Best tank engines of WWII

[marathag]

The army also didn't want two different types the same vehicle doing the same job.

They had that in spades already

The Wright powered M4 and M4A1, the Diesel M4A2 , Ford V8 M4A3 all did the same job, and that's leaving out the M4A4 for lend lease

Then the mix of 75mm, 76mm and 105mm armament in a variety of different turrets.

 

[WARSPITER]

Still all on Sherman chassis is the point though. Production, parts, and especially maintenance knowledge not a problem.

The non use of the T-23 etc allowed more time to build a bigger and better vehicle.

 

[Shortround6]

Sort of like the M7 Light tank.
Supposed to be an improved M3/M5 light tank but by the time they got done "improving" it wound up weighing over 25 tons and then a few errors in casting thickness added add a few more tons to the weight.

Since in used the same engine as the M4, the same gun and since it was only a few ton lighter and wasn't any faster, they canceled the order for 3000 from International Harvester.
International Harvester had nothing to do with the design. That was all Army ordnance, IH just got picked to produce it.

 

[ThomasP]

The new light tank to go with the new medium tank M26?

 

[marathag]

Since in used the same engine as the M4, the same gun and since it was only a few ton lighter and wasn't any faster, they canceled the order for 3000 from International Harvester.

missed opportunity, really.

Was a Sherman, yep, pretty much.

with the casting errors, was about as well armored as a Sherman, but lower profile/smaller target.

But the big miss was in servicing

Quick change for both engine and differential

slide out on rails.

The M18 Hellcat used the idea for its Wright radial

 

[WARSPITER]

The Sherman had a couple of good reasons for continuing in production rather than changing to what would be a similar tank.

First, it was already in production. This is important as spares and maintenance knowledge were all there and going.
The Sherman was much easier than other tanks to maintain already.

Second, it was already in production. Around 45 per day produced and sent out. Very few issues (if any) mechanically
and easy to ship. Also important as they had to get to conflict areas that way. It was not seen as a good idea to stop
production for any period to change over to another vehicle that would essentially be given the same tasks.

 

[swampyankee]

The Sherman had a couple of good reasons for continuing in production rather than changing to what would be a similar tank.

First, it was already in production. This is important as spares and maintenance knowledge were all there and going.
The Sherman was much easier than other tanks to maintain already.

Second, it was already in production. Around 45 per day produced and sent out. Very few issues (if any) mechanically
and easy to ship. Also important as they had to get to conflict areas that way. It was not seen as a good idea to stop
production for any period to change over to another vehicle that would essentially be given the same tasks.

There was also one bad reason: internal, i.e., uniformed, politics within the US Army.

 

[WARSPITER]

There was also one bad reason: internal, i.e., uniformed, politics within the US Army.

That was an unfortunate case in many countries. In Britain the cavalry still held sway in the thirties even after exercises
involving tanks clearly showed the ascendancy of the vehicle over the horse. British armour suffered for this in the war.

The US situation was not as drastic as what happened in Britain, thankfully.

Germany was able to grab a lead in tank and aircraft use as they were rebuilding from scratch.

 

[marathag]

The Sherman had a couple of good reasons for continuing in production rather than changing to what would be a similar tank.

Not saying M4 production had to end. The US had enough production capability to do more than one type, and able to do logistics for more than one type.
Army was able to keep diesel powered M10 TDs in supply in an otherwise sea of gasoline powered engines in the MTO and ETO

Sherman wasn't perfect. T23 wouldn't be perfect, either.

But would have advantages in some areas where the M4 was lacking, and would have some commonality in major subsystems, like powerplant, turret, and so on.

 

[WARSPITER]

As I posted earlier, the T23 certainly wasn't wasted as a project.

HVSS suspension and the larger turret to house the 76mm are two of the main advances which were transferred to the Sherman
as it didn't mean any major changes to production.

The rest of the project lead to the T26 series which was also a bonus in the long run.

It has to be remembered that the 4th armoured didn't even want the 76 as they preferred the 75 anyway. 85% of the Shermans
ammunition use was high explosive which saved a lot of infantry casualties. There wasn't much need to change that.

 

[Geoffrey Sinclair]

I have not seen this explicitly mentioned but apart from powerful enough engines, strong enough suspensions and maximum rail load widths the allies had a fourth limit on vehicle sizes. That being the height, width, length and weight limits for vehicles loaded onto the thousands of LCT and hundreds of LST. No point making vehicles that exceeded these limits until the allies had working continental ports, and the size of LST had to be fixed early if the allies wanted lots. Given the changes in AFV vehicles, unit organisation and doctrine not that surprising there were multiple LCT versions. As well as the individual vehicles amphibious assault requires delivering units to the same place and time, the more shipping/ships a unit required the harder the delivery task became.

 

[EwenS]

Further to Geoffrey's post, there was another shipping issue - the capacity of the cargo handling booms on the cargo ships that carried the tanks from the USA to the operational theatres.

