Improved Early War British Tanks?

By later in the war, with 75mm HE in use in tank guns, then they could support each other and their infantry with HE fire but it is a rule of thumb that a 75mm shell is the minimum needed for effective HE fire. Hence the 75mm on the Char B.
Yet 3" and 3.7" CS
diameter was good, the propelling charge, not so much.
3.7" was 94mm, with a 20 pound shell. Its 1000fps MV, not much better than some mortars. US 75mm Pack Howitzer had an 18 pound HE shell, with 1250fps velocity.
Well liked with the M8 GMC and LVT(A)4
 
There is no radioman. The Vanguard had the same layout as the Valentine - a driver up front with a hatch on either side.
It has a two man turret - commander/loader and gunner.
I went off faulty data: actually makes it all worse; driver trapped by Z hatch escape route, TC/gunner trapped by gun recoil safety cage, loader killed when he bails out the side hatch by enemy delousing fire. it equals 100% loss of crew in an "OMG, the tank is on fire." evolution. NTG.
My mileage will vary

British army will do themselves the favor with not designing the 2pdr, and the Treasury will be satisfied.
Vickers QF 2 pounder.

Specifications:
Mass: 814 kg (1,795 lb)
Barrel length overall: 2.08 m (6 ft 10 in) L/52...bore: 2 m (6 ft 7 in) L/50
Crew: 3–5 to serve.
Shell: 40×304 mm. R
Calibre: 40 mm (1.575 in)
Breech: Semi-automatic vertical sliding-block
Recoil: Hydro-spring
Carriage: three-leg platform or tank trunnion
Elevation: -13° to +15°
Traverse: 360°
Rate of fire: 22 rounds per minute (theoretical as aimed shots depended on gunner skill.)
Muzzle velocity: 792 m/s (2,600 ft/s) with AP shot
Effective firing range: 914 m (1,000 yd)
Maximum firing range: 1000 m (1093.6 yd)[3]
Feed system: Breech-loaded
Sights: No.24b

3 pounder: Vickers;

Specifications
Mass: 1,323 lb (600 kg) in total
Barrel length: 8 ft 8 in (2.64 m) bore (50 calibres)
Shell: 47×360mmR 3.3 lb (1.50 kg) shell.
Calibre: 47 mm (1.85 in)
Breech: semi-automatic vertical block
Carriage: three-leg platform
Elevation:-5° to +12°
Traverse: 360°
Rate of fire: 20 rounds per minute (Theoretical depends on the skill of the gunner to lay on target.)
Muzzle velocity: 2,575 ft/s (785 m/s) (HE)
Effective firing range: 2,000 yd (1,829 m)(AA)
Maximum firing range: 5,600 yd (5,100 m) at 12° elevation;15,000 ft (4,600 m) (AA ceiling)
Sights: telescopic

Sources: Wiki.

Performance: (Credit: Anthony Williams)

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Source data: http://www.quarryhs.co.uk/ammotables.htm

Anthony Williams; credit. Work is not mine.

Pick a caliber and see the results.

The 3pdr Vickers is in the warehouses, so it is it's ammo. Or, make a good APC shot to the inter-war 3pdr and it will be killing German tanks in 1940. Or, make an APC shot for the ww1 vinatge 6pdr, it will still be killing German tanks. The better HE performance of the 3pdr, and even better HE performance of the 6pdr is there by default.
Or, use the new 6pdr 10cwt that is in production by mid-1930s.
Prefer a 6 pounder NAVAL gun in production. See below.

This is before we go for tank guns that use ammo of 12lb 12cwt, 13 lb or 18lb guns that is already in the warehouses, that would've make a lot of sense for late 1930s and on.
If you have HEAT and a Foresight guy, the 18 pounder is the gun of choice. Also...

