Landships II

Long Tom · Brigadier

How Well Did The St. Chamond Actually Work?

CharlieC · Legend

A petro-electric system was also used on the WW2 Porsche Tiger/Ferdinand/Elephant tanks and SPGs. Porsche was an enthusiast for this

drive system for heavy vehicles. Not certain but the German super heavy tank - the Maus - may have had a petro-electric drive.

The Saint-Chamond drive was lifted from a French railcar design - it seems to have been fairly effective but I've seen comments it was a bit

fragile.

The main problem with the Saint-Chamond was the long overhang at the front which severely limited the trench crossing capability. The length

of the overhang is a simple consequence of trying to put a French designed field gun into the hull. The way the French gun's traverse worked

meant that the whole trail has to be incorporated into the hull. Late in the war the Saint-Chamonds were used quite successfully as SPGs supporting

Renault FTs - this role meant they didn't have to cross trenches.

Regards,

Charlie

Roger Todd · Legend

CharlieC wrote:
A petro-electric system was also used on the WW2 Porsche Tiger/Ferdinand/Elephant tanks and SPGs. Porsche was an enthusiast for this drive system for heavy vehicles. Not certain but the German super heavy tank - the Maus - may have had a petro-electric drive.

It did indeed.

Also, getting back to the French, the Char 2C had petrol-electric drive.

And interestingly*, though nothing to do with tanks, many American dreadnoughts had turboelectric drive, which no other navy did.

*Or not.

TinCanTadpole · Legend

I think at least one of the British tanks at the (Hatfield or Oldbury? - I've forgotten) 1917 tank transmission trials had a petrol-electric drive, but it was deemed insufficiently powerful to climb out of shell-holes.

On the subject of US dreadnoughts, or more accurately, I think they were super-dreadnoughts, the turbo-electric drive was chosen because trials of a turbo-electric system in a collier had found it improved the vessel's economy.

Charlie is correct about the WW2 Maus, it did indeed have electric drive - given the 188 long tons weight of the beast, I doubt a mechanical drive strong enough could have been used without taking up the entire interior of the tank.

Finally, the St Chamond: I don't know where, but I think I read somewhere that it had steering clutches - which rather surprised me, given that the obvious way to steer a petrol-electric tank is to slow or stop one track motor; perhaps the St Chamond had only one motor driving both tracks?

CharlieC · Legend

TinCanTadpole wrote:
I think at least one of the British tanks at the (Hatfield or Oldbury? - I've forgotten) 1917 tank transmission trials had a petrol-electric drive, but it was deemed insufficiently powerful to climb out of shell-holes.

Finally, the St Chamond: I don't know where, but I think I read somewhere that it had steering clutches - which rather surprised me, given that the obvious way to steer a petrol-electric tank is to slow or stop one track motor; perhaps the St Chamond had only one motor driving both tracks?

One Mark IV was sent to Saint-Chamond to be fitted with a petro-electric drive. It wouldn't be too surprising if the Saint-Chamond power train was thought underpowered for a Mark IV -

the Saint-Chamond tank was 23 tons, the Mark IV 28 tons.

Nope - the Saint-Chamond didn't have steering clutches - this impression might have been created by the three pedals on the floor of the driver's position - the outer two were brake pedals

and the centre one was the accelerator. There was only one lever (on the right of the driver) which was the parking brake - this could be confused with a clutch lever on conventional tanks.

Just to clear up how the Saint-Chamond electric drive worked - from the manual (Vol. III):

----------------------------------------------

Transmission électrique.

I.a transmission électrique comprend :

A ) Une dynamo génératrice, entraînée directement par l'arbre du moteur à essence et qui produit du courant ;

B) Deux moteurs électriques qui reçoivent le courant produit par cette génératrice. Chacun des moteurs actionne par l'intermédiaire d'engrenages réducteurs de vitesse, une des chenilles motrices.

Les deux moteurs qui. dans la marche en ligne droite, tournent à la même vitesse, peuvent être rendus indépendants pour virer, l'un ne recevant plus de courant et se trouvant freiné, par exemple, tandis que l'autre continue a faire mouvoir une chenille.

------------ Google Translation --------------

Electric transmission.

I.a electric transmission includes:

A) A generator dvnamo, directly driven by the shaft of the engine and which produces electricity;

B) Two electric motors, which receive the current generated by this generator. Each motor operates via reducing gear, a caterpillar drive.

Both motors. walking in a straight line, turn at the same speed can be made independent to transfer, one no longer receiving power and being braked, for example, while the other continues to move to a caterpillar.

--------------------------------------------------

Regards,

Charlie

-- Edited by CharlieC on Monday 28th of July 2014 08:03:36 AM

-- Edited by CharlieC on Monday 28th of July 2014 08:04:05 AM

Long Tom · Brigadier

Just to let you know that I read that the reason diesel locomotives all have fuel-driven generators is because it is physically impossible to make a transmission system which would allow the engine to drive the running gear directly.