear and this often resulted in the loss of three or four of the Shermans, sometimes the only survivor was the Panzer. 

There were references to Pattons involvement in selecting the Sherman as the main tank to be used in western Europe, rating reliability, speed and transportability over protection and firepower, numbers and availability over combat power.  Reference to the ability to produce tens of thousands of them and move them to the front easily. While I understand that quantity has a quality all of its own you have to wonder if you've got it wrong when there is such a miss match in firepower and protection.  The fact that both the Firefly and the Jumbo exist show what could be achieved, the fact that the Pershing could have been made available, the fact that the Churchill was competitive in protection. 

Was the issue the Tank Destroyer doctrine?  Did the US Army actually believe, in spite of almost five years of war, that this was actually workable?  The Sherman was more than adequate against most infantry weapons and indirect fire but screwed against tanks, AT guns, assault guns and specialist tank destroyers, the trouble is the whole idea of Blitzkrieg is combined arms operations, they were pretty much always going to find German armour and AT assets mixed in with infantry.  To destroy tanks the US Army relied on TD battalions, towed or SP or, in reality, trading numbers (and lives) in the tank battalions.  Maybe there weren't enough Jumbos and the Churchill would have been a logistical nightmare but they definitely needed better protected vehicles that could survive a hit as well as a vehicle that could effectively engage German armour over combat ranges.

The US had no interest in building material of foreign design but were perfectly willing to supply US designed gear to allies.  This is too bad in my opinion as US industrial capacity combined with British combat experience could easily have produced a superior vehicle (or two), in Sherman like numbers, in time for the Normandy invasion.  Imagine a heavy tank based on the Churchill with a Packard version of the Meteor and a 17pdr as well as a version of the Cromwell, again with the Meteor and 17pdr (ironically as originally intended before they realised it didn't fit).  The US, with their resources could have refined and perfected these vehicles and had them in mass production well in time for Normandy.  It would have dramatically improved the combat performance of the Allies and more importantly reduced losses, therefore reducing the need to produce so many vehicles and train so many replacements.  It would also have better set up the Allies to counter the shock of seeing the IS3 for the first time.
: Re: Churchill Tank
: Volkodav January 04, 2015, 12:18:25 AM
Would a Comet turret fit a Churchill?
: Re: Churchill Tank
: Rickshaw January 04, 2015, 09:37:11 AM
Would a Comet turret fit a Churchill?

Churchill turret ring - 54.25 inches
Comet turret ring - 64 inches

You'd need an adapter structure.
: Re: Churchill Tank
: Old Wombat January 04, 2015, 09:38:09 AM
Widen the Churchill? ???
: Re: Churchill Tank
: elmayerle January 04, 2015, 10:56:14 AM
Widen the Churchill? ???
Well, if you absolutely needed to fit a Comet turret, I can envision how it could be done, a huge adaptor flange that would fit over the Churchill turret ring and properly support the Comet turret.  Loads would definitely require it to be made out of high-strength steel and it would be a right pain to machine and add significantly to the final vehicle's weight.  Something definitely more suited to whif-dom than reality.
: Re: Churchill Tank
: jcf January 04, 2015, 12:11:50 PM
Widen the Churchill? ???


Which just gives you Black Prince.
http://en.wikipedia.org/wiki/Black_Prince_(tank) (http://en.wikipedia.org/wiki/Black_Prince_(tank))

Churchill, and the 'infantry tank' concept, was a dead end.
: Re: Churchill Tank
: dy031101 January 04, 2015, 01:10:07 PM
Since I came across people during this past week talking about how Yugoslavia was able to keep their T-34-85 somewhat useful during the Cold War with domestically-developed HEAT ammunition, I couldn't help to think of a Churchill with 25-pounder tank howitzer again...... this time in Yugoslav colours even though they used neither, IIRC......
: Re: Churchill Tank
: raafif January 04, 2015, 01:43:57 PM
Since I came across people during this past week talking about how Yugoslavia was able to keep their T-34-85 somewhat useful during the Cold War with domestically-developed HEAT ammunition, I couldn't help to think of a Churchill with 25-pounder tank howitzer again...... this time in Yugoslav colours even though they used neither, IIRC......

I'll have to read the book again but I'm fairly sure Tito wanted Churchill tanks but it was recognized that the war would probably be over before the Yugos could be trained to maintain them & put the necessary workshops & parts-supplies in place.  Tito's Soviet leanings precluded post-WW2 supplies of anything from the UK.  Smaller tanks were more suited to the hilly terrain too.
: Re: Churchill Tank
: Volkodav January 04, 2015, 03:32:49 PM
Following experience in the Pacific Australia ordered the Churchill, predominantly CS and flamethrower versions, to supplement and replace the Matildas that the RAAC was using in theatre in preference to the M-3 Mediums in-service.  The Churchill was actually ordered after evaluation of a number of types in Australia, including the Sherman and Cromwell.

My gut feeling is if the US had developed the Churchill for the UK they would have been able to widen the hull and fit a larger turret quite easily.
: Re: Churchill Tank
: ChernayaAkula January 05, 2015, 05:41:18 AM
<...>  Tito's Soviet leanings precluded post-WW2 supplies of anything from the UK.  <...>


Did they?  ;)

(http://i262.photobucket.com/albums/ii120/Duggy009/Mosquito-Yugo.jpg)

If you look at Yugoslav history, there's a very good possibility of such a whif scenario ( Yugoslav Churchills) actually coming to fruition.
LINK #1! (http://en.wikipedia.org/wiki/Tito%E2%80%93Stalin_Split)
LINK #2! (http://en.wikipedia.org/wiki/Informbiro_period)
It was during that time that Yugoslavia received Western tanks (M18, M36 and M47) and aircraft, jets (T-33, F-84G, F-86D and Canadair Sabres) as well as props (F-47 Thunderbolts and D.H. Mosquitoes).
: Re: Churchill Tank
: Volkodav January 05, 2015, 06:12:02 PM
Oh and the small matter or the Nenes and Derwents the UK exported to the USSR, making the MIG 15, and other advanced types whose development was held up by the lack of suitable engines, possible.
: Re: Churchill Tank
: Weaver January 05, 2015, 09:41:07 PM
Britain sent two Gnat F.1s to Yugoslavia for evaluation as late as 1958 and if they'd been selected, there seems little doubt a production order would have followed, possbily even with licenced production.

