Author Topic: Churchill Tank  (Read 35843 times)

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #30 on: 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.

Quote
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. 



Offline Old Wombat

  • "We'll see when I've finished whether I'm showing off or simply embarrassing myself."
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Re: Churchill Tank
« Reply #31 on: 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
"This is the Captain. We have a little problem with our engine sequence, so we may experience some slight turbulence and, ah, explode."

Offline dy031101

  • Yuri Fanboy and making cute stuff practical- at least that's the plan anyway
  • Prefers Guns And Tanks Over Swords And Magic
Re: Churchill Tank
« Reply #32 on: 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??
Forget about his bow and arrows- why wait until that sparrow has done his deed when I can just bury him right now 'cause I'm sick and tired of hearing why he wants to have his way with the cock robin!?

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #33 on: 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:


Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #34 on: 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.

Quote
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]

Of course all armour penetration figures should be taken with a grain of salt when no methodology or hardness figures are provided.

Offline tankmodeler

  • Wisely picking parts of the real universe 2 ignore
Re: Churchill Tank
« Reply #35 on: 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
« Last Edit: December 01, 2013, 11:08:38 AM by tankmodeler »

Offline Volkodav

  • Counts rivits with his abacus...
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Re: Churchill Tank
« Reply #36 on: 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.

Offline dy031101

  • Yuri Fanboy and making cute stuff practical- at least that's the plan anyway
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Re: Churchill Tank
« Reply #37 on: 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?
Forget about his bow and arrows- why wait until that sparrow has done his deed when I can just bury him right now 'cause I'm sick and tired of hearing why he wants to have his way with the cock robin!?

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #38 on: 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.

Offline Volkodav

  • Counts rivits with his abacus...
  • Much older now...but procrastinating about it
Re: Churchill Tank
« Reply #39 on: 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.

Offline tankmodeler

  • Wisely picking parts of the real universe 2 ignore
Re: Churchill Tank
« Reply #40 on: 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

Offline tankmodeler

  • Wisely picking parts of the real universe 2 ignore
Re: Churchill Tank
« Reply #41 on: 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

Offline dy031101

  • Yuri Fanboy and making cute stuff practical- at least that's the plan anyway
  • Prefers Guns And Tanks Over Swords And Magic
Re: Churchill Tank
« Reply #42 on: 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"?)
Forget about his bow and arrows- why wait until that sparrow has done his deed when I can just bury him right now 'cause I'm sick and tired of hearing why he wants to have his way with the cock robin!?

Offline dy031101

  • Yuri Fanboy and making cute stuff practical- at least that's the plan anyway
  • Prefers Guns And Tanks Over Swords And Magic
Re: Churchill Tank
« Reply #43 on: December 02, 2013, 04:23:52 AM »
I mistakenly believed that I failed to save a copy on my hard drive:




I still either never knew or have forgotten who the author is though.
Forget about his bow and arrows- why wait until that sparrow has done his deed when I can just bury him right now 'cause I'm sick and tired of hearing why he wants to have his way with the cock robin!?

Offline buzzbomb

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Re: Churchill Tank
« Reply #44 on: December 02, 2013, 05:49:50 AM »
I like that.. nice and subtle.. works for me