Alternative German tanks & AFVs

[Reluctant Poster]

The S-40 is an interesting what if

Don't Leave Well Enough Alone

A blog about World War II era archive documents, primarily dealing with armoured warfare.

www.tankarchives.ca

 

[Reluctant Poster]

Good point about the size of the cartridge maximum diameter.

As for diesel, I think we've discussed it in several threads over the past few years. At the level of the individual tank the difference might not be hugely significant, as the smaller fuel tanks for a given range are offset by a bigger and heavier engine?

But reducing the logistics volume might be significant, although partially offset by requirement to support both petrol and diesel rather than only petrol?

But the biggest benefits would have been in the fuel production itself. Fischer Tropsch plants (suitable for diesel type fuels) are much less capital intensive than the Bergius process plants that produce high octane petrol. And even if you have access to crude oil, diesel production requires only fractional distillation and none of the petrochemical heroics required for high octane petrol.

The Germans originally chose petrol for their tanks because they thought that petrol would be easier to come by. When eventually it was reported to them that synthetic diesel production would be easier they started programs to design diesel tank engines, but nothing became of them before the end of the war.

I have read that rational in the past but it has never made sense to me. The German Army was largely diesel powered all through the war. All of their heavy trucks (4 1/2 ton and above) were diesel powered. Their Einheits (standard ) trucks developed in the prewar era were diesel powered. It was only after the war had started that they realized that they would not have enough of them prompting the standardization on the gasoline fueled Opel and Ford trucks in the 3 ton category. Even then Borgward , Mercedes and KHD continued to produce diesel trucks in that size category. Germany was the world leader in the development of the light weight automotive diesel with diesel production at MAN, Mercedes, Deutz, Bussing NAG, Sauer, Henshel, Krupp, Tatra, Borgward, Phanomen, etc. well established.
The puzzle is why the Germans standardized on Maybach gasoline engines for their fighting vehicles when there were so many alternatives.

How the Wehrmacht's Diesel Stalled

A blog about World War II era archive documents, primarily dealing with armoured warfare.

www.tankarchives.ca

Mercedes-Benz 500 Series Diesel Marine Engines

The Mercedes-Benz MB 500 series diesel marine engines evolved from the Daimler-Benz DB 602 aviation engine and were first built in the 1930s. Some versions of MB 500 series are still in use today.

oldmachinepress.com

 

[Shortround6]

I have read that rational in the past but it has never made sense to me. The German Army was largely diesel powered all through the war. All of their heavy trucks (4 1/2 ton and above) were diesel powered. Their Einheits (standard ) trucks developed in the prewar era were diesel powered. It was only after the war had started that they realized that they would not have enough of them prompting the standardization on the gasoline fueled Opel and Ford trucks in the 3 ton category. Even then Borgward , Mercedes and KHD continued to produce diesel trucks in that size category. Germany was the world leader in the development of the light weight automotive diesel with diesel production at MAN, Mercedes, Deutz, Bussing NAG, Sauer, Henshel, Krupp, Tatra, Borgward, Phanomen, etc. well established.

I would like to some numbers for this. The Germans made a lot of trucks that could be diesel powered. Most also had a petrol engined model. Production was split how? Many types of trucks had 4 wheel drive models also, but those were usually a fraction of total production. Total production of large German trucks was in the thousands. The smaller trucks were in the tens of thousands, The US was making large trucks by the tens of thousands and 'smaller' trucks by the hundreds of thousands. Canada made something like over 600,000 motor vehicles.
I would also note that diesel engines in 1930s and 40s were not easy to start in cold weather, or sometimes to even keep running. The Diesel Soviet tanks used compressed air for starting. I have used small diesel auxiliary engines in Firetrucks that used an electric heating element in the intake to warm the air in the manifold/intake system before you engaged the starter motor. Once the engine fired you let go of the heater switch (and this was sometimes in the heated truck bay.) Basically Petrol will give off flammable vapors over 40 degrees below zero (both scales), not many but some. You have to be closer to 100 degrees F (37 degrees C) above freezing for diesel fuel to give off flammable vapors. There are ways to warm the fuel (or air) and some diesels used either sprayed into the intake to start in cold weather (this may have been post war?). This one reason that truckers will just let the engine run while parked. My department's fire trucks were kept in heated bays (at least high 60s F) in New England.
You can solve a lot of problems, but if you need a lot of trucks in a hurry and you can get petrol engined ones that don't require as much work to operate in cold weather you may want to think about that aspect.

 

[special ed]

I went to high school (late 50s) with a boy whose father was a German POW, interned in Mississippi, returned to U.S. to marry a young woman he apparently met while a POW. Many enlisted were directed as farm labor until they returned to Germany. During our high school years my friend's father worked primarily as a diesel mechanic for the U.S. Navy. He would buy surplus Chevvy Carryalls, make repairs as needed, drive them daily to work, then sell them.

 

[tomo pauk]

You can solve a lot of problems, but if you need a lot of trucks in a hurry and you can get petrol engined ones that don't require as much work to operate in cold weather you may want to think about that aspect.

There were several cold weather 'layers' where the German forces were expected to operate. Winters in better part of Germany, France, Balkans etc. were not as harsh as the winters in the Soviet Union. Winters in the Med basin were milder still. So having the diesel engines dominating there would've provided a lot of fuel saving without the troubles and risks associated with the dieselised force needed in the SU.
Germans have had years to test and tweak the diesels for the use in harsh conditions, and then apply that knowledge.