It's worth remembering that all Yugoslavia's post-war jets (Galeb, Jastreb, Orao, Super Galeb) were powered by licence-built RR Vipers and they also built Gazelles and Sikorsky S-55s under licence: http://www.airliners.net/photo/Yugoslavia---Air/Westland-WS-55-2-Whirlwind/1335527/L/&sid=b84dfc9613be7729df65a9e177ee2194 (http://www.airliners.net/photo/Yugoslavia---Air/Westland-WS-55-2-Whirlwind/1335527/L/&sid=b84dfc9613be7729df65a9e177ee2194)
: Re: Churchill Tank
: Volkodav January 07, 2015, 12:00:06 AM
Rickshaw, I am reading a very good e-book at the moment called "Fallen Sentinel" that covers the history of Australia's WWII tank program, covering the military, engineering, industrial, political and strategic factors.  It's one of the new series of thoroughly and impartially researched books on Australian military history using cabinet papers and original source documents.

Only about a third through at the moment, really enjoying it and the number of facts I never realised relating to timings and industrial capacity.  I was interested to read that, although initially supporting the program, the US later wanted Australia to drop the indigenous design and build M-4s instead threatening to withhold promised machine tools to force Australia to comply.

Really looking forward to getting onto the tropical tank trials and the selection of the Churchill over the Sherman and Cromwell.  I have read some pieces on that previously but get the feeling this book will be much more informative.
: Re: Churchill Tank
: dy031101 January 07, 2015, 01:43:01 AM
Despite this, want to know what one of my favorite tank models on Beyond the Sprues is? Claymore's Big Mac. ([url]http://beyondthesprues.com/Forum/index.php?topic=2684.msg38702[/url])

I think it's completely impractical and a combination Churchill/King Tiger sounds like an unholy spawn that would be lucky to make it out of the marshalling yard, let alone drive all around sub-Saharan Africa, but MAN it looks right!


Damn, and I wanted to (and still kind of do) combine a M103 or Conqueror turret with the Black Prince!

(Yes, I also toyed with the idea with Centurion turret, but since Black Prince is nowhere near as mobile as a Centurion, I figured it could use some superior firepower......)
: Re: Churchill Tank
: GTX_Admin January 07, 2015, 02:46:04 AM
I have removed some posts here - they may be partially returned in the future after I have reviewed them for relevance.
: Re: Churchill Tank
: tankmodeler January 07, 2015, 04:05:07 AM
Damn, and I wanted to (and still kind of do) combine a M103 or Conqueror turret with the Black Prince!
If we ever see an injected Black Prince, I promise you can have the turret from my Dragon M103A1. Actually, if you have a resin Black Prince (didn't Accurate Armour do one??) you can still have the turret from my Dragon M103A1. It's certainly no good as an accurate 103 turret...

:-)

Seriously, if you want it, you can have it.

Paul
: Re: Churchill Tank
: Volkodav January 07, 2015, 07:03:16 AM
Widen the Churchill? ???
Well, if you absolutely needed to fit a Comet turret, I can envision how it could be done, a huge adaptor flange that would fit over the Churchill turret ring and properly support the Comet turret.  Loads would definitely require it to be made out of high-strength steel and it would be a right pain to machine and add significantly to the final vehicle's weight.  Something definitely more suited to whif-dom than reality.

There's a photo I've seen of a Matilda II with a Cromwell / Cavalier turret that uses that method, apart from the turret just looking wrong on a Matilda you need to look closely to see the built up area.  British tanks, for the most part, also have a lower profile than US tanks, but also lack the sponsons of the M-3/4 etc.which is how the M-4 manages to have such a large diameter turret ring.

  Technically the Churchill and the Cromwell for that matter, could have their hulls built up over the tracks but that would increase weight and profile height, making the tank a bigger target, while the new superstructure would require thinner armour for stability reasons as well as perhaps a reduction in existing armour to control weight growth.  Overall widening the hull may be both technically easier and result in a better balanced design.especially if it incorporates a better engine as well.

The issue is the UK really needed, either a clean sheet design that could easily accommodate the 17pdr, or an intermediate tank gun that could replace the 75mm while providing superior anti-armour performance to the 6pdr.  It all seems to come back to some incorrect assumptions made during development in regards to the size and platform impact of the 17pdr, that had it been realised would have resulted in design changes to address the problem.
: Re: Churchill Tank
: Rickshaw January 07, 2015, 08:43:28 AM
The issue is the UK really needed, either a clean sheet design that could easily accommodate the 17pdr, or an intermediate tank gun that could replace the 75mm while providing superior anti-armour performance to the 6pdr.  It all seems to come back to some incorrect assumptions made during development in regards to the size and platform impact of the 17pdr, that had it been realised would have resulted in design changes to address the problem.

Enter the Centurion.  A clean sheet design and the first complete one undertaken by the Ministry of Supply's Department of Tank Design, rather than the individual manufacturers (the Department had up till that point acted as a contracting department, requesting the individual manufacturers to design the vehicles themselves).  The Department was much closer and more clearly understood the requirements of the end users and so the Centurion incorporated the lessons learned from the previous five years of warfare.   It was intended to fulfil both cruiser and infantry tank requirements.  In the end, the infantry tank version wasn't built, beyond a few prototypes (it incorporated heavier armour and wider tracks IIRC).

You should also remember the 17 Pdr was designed first and foremost as an anti-tank gun, not a tank gun.  Only after it's development was the idea of putting it into a tank first mooted.  The British suddenly found they didn't have a turret big enough to accept the weapon and so it became a seemingly endless chase to either adapt or built a new vehicle.  Vickers tried to fix that by developing their high velocity 75mm gun, which eventually morphed into a 76.2mm weapon firing the same ammunition as the 17 Pdr with a shorter, fatter case and was finally designated the 77mm (despite actually remaining 76.2mm).  While it's velocity wasn't quite as good as the 17 Pdr. it was close enough for most jobs.