For example while a Liberty ship had 10 cargo handling booms, 7 of these were rated at 5 tons safe working load, one at 15 tons, one at 30 tons and the last at 50 tons. Accordingly the built 8 of a specialised tank carrier version which had 4 holds instead of 5, larger deck hatches & 6x30 ton, 6x15 ton & 2x 5ton booms. So they were dependent to a large extent on the port facilities at the ports they visited or floating cranes of sufficient capacity being available.

Britain built a class of 10 heavy lift ships with 3x120 ton booms to move tanks, landing craft and railway rolling stock around the world.

 

[hobbes154]

Edit: I skimmed my old AFV Profiles for Cromwell, Churchill and Crusader and width doesn't come up - they don't go into great detail into the design process admittedly. But then there's that book quoted in Wiki saying "The British railway loading gauge required that the width should not exceed 10 ft 8 in (3.25 m) and the optimum width was 10 ft 3 in (3.12 m),[15]" So ?

I was wrong, the Churchill one does say:

Original restriction to within British rail loading gauge limits
was one of the factors which later prohibited the fitting of the
17 pdr. gun to the Churchill, which was too narrow to take a
large turret. Engine intake louvres were removable for rail
transportation. (p.12)​

Width: 10ft. 8 in. (9 ft. 2 in. without side air louvres). (p.19)​

Edit: Rereading others still can't find rail explicitly but see attachment on Cromwell. British didn't see any need for gun bigger than 2-pdr until 1940 and Jan 1941 spec wanted 6-pdr in 5' turret ring. (Then by late '41 they wanted something even bigger which led to Challenger & Comet.)

Also interesting that Cromwell and Comet were practically the same overall width 10'0 and 10'1 but "over tracks" 9'3.75 vs 9'10.25. Track width 14" vs 18" which accounts (x2) for the entire increase in width over tracks: "the increased turret ring diameter ... was achieved without adding a wider centre section to the hull". (p.35)

My conclusions from that are:
1. they weren't putting the biggest possible turret ring on Cromwell given its width
2. they weren't trying very hard to keep the Cromwell's width down
3. with thinner armour or higher ground pressure on the Comet it could have been no wider over tracks than Cromwell.

Pics (Churchill/Cromwell/Comet) don't show anything like the Churchill's air louvres on Cromwell but does look like the mudguards have a bit of extra clearance outside tracks compared to Comet. Presumably you could take them off for rail travel?


So this points to the loading gauge being more of a constraint on Churchill than Cromwell. I guess this makes sense since it's an older specification (Sep 1939), and infantry tanks are maybe more dependent on rail then cruiser tanks.

 

[ThomasP]

Just for a visual reference.

Churchill Mk VII on a flat car with side air louvres removed.

Note that the Mk VII incorporated thicker armour on front and sides, the additional side armour increased the overall width to 10'11" (9' 5" with the side air louvres removed.

 

[GrauGeist]

In order to transport the Tiger I by rail, transport tracks were installed and the mudguards removed, so I imagine the British did something similar.

 

[Shortround6]

In order to transport the Tiger I by rail, transport tracks were installed and the mudguards removed, so I imagine the British did something similar.

They also removed the outer row of road wheels

Combat track was laid out under the tank.
Most or all British tanks didn't have road wheels that were that 'modular'.

Google "Tiger tank rail transport"

 

[marathag]

US Railcars somewhere in the ETO

Probably 50' 70 ton capacity flatcars
Note duckbill extenders on the Shermans

and E8 with the wider track

and in the USA

 

[SaparotRob]

The Stuart is my favorite. Anyone remember the DC Comics' "Haunted Tank"?

 

[z42]

They also removed the outer row of road wheels
View attachment 762644
Combat track was laid out under the tank.
Most or all British tanks didn't have road wheels that were that 'modular'.

Google "Tiger tank rail transport"

Perhaps more accurately stated as British tanks didn't commit the mistake of interleaved road wheels, so there were no outer road wheels that could be removed.

 

[PStickney]

The army also didn't want two different types the same vehicle doing the same job.

This turned out to be a correct decision. The T23 cast turret for the 76mm gun was used as the basis for 76mm
gunned Shermans as the original turret was unsatisfactory.

Work with the T-23 evolved into the T-25 and T-26 which became the Pershing. This was then upgraded to become
the Patton.

Yes - the T23 turret was basically a drop-in replacement for the original Sherman turret. It must be noted that even before the original Shermans were deployed to North Africa, fitting the 3" High Velocity Gun (The same as the M10 Tank destroyer) was already well under way. The problem was, that while they could wedge it in, Armored Force concluded that, while teh gun performance was fine, there was no way to effectively us it in that turret. So - it was back to the drawing board, and the process was slowed by the emphasis on T23. But it paid off, and by early 1944, all further Sherman production was to be 76mm Gun armed. (Other than the 105mm Howitzer armed Assault Guns)