So instead of 40 rounds of 4cm bore diameter Vickers shells in the very cramped Matilda 2 tanks for France 1940, we now have 30 rounds of 4.7cm HOTCHKISS (License fee to make.) shells in Matildas and in the Cruiser Mark 1s and 2s? UK Treasury will not like that one bit.
If you go back to 1919 insist that all future tank designs use a gunner and a loader who cannot be the TC. The Tank Commander can be anywhere in the tank but must not be given a gun or loading a gun to manage his sole job is to command and be the lookout. This leads to a three man turret by default, further insist that all new designs use the 6 pounder 6 cwt or bigger guns this forces a decent size turret ring. Vickers probably has a design for a three inch low velocity smoke and HE firing mountain gun in its commercial catalogue this should be redesigned to fit a bored out 6 pounder breech and barrel.
How big a tank can the British army afford? Those guys are crying in 1935 over 12-14 tonne mass machines for an expeditionary tank. Now if 20 tonnes is the standard, a 5.7cm bore diameter/L50 is the logical weapon, since the can opener is usually rated to the likely armor (4.5 cm glacis) to be faced in corresponding equivalent enemy machines (PZKWIII for example.).

Ask Ricardo to work with a commercial engine company on the design of a new series of engine capable of being built in 2, 4, 6, 8 or 12 cylinder configuration. Air cooled and must have good filtration for Imperial use. The new engine will be suitable for commercial and passenger transport vehicles in the 4 and 6 cylinder configuration. The 8 and 12 cylinder configuration is for tanks, heavy vehicles, boats and airships.
Good luck with that one. British tank engine tech watts/kgs/reliability is fair compared to German but compared to American, Japanese, Italian or Russian is kind of CRAPPY. Filters, trained mechanics, and spare parts; based on historical record is always a big problem for period British armor. Solve those and the tank engines improve enormously and CRAPPY is not a word one should see at all. Human factors and errors is the problem, not the mechanicals.
By dictating the 3 man turret and 6 pounder you force designers to build a big turret ring. The V8 or V12 engine forces a decent size engine bay.
Too much foresight. PoD would suggest incremental improvements on the WWI Liberty with maybe a slide into RR aero engine derived powerplants NET than 1939.

One of the major problems with Crusader was the hull was made so much lower than the previous cruiser designs there wasn't room for internal air intake filters so they got put on the rear track guard just where all the muck and dust is. The cooling system was also cramped and instead of running the cooling fan off the engine crankshaft it was powered by 9 feet of motorcycle chain. The chain wasn't protected from dust so it wore, stretched and slipped result tank engine blows up.
Repeat after me... raise the engine deck 15 cms move the filters under the turret rear and exhaust through the top.

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Blueprints: com, modified by McPherson (Chrysler twin-pack 8 cylinder.)
Gun wise - my opinion has been changed by this actual thread

The Czechoslovakian 47mm is the gun of choice

This had a superior AT round to the 2 pounder and had a larger HE shell - and like the BESA was ready!

Basically late 30s British tanks go Czechoslovakian for both gun and MMG (BESA) - and possibly even some Czech armour plate!
Why? Czechoslovakia is tugats (1938) and I would be looking at the USN 5.7cm/L50 (M1899) Driggs-Schroeder and Midvale Unbreakable for the plate.
 

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Why? Czechoslovakia is tugats (1938) and I would be looking at the USN 5.7cm/L50 (M1899) Driggs-Schroeder and Midvale Unbreakable for the plate.
What does that matter? They wont be making it anymore than they made the Bren or BESA

Its the design I am interested in.

The Driggs-Schroeder is as I understand it a Victorian era US version of the Hotchkiss guns all of which were deemed obsolete by WW1

The Czech weapon was a late 30s weapon and best of the 47mm weapons of that pre war period.

So 'why?' back at you ;)
 
Put Tetrarch turrets on them. You pair up the decent turret from an unreliable tank to the reliable hull of a badly under armed tank.
 
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What does that matter? They wont be making it anymore than they made the Bren or BESA.
I suppose the SKODA metallurgy is available to Vickers as well as the built up hoop gun methods and breech design is something in the Vickers tech tree?

