Venomstick121
Airman 1st Class
- 291
- Dec 21, 2023
who needs a firewall when your tank is covered in stalinum
Best tank engines of WWII
- Thread starter z42
- Start date
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GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
I wonder how Packard's 3M-2500 (marine version of the above-mentioned Liberty) would have worked in an AFV?
Admiral Beez
Major
I'd want the least number of cylinders for the max amount of output. On one side we have the 370 hp 30-cylinder Chrysler A57 Multibank, used in the M4A4. On the other the (up to) 500 hp 8-cylinder Ford GAA used on the M4A3.
Shortround6
Major General
The 30 cylinder Chrysler was not designed to be the ultimate engine. It was designed to be something at could be put into tanks very quickly.
Five cast iron, flat head 6 cylinder engines ganged together. You had an engine factory that was spitting out the car engines at thousands per week vs a set of drawings and a prototype?
Yes the Ford was better engine, but it arrived late.
They built 109 M3 Grants with the Chrysler engine.
In 1941/42 when they were trying to figure out how to make wooden airplanes in case there was a shortage of aluminum, ordering thousands of aluminum tank engines might not have been high on the priority list. Took a while but it turns out the aluminum shortage didn't exist.
Five cast iron, flat head 6 cylinder engines ganged together. You had an engine factory that was spitting out the car engines at thousands per week vs a set of drawings and a prototype?
Yes the Ford was better engine, but it arrived late.
They built 109 M3 Grants with the Chrysler engine.
In 1941/42 when they were trying to figure out how to make wooden airplanes in case there was a shortage of aluminum, ordering thousands of aluminum tank engines might not have been high on the priority list. Took a while but it turns out the aluminum shortage didn't exist.
- Thread starter
- #225
A single cylinder two-stroke marine diesel then?
Or even better, a gas turbine. Zero cylinders!
Admiral Beez
Major
Or... take the Lycoming xr-7755 and design a tank around it.
www.macsmotorcitygarage.com
Lycoming's Leviathan: XR-7755, the Largest U.S. Aircraft Engine of World War II
Lycoming, supplier of engines to Auburn, Cord, and Duesenberg, has an additional claim to fame: builder of the XR7755, the largest U.S. aircraft engine of World War II. As part of E.L. Cord’s vast corporate empire, Lycoming Aircraft Engines … Continue reading →
www.macsmotorcitygarage.com
Shortround6
Major General
The thing for the British is that they ordered 100 Covenantors off the drawing board in April 1939. Which means somebody/s were already designing the engine and somebody/s had OK'd it. The British had much of 1938 and early 1939 to figure out the successor to the Liberty and this was what they went with. 
After testing in the summer of 1940, instead of be being sensible and calling up the Royal Navy on the phone telling them "Hello, we have got several hundred of these 20 ton boat anchors we would like to get rid of, Do you want any for the large number of ships you are building" The army doubled down and ordered more and more.
After testing in the summer of 1940, instead of be being sensible and calling up the Royal Navy on the phone telling them "Hello, we have got several hundred of these 20 ton boat anchors we would like to get rid of, Do you want any for the large number of ships you are building" The army doubled down and ordered more and more.
Shortround6
Major General
How many tons of armor just in the engine compartment?
- Thread starter
- #229
Where we're going, we don't need "
That chunky boy provides it's own. Shoot away a cylinder, so what there's 35 left! Heck, shoot away an entire bank of them.
ThomasP
Senior Master Sergeant
re
Agreed, although I can see a reason for at least trying to develop the Meadows DAV flat 12-cylinder. IIRC the intent was to design an engine that would allow the hull height to be kept to a minimum.
The thing for the British is that they ordered 100 Covenantors off the drawing board in April 1939. Which means somebody/s were already designing the engine and somebody/s had OK'd it. The British had much of 1938 and early 1939 to figure out the successor to the Liberty and this was what they went with.
Agreed, although I can see a reason for at least trying to develop the Meadows DAV flat 12-cylinder. IIRC the intent was to design an engine that would allow the hull height to be kept to a minimum.
- Thread starter
- #231
On a more serious note, there are of course tradeoffs. In particular, smaller cylinders enable higher rpm for a given mps. And for petrol engines, issues with flame propagation etc. And then you have balance. Some cylinder configurations provide better balance than others. In particular, I6, V12 and 90 degree V8 are all nice. Maybe less of a problem on a tank engine where you can to an extent paper over such sins with mass.
All this to say, a V12 is a very nice spot on the spectrum, and it's not without reasons it has been and still is one of the most common choices for larg(ish) engines.
Admiral Beez
Major
Could the RR Kestrel or Peregrine have made a good tank engine, akin to its larger cousin the Merlin-derived Meteor?
Shortround6
Major General
Not sure what the Liberty and the big Packard had in common?
Both V-12s.
Both used separate water jackets.
Both used overhead cams.
After that????
Different bore and stroke, Packard was a much bigger engine, but used a shorter stroke.
Different angle between the banks.
Different number of valves per cylinder.
Liberty used separate cylinders. This includes sperate cylinder heads, There was a cam box/tube connecting the cylinder heads.
Packard used once piece heads, or at least two heads per engine.
Separate cylinder barrels and water jackets but one piece heads. One cam, two rocker shafts.