An argument could be made that the Centurion was the first successful design to be able to mount the 17 Pdr properly.  In that case, the decision made very early on was to give it as large a turret ring as could be managed, which meant it was able to survive the succession of up gunning, from 17 to 20 Pdr and finally 105mm.   The Firefly was only ever an extemporised weapon, forced on the RAC by circumstance (and the happy coincidence that the RAAC had done the experimental work with it's twin 25 Pdrs mounted in a Sentinel in Australia which proved it was possible).  As it was, it was only accomplished by turning the gun on it's side.  The Black Prince, was the last gasp of the "old school" and they failed as they usually did by trying to do more with less and failing to produce a balanced design as far as it's engine power went.

One thing I've never quite understood is why the Allies never followed the German route in seeking a higher velocity tank gun - lengthening the barrel and increasing the chamber size of the standard 75mm tank gun.   It would have made a better tank killing weapon without necessarily needing a new mounting.   As it was, they stuck with a gun which was adequate in 1942 until the end of the war, when it was decidely passe.  While the primarily role of the tank in US doctrine might have been infantry support, a higher velocity 75mm would have taken little from that and ensured the tanks had a better weapon with which to defend themselves against other tanks.
: Re: Churchill Tank
: tankmodeler January 07, 2015, 10:58:52 AM
British tanks, for the most part, also have a lower profile than US tanks, but also lack the sponsons of the M-3/4 etc.which is how the M-4 manages to have such a large diameter turret ring.
Absolutely. Another thing to consider is the turret basket under the ring. There needs to be enough room for the crew (and possibly a larger crew if you are going from a two-man to a three-man turret) to work effectively. The Churchill has no effective access to the sponsons so a larger turret ring doesn't help you if you can't install a larger turret basket.

  Technically the Churchill and the Cromwell for that matter, could have their hulls built up over the tracks but that would increase weight and profile height, making the tank a bigger target, while the new superstructure would require thinner armour for stability reasons as well as perhaps a reduction in existing armour to control weight growth.
I think you may be overestimating the negative effect on stability unless the additional mass is truly egregious, however, keeping the mass in check so the mobility isn't overly affected is a good idea. Of course, compromising the protection can be counterproductive if you've gone to great lengths to increase the firepower through a new turret. The balancing act can be brutal.

Overall widening the hull may be both technically easier and result in a better balanced design.especially if it incorporates a better engine as well.
The one major problem, especially during WW II, was the relatively narrow railway gauges in both the UK and continental Europe. The Churchill is absolutely at the limit of the UK gauge and actually had to have the air inlet boxes removed for rail shipment, never a good thing for strategic mobility. Widening a tank past the gauge limit wasn't an acceptable option during the war and had a huge (and mostly negative) effect on UK tank design.

The issue is the UK really needed, either a clean sheet design that could easily accommodate the 17pdr, or an intermediate tank gun that could replace the 75mm while providing superior anti-armour performance to the 6pdr.  It all seems to come back to some incorrect assumptions made during development in regards to the size and platform impact of the 17pdr, that had it been realised would have resulted in design changes to address the problem.
Indeed, the UK was plagued by several factors that all contributed to a string of what were generally really bad tanks. The book "The Great Tank Scandal" does a great job of describing the many ins and outs of why the UK simply didn't get their act together until the Comet. Which, as you say, was fundamentally a clean sheet design that started once some of the background essentials were in place, like a powerful engine, a great gun and a reliable chassis.

Paul
: Re: Churchill Tank
: buzzbomb January 07, 2015, 02:37:03 PM
This is an interesting discussion.

Damn, and I wanted to (and still kind of do) combine a M103 or Conqueror turret with the Black Prince!


I have a 1/35 Conqueror (Accurate Armour kit, you can thank me for the injection version announced) and a scratchbuilt Black Prince (no doubt to be announced shortly)
Fossicked them out and some turret swappage and you get.
(http://www.modelblokez.org.au/bthpix/whatif/blackeror.jpg)

: Re: Churchill Tank
: tankmodeler January 07, 2015, 09:11:50 PM
One thing I've never quite understood is why the Allies never followed the German route in seeking a higher velocity tank gun - lengthening the barrel and increasing the chamber size of the standard 75mm tank gun.   It would have made a better tank killing weapon without necessarily needing a new mounting.   As it was, they stuck with a gun which was adequate in 1942 until the end of the war, when it was decidely passe.  While the primarily role of the tank in US doctrine might have been infantry support, a higher velocity 75mm would have taken little from that and ensured the tanks had a better weapon with which to defend themselves against other tanks.
Well, the M1 76mm gun was essentially an attempt to do just that. Longer tube, higher nuzzle velocity and nominally improved AT performance. As it turned out, the AT performance was only a bit better than the 75mm M3 and the HE performance was considerably worse.

The HE performance of the 17 pdr was dismal.

The muzzle velocities needed to really compete with the German armour inevitably leads to guns that have much greater wall thicknesses to deal with the pressures and forces and thus less HE filling and therefore crappy HE performance. There was no way around that. And the US wasn't really happy to ever accept that. Their doctrine continued to lead them to believe that someone other than tanks could be the main weapon against tanks so they figured that they could put the AT performance aside. They were wrong, but they didn't come to terms with that until pretty much the end of the war.
: Re: Churchill Tank
: Rickshaw January 07, 2015, 11:26:28 PM
One thing I've never quite understood is why the Allies never followed the German route in seeking a higher velocity tank gun - lengthening the barrel and increasing the chamber size of the standard 75mm tank gun.   It would have made a better tank killing weapon without necessarily needing a new mounting.   As it was, they stuck with a gun which was adequate in 1942 until the end of the war, when it was decidely passe.  While the primarily role of the tank in US doctrine might have been infantry support, a higher velocity 75mm would have taken little from that and ensured the tanks had a better weapon with which to defend themselves against other tanks.
Well, the M1 76mm gun was essentially an attempt to do just that. Longer tube, higher nuzzle velocity and nominally improved AT performance. As it turned out, the AT performance was only a bit better than the 75mm M3 and the HE performance was considerably worse.

The HE performance of the 17 pdr was dismal.

The muzzle velocities needed to really compete with the German armour inevitably leads to guns that have much greater wall thicknesses to deal with the pressures and forces and thus less HE filling and therefore crappy HE performance. There was no way around that. And the US wasn't really happy to ever accept that. Their doctrine continued to lead them to believe that someone other than tanks could be the main weapon against tanks so they figured that they could put the AT performance aside. They were wrong, but they didn't come to terms with that until pretty much the end of the war.