Its the design I am interested in.
Manufacture and supply sources interest me; because while BSA can fake a BESA, an artillery piece is another magnitude order of problem.

The Driggs-Schroeder is as I understand it a Victorian era US version of the Hotchkiss guns all of which were deemed obsolete by WW1
KRUPP essentially; not Hotchkiss with a Fletcher breechblock. Also US mono-block method for the barrels. Makes for a STIFFER barrel able to handle long burn high pressure gasses well. Nice long barrel life means fewer depot level gun barrel replacements per tank. Big US mistake. BTW, the M2/M3 7.5cm/L40 tank gun was first designed in FRANCE around 1890, so it is a WW1 US copy of the Canon de 75 modèle 1897.

The Czech weapon was a late 30s weapon and best of the 47mm weapons of that pre war period.
The US weapon threw farther and hit harder with a SAPPY steel shell since it was a naval gun designed to kill (Spanish and British) destroyers.

So 'why?' back at you ;)
"As you like it."

:cool:
 
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Would it have been a good to extend the gun further foward over the driver hatches in order to make room for a larger gun? The hull already has side hatches alonside the bottom escape hatch.

 
Would it have been a good to extend the gun further foward over the driver hatches in order to make room for a larger gun? The hull already has side hatches alonside the bottom escape hatch.

OTL Churchill 75mm NA, a field mod of a Sherman M34 Mount and M3 75mm gun to a torched out opening
 
Churchill NA 75, Churchill with Sherman 75 gun and mantel.
OTL Churchill 75mm NA, a field mod of a Sherman M34 Mount and M3 75mm gun to a torched out opening
I've heard of the NAs tanks. The problem is it's still a 75mm gun.
Well what I really meant was it possible to extend the turret front enough to fit in a bigger gun without concern over the front hatches? It would seem unnessesary to even have the top hatches on the hull witht the side ones.
 
Would it have been a good to extend the gun further foward over the driver hatches in order to make room for a larger gun? The hull already has side hatches alonside the bottom escape hatch.

I've heard of the NAs tanks. The problem is it's still a 75mm gun.
Well what I really meant was it possible to extend the turret front enough to fit in a bigger gun without concern over the front hatches? It would seem unnessesary to even have the top hatches on the hull witht the side ones.
Shrug. The average crew death in a brewed up Sherman in France 1944 was something like 0.9 Americans and 1.2 British crewmembers killed. (The difference was helmets.). I have no numbers on Churchills.


So many caveats as to be worthless,

If you have the stomach for it...


The point is that the "OMG, the tank is on fire test." has real and serious consequences for crew morale for the soldiers manning those machines. In WWII, "the hook and mop boys" and the "hosers" knew through bitter experience during tank recoveries for return to service just how Murphy awful some of the allied designed tanks were to "sanitize" and what HFE disasters the machines were once they brewed up. The crews have got to have a chance. I would fundamentally suggest that overhanging a Sherman type external or projecting mantlet over and interfering with the opening operations of a Churchill's driver's or co-driver's hinged escape hatches would not be a good idea at all. In fact this might be why the British used recessed gun mantlets on some of their tank models to give clearance for driver hatches.
 
Shrug. The average crew death in a brewed up Sherman in France 1944 was something like 0.9 Americans and 1.2 British crewmembers killed. (The difference was helmets.). I have no numbers on Churchills.


So many caveats as to be worthless,

If you have the stomach for it...