Shortround6
Major General
That is part of the "crime". They "saved" 14 inches (350mm?) and about 1/2 (more more?) was by chopping the commanders copula off.
Granted is was not a good cupola but it was better than the Periscope they replaced it with.
It turns out that flat engines are never as "flat" as people think they are. All the bits and bobs that go along side or in between Vs or somewhere else had to go over or under the "flat" engine.
And then you run into things like my parents Subaru in the 1960s. Bad head gasket, You have to pull the engine out of the car to have enough room to pull a cylinder head
Interesting background to British tank development in late 1930s onwards. Couple of points to note:-
1. British Army last in queue for rearmament monies
2. How railway gauge & width affected tank development
3. Production numbers over quality was the priority in the early WW2 years.
www.iwm.org.uk
Worthwhile remembering the US M3 Stuart light tank, grew out of the 1939 M2A4 (earlier M2 versions from 1935 were armed only with MG). M3 light production began in March 1941 and it reached North Africa in July.
1939 saw the M2 Medium being developed out of the M2 light with a 37mm gun. Production of 112 in 1940. Late 1940 saw development of the M3 Lee/Grant begin, incorporating the experience of the war in Europe to that point. Production began June 1941.
1. British Army last in queue for rearmament monies
2. How railway gauge & width affected tank development
3. Production numbers over quality was the priority in the early WW2 years.
Britain's Struggle To Build Effective Tanks During The Second World War
For much of the Second World War, the British Army was saddled with a succession of tanks that ranged from the bad to the barely adequate. Some were rushed into service too quickly and proved notoriously unreliable. Others spent too long in development, or only achieved a degree of usefulness...
Worthwhile remembering the US M3 Stuart light tank, grew out of the 1939 M2A4 (earlier M2 versions from 1935 were armed only with MG). M3 light production began in March 1941 and it reached North Africa in July.
1939 saw the M2 Medium being developed out of the M2 light with a 37mm gun. Production of 112 in 1940. Late 1940 saw development of the M3 Lee/Grant begin, incorporating the experience of the war in Europe to that point. Production began June 1941.
- Thread starter
- #237
Sure, and that's certainly a significant advantage.
Just saying that if you started from a clean sheet of paper, IMHO in the vast majority of cases a V-12 would be preferable to a W-12.
That's true, but OTOH the width and height of a W-12 does have an impact as well, in how you can place stuff like auxiliaries, fuel tanks, radiators, etc.
If you compare the volume of the "bounding box" of the Lion with the Kestrel, an engine with very similar displacement but a V-12 instead of a W-12, using numbers from wikipedia one gets:
Lion: 1.460*1.067*1.105 = 1.72 m^3
Kestrel: 1.895*.620*.905 = 1.06 m^3
One can see that while the Kestrel is 44 cm longer than the Lion, it is much narrower and slightly lower as well.
- Thread starter
- #238
As has been repeatedly discussed in this and other threads, probably yes. The big benefit vs. a Merlin derivative is that the Kestrel started volume production already around 1930, so that would have given time to select it as the standard tank engine, design tanks around it and have them in service with troops by the time the war breaks out.
The problem with this scenario, as has been mentioned, is RR's unwillingness to enter the tank engine business as well as selling the rights to somebody else to produce it for that purpose. By the time their hand was forced in this matter, it made sense to base it on the Merlin as that design provided more legroom than previous ones, and the Merlin was in very large scale production, and the idea was to reuse Merlin components that didn't pass airworthiness checks
Shortround6
Major General
If somebody wants a shorter engine than the Liberty it is simple.
Don't use an engine with a stroke 2.2 mm shorter than a DB 603. Even a Merlin will save 1 in (25mm) off stroke and with the shorter rod engine height gets even shorter.
Kestrel could cut over 2in off the Liberty, may 3in.
Open the V angle to 60 degrees instead of 45 degrees, not a lot but a few mm shaved off.
A big part of the problem was the insistence of a 600hp engine for 'future' use so they would have 20hp per ton for mobility. Just in case they actually came up with a suspension and track system that would survive operating at that speed/mobility and just in case they came up with soldiers/crewmen who could survive banging around inside a tank at that speed/mobility.
Not exactly a new problem. A WW I demonstration in England for members of parliament of one of the early large tanks going up and over a simulated entrenchment at 2-3mph (and crashing 15ft of more down) resulted in a number of injuries to crew, concussions and short term loss of consciousness.
Don't use an engine with a stroke 2.2 mm shorter than a DB 603. Even a Merlin will save 1 in (25mm) off stroke and with the shorter rod engine height gets even shorter.
Kestrel could cut over 2in off the Liberty, may 3in.
Open the V angle to 60 degrees instead of 45 degrees, not a lot but a few mm shaved off.
A big part of the problem was the insistence of a 600hp engine for 'future' use so they would have 20hp per ton for mobility. Just in case they actually came up with a suspension and track system that would survive operating at that speed/mobility and just in case they came up with soldiers/crewmen who could survive banging around inside a tank at that speed/mobility.
Not exactly a new problem. A WW I demonstration in England for members of parliament of one of the early large tanks going up and over a simulated entrenchment at 2-3mph (and crashing 15ft of more down) resulted in a number of injuries to crew, concussions and short term loss of consciousness.
