I've always thought that the sloping armour reduces internal space argument to be a bit spurious.
If anything it can increase the available space.
Sir John Valentine Carden survives.
- Thread starter allanpcameron
- Start date
- Status
If anything it can increase the available space.
allanpcameron
Donor
Thanks.
What I found interesting when looking at this was that the 2-pdr to 6-pdr to 17-pdr OTL matches what machines were available: the 6-pdr (57mm) is old naval gun size; the 17-pdr (76.2mm) is the 3-inch AA gun size. The principle I was working back from was the Soviet T28 is already using the 76.2mm gun, which is where we could end up. One difference is that OTL 6-pdr and 17-pdr were first and foremost designed for anti-tank work without much thought given to HE rounds. What Carden was saying was if a tank isn't just for tackling other tanks, then a decent HE capability has to be thought of too.
Allan
There is an existing british gun that would fit the desire for a universal tank gun
That is the 3" 13 pounder 9 cwt gun (457 kg) - it is approx. twice the weight of the barrel and breech of the 2 pounder
IN 1918 it was firing a 12.5 pound / 5.6 kg round at 660 MPS / 2,150 FPS
Had Carden decided that not only should tanks be mugging other tanks but also capable of lobbing HE at lesser beings then this design brought kicking and screaming into the 1930s is my go to design
The only downside is that the ammo is quite larger - an 18 pounder case necked to a 13 pound shot - meaning that the tank would be carrying a lot less ammo compared to a 2 pound analogous weapon.
Size wise the gun would not that much bigger than the 3" howitzer although longer and heavier
So a gun armed tank design of this era might not look much different to the below - I imagine that the gun being longer with a longer recoil (24" in 1918 - likely shorter in the late 30s) - the turret would have to be larger or certainly longer.
With an external mantle I think it could be done.
That is the 3" 13 pounder 9 cwt gun (457 kg) - it is approx. twice the weight of the barrel and breech of the 2 pounder
IN 1918 it was firing a 12.5 pound / 5.6 kg round at 660 MPS / 2,150 FPS
Had Carden decided that not only should tanks be mugging other tanks but also capable of lobbing HE at lesser beings then this design brought kicking and screaming into the 1930s is my go to design
The only downside is that the ammo is quite larger - an 18 pounder case necked to a 13 pound shot - meaning that the tank would be carrying a lot less ammo compared to a 2 pound analogous weapon.
Size wise the gun would not that much bigger than the 3" howitzer although longer and heavier
So a gun armed tank design of this era might not look much different to the below - I imagine that the gun being longer with a longer recoil (24" in 1918 - likely shorter in the late 30s) - the turret would have to be larger or certainly longer.
With an external mantle I think it could be done.
As I understand it one of the two differing schemes is sloping armour, which increases the effectiveness of a given piece of armour. The slope requires more volume some of which translates into more interior space. This means a greater surface area which implies more weight to cover that greater are even if it is thinner due to the extra effectiveness of sloped armour.I've always thought that the sloping armour reduces internal space argument to be a bit spurious.
If anything it can increase the available space.
The opposite scheme is typified by the OTL Valentine and Matilda I where the decision was made to minimise the volume of the hull thus, for the same weight, the armour can be thicker.
However, and as ever, it is not that simple. If the armour plate is flat it may be sloped in effect if the shot comes from a shallow angle. If t is classically sloped the shot may arrive flat onto an individual plate depending upon the trajectory of the shot and the attitude of the target.
The MBT Cold War era saw the common practice of a sloping front glacis plate but a flat box hull thereafter. Modern composite and reactive armour behave differently to WW2 plate/cast armour so their lessons do not apply. One particularly notes that the T34/PzV classic sloping sides were not generally copied post WW2 despite adding extra interior volume. Sloping armour is only one of several techniques for WW2 tanks but the final design is a chosen mix of assorted compromises and available fittings in which sloping armour is but one option.
marathag
Banned
Now put in 4 crew, and areas to store large 122mm rounds and then move them to the breech. Then ammo for the machine guns, and some fuel. Not enough room on just the engine compartment.I've always thought that the sloping armour reduces internal space argument to be a bit spurious.
