Radial engines favored for powering the tanks & AFVs, 1935-45

Basically, only the Americans used them, and, despite the engines not being the bestest of the lot, they still gave a good service.
So - premise of the thread is that radial engines are favored also by the other tank-manufacturing countries. Be these with 5, 7, or 9 cylinders, 1-row types (doh). What advantages and disadvantages could be expected vs. the historical engines used? What type of military vehicle will be better off, whet will be worse off?

The Jagdtiger will be really tall?

SaparotRob said:

The Jagdtiger will be really tall?

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How comes?

The Sherman is tall because of its radial engine design, or so I've read. If the Jaagdtiger is being redesigned for a radial engine, wouldn't it have to have a taller engine bay? Or are we keeping it underpowered?

The Tiger II/Jagdtiger hull is already fairly tall, at 7' 2.6" from the bottom of the track to the top of the engine deck plate. The hull is 5' 4.6" deep from the top of the engine deck plate to the bottom of the hull belly plate.

The Sherman hull is 6' 4"(?) from the bottom of the track to the top of the engine deck plate just behind the turret. The hull is 4'11" deep from the top of the engine deck plate just behind the turret to the bottom of the belly plate.

What would be the diameter of a radial for the Tiger II/Jagdtiger?

SaparotRob said:

The Sherman is tall because of its radial engine design, or so I've read.

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We can take a look at the M18 tank destroyer, too. It used the same radial engine as the Sherman, but it was much lower because the transfer of the engine power 1st went through the 'intermediate' gearbox that made possible lowering of the prop shaft, that in return allowed for the turret to be set lower.
See here the Sherman prop shaft; same layout was at M3 medium and M3 light tanks. Unfortunately, my Google-fu is weak today so I cant find a good cutaway of the M18.

SaparotRob said:

If the Jaagdtiger is being redesigned for a radial engine, wouldn't it have to have a taller engine bay? Or are we keeping it underpowered?

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As noted by Thomas above, the Jagdtiger was already a very tall AFV.
It will need something like a 1400+ cu in engine - talk a BMW 132 that received the short-stroke treatment?

ThomasP said:

What would be the diameter of a radial for the Tiger II/Jagdtiger?

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50+ inches; in-between the 45in R-975 and the 55in R-1820 from the M6 heavy tank?

tomo pauk said:

...

As noted by Thomas above, the Jagdtiger was already a very tall AFV....

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I meant to write that "wouldn't the tank have to be even taller?", which you answered.

A decent idea, if your industry can supply decent aircraft radials at the same time as they can supply the needed aircraft engines.
Why did the US figure out the
Medium M3A1 28 were experimentally converted with the Guiberson T-1400-2 350 hp radial diesel engine,
Medium M3A3 Twin GM 6-71 diesel engines coupled together to make the GM6046 powerpack.
Medium M3A4 Stretched riveted hull to accommodate the Chrysler A57 multibank engine, made up of five 4.12 liter displacement, 6-cyl L-head car engines (block upwards) mated to a common crankshaft.
Note this was before the M4 Medium showed up which added several more engine choices.
Also note that the M3 light tank series switched to twin Cadillac V-8s by 1943 and kept them for the M-24 light tank.

Again note the the US radials were being used in trainer/light transport aircraft and even the US could not afford to keep using "aircraft" engines in tanks.