The Germans used essentially the same 75mm HE round in all their 75mm tank guns, no matter what length of barrel.  So how did they managed that?

HE doesn't have to be fired at the same MV as AP.    Keeping the MV lower means that the stresses on the HE round are lower and so you don't need thicker walls in your HE rounds and so can have the same filling, keeping it's effectiveness.

Having a longer barrel though, allows you to increase the MV of AP.   L/33, L/43, L/48, L/70....

Admittedly there were also chamber increases as well, from L/48 to L/70 but essentially it remained the same weapon and mount.

: Re: Churchill Tank
: dy031101 January 07, 2015, 11:48:10 PM
Damn, and I wanted to (and still kind of do) combine a M103 or Conqueror turret with the Black Prince!
If we ever see an injected Black Prince, I promise you can have the turret from my Dragon M103A1. Actually, if you have a resin Black Prince (didn't Accurate Armour do one??) you can still have the turret from my Dragon M103A1. It's certainly no good as an accurate 103 turret...

:-)

Seriously, if you want it, you can have it.

 ;D I need to determine if I want to do it in plastic or in digital triangles.  I did buy a bigger house, but it seems like my parents' post-retirement activities will take up plenties of room.

Damn, and I wanted to (and still kind of do) combine a M103 or Conqueror turret with the Black Prince!

I have a 1/35 Conqueror (Accurate Armour kit, you can thank me for the injection version announced) and a scratchbuilt Black Prince (no doubt to be announced shortly)
Fossicked them out and some turret swappage and you get...

Thanks.  It really helps me planning things out.  :)

Those vertical protrusions on the engine deck are a cause of my concern...... as expected  ;)
: Re: Churchill Tank
: Logan Hartke January 08, 2015, 12:35:40 AM
Admittedly there were also chamber increases as well, from L/48 to L/70 but essentially it remained the same weapon and mount.


That's not the case, Rickshaw. The KwK 40 and KwK 42 were completely different weapons that fired completely different rounds. Yes, it's true that the Panther's HE round was fired at a much lower muzzle velocity than the AP round, but it wasn't the same round that was used on the PzKpfw IV. They were not the same at all. Different cartridge case, length, shape, propellant charge, and muzzle velocity.

(http://milpas.cc/rifles/ZFiles/Misc/Cartridge%20Collection/tankger.jpg)

The KwK 40 saw the barrel lengthened from L/43 to L/48, but the L/70 KwK 42 was a totally different weapon, far from just another barrel increase.

Cheers,

Logan
: Re: Churchill Tank
: Volkodav January 08, 2015, 09:16:54 PM
One gun I am surprised didn't have a longer barrel was the 95mm howitzer although there is probably a perfectly logical reason for the chosen length perhaps relating to the infantry version that didn't in the end enter service but I really don't know. 

As I understand it the weapon was a bit of a Frankenstein using a section of 3.7" AA gun barrel, 25pdr breach mechanism and the 6pdr recoil mechanism and a large counter weight to balance the weapon in the turret.  It apparently also suffered from poor accuracy and low muzzle velocity, although that was probably irrelevant.  Why then didn't they just increase the length of the barrel, removing the need for the counter weight and potentially improving accuracy and increasing muzzle velocity (note I did say potentially as I know there are other factors involved).
: Re: Churchill Tank
: dy031101 January 09, 2015, 10:04:00 AM
(http://i.imgur.com/iXvShp0.jpg)

I know it will be easier said than done once I actually get around doing something about the idea......
: Re: Churchill Tank
: GTX_Admin January 10, 2015, 03:41:49 AM
Interesting…

What about a dedicated SPH based upon the Churchill?  I am thinking of something more than the Churchill VIII with 95 mm howitzer shown below:

(http://www.wwiivehicles.com/great-britain/vehicle/infantry/infantry-mk-iv-a22-churchill/mk-viii/infantry-mk-iv-churchill-mk-viii-01.jpg)(http://www.wwiivehicles.com/great-britain/vehicle/infantry/infantry-mk-iv-a22-churchill/mk-viii/infantry-mk-iv-churchill-mk-viii-02.jpg)

Maybe something like a 105mm or 155mm gun?
: Re: Churchill Tank
: Volkodav January 10, 2015, 04:11:46 PM
Well the Australian 25pdr setup, developed for the AC3, should fit and the 95mm does have the 25pdr breach mechanism.  The 165mm demolition gun was retrofitted to some Churchill AVREs post war, is a howitzer version of this gun possible?  Actually I do remember reading somewhere that the L9 165mm was originally developed as a replacement CS howitzer for the 95mm.
: Re: Churchill Tank
: tankmodeler January 11, 2015, 10:28:36 PM
One of the problems with Churchill based SPG variants is the lack of space to work the piece. You would need to build an entire superstructure above the upper track run to provide enough room for a crew to work easily. The 95mm and 165 mm demo guns were not meant for sustained rates of fire so the rather cramped turret of the Churchill was fine. When you are trying to lay down a support mission of 30 rounds on target, that's just not easy at all in any rotating turret and almost impossible in a turret like the Churchill's. The Bishop was the first Brit attempt and the turret was actually a "casemate"; it didn't turn at all. The whole back opened up when firing and the elevation of the 25 pdr inside was limited.

Now, if you are willing to add a full superstructure, kinda like a Priest, above the track-line, then the vehicle itself would easily support it, but there were better vehicles available at the time, so why bother. But it wouldn't be impossible. just clumsy and likely pretty ugly. :-)

It would be kinda interesting to see what someone could come up with, though, as a WHIF.

Paul
: Re: Churchill Tank
: GTX_Admin January 12, 2015, 02:09:38 AM

Now, if you are willing to add a full superstructure, kinda like a Priest, above the track-line, then the vehicle itself would easily support it, but there were better vehicles available at the time, so why bother. But it wouldn't be impossible. just clumsy and likely pretty ugly. :-)


That was more what I was thinking.  As for practicality…bah!
: Re: Churchill Tank
: buzzbomb January 12, 2015, 09:48:58 AM

Now, if you are willing to add a full superstructure, kinda like a Priest, above the track-line, then the vehicle itself would easily support it, but there were better vehicles available at the time, so why bother. But it wouldn't be impossible. just clumsy and likely pretty ugly. :-)



That was more what I was thinking.  As for practicality…bah!


