Best tank engines of WWII

z42 said:

With the transmission in the front, the driver can be equipped with a hammer to give the transmission a whack if it's misbehaving!

Click to expand...

Which is why, back in the '80s, we got the Sherman (M4A1E8), instead of the T34 (T34/85, Fresh out of Polish Army Reserve Stock. The Russian Stuff - Simple, in its way, and, as you note, you can fix it with a rock. But you need a lot of rocks.

z42 said:

Indeed, this is often explained as the reason for the Merkava series layout. But there must be some significant downsides to this arrangement considering that nobody else has adopted it? (Except for IFV's where something like that is common)

Click to expand...

Merkeva was born out of the experience of the 1973 Yom Kippur War against Egypt & Syria. Out of 2,500 Israeli Army dead, nearly 1,500 came from the Armoured Corps. That included many experienced reservists and severely weakened the Corps with the threat still remaining. So existing armour was extensively modified to make it more survivable.

But for the new tank "...the vehicle would have to be capable of withstanding an enormous amount of punishment without endangering the crew's lives. Since crew protection was the over-riding concern, every aspect of the tank had to adapt to this demand; firepower would have to come second and mobility, third. In addition, the tank would have to be large enough, and sufficiently comfortable, to accomodate a four man crew through long hours of operational duty, and eventually combat............. The primary concept was to make every part of the tank play its part in the crew's protection"

Merkeva was designed after studying Leopard, AMX-30, Chieftain & XM-1 as well as the T-72.

The main sacrifice seems to have been speed. Probably less important when fighting around the rocky Golan Heights than the plains of Europe. Arab-Israeli tank battles were fought at much closer ranges than were envisaged by NATO so less needd to move quickly around the battlefield. Firepower saw the 105mm gun selected (120mm in later versions) but with more ammunition than in many tanks (again borne out of experience when tanks ran out of ammunition in 1973 and had to withdraw from the fight)

New Vanguard 21 Merkeva Main Battle Tank 1977-1996

As with so many other pieces of equipment you can't have everything in the Protection/Mobility/Armament equation. What you choose of this mix is driven by the kind of war that you expect to fight. The Golan Heights isn't the northern plains of Germany.

z42 said:

With the transmission in the front, the driver can be equipped with a hammer to give the transmission a whack if it's misbehaving!

Click to expand...

The German and US Tanks with front differentials were built well enough that it was unnecessary to use 'Percussive Maintenance'

British stuff worked well enough, but they typically went with more expensive pre-selector gearboxes. Shifting was easy.
Soviets?
Long shift rods that worked with the strength of the Mighty Arm of the Soviet Fighting Man. Sometimes aided by the more than symbolic Soviet Hammer. Gearbox wasn't synchronized, so took more skill with shifting gears, even without the long separation between the shifter and transmission

You can make a very compact drive section by having everything in the front or the rear, but that make servicing more difficult, and in the T-34 example, even operation. Note this wasn't a problem with the KV or later IS tanks

A lot of times many countries used legacy engineering.
US built a small quantity of these.

And in prototype form it used the same bogies and wheels as the M2 LIght tank, just with 3 bogies instead of 2 and just made the tracks longer. Needed new engine and transmission but they used a similar but larger layout. Tracks may have changed.
Then they came up with the T-20 series of tanks to replace the M-4 (decedent of the M-2) the US kept the same basic suspension, hull layout, and drive line layout (although the parts changed) from the M-26 Medium of 1944/45 to the M-60A3s of the early 1980s, almost 40 years of production, granted you can't make an M-60 out of a M-26 but you can trace the evolution.

Manufacturing materials and facilities were expensive and time consuming to change so it was easier to go with
engine / transmission / steering etc configurations that were already in use. Although different engines and transmissions
went into later designs they ended to go in the same hill placings because that was easier.

There were also clashes when it came to what was the best way to go and that at times depended on who made the decisions.
German interleaved suspensions are an example.

Germany in particular had a real problem with fuel - especially after the initial failure to take the Soviet Union out of the war.
The amount of fuel expended was exacerbated due to the Army using so much petrol which put pressure on the Luftwaffe
for the rest of the war.