If anything it can increase the available space.
Extra points for ergonomics if the crew aren't required to be midgets though that was more an IS-3 issue.
The T-34 and IS-2's sloped rear plates did not waste space, because for easy access to the transmission at the far end you had to have nothing above, so it was effectively empty space in the KV-1 with the same powerpack. The IS-2 effectively removed that empty space with a sloped plate, while increasing protection and reducing the surface to armor and thus weight as a bonus.
As for stepped (very sloped middle plate with a flat superstructure next) vs single upper plate layout, it's a bit complicated because while the surface of the single sloped plate is lower than the combined surfaces of the flat plate and nearly horizontal middle plate, the single plate is likely thicker than the middle plate, and thinner than the flat plate. Add in the extra side armor to extend, and the calculation for weight is quite difficult.
But generally, going from the stepped to the single sloped plate layout improved the armor without changing weight much, and indeed a sloped plate will have a greater mass efficiency (ratio of mass of this plate to the vertical plate of equivalent effective thickness).
As for stepped (very sloped middle plate with a flat superstructure next) vs single upper plate layout, it's a bit complicated because while the surface of the single sloped plate is lower than the combined surfaces of the flat plate and nearly horizontal middle plate, the single plate is likely thicker than the middle plate, and thinner than the flat plate. Add in the extra side armor to extend, and the calculation for weight is quite difficult.
But generally, going from the stepped to the single sloped plate layout improved the armor without changing weight much, and indeed a sloped plate will have a greater mass efficiency (ratio of mass of this plate to the vertical plate of equivalent effective thickness).
Another design issue is that for decades, tank designers had the driver/hull gunner seating perfectly upright when closed down, with their feet only a few inches ahead of their knees.
This made for a higher, albeit shorter hull.
Designing the driver position so that the driver is partially reclined when closed down, with his legs more forward optimizes the sloped glacis plate of the hull and uses space more efficiently.
The M4 certainly could have had a lower hull, for example.
But ergonomics was in its infancy back then.
This made for a higher, albeit shorter hull.
Designing the driver position so that the driver is partially reclined when closed down, with his legs more forward optimizes the sloped glacis plate of the hull and uses space more efficiently.
The M4 certainly could have had a lower hull, for example.
But ergonomics was in its infancy back then.
A sloped plate can be thinner, but it's also larger in the same proportion than a vertical plate of the same frontal area. As discussed upthread, any weight advantage of a sloped plate over a stepped horizontal-and-vertical arrangement is that it reduces the area to be covered by horizontal plates - which usually aren't armoured as much, but still add some weight.
The other advantage of a sloped plate is that it is more likely to make an incoming shot glance off, rather than striking full force.
The trick of angling the sides out and then in again to get more volume on the same base was used on the A13 and Crusader turrets, so it would have been known to British designers at the time. The trouble is that while it increases volume it also increases the width at the widest point. If you're limited to a maximum total width (those loading gauges again!) a slab-sided box will give you the maximum volume.
Escapability should also be a key feature
I have seen the chieftan do the 'the tanks o fire' test on a number of tanks - some were more death traps than others.
If you realise trained crew are a limited resource you want to get them back.....
Well good ammunition handling practices help that issue immensely too. And that all comes under the heading of 'ergonomics'.
Going away from the stepped layout also simplifies production and manufacture since you only have one plate instead of 2 (or simplifies the frame for riveted armor), and one less weld to worry about. When IS-2 was redesigned as such it was found that the sloped plate was easier to get of good quality.
One problem during WW2 however was that view ports for the driver were common and periscopes less so early on, so the stepped design was necessary to keep adequate vision. That or you have a flat extension for the driver, but that complicates things.
The problem with the Crusader method is that if the plates are thick and well-sloped enough it will act as a shot trap, so you're better off having a larger turret with flatter sides if you can fit it. British turrets were cramped and the plates on Crusader were thin enough that this measure was worth taking.
My preferred interwar tank guns are development of the below naval guns, Monoblock barrels and semiauto breaches.
Interwar existing HE ammo can be use and all have a useful AT capability.