Something like this but using more space over the track guards for ammo storage and the like, which makes a lot of sense.
(http://www.modelblokez.org.au/bthpix/whatif/churchill/churchy5.jpg)
: Re: Churchill Tank
: Logan Hartke January 12, 2015, 10:09:54 AM
The Churchill Toad extended the superstructure over the tracks, or at least appears to have. That should provide you with a lot more internal space, going with a similar configuration.

(https://c1.staticflickr.com/5/4087/5079622024_c5b92d3a7c_z.jpg)

(http://www.japan-militaire.com/img/members/166/s-IMG_2245.jpg)

(http://www.japan-militaire.com/img/members/166/IMG_3112.jpg)

Cheers,

Logan
: Re: Churchill Tank
: tankmodeler January 12, 2015, 12:32:26 PM
One gun I am surprised didn't have a longer barrel was the 95mm howitzer although there is probably a perfectly logical reason for the chosen length perhaps relating to the infantry version that didn't in the end enter service but I really don't know. 
I think the main reason is that it didn't need to. The CS guns were supposed to be line of sight, direct assault guns for laying down smoke or HE on targets immediately near the tanks, not for indirect artillery fire. Range and accuracy were not important in that role. Range was seldom more than several hundred yards and the accuracy was sufficient with the quite good HE or smoke rounds.

Why then didn't they just increase the length of the barrel, removing the need for the counter weight and potentially improving accuracy and increasing muzzle velocity (note I did say potentially as I know there are other factors involved).
As they say, perfect is the enemy of good enough. The gun was good enough, why waste a second or a penny on making it better than was needed?

Paul
: Re: Churchill Tank
: GTX_Admin January 12, 2015, 06:49:12 PM

Now, if you are willing to add a full superstructure, kinda like a Priest, above the track-line, then the vehicle itself would easily support it, but there were better vehicles available at the time, so why bother. But it wouldn't be impossible. just clumsy and likely pretty ugly. :-)



That was more what I was thinking.  As for practicality…bah!


Something like this but using more space over the track guards for ammo storage and the like, which makes a lot of sense.
([url]http://www.modelblokez.org.au/bthpix/whatif/churchill/churchy5.jpg[/url])


Love it!
: Re: Churchill Tank
: Volkodav January 12, 2015, 10:35:19 PM
One gun I am surprised didn't have a longer barrel was the 95mm howitzer although there is probably a perfectly logical reason for the chosen length perhaps relating to the infantry version that didn't in the end enter service but I really don't know. 
I think the main reason is that it didn't need to. The CS guns were supposed to be line of sight, direct assault guns for laying down smoke or HE on targets immediately near the tanks, not for indirect artillery fire. Range and accuracy were not important in that role. Range was seldom more than several hundred yards and the accuracy was sufficient with the quite good HE or smoke rounds.

Why then didn't they just increase the length of the barrel, removing the need for the counter weight and potentially improving accuracy and increasing muzzle velocity (note I did say potentially as I know there are other factors involved).
As they say, perfect is the enemy of good enough. The gun was good enough, why waste a second or a penny on making it better than was needed?

Paul

While I agree with the sentiment of "perfect is the enemy of good enough", and have seen examples of it, there are also many examples of temporary, or band aid fixes becoming permanent in place of, sometimes highly affordable, or even cheaper, occasionally elegant, permanent solutions.  Apart from those you read about I have seen more than my fair share in over two decades working in engineering, both automotive and defence, some are perfectly good enough and don't need to be replaced while others can be quite troublesome but for one reason or another are never superceded. 

The 95mm howitzers barrel was a short length of the 3.7" AA barrel suggesting that it would not have been difficult to produce a slightly longer version of it, if for no other reason than to balance the weapon in the turret, compared to the added complexity and cost of fabricating and fitting the counter weight.  I recall reading that accuracy was a problem with the 95mm compared to the preceding 3"howitzer, from memory inadequate muzzle velocity was also mentioned but I am not as certain of this as the accuracy problem.  For all I know a longer barrel may have been trialed and / or rejected for perfectly valid reasons, it's just persisting with a counter weight instead of lengthening a barrel that was a shorter version of a longer barrel, especially when accuracy is a criticism of the weapon seems a bit odd to me.
: Re: Churchill Tank
: finsrin January 13, 2015, 05:45:40 AM
Dang nice :)
Would not thought of this configuration.
Like it better than original Churchill.
: Re: Churchill Tank
: Rickshaw January 13, 2015, 11:18:45 AM
Volkodav, like most high performance, high velocity guns, the 3.7in AA gun used multiple tubes to create what we call a "barrel".  These are held inside the externally visible, monoblock "barrel" and are designed, as they wear to be easily replaced.  They lock together to form one continuous tube which the shell travels down. The 95mm How. utilised one of these tubes, attached to, as you've already noted a 25 Pdr breech block on a 6 Pdr mount.  Ian Hogg IIRC described it as a "bit of a mongrel of a gun" with descent from many different breeds.   

The idea was to make a "cheap" infantry support gun (during the period when everybody thought that one of the keys to German successes on the battlefield was their provision of infantry guns to directly support their infantry in the attack.   The American 105mm Airborne How. also got pressed into this use by the US Army).  While this meant that it could be easy to upgrade the barrel length it also meant that it would rather defeat the concept of "cheap".  You'd have to make new barrels rather than utilising existing tubes.  You could, I suppose extend the barrel by adding two tubes instead of one and accept the limitations that would entail.

My question is why?  While the 95mm How's performance was pretty weak with a muzzle velocity of only 330 m/s (which must have made watching it a lot of fun 'cause you could easily have seen the shell in flight!) it was intended for HE firing (mainly) and used a HEAT round for AT use (which meant MV was immaterial to penetration).  It's MV was adequate for the role envisaged for it of direct fire support for infantry and armoured units.  Its shells were essentially the same weight as 25 Pdr rounds (although that idea fell by the wayside along the ways when a fixed round was adopted) so they carried about the same explosive filling as the then standard British field artillery round.   You'd get a higher MV with a longer tube but as the weapon wasn't intended for indirect fire there appears little point as the increased range wasn't required.

