Author Topic: Churchill Tank  (Read 88685 times)

Offline Old Wombat

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Re: Churchill Tank
« Reply #75 on: 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
"This is the Captain. We have a little problem with our engine sequence, so we may experience some slight turbulence and, ah, explode."

Offline Volkodav

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Re: Churchill Tank
« Reply #76 on: 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"

Offline Volkodav

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Re: Churchill Tank
« Reply #77 on: 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.

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #78 on: 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.

Offline Volkodav

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Re: Churchill Tank
« Reply #79 on: 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.

Offline tankmodeler

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Re: Churchill Tank
« Reply #80 on: 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

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #81 on: 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.

Quote
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.

Offline GTX_Admin

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Re: Churchill Tank
« Reply #82 on: 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.
« Last Edit: December 11, 2013, 05:15:14 PM by GTX_Admin »
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Offline Old Wombat

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Re: Churchill Tank
« Reply #83 on: 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))
« Last Edit: December 11, 2013, 05:45:36 PM by Old Wombat »
"This is the Captain. We have a little problem with our engine sequence, so we may experience some slight turbulence and, ah, explode."

Offline Volkodav

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Re: Churchill Tank
« Reply #84 on: 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

Offline GTX_Admin

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Re: Churchill Tank
« Reply #85 on: December 12, 2013, 04:23:33 AM »
All hail the God of Frustration!!!

You can't outrun Death forever.
But you can make the Bastard work for it.

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #86 on: 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.

Offline tankmodeler

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Re: Churchill Tank
« Reply #87 on: 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".

Offline tankmodeler

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Re: Churchill Tank
« Reply #88 on: December 12, 2013, 11:39:22 AM »
Quote
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

Offline Old Wombat

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Re: Churchill Tank
« Reply #89 on: 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
"This is the Captain. We have a little problem with our engine sequence, so we may experience some slight turbulence and, ah, explode."

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #90 on: 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.

Offline tankmodeler

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Re: Churchill Tank
« Reply #91 on: 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

Offline tankmodeler

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Re: Churchill Tank
« Reply #92 on: 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

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #93 on: 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.

Offline tankmodeler

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Re: Churchill Tank
« Reply #94 on: 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

Offline Volkodav

  • Counts rivits with his abacus...
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Re: Churchill Tank
« Reply #95 on: 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)

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #96 on: 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).   ;)

Offline tankmodeler

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Re: Churchill Tank
« Reply #97 on: 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

Offline Volkodav

  • Counts rivits with his abacus...
  • Much older now...but procrastinating about it
Re: Churchill Tank
« Reply #98 on: December 15, 2013, 05:19:53 PM »
 ;D loving it, keep up the great ideas

Offline Rickshaw

  • "Of course, I could be talking out of my hat"
Re: Churchill Tank
« Reply #99 on: 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...