Vickers 3-pdr (1.4 kg) [1.85"/50 (47 mm)] QF Marks I and II
6-pdr / 8cwt [2.244"/40 (57 mm)] QF Marks I and II
12-pdr [3"/45 (76.2 cm)] 20cwt QF HA Marks I, II, III and IV
Interwar existing HE ammo can be use and all have a useful AT capability.
Vickers 3-pdr (1.4 kg) [1.85"/50 (47 mm)] QF Marks I and II
6-pdr / 8cwt [2.244"/40 (57 mm)] QF Marks I and II
12-pdr [3"/45 (76.2 cm)] 20cwt QF HA Marks I, II, III and IV
The best tank guns for this period would be those designed for anti-aircraft.
Quick firing, and high muzzle velocities were design features of those guns.
Recoil systems would have to be modified, and the center of balance would have to be sorted out, if barrel end heavy, by a larger breech ring, and if breech heavy by a muzzle end weight.
Quick firing, and high muzzle velocities were design features of those guns.
Recoil systems would have to be modified, and the center of balance would have to be sorted out, if barrel end heavy, by a larger breech ring, and if breech heavy by a muzzle end weight.
Given the POD the 2 pounder is already in service so the 3 pounder offers no real benefit, you'd have to go back to early 33 to change that and why bother? The 2 pounder was a very good hole puncher even up until mid war so why change it? Getting started on something like the 6 pounder 12-24 months earlier means no Dunkirk delay, even 6 months earlier and your good.
Beyond that it's up for debate. Going for a 12 pounder does make some sense, especially adapted to tank use. However it is going to be hard to keep competitive late war so needs some replacement and while it will have a better HE shell what does it offer that the 6 pounder doesn't? They effectively fill the same role so you only need one and the 6 pounder is also a very good AT gun, the 12 pounder is really too heavy. A purpose designed 3-inch tank/AT gun like the 17 pounder is going to be good for the whole war. The other option would be to go the 32 pounder route using the 3.7inch AA gun as a base but that is a bit overkill/big so maybe an 85mmish gun so 20-25 pounds? that should be golden.
I do know of the OTL QF 20 pounder but this would be something completely different.
If we review the uses of tanks by the British in WW2 we can see that 1944/5 the principal weapon used and by far the most used ammunition was the ROF QF 75mm and standard Wally ammunition for it overwhelmingly in HE. The OTL 6 Pounder was to enter production in the summer of 1940. It takes little in the way of a POD to do that a year early and not choose to keep the 2 Pounder in production and the 6 Pounder to QF75mm is only a new barrel so by 1940 the gun going into new British tanks if the ROF QF 75mm gun with good HE and capable of killing any tank on the planet. All it needs is a reliable hull to carry it around. Minimising PODs we have the OTL (yes 2 man turret with the big gun) Valentine. Job done. Keep on upgrading the engines, tracks and armour and the beastie will see you to Italy with ease and, at a pinch, to the end. Certainly while you look to a decent large Medium with a 17 Pounder with 1 loader and no hull BESA and gunner using a Meteor engine. Tiny tank, adequate armour, big gun. Keeps on working. When production allows then an Archer equivalent for the 25 Pounder and then 17 Pounder on the same hull and as a tractor for towed artillery and 17 Pounder AT. One national tank, many factories. A national lorry? CMP copy?
Really this is a minimum type reduction from the plethora of OTL. Just as the Cheetah and Merlin would do for all RAF needs for the war.
Now our infantry can get armoured fire support and mobile enemy tinned soldier protection.
Nothing complex, but nothing 'cool'.
Really this is a minimum type reduction from the plethora of OTL. Just as the Cheetah and Merlin would do for all RAF needs for the war.
Now our infantry can get armoured fire support and mobile enemy tinned soldier protection.
Nothing complex, but nothing 'cool'.
Whilst the primarily used weapon was the 75mm doesn't mean that is the weapon the British wanted to be using. The leap however of going from getting the 6 pounder a year early to then changing it to a 75mm almost immediately to get a good HE round by 1940 is a bit convoluted.
Why not just start on the 6 pounder early and design a decent enough HE round for it?