: Re: Churchill Tank
: Volkodav January 13, 2015, 12:46:07 PM
Based on the length of an existing barrel segment, now that makes sense.  I didn't realise the 3.7" was built up with a segmented, or even separate, barrel liner.  Anyway that would explain the barrel length and the resulting need for a counter weight, the whole thing just seems to make the 25pdr as trialed in the AC3 a more sensible approach as that weapon excelled in both direct and indirect fire.

On the 95mm not being intended for direct fire, while I realise CS tanks could be used for indirect fires, I was under the impression that the reason for their existence was to provide direct, high explosive, fire support against enemy emplacements (bunkers, pillboxes, MG nests etc.), AT guns and infantry, the sort of targets the 6pdr was not well equipped to engage.  Engaging such point targets requires a degree of accuracy that cannot be achieved with indirect fire, here increased velocity and a flatter trajectory would help but is not vital.
: Re: Churchill Tank
: Rickshaw January 13, 2015, 02:25:33 PM
Based on the length of an existing barrel segment, now that makes sense.  I didn't realise the 3.7" was built up with a segmented, or even separate, barrel liner. 

Most modern guns are.  It makes them easier to manufacture and maintain.

Anyway that would explain the barrel length and the resulting need for a counter weight, the whole thing just seems to make the 25pdr as trialed in the AC3 a more sensible approach as that weapon excelled in both direct and indirect fire.

The problem with using a tank mounted gun for indirect fire is that you really need a higher elevation than most turrets can handle for it to really be effective as a tactical use of such a weapon.  Without higher elevation angles, your range actually remains rather short to be really useful in such a role.  A 25 Pdr CS weapon would make sense but by the time that became obvious, the days of the 25 Pdr were starting to be numbered.  25 Pdr is a bit light for destructive shoots and was really intended for suppressive shoots.

On the 95mm not being intended for direct fire, while I realise CS tanks could be used for indirect fires, I was under the impression that the reason for their existence was to provide direct, high explosive, fire support against enemy emplacements (bunkers, pillboxes, MG nests etc.), AT guns and infantry, the sort of targets the 6pdr was not well equipped to engage.  Engaging such point targets requires a degree of accuracy that cannot be achieved with indirect fire, here increased velocity and a flatter trajectory would help but is not vital.

It is also important because it just becomes a larger tank gun, so tank gunnery training can be used.  Artillery training is a different kettle of fish.  The role of British field artillery was to suppress the enemy, to prevent him from being able to shoot at the infantry while they advanced to the assault.  This was based on WWI practice, which had been so successful.  Having a close support weapon under the direct command of the assaulting commander means that he can direct and control it himself and not have to go through several layers of command in order to get a target destroyed.
: Re: Churchill Tank
: tankmodeler January 13, 2015, 11:45:02 PM
On the 95mm not being intended for direct fire,
I think you may have misread Rickshaw's comment:
You'd get a higher MV with a longer tube but as the weapon wasn't intended for indirect fire there appears little point as the increased range wasn't required.
The 95 was not intended for indirect fire for exactly the reasons you state. As for accuracy, accuracy is relative. Something that for an indirect shoot to 9 km is considered inaccurate may be quite accurate enough to put a round into or quite near an embrasure opening at 300-400m.

The muzzle velocity of the 95 was so low that almost everything would be lobbed anyway. Hitting the enemy house or bunker would be enough to surpress that fire from 400m and allow the infantry to close and knock it out. Putting a round into the hole is nice, but not normally required.

Paul
: Re: Churchill Tank
: Volkodav January 14, 2015, 02:21:03 AM
Yes I did miss read his post, I thought it odd as CS tanks are quite clearly intended for direct fire.  Getting a round through a window may not have been necessary, but hitting a dug in AT gun or machinegun emplacement could be critical.  Interestingly modern CS and even demolition is provided by specific ammunition types fired by regular tanks.
: Re: Churchill Tank
: tankmodeler January 14, 2015, 02:48:50 AM
Getting a round through a window may not have been necessary, but hitting a dug in AT gun or machinegun emplacement could be critical.
Indeed and the 95mm was quite good enough to hit a Pak 38 at 600m.

Interestingly modern CS and even demolition is provided by specific ammunition types fired by regular tanks.
Modern tank HE rounds are generally either a HEAT round or a HESH round, AT rounds used in a duel purpose mode. Even if the explosive filling is less than an equivalent arty shell, it is generally good enough for infantry support, especially compared to the ww II 75mm round.
: Re: Churchill Tank
: GTX_Admin January 14, 2015, 04:10:42 AM
Moving away from Howitzer based systems, what about a self propelled weapon using a heavy mortar as its main weapon - say an Ordnance ML 4.2 inch Mortar mounted in a Churchill hull?  Or for something different, maybe have one of the large Soviet weapons put into production?
: Re: Churchill Tank
: tankmodeler January 14, 2015, 04:28:43 AM
Moving away from Howitzer based systems, what about a self propelled weapon using a heavy mortar as its main weapon
Make it a major change.

Put a large open topped casemate in the front of the tank. Have the driver either in a fold-away seat in front or in a permanent maount above the engine over the track guard. Place the baceplate on a reinforced floor and shortened support legs on a 360 ish deg turntable at trackguard height. Ammo stored in the corners of the casement or, if the baseplate is hieng enough off the floor of the chassis, under the level of the baseplate. Fold down side doors to permit rapid replenishment during sustained fire missions as opposed to using the ready rounds stored onboard.