The point is that the "OMG, the tank is on fire test." has real and serious consequences for crew morale for the soldiers manning those machines. In WWII, "the hook and mop boys" and the "hosers" knew through bitter experience during tank recoveries for return to service just how Murphy awful some of the allied designed tanks were to "sanitize" and what HFE disasters the machines were once they brewed up. The crews have got to have a chance. I would fundamentally suggest that overhanging a Sherman type external or projecting mantlet over and interfering with the opening operations of a Churchill's driver's or co-driver's hinged escape hatches would not be a good idea at all. In fact this might be why the British used recessed gun mantlets on some of their tank models to give clearance for driver hatches.
Well in the case of the Churchill, they top hatches weren't spring supported and required the turret to face foward for the back hatch piece to open leaving only the front piece for the crew to squeeze through. The side hatches atleast don't have to fight gravity or the turret blocking it, they driver and just crawl right through. The only scenario I can think of that would be a detriment is if the churchill was literally between a rock and a hard place.

 
Well in the case of the Churchill, they top hatches weren't spring supported and required the turret to face foward for the back hatch piece to open leaving only the front piece for the crew to squeeze through. The side hatches atleast don't have to fight gravity or the turret blocking it, they driver and just crawl right through. The only scenario I can think of that would be a detriment is if the churchill was literally between a rock and a hard place.

The driver trades a vertical Z route out of a Valentine for an S route over all that garbage I see as he earthworms his way out through the round side hatch of that Churchill and is deloused by some nut with a machine gun as he emerges.

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The Blueprints. com is the source.

Weren't the Crocodiles the round side hatch Churchills?
 
Round escape hatches on all Churchills from I think Mk VII onwards. Less stress points than the square hatches. As an aside, I believe one of the reasons the RE liked Churchills was because of ease of access through these hatches to carry out demo work, etc. (Though possibly not in an "OMG the tank is on fire" scenario?)
 
Crew deaths in British tank units were invariably outside the tank not in it - and often caused by indirect fire or when they thought they were safe - often making a brew

Indeed later British AFVs to this day have the ubiquitous boiling vessel installed to reduce the amount of time spent outside for this very reason.

Helmets again seemed to be a fashion choice - need to knock that on the head (honestly no pun intended) as early as possible.

On hatch designs - for some reason the memo to British industry regarding 'please can we have better hatches' kept getting lost - its not like there was a lack of experience in AFV combat yet we see the Cromwell and Comet both with relatively poor hatches until we get to the Cent.

I once many years ago at a Bovingonton Tank Fest tried to get out of a Sherman ASAP from the Gunners position - my mate being in the Commanders seat - it took him long enough to get out - I think it took me about 40 seconds in total as I had to wait for him to clear the Commanders position

And that is with a good hatch.

And I still have no idea how they were able to see anything from inside and still fight effectively - the TC would have had to have fought unbuttoned.

On internal Mantle - this was a throwback to the doctrine of balancing the gun and the first Churchill had the same 2 pounder setups and then 6 pounder setups and the hatches were probably fine.

The answer here is better hatches.

And as for getting hosed when abandoning a given AFV that's situational and not related to the hatch!
 
The crews have got to have a chance. I would fundamentally suggest that overhanging a Sherman type external or projecting mantlet over and interfering with the opening operations of a Churchill's driver's or co-driver's hinged escape hatches would not be a good idea at all. In fact this might be why the British used recessed gun mantlets on some of their tank models to give clearance for driver hatches.
Agreed on crew safety. Tanks aren't cheap to build, but manpower and experience is truly precious. What about a belly hatch, as in, an emergency exit in the tank floor? I've found a diagram of the one on the Sherman...



...and it seems like it could be a workable solution for some of the heftier British tanks. I'm not sure about the Val (possibly in the very middle, allowing one of the three turret members to go out the bottom whilst the others go out the top? Ideally no crewmember should ever be over the hatch in case of a mine, but it should be nearby, and a quick glance at Wiki mentions an underside escape hatch for the driver already), but it should be able to fit into some of the heftier tanks like the Churchill and probably the Cromwell, too. I also found out about this useful little feature:

