WW2 Tanks

[5MadFarmers]

Wrote a paper covering it. Read it if interested.

Tanks for the memories (http://5madfarmers.com/tankpaper/FarmersNotesWW2Tanks.pdf)

[jgaynor]

Wrote a paper covering it. Read it if interested.

Tanks for the memories (http://5madfarmers.com/tankpaper/FarmersNotesWW2Tanks.pdf)

Interesting paper! Thanks for sharing. My dad commanded a company of anti-tank guns in the Hurtgen Forest and in Luxembourg during the Bulge - so i was very interested:icon_salut:

[5MadFarmers]

Interesting paper! Thanks for sharing. My dad commanded a company of anti-tank guns in the Hurtgen Forest and in Luxembourg during the Bulge - so i was very interested:icon_salut:

Brutal place. The idea was right but, once it became clear it wasn't working as intended, they should have stopped instead of just piling on in hoping it would succeed. From Strasbourg they could have walked up the left bank of the Rhine as it's nice territory for an advance. The river is a barrier to the Germans as well.... Force a quick crossing between Karlsruhe and Mannheim and it's off the the races. That would have meant more forces in the 6th AG instead of 12th AG though and that wasn't likely.

[PhillipM]

Minor nit. In the engine section you omitted that the M4A2 GM engine is a diesel two stroke with a blower, which while technically a supercharger, really existed to blow out exhaust gasses from the combustion chamber rather than add positive pressure.

Overall, very well done!

[5MadFarmers]

Minor nit. In the engine section you omitted that the M4A2 GM engine is a diesel two stroke with a blower, which while technically a supercharger, really existed to blow out exhaust gasses from the combustion chamber rather than add positive pressure.

Overall, very well done!

I'll update it for version two.

The M4A6 took 45 octane diesel but that GM took 50. Produced max torque at a slightly higher RPM. Weird.

Thanks for pointing that out.

[PhillipM]

I'll update it for version two.

The M4A6 took 45 octane diesel but that GM took 50. Produced max torque at a slightly higher RPM. Weird.

Thanks for pointing that out.

Its not weird, just the nature of the beast. The Cat engine is 4 stroke cycle, while the GM is 2 stroke cycle. This means the 4 stroke engine fires once every 720 degrees of crankshaft rotation, while the 2 stroke fires every 360 degrees. I can't remember the physics of it, but the 4 stroke is known for better low speed torque, while the 2 stroke is a high speed horsepower engine, common in older outboards, weed eaters, chainsaws , and the like. GM made the 6-71 into the 80's. Hot rods commonly use the blower as a supercharger on gas engines, thats the big housing sticking out of the hood.

Diesel is not measured in octane, but in cetane. The higher the cetane number, the faster it burns, so it makes sense the higher rpm GM needs to burn the fuel faster.

Cetane explained video

https://youtu.be/cPfow6luNjc

[5MadFarmers]

Updated. Thanks, that was an improvement.

[dave]

I worked wit a guy who was a tank crewman in 3rd. Army. He said they had two caddy engines with hydromantic Xmissions. True? or did such a thing not exist?

[5MadFarmers]

I worked wit a guy who was a tank crewman in 3rd. Army. He said they had two caddy engines with hydromantic Xmissions. True? or did such a thing not exist?

One of my favorite tanks! If I could have any tank privately that'd be it.

Most countries tended to use armored cars for scouting duties. The U.S. had the M3 and M5 lights but both kind of sucked. Then came the M24. The bee's knees of light tanks. That begat the Walker Bulldog but I want the M24.

Engine: Cadillac, Series 42
Type: Dual, V-8, L.C.
No. of cylinders: 16
Fuel (gasoline): 80 octane
Max. governed speed: 4,000 rpm
Net hp: 220 at 3,400 rpm
Max torque: 488lb ft at 1,200 rpm
Transmission, type. Hydra-Matic with transfer unit and synchronizer.

8 forward gears and 4 reverse.

Early in the Pacific war they wanted to give the B-25 some pop. Paul "Pappy" Gunn, an appropriate name if there ever was one, started playing with the B-25s. Initially it was putting a lot of .50 MGs on them but they wanted more pop for hitting Japanese ships. A light-weight 75mm cannon was developed and that was installed on B-25s for that. As they'd developed the light 75mm gun for that airplane, it was a natural for light tanks. The M24 received it.

If you ever watched that old "Battle of the Bulge" movie, the tank Telly Savalas is on is the M24.

38271

[dave]

He also said that the heavy German tanks had to stick to the roads while the Sherman could go off into fields and such where the heavies would bog down. And he talked about the electric turret's on the Sherman's while the Germans were hand cranked ?? He thought the Sherman's were overall better suited for what they did. Also said they were told never start one engine with the other (as you would push a car) but in combat if one would not start, they did it all the time! He may have been there late in the war, always talked about Germany, never France, etc. that I remember. And of course there seemed to be an unending supply of Sherman's, and they had to be shipped overseas.
Oh yeh, Bargain Basement, Telly the 'ol wheeler dealer!

[5MadFarmers]

He also said that the heavy German tanks had to stick to the roads while the Sherman could go off into fields and such where the heavies would bog down.

Total weight of tank on total area of track = ground pressure. The less the ground pressure the more "floatation" the tank had. Wider tracks provide better floatation in mud and snow.
M3 Medium: 13.3lbs
M4 Medium: 13.4-14.2lbs
M26 Medium: 12.7lbs
M5 Light: 12.5lbs
M24 Light: 10.7lbs

The M24 had awesome floatation.

Mark IV: 11lbs
Mark V: 12.5lbs
Mark VI: 15.6lbs
Mark VIB: 13.2lbs

Tiger was higher. Tiger II not bad as it had a longer and wider track. Modern M1A2 is at 15.4lbs. M24 could swim away from any....


And he talked about the electric turret's on the Sherman's while the Germans were hand cranked ??

Yup. Additionally the Sherman had a gyrostabilizer and could thus shoot on the move. The Panther received a nitrogen "stabilizer" but it wasn't a gyrostabilizer. Mark IV had electric turret but late models lost it due to cost and such.


He thought the Sherman's were overall better suited for what they did.

Point of the paper. The M4 is still used in places. Panthers, captured in huge numbers, were discarded. The Russians saved the Mark IVs but not the heavier German stuff as, their reports were clear, it wasn't worth using as it wasn't reliable.

[psteinmayer]

Speaking about the tank engines, I actually prefer the M4 with the Continental R975 Radial engine. Sorry, I have a thing for huge thumpin radial engines!