Governors on shermans

IA seems to have improved in this area:

M4a3:
https://archive.org/details/TM9-759

M4a4:
https://archive.org/details/TM9-754

M3/M4 Diffs:
https://archive.org/details/TM9-1750

Guiberson:
https://archive.org/details/TM9-1750E

GM Twin:
https://archive.org/details/TM9-1750G

A4 accessories:
https://archive.org/details/TM9-1750G

Etc. etc. etc.
Get digging... if you're quite bored.

 

Damn it Adam, I'm supposed to be working and you are giving me all of this great stuff to read.

I did find a ref to governors on the diesel radial, which is the only one I looked at so far. I'll paste the link since it is pdf and I can't paste the passage

https://archive.org/stream/TM9-1750E#page/n169/mode/2up


Edit:

Here is the one on the Ford. Makes sense since it was based on the V-12 Henry designed for airplane use

https://archive.org/stream/TM9-759#page/n49/mode/2up

 

Damn you guys are good.

I was going to give up due to governors not being sexy enough to include in books much less the internet.

 

Give all the credit to Von Poop. He is the resident Shermaholic

 

Stop it now.
What this is mostly making me realise, Dave, is that I'm completely rusty.
Might have been a time I'd have read the right passage at some point in the previous month. Not any more though.
Hoping others with fresher knowledge will chip in.

I was thinking about the aero engines.
Does something that converts a screaming radial down to more earth-bound use really qualify as a limiter?
Maybe better described as a stop-things-melting-exploding-cracking-or-bursting-into-flames-er. Perhaps best not messed with by the knowlessman.

 

Actually, that's not true. Patton forbade sandbag armor, but instituted a program in the Third Army to weld salvaged armor plates from wrecked M4s as well as Panthers onto medium tanks and coat them in cement. This was believed to be of real benefit to the survival of the tanks against Panzerfauste rounds as opposed to sandbags piled in logs, which were considered to be merely psychological comfort blankets by Patton's technical advisers. I am pretty sure the relevant passages are in Hunnicut and/or Zaloga's various books on the subject. I think there was a photograph of Patton who were walking away from a 11th AD tank with the said improvised sandbag/log armor looking very angry.

 

As pointed out, the Ford GAA used on the M4 did indeed have a governor. Per the TM9-759 section on tachometers, it gives us some details:

"Tachometer:
The maximum speed of the engine is governed by a flyball type governor located at the rear of the right hand cylinder head. This governor is set to limit the engine speed to 2650 rpm under full load
with wide open throttle (10-inch vacuum). If during operation under full load it is possible to run the engine at speeds above 2650 rpm, or if the governor limits the speed at some point below 2650
rpm, the ordnance maintenance personnel will be notified. If the governor is set too low it will be impossible to get maximum speed and power from the vehicle; on the other hand if the governor is set
too high, damage to the engine and other working parts could result."

In my interviews with M4 and M5 drivers of the 781st Tank Battalion; wiring the governor was one of the first things that troops did once they were deployed. The Shermans were routinely run overspeed until the valves floated with no problems.

The additional weight of the sandbags/cement/steel did overtax the suspension and caused rapid wear of the bogies. In my archives somewhere I have the supporting docs for this excerpt from my book:


"The 1st Armored Report at the end of March was again concerned with the suspected vulnerability of the Sherman tank. This report tells the results of an analysis and subsequent test that Division had done on a M4 tank that had been hit by a 75mm A/P shell at a range of 250 yards. Analysis showed that despite having approximately 7 inches of reinforced concrete on the sides, and even though the round cracked but failed to penetrate the side armor, the M4’s gas tank ruptured and caught fire, and the ammunition stored inside exploded even though it was a wet-storage unit that kept the ammunition in a liquid. After burning out, the same tank was tested to see if a Panzerfaust could penetrate the opposite side through the concrete. Depressingly, it did."

Despite this evidence, troops were allowed to keep a reasonable amount of added "armor" mainly for the morale value.

 

As you might expect my heroes are the men in the M10s M18s, M36 and Archer SP anti tank guns who duelled with tanks in the knowledge that their turret arm,our was not designed to keep pout anything heaver than a rifle calibre bullet.

 

Always amazed they were willing to send open topped SP's into towns that had artillery incoming and enemy snipers in the houses.

Up From Marseille that's more like I anticipated from the drivers side. Willing to do anything to gain an advantage regardless of the bean counters back home.

Wish there were numbers to show HP and MPH of a sherman/stuart with and without governor.
Also helps explain why there are rumors of the germans using capured shermans to tow tigers.

 

While the HP is up for conjecture, the MPH is fairly easy to calculate!

An M4A3 with a Ford GAA governed at 2650rpm was good for about 26mph in fourth gear.

The GAA would rev until the valves floated, which occurred between 3800-4000rpm, but let's take 3800 to be conservative.

Crunching some mathemetrical stuff yields an ungoverned top speed of 37mph for an M4A3 in fourth gear. That's haulin'!

 

I hadn't heard about that before. Be interesting to see some pictures but it probably isn't something the Germans would boast about.

Not suprising though. They had more HP than any of the German (or American) prime movers and should have been able to tow anything on the battlefield. There were German recovery vehicles based on Panthers and Tigers that could also do the trick.

 

I think it was in Italy and I believe I've seen picture of it. From what I recall the Shermans were missing their turrets and I think at least one of the pictures showed a couple of them towing a single Tiger although they may have been trying to pull it out of a hole.

 

https://www.youtube.com/watch?v=_a7NZw-qQhA
Describes a runaway Sherman pushing 2 other tanks into a third.

 

Hey that was good. Great to hear the old timers saying how it was...Buddy had quite the whistle while speaking. ..Enjoyed it.

 

There are so many great facts and tidbits in there. Plus the guy sounds like Fess Parker. Great tape. Thanks for posting

 

Fess Parker?
lol A purple shafted nut slinger-
http://www.youtube.com/watch?v=No6k_DSurJY

 

"Was supposed to be a mesh, as that worked best, but material supply issues made it plate."

Wonder if mesh was harder/more expensive to produce.
Maybe they use hanging chain now.

 

Roughly.
Plate: Roll/cast some plate. Cut.
Mesh: Roll/cast steel. Roll/Extrude/draw to wire. Cut wire. Place in Jig. Weld. Weld some more. Then weld a bit more. Cut.

I honestly don't know what the specific mesh issues were, but it's a more complex material to create than sheets, might well have been needed elsewhere, could even have been the amount of welding time/materials required. Specifically, lord knows... or maybe somebody here will.

Hanging chains?

 

Nice picture ViP...looks like a Centurions about to do the 7 veils dance...Wonder who came up with the chain defense. Going to say Israel. They come up with cheap effective, then sell it as cost efficient...Kidding. Love the Israel.