Something vaguely like this?
: Re: Churchill Tank
: raafif January 14, 2015, 04:35:27 AM
mortars are just a one-bang device :icon_nif: .... what you need (& that superstructure suggests it) is a bank of rockets ala LCT (R) C:-)
: Re: Churchill Tank
: tankmodeler January 14, 2015, 06:13:01 AM
mortars are just a one-bang device :icon_nif: .... what you need (& that superstructure suggests it) is a bank of rockets ala LCT (R) C:-)

Oooo! Mount a Canadian "Land Mattress" (q.v) rocket rack on that puppy! Loads of bang thrown essentially randomly down range!

http://i661.photobucket.com/albums/uu336/8Hussar/Allied%20Artillery/Canadian%20Land%20Mattress%203%20Inch%20Rocket%20System/IMG_9262.jpg (http://i661.photobucket.com/albums/uu336/8Hussar/Allied%20Artillery/Canadian%20Land%20Mattress%203%20Inch%20Rocket%20System/IMG_9262.jpg)

Paul
: Re: Churchill Tank
: Rickshaw January 14, 2015, 08:21:18 AM
The British 4.2in mortar wasn't a terribly good weapon being out ranged initially by the smaller 3in weapon.

The 4.2in was originally designed expressly for chemical use and only later pressed into service as a general heavy mortar.   It would be a bit of a small weapon for a vehicle the size of a Churchill.  Land mattress would be an interesting weapon to use although, it appeared rather late.  However, in either case would such vehicles really need as much armour as the Churchill carried?  Surely there are better uses for such a vehicle?

How about a Conga mine clearing system? Although carrying and pumping nitro-glycerine around next to me would not be something I'd particularly want to be doing (which is why putting it in an engineless Universal Carrier trailer was a much better idea IMHO).

Here is a trick question - what calibre was the British 3in infantry mortar?

: Re: Churchill Tank
: buzzbomb January 14, 2015, 11:38:30 AM
There Germans had a plan to put the Soviet 120mm Mortar into a 38T chassies, a much more compact vehicle.
(http://www.modelblokez.org.au/gallery/others/afv/trager/morsertrager3.jpg)
Having a Churchill size chassis for single tube does not sound practical. Especially if you plan to shoot n scoot.
Plenty of old Crusaders around for that gig.

Now a 380mm Sturmtiger type mortar, that would make more sense, if totally impractical in a Churchill.
Using the Navy hedgehogs on a heavy tank chassis as a grid square removal system sounds almost practical.
: Re: Churchill Tank
: Volkodav January 14, 2015, 12:36:02 PM
How about a medium or heavy breach loading mortar fired from a modified turret?  6 or 8" calibre with a range of 5-6000m.
: Re: Churchill Tank
: Rickshaw January 14, 2015, 01:12:01 PM
Well, in RL remember they did put the "Flying Dustbin" on the AVRE.   :o
: Re: Churchill Tank
: buzzbomb January 14, 2015, 01:16:17 PM
Well, in RL remember they did put the "Flying Dustbin" on the AVRE.   :o


yes.. but more is always better ;)
(http://upload.wikimedia.org/wikipedia/commons/thumb/3/33/Hedgehog_anti-submarine_mortar.jpg/781px-Hedgehog_anti-submarine_mortar.jpg)
: Re: Churchill Tank
: tankmodeler January 14, 2015, 02:18:50 PM
However, in either case would such vehicles really need as much armour as the Churchill carried?  Surely there are better uses for such a vehicle?

No, wouldn't need the armour, was thinking the casemate would only be splinter proof, like Priest or Sexton. The rest of the hull would remain as built for simplicity's sake.

And yeah, neither idea is terribly practical, we're definitely trending to the "Cool!" side of WHIFing as opposed to the "realistic" side.

What about removing the turret and making an Allied Wirblewind with the 4-barrelled Polsten turret? Replace the 60- round snail magazines for the Polstens with larger capacity "tombstone" boxes?

That'd be kind neat.

(http://www.ponsteen.info/polsten/83744382_808gHojC_2014Polsten.jpg)
: Re: Churchill Tank
: Volkodav January 14, 2015, 09:42:14 PM
I know it is totally unreasonable, unrealistic and possibly insane but the Churchill will look good with an AMOS twin 120mm auto-loading mortar turret, a NEMO single 120mm would also be interesting but would result in a more sci-fi look.
: Re: Churchill Tank
: apophenia January 16, 2015, 07:12:12 AM
What about removing the turret and making an Allied Wirblewind with the 4-barrelled Polsten turret? Replace the 60- round snail magazines for the Polstens with larger capacity "tombstone" boxes?

Or just take the complete turret from the Canadian Tank AA, 20 mm Quad, Skink.
: Re: Churchill Tank
: tankmodeler January 16, 2015, 12:34:31 PM
What about removing the turret and making an Allied Wirblewind with the 4-barrelled Polsten turret? Replace the 60- round snail magazines for the Polstens with larger capacity "tombstone" boxes?

Or just take the complete turret from the Canadian Tank AA, 20 mm Quad, Skink.
I suggested the Polsten turret because the Skink turret needs the 60" turret ring of the Sherman and wouldn't work with the smaller ring of the Churchill. All of the polsten turret is above the turret platform so if doesn't care about the ring diameter. But is sure would look cool!
: Re: Churchill Tank
: GTX_Admin June 13, 2015, 07:05:04 AM
Royal Iraqi Army Churchill tanks in 1957:

(https://milinme.files.wordpress.com/2013/11/churchill-b879fd5edcf6be7f_large.jpg)
(https://milinme.files.wordpress.com/2013/11/churchill-df07272233139b20_large.jpg)
: Re: Churchill Tank
: tankmodeler June 13, 2015, 09:53:00 AM
Right, at long last, my finished Australian Churchill Mk XX:

 (http://i139.photobucket.com/albums/q308/tankmodeler/top.jpg)

 (http://i139.photobucket.com/albums/q308/tankmodeler/RightF3-4.jpg)

 (http://i139.photobucket.com/albums/q308/tankmodeler/LeftF3-4.jpg)

 (http://i139.photobucket.com/albums/q308/tankmodeler/RightR3-4.jpg)

 (http://i139.photobucket.com/albums/q308/tankmodeler/LeftR3-4.jpg)


Now working on a recce vehicle based on an un-gunned STRV 103...

Paul
: Re: Churchill Tank
: Rickshaw June 13, 2015, 08:47:16 PM
Interesting.  What turret did you use?
: Re: Churchill Tank
: Volkodav June 13, 2015, 08:57:14 PM
Nice, M-24 turret?

