Shortround6
Major General
We are getting rather far afield but tank engines are a special breed unto themselves. The weight of tank engine is not particularity important compared to an aircraft engine. However size/volume is very important to a tank engine or more correctly the size/volume of the engine installation is very important.
The Original Shermans using using Wright (or Continental built Wrights) 9 cylinder radial engines were shorter in length than the liquid cooled versions. the weight of the armor used to cover the extra length of the hull (steel is roughly 40lbs per sq ft of 1in/25.4mm thickness) can easily out weigh the difference between two different engines.
I would note that the 250hp engine referred to by Wiki was a 7 cylinder Continental radial used in the light tanks. The M2/M3/M4 were based on the 975 cu in Wright Whirlwind 9 cylinder radial and the M6 heavy tank used the 1820 cu in Wright Cyclone 9 cylinder radial but they didn't want to use B-17 (Or SBD dive bomber)engines in tanks.
You also have to figure the actual width of the available engine compartments and the ability to service the engine/s. The Grant/Sherman being designed for the radial did have a wide and high engine compartment. While the air cooled engines requires fans and ducts they were smaller than the fans/ducts and radiators needed for liquid cooled engines. Not to mention air cooled engines didn't have the coolant leak problems the liquid cooled engines did.
Need for an 800hp engine for a 35 ton tank was much more theoretical than practical. Once you have left paved roads behind the cross country ability of a tank is dependent on the suspension and the ability of the crew to survive repeated impacts against the interior of the tank.
A Demonstration of an early British tank for the King of England during WW I left a large part of the crew unconscious after about a 4mph impact. Tank went very nose high climbing an obstacle and the ensuing drop threw the crew around.
View: https://www.youtube.com/watch?v=h_0i_g2PpEU
The Original Shermans using using Wright (or Continental built Wrights) 9 cylinder radial engines were shorter in length than the liquid cooled versions. the weight of the armor used to cover the extra length of the hull (steel is roughly 40lbs per sq ft of 1in/25.4mm thickness) can easily out weigh the difference between two different engines.
I would note that the 250hp engine referred to by Wiki was a 7 cylinder Continental radial used in the light tanks. The M2/M3/M4 were based on the 975 cu in Wright Whirlwind 9 cylinder radial and the M6 heavy tank used the 1820 cu in Wright Cyclone 9 cylinder radial but they didn't want to use B-17 (Or SBD dive bomber)engines in tanks.
You also have to figure the actual width of the available engine compartments and the ability to service the engine/s. The Grant/Sherman being designed for the radial did have a wide and high engine compartment. While the air cooled engines requires fans and ducts they were smaller than the fans/ducts and radiators needed for liquid cooled engines. Not to mention air cooled engines didn't have the coolant leak problems the liquid cooled engines did.
Need for an 800hp engine for a 35 ton tank was much more theoretical than practical. Once you have left paved roads behind the cross country ability of a tank is dependent on the suspension and the ability of the crew to survive repeated impacts against the interior of the tank.
A Demonstration of an early British tank for the King of England during WW I left a large part of the crew unconscious after about a 4mph impact. Tank went very nose high climbing an obstacle and the ensuing drop threw the crew around.
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