The Shermans escape hatch was located just behind the 1-inch thick armor under the driver and BOG, where it was only half an inch thick. Far enough back there was not much of a chance of the crew being seen as they exit. The hatch was not used for just escape, I’ve read many accounts of the hatch being used to rescue wounded and or just pinned down men under heavy machine gun fire. The men would be told to lay still, and the tank would be directed onto them by the infantry in the area, in some cases one of them riding in the tank and when close the man on the ground would make sure the tank was going to straddle him and then waited to be run over. Once the tank was over the man, the escape hatch was dropped, the man pulled in and the tank would back out. This could be repeated as needed in the Pacific since in many cases the Japanese had nothing that could take on the Sherman locally.
I'm sure the infantry wouldn't be very happy about having to lie down whilst one of their own tanks drives ontop of them, though :p
 
Well in the case of the Churchill, they top hatches weren't spring supported and required the turret to face foward for the back hatch piece to open leaving only the front piece for the crew to squeeze through.
Real case for a 'lift and rotate' hatch, with lower profile periscopes
 
Crew deaths in British tank units were invariably outside the tank not in it - and often caused by indirect fire or when they thought they were safe - often making a brew
1. 21st army group and 12 army group battle deaths, among Sherman crews NW France 1944, loss of tank due to mine, artillery burst or "other". Crew killed outside of tank was "Outside of tank". About 6000 Shermans US and 2500 Shermans UK hit was the total data sets. Averages were medical data harvested by injury type.

Indeed later British AFVs to this day have the ubiquitous boiling vessel installed to reduce the amount of time spent outside for this very reason.
2. Tanks, like infantry, should not be exposed to unnecessary fire without due good reason.

Helmets again seemed to be a fashion choice - need to knock that on the head (honestly no pun intended) as early as possible.
3. If even the Russians know that head injury is the most common incapacitant after a tank is subjected to kinetic shock that renders human crew befuddlement and failure to bail out and thus death as the tank burns out, then it is only common sense to wear a helmet. Berets and cowboy hats are for parade. Ditto SPURS.

On hatch designs - for some reason the memo to British industry regarding 'please can we have better hatches' kept getting lost - its not like there was a lack of experience in AFV combat yet we see the Cromwell and Comet both with relatively poor hatches until we get to the Cent.
I once many years ago at a Bovingonton Tank Fest tried to get out of a Sherman ASAP from the Gunners position - my mate being in the Commanders seat - it took him long enough to get out - I think it took me about 40 seconds in total as I had to wait for him to clear the Commanders position
4a. Arms first, pull up on anything to hand. Drop seat if not in down position. Pop hatch if not open. Stand on seat. JUMP UP. Clear. 5 seconds. Tank gunner twists orients and clears his position using anything to hand to crawl into commander position. Then same as commander. Time him at no more than 15 seconds. Escape drills are part of crew training (USMC.). Fire is a great incentive.

And that is with a good hatch.
5. Requires practice.

And I still have no idea how they were able to see anything from inside and still fight effectively - the TC would have had to have fought unbuttoned.
Stick your head up Terry Tanker, to see what's happening and watch out for low planes, low wires, infantry snipers, and that tree branch that has your name on it.
On internal Mantle - this was a throwback to the doctrine of balancing the gun and the first Churchill had the same 2 pounder setups and then 6 pounder setups and the hatches were probably fine.
6. My comment was speculation, but I am aware of "shoulder stabilization" for the 4.0cm/L60 and then 5.7cm/L60 which may have been British practice, but which was NUTS, when fine control for Arty work from the tank needed to be laid in. Mechanical repeatable lay is the only way in direct fire with HE, no matter the gun "balance" at the trunnion pivots.

OMGTTIOF.

The answer here is better hatches.
Better escape routes.

And as for getting hosed when abandoning a given AFV that's situational and not related to the hatch!
Consider how long it takes to train a competent tank crew. Now if you are Mister Enemy and that crew is bailing out of their burning tank; "One wounded carried by four buddies." no longer applies. It is "Kill the pilots; so they don't come back at you with lessons learned and passed on to others." Aimed fire at the tank to delouse it, is almost expected.
 
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