► Photothread: Wood gas generators

[BDV]

A question for the Section members:

It seems that wood-gas use was quite widespread and to some extent effective. Are there any specific reasons why this was not standardized (/considered for standardization) for tracked and half-tracked support vehicles? In particular a Lorraine L37 design pulling a gasifier unit in its trailer could have been produced and deployed in (relatively) large numbers ~50/month.

[John Hilly]

Wood-gas didn't produce enough power compared with gasoline and diesel.
Passengers had to help pulling wood-gas busses uphills in Finland.

With best, J-P

[BDV]

Hello,

The method seems to be producing plenty power; right now many applications are for pick-up trucks. Maybe the Finnish buses were using small units, not to overload the chassis? That's why I thought that the gas unit could/would/should be placed in a towed trailer...

[Luftflotte2]

Take a look at the specific energy of different fuels. Gasoline - 40-48MJ/kg; diesel - 47MJ/kg; wood 16-21MJ/kg. This is why wood gas vehicles were not used as front-line equipment. Prime movers such as half-tracks need power, and wood-gas cannot produce enough.

[BDV]

Take a look at the specific energy of different fuels. Gasoline - 40-48MJ/kg; diesel - 47MJ/kg; wood 16-21MJ/kg. This is why wood gas vehicles were not used as front-line equipment. Prime movers such as half-tracks need power, and wood-gas cannot produce enough.

Quite.

AFAIK the energy density of the wood gas itself, does limit the top RPM and the top speed of a vehicle. But beggars can't be choosers, and a fleet of support vehicles that do not require additional petroleum shipments can/should be an important consideration .

[ilfil]

The considerable reducing of the engine power of those gas-genarator equipped vehicles apart (up to 50%!), have you ever considered the problems with the "fuel" supply on the front line? Also, what about all those time-consuming steps to produce the right wood for fuel, which may take up to 18 months, if starting from a fresh lumber?
Just my 2 cents.

[BDV]

The considerable reducing of the engine power of those gas-genarator equipped vehicles apart (up to 50%!), have you ever considered the problems with the "fuel" supply on the front line? Also, what about all those time-consuming steps to produce the right wood for fuel, which may take up to 18 months, if starting from a fresh lumber?
Just my 2 cents.

the up to 50% loss of power is definitely a consideration (those tracked vehicles won't be popping any wheelies).

OTOH, the drying of wood definitely takes less than that, because unlike lumber, you can cut up the wood upfront. Also, AFAIK, you can switch back to petrol any time, with minimal changes, so in case things heat up, the vehicles can be fueled up back to top power to assist with the march hin und zuruck!

[ilfil]

To run on petrol (or gasoline, if you're across tha pond) an engine modified for wood gas, the "minimal changes" will include replacing the engine head and fitting back a carburetor instead of the gas-air mixer. Often on the modified engines also the pistons were changed.
Indeed, on many such modified engines also a carburetor was fitted, but it was of different construction, so-called "starter carburetor". It allows engine to run on petrol but not more than about 15-20 mins. But even this wasn't recommended, for the detonation was able to ruin the engine.
Talking about wood drying times, the best recorded results were about a week to 10 days, in special drying facilities built for the purpose. Also, to keep the wood in usable condition, the dried "fuel" usualy was stored in well ventilated places with strictly fixed temperature and humidity.
In a word, the gas generators were more headache than advantage and apparently were forced solution of necessity, that's why they weren't used on battle vehicles. Producing synthetic fuel was also a headache but, according to the Germans, still better solution.
All above apart, let's see the things from the logistics point of view. A cubic yard of prepared wood was roughly an equivalent of a 20 l. jerrycan of petrol. Consider the volumes needed to deliver both fuels to the front.

[BDV]

Talking about wood drying times, the best recorded results were about a week to 10 days, in special drying facilities built for the purpose. Also, to keep the wood in usable condition, the dried "fuel" usualy was stored in well ventilated places with strictly fixed temperature and humidity.

Even if it takes 3 times longer than that, it's significantly less than 18 months. As to the strict requirements on the wood, I thought that there is some leeway, depending on how clean one wants to run, and how much filtering is done.

In a word, the gas generators were more headache than advantage and apparently were forced solution of necessity, that's why they weren't used on battle vehicles.

Who said anything about battle vehicles?

Producing synthetic fuel was also a headache but, according to the Germans, still better solution.

Is there proof that was even considered?

All above apart, let's see the things from the logistics point of view. A cubic yard of prepared wood was roughly an equivalent of a 20 l. jerrycan of petrol. Consider the volumes needed to deliver both fuels to the front.

One can make the thing locally, maybe move it locally a few tens of miles, vs. having to schlepp it thousands of miles.

[SIS 5]

Hi,

here a good pic of a Bedford with a gas generator (source of the pic: an expired ebay auction).

Regards

Bert

[Luftflotte2]

A truck before and after wood-gas conversion.
source: ebay.de

[Maxschnauzer]

1939-1941 Ford G 087 TG three tonner.

[Luftflotte2]

I will post what is written on the back to give some context to these photos:

[Luftflotte2]

Opel Admiral with two-tone camouflage.
source: ebay.de

[Maxschnauzer]

I will post what is written on the back to give some context to these photos:

Thank you Luftflotte,
I had not seen the others.