What's the back story again?
: Re: Churchill Tank
: tankmodeler June 13, 2015, 10:38:42 PM
Back story: Imagine if the Aussies had decided to build a tank based on the Churchill instead of the Sentinel they did build. Cast hull and new turret. No shot trap in front of the driver, better shaped turret and hull, 25 pdr lengthened 10 calibres for better AT performance against weak Japanese armour while retaining the excellent HE punch of the 25 pdr for infantry support.

Scratch-built turret, though it does have an M24 look to it, to be sure. I kept the same height of the Churchill turret but moved the hatches a tad outboard to account for the larger breech of the 25 pdr. I imagined a better, shorter stroke recoil system that would have allowed the system to stay under armour and to limit the stroke to something that could stay within the Churchill's relatively limited turret ring. Better ballistic shape to the turret with a narrower front, slightly elongated nose to put the trunions a tad further forward for recoil management, a heavy, external mantlet with integral co-ax and sighting telescope with a back-up American style sight periscope. Gunner and commander on the left with loader to the right. Enough room in the ballistic shape of the rear of the turret for the radio, the good old No.19 set.

Aussie railway gauge was a bit larger than the UK one so the need to remove the air cleaners and have the narrow hull didn't exist. The Aussie designers took advantage of this to shape the hull sides better and get rid of the side doors. This provided additional stowage space for ammo and crew kit but also provided additional stowage points on the sides for blankets and tarps.

We kicked around a lot of the concept about a year ago when I started it.
: Re: Churchill Tank
: dy031101 June 14, 2015, 01:26:37 AM
Aussie railway gauge was a bit larger than the UK one so the need to remove the air cleaners and have the narrow hull didn't exist. The Aussie designers took advantage of this to shape the hull sides better and get rid of the side doors. This provided additional stowage space for ammo and crew kit but also provided additional stowage points on the sides for blankets and tarps.

Did you enlarge the turret ring, or did you just give the tank thicker side skirts?
: Re: Churchill Tank
: GTX_Admin June 14, 2015, 04:27:36 AM
Very attractive
: Re: Churchill Tank
: tankmodeler June 14, 2015, 08:30:50 AM
Did you enlarge the turret ring, or did you just give the tank thicker side skirts?
Did not enlarge the turret ring, that would have meant widening the hull. The hull sponson sides are (in the design in my head) not "thicker" but they are wider due to the wedge shape. They are the same width as the air cleaner inlets.

BTW, on the Churchill, the hull sides you see are not "skirts" (a thin metal side armour), they are the actual structural sides of the vehicle and the suspension is mounted around the circumference of those extended side panels.

Paul
: Re: Churchill Tank
: GTX_Admin June 14, 2015, 08:58:25 AM

BTW, on the Churchill, the hull sides you see are not "skirts" (a thin metal side armour), they are the actual structural sides of the vehicle and the suspension is mounted around the circumference of those extended side panels.



As shown here:

(http://img.photobucket.com/albums/v722/Panzerserra/Churchill%20Mk%20I/ChurchillMkI005.jpg)
: Re: Churchill Tank
: dy031101 June 14, 2015, 10:05:33 AM
Did not enlarge the turret ring, that would have meant widening the hull.

So it can be retrofitted to older Churchill models  >:D

BTW, on the Churchill, the hull sides you see are not "skirts" (a thin metal side armour), they are the actual structural sides of the vehicle and the suspension is mounted around the circumference of those extended side panels.

As shown here......

Totally forgot about it  ;D
: Re: Churchill Tank
: tankmodeler June 14, 2015, 11:34:29 AM
Did not enlarge the turret ring, that would have meant widening the hull.

So it can be retrofitted to older Churchill models  >:D
Yes, yes it could.
: Re: Churchill Tank
: Rickshaw October 11, 2018, 08:01:31 PM
(https://i.redd.it/ux1nw3j8do601.jpg)
Crew of an Australian A22 Churchill IV inspecting the tank on trials at Madang, Papua New Guinea, 23/8/1944
[Source (https://www.reddit.com/r/Warthunder/comments/7mmxsx/crew_of_an_australian_a22_churchill_iv_inspecting/)]

In 1943 the Australian government placed an order for six A22 Churchill tanks and three M4A2 Sherman tanks for trials to replace the A12 Matilda. Australia received two A22 Churchill mk. IV tanks as pictured (registration no. T172724B and T173033B), two A22 Churchill mk. V tanks (registration no. T173250B (named "the stork") and T173254B), one A22 Churchill mk. VI (registration no. T173279C) and one A42 Churchill VII with the registration no. T173165, which could be found in Melbourne tank museum before it was auctioned off in 2009. The Churchill tank design was preferred as it was judged to have superior armour (...six inch frontal armour tho), superior firepower, ground clearance and - get this - BETTER JUNGLE MOBILITY, PARTICULARLY IN LOW GEAR, something that OP finds hilarious. The order for 510 Churchill VII and VIII models was placed, but in the end only 45 (plus six trial vehicles) were received.

(https://s3-ap-southeast-2.amazonaws.com/awm-media/collection/082676/screen/3909016.JPG)
[Source (https://www.awm.gov.au/collection/C81758)]
MADANG, NEW GUINEA. 1944-10-12. A CHURCHILL V TANK BOGGED DOWN FOR RECOVERY DURING TESTS ...

(https://s3-ap-southeast-2.amazonaws.com/awm-media/collection/P05457.029/screen/4040966.JPG)
[Source (https://www.awm.gov.au/collection/C1196807)]
An Infantry Tank Mk IV, also known as a Churchill Mk VII. Similar vehicles are visible in the ...

(https://s3-ap-southeast-2.amazonaws.com/awm-media/collection/082732/screen/3888328.JPG)
MADANG, NEW GUINEA. 1944-10-12. A CHURCHILL V FOLLOWED BY A CHURCHILL IV TANK RETURNING TO THE TANK PARK DURING TESTS CONDUCTED AT HQ 4 ARMOURED BRIGADE


: Re: Churchill Tank
: tankmodeler October 11, 2018, 10:22:35 PM
BETTER JUNGLE MOBILITY, PARTICULARLY IN LOW GEAR, something that OP finds hilarious
The OP may have found it hilarious, but the Churchill was well known for being able to get places that Shermans, Cromwells and even Carriers could not. In low gear, as said, it could climb almost anything a human could walk up.

Paul