Tank Design Questions never asked!

[MartinCummins]

Over the years, I have asked the following, and without success! So I've come to the fount of all knowledge, tank wise!
1)- Churchill MkV111-The rear Air Inlet Ducts for the radiators have, just below the top cowls, three horizontally placed blanking plates. These cover three openings, protected by wire mesh. What purpose-even Bovington does not know, and a MkV111 guards their entrance! As there was an overheating problem, perhaps the plates (Three for ease of handling/storage) were removed when deployed in a tropical country? Dust intake would increase though.Another hypothesis was that they could be quickly opened when Elephant Trunk wading ducts were mounted, imposing additional restriction. Sure, normally one would swipe them off with the barrel, but perhaps you wanted to use them again. Unbolting would take time, and they would be unwieldy to stow. Any takers?

2)-All British tanks using a Jack were supplied with a pair of Wood Jacking Blocks. As I have never met a tanker who ever used a jack, and the manuals never discuss the use of the blocks, why two? As the base of the Hydraulic Jack sat half on the track, a packing piece would be needed to fill the space between road and base. Perhaps, you used the second block when on bare ground, as one block would sink into the soil?

3)Many WW2 tanks had sight vanes for use of the commander, in assisting the gunner to locate an object. US tanks did not fit "Donkey Sights", so how did their commander assist the gunner?

4)-Some Cruiser Tanks had minimal silencers-The Cromwell relied on Fishtails inside hull apertures. Was it felt that track noise at speed was louder than the exhaust? The Russian T34 had exhausts into boxes in the hull! Could it be that silencers were just intended to assist the accompanying infantry behind a Churchill in communicating with each other. I understand that open areas for exhaust were potential areas for a Flame thrower attack!

5)-The Churchill and other tanks of that era had round ports cut in the rear of the turret.This was to allow a barrel change, presumably the breach being removed first via a top access and overhead gantry. This system seems to be paired up with an inside mantlet. Was the idea behind this design to allow the enlarged breach to exit rearwards, so a smaller port was needed for the turret front. There was less area of mantlet exposed to shell impact, so less chance of damaged trunnions. An external mantlet might be battered back into contact with the turret, but it probably was more rainproof, before gaiters?


Thanks for assistance,
Martin Cummins
Dunstable,
England.