Tank start ups

[Bortig the Viking]

Hi all, been looking at some tank videos and I have a question, they seem to have to hand crank for some time before getting it to start, did they have to do this each time, might be awkward in an an ambush.

[Dave Ward]

Mark,
which particular tanks are you looking at - old, or modern? All larger engines need to crank up to speed before they fire up - diesel engines especially. If you're talking about gas turbine tanks, then they really have to spin up to speed before power kicks in.
Keeping the engine warm would reduce the start up time ( 5-10 mins running an hour would do this ). Most tanks now have an APU, which keeps the batteries charged & radios working, without running the thirsty main engine - the cooling water from this keeps the main engine hot & ready to go.
Climate has a strong influence on start up times - if it's really cold, then cranking times can be extended, and you have to use starting aids - not good for the life of an engine!
I was involved with designing & testing auxy. gens sets for the military, and some had to be started at -15C!
Dave

[Bortig the Viking]

Hi, the videos I've watched are ww2 Stugs, Panthers and Tigers, looks like hard work to be honest.

[Guest]

some had to be started at -15C!

I’m fairly sure soldiers having to start their engines in the middle of the Russian winter would have loved to be doing that in only -15 degrees German tanks eventually began to be fitted with coolant exchange systems, so a running engine in one tank could be used to warm up that in another far enough to get it started.

[Dave Ward]

One odd feature of German tanks was that they were petrol engined - from a country where the diesel was invented, and good diesels used in S-boats & U-boats.............
I seem to remember Panthers could be cranked by a drive shaft mounted to a Kubelwagen.
The cold weather, poor petrol, problems with lubricating oil viscosity at low temperature woulds all contribute to starting problems. Another factor is that conventional lead/acid batteries stop working at the lower temperatures - so no electric start!
Coffman starters - which use a shotgun like cartridge to generate a large volume of gas to turn an engine were often used, in both tanks & aeroplanes - especially in cold conditions, but not, I believe by the Germans.............
Dave

[Bortig the Viking]

Hi, thanks for the replies, just shows how hard it was being a tanker especially on the eastern front, my grandfather was on the eastern front where he died, the stories he would have been able to tell. So many lives lost.

[Dave Ward]

The Russians used diesels in their T-34 & KV series - and were more used to operating vehicles in the harsh conditions of the Russian winters - ie special lube oil - not only for engines, but weapons ( or none at all ).
Being a tanker, whether Nazi or Soviet cannot have been a pleasurable experience - the German tanks were produced to a higher quality, but much more complicated, hard to manufacture, maintain & less reliable, needing well trained crews . The Soviets tanks were simple & robust ideally suited to less educated soldiers, earier to manufacture & being diesel had better range, and not so flammable as petrol AFVs
Dave

[eddiesolo]

The tanks had various start up procedures.

After first inspection the tanks were usually started via a normal electric start however, in cold weather there was pressurised air tanks that they used to crank the engine over. The hand crank was always a last resort as it does take a lot of work. They used the hand crank for maintenance procedures.

[Guest]

Many American (and other Allied, but especially American) tankers needed to use the starting crank as a matter of course. All those American tanks with radial engines (M3 light, a few varieties of M3 and M4 mediums, and everything derived from them) needed to have the engine turned over a few times before starting if the engine had been off for a while, in order to pump the lubricating oil around. It would pool in the bottom of the engine and so they’d run the risk of the upper cylinders seizing if they didn’t hand-crank the engine first.

Ah, here we go. I just dug up my copy of TM 9-731A, Technical Manual Medium Tanks M4 and M4A1, 14 November 1942, and found this on page 26:

8. ENGINE STARTING AND WARMING UP
(…)
b. Procedure, Gasoline Engine (fig. 19).
(1) Have engine turned over four complete crankshaft revolutions by hand (about 50 turns of the hand crank).

A similar line appears in the start-up procedure for the Diesel engine a few pages on.

[stillp]

It would pool in the bottom of the engine and so they’d run the risk of the upper cylinders seizing if they didn’t hand-crank the engine first.

To say nothing of the hydraulic lock that would occur in the lower cylinders!
Pete

[Bortig the Viking]

Crikes

[Dave Ward]

You can see that - watching B-17, B-24 & B-29 start ups, the ground crew turning the engines over by pushing on the props - not easy with 18 cylinders on the B-29!
Dave

[Guest]

At least they had far more leverage than a tanker turning a hand crank About ten times more, at an educated guess, and I don’t think the engine would take ten times the force to turn over — at the expense of having to walk a lot more, of course.

[Mini Me]

I was run up qualified on T-28 Trojans while in the Navy. Standard procedure required allowing the engine to turn over eight revolutions before switching on the magneto to initiate the start up. All done on battery power. If in very cold weather, a ground power unit was used to assist with additional cranking power.