Trying to push the Valentine to Italy is a big ask let alone the end of the war. The tank was very good when developed despite the 2 man turret but really it only had limited room to grow and was a but slow. Add more armour and a bigger gun with heavier ammo and your really pushing it even with whatever larger engine you can fit into it. If you cant upgrade it enough it becomes fodder for later German tanks.
The QF75mm did what was needed, if not what crews very reasonably wanted by 1944. It was weak in AT capability but was fitted to the OTL late production Valentines and many earlier OTL Valentines were 6 Pounder armed so we can keep close to OTL. Given a slightly earlier 6 Pounder then choosing a 75mm is just a matter of choosing a larger barrel dimension and chamber from the start. It asks no more of industry than the 6 Pounder and has commonality with the French 75mm ammunition. My father was involved in transporting captured French 75mm ammunition to Egypt from Syria where it was mated with captured German AP and used in Grants in the Western Desert. There is no need to stretch the Valentine further than OTL. A Valentine national tank gives industry time to digest the lessons of actual tank warfare and prepare a design to carry the 17 Pounder in a sound hull with a Meteor engine with careful trials bringing in a better 17 Pounder Comet/Centurion as the AH Cromwell to replace the Valentine in service as the new national tank.
But I am guilty of seeing with hindsight and not Carden's period sight. The real difficulty would be the commercial and political issues of refusing to offer orders to other than the national tank and forcing that direction onto recalcitrant manufacturers. Effectively a sub contract nationalisation of the potential tank industry into one manufacturing entity.
Yes the QF75 was a good gun, i'm not denying it. It was a Weak AT gun though. I'm still taking a 6 pounder especially early war but I would want a proper HE round developed. Historically one of the biggest barriers was doctrinal rather than technical. I would be concerned about North Africa if the 75mm is the main tank weapon as at the ranges that could be found their it would be lacking, the 6 pounder much less so. Another advantage of having the 6 pounder brought forward is it shows how good AT guns can get with not much effort. It could potentially lead to changing requirements for tanks so that they can 1, Take a gun that large in a 3 man turret and 2, make an increase of armour much more attractive earlier. Think of the 1938 specification tanks, the Covenanter and Crusader, if they were built for and in mind of the 6 pounder you get a bigger heavier tank yes but one with a better gun and more armour. Put them into north Africa and your in a much better position.
As for the Valentine, if you offered it to me for the British in 1940 i'm biting your hand off. if you offered it to me in 1940 with the 3 man 2 pounder turret I bite your hand, arm and shoulder off. The problem is it really does have limited room for growth and is too slow. By the time you are into 42 it is pretty much out of contention and past that not worth it apart form as a hull for things like the Archer. The thing is though make it a bit bigger so it can take a 3 man 6 pounder turret and make it 5mph faster, 10 if you can manage it and it is perfect until late 42 and still really good until early 44.
A big problem (if not the biggest with British tanks in WW2) was their appalling reliability. It doesn’t matter how good they are if only half of them are available due to mechanical issues. Would Sir John living and continuing at Vickers have any effect on this? And if he does, how big an effect would more reliable tanks have on the British Armies performance?
Agreed, the 6 pounder was an excellent gun, and would be effective up until Overlord. (providing an HE round was provided for it)
The Valentine suffered, under-powered and with too small a turret. It was, however much more reliable than the Convenater and Crusader.
The Covenanter actually had a well shaped hull, but the totally weird engine cooling system and the much too small turret ring pretty much doomed that tank.
The Crusader was better, but still had a cramped turret, small turret ring and cooling problems.
If the original specifications actually requested a capabiity of mounting the 6 pounder gun from the beginning, instead of the 2 pounder, this would undoubtedly made for better designed tanks in the 1930's.
The Valentine suffered, under-powered and with too small a turret. It was, however much more reliable than the Convenater and Crusader.
The Covenanter actually had a well shaped hull, but the totally weird engine cooling system and the much too small turret ring pretty much doomed that tank.
The Crusader was better, but still had a cramped turret, small turret ring and cooling problems.
If the original specifications actually requested a capabiity of mounting the 6 pounder gun from the beginning, instead of the 2 pounder, this would undoubtedly made for better designed tanks in the 1930's.
- Status