I have used small diesel auxiliary engines in Firetrucks that used an electric heating element in the intake to warm the air in the manifold/intake system before you engaged the starter motor. Once the engine fired you let go of the heater switch (and this was sometimes in the heated truck bay.)

The APUs would've made sense in the big & heavy tanks/AFVs. One can keep the batteries full with them, as well as the crew compartment, without the need for intermittent starting of the main engine. A much more elegant solution than lightning the fires under the engine, too.

Basically Petrol will give off flammable vapors over 40 degrees below zero (both scales), not many but some. You have to be closer to 100 degrees F (37 degrees C) above freezing for diesel fuel to give off flammable vapors. There are ways to warm the fuel (or air) and some diesels used either sprayed into the intake to start in cold weather (this may have been post war?).

Thinning of the diesel fuel by pouring in the gasoline was a know 'trick' IIRC even back in the 1940s.

 

[Shortround6]

The APUs would've made sense in the big & heavy tanks/AFVs. One can keep the batteries full with them, as well as the crew compartment, without the need for intermittent starting of the main engine. A much more elegant solution than lightning the fires under the engine, too.

The firetrucks (at times) had an electric generator that ran on Diesel. A very nice improvement on the older gas powered generators that had to be removed from the compartments, placed on the ground, started with a pull rope, and usually had a leaky carburetor. They were stored 'dry'. fuel in the tank but the carb had been run dry when shut off, which meant that the gaskets all dried out (1970s/80s) so they leaked when you turned the tank on. With the diesel generator on the ladder truck we did have open the compartment doors for cooling.

Basically for the Germans and diesel question, they didn't have the infrastructure. By that I meant the manufacturing plant to make the engines. Trying to develop new engines in the middle of a war is a lot of work. Trying to replace ALL of the types of gasoline engines being used in the German motor vehicle industry would be a huge undertaking. Either with each manufacturer or with some common engines being distributed to a number of chassis manufacturers and adopting their vehicles (radiators, frame/engine mounts, transmissions) to the standard engines. It could be done but by the time they realized they should have done it, it was too late. A number of German truck companies made diesels in the 1930s but most of the time the diesel models were well under 1/2 total production. Germans had spent too much time fooling with things like this.

Around 7000 built despite the numbers of photos, newsreels and models Used about the same engine as the Pz Ia tank. Air-cooled flat 4. Only the rear wheels were driven.
They stopped production in 1941 for more mundane trucks (civil commercial with grey paint).

The Germans should have done a lot of things. They didn't have the money to do everything and they waited too long to do a lot of things.

 

[tomo pauk]

Basically for the Germans and diesel question, they didn't have the infrastructure. By that I meant the manufacturing plant to make the engines. Trying to develop new engines in the middle of a war is a lot of work. Trying to replace ALL of the types of gasoline engines being used in the German motor vehicle industry would be a huge undertaking.

Nobody said that they need to wait until mid-war to develop the new engines, nor that they need to replace ALL of the types of gasoline engines with diesels. They could've started out by the time the 15-20 to tanks were mooted, so that after a few years the workable types can be put in series production.

Germans have had far less problems in making this or that engine, than it was a problem for them to gain the access to the fuel quantity required.

 

[don4331]

Basically for the Germans and diesel question, they didn't have the infrastructure. By that I meant the manufacturing plant to make the engines. Trying to develop new engines in the middle of a war is a lot of work. Trying to replace ALL of the types of gasoline engines being used in the German motor vehicle industry would be a huge undertaking. Either with each manufacturer or with some common engines being distributed to a number of chassis manufacturers and adopting their vehicles (radiators, frame/engine mounts, transmissions) to the standard engines. It could be done but by the time they realized they should have done it, it was too late. A number of German truck companies made diesels in the 1930s but most of the time the diesel models were well under 1/2 total production. Germans had spent too much time fooling with things like this.

Around 7000 built despite the numbers of photos, newsreels and models Used about the same engine as the Pz Ia tank. Air-cooled flat 4. Only the rear wheels were driven.
They stopped production in 1941 for more mundane trucks (civil commercial with grey paint).

The Germans should have done a lot of things. They didn't have the money to do everything and they waited too long to do a lot of things.

How is the Krupp Protze different from say a Dodge WC-62

Other than the powered front axle?

Allies needing >300k is more about the destruction of the rail infrastructure.

Note: I agree with the philosophy of making the enemy fight to your strength - if Germans needed to move materiel by rail and Allies could move materiel by automotive, destroy the rail and limit German movement.​

Moving materiel by rail in way more efficient (barge is even more efficient), but if you have the resources...​

 

[don4331]

Nobody said that they need to wait until mid-war to develop the new engines, nor that they need to replace ALL of the types of gasoline engines with diesels. They could've started out by the time the 15-20 to tanks were mooted, so that after a few years the workable types can be put in series production.

Germans have had far less problems in making this or that engine, than it was a problem for them to gain the access to the fuel quantity required.

But when you're not a war, the fuel for the diesel engine costs 20% more to refine from petroleum stocks; cost here in Calgary for gas is $1.339; for diesel $1.549 And that diesel engine costs 20% more largely because it needs to be heavier. Just look at the price uplift of a Dodge 3/4 ton - that Cummins diesel adds $9,500 (Cdn) to a $59k truck (base) <for reference, 4wd adds $4k Cdn.> The diesel has to be a lot more fuel efficient and you have to drive a lot of miles to recover the cost.

I'm with S Shortround6 ; we left the diesels running - as it was so hard to start them/they use so little fuel idling. Petrol engines are so much easier to start, that you turned them off.

And who had the crystal ball, that said diesel was going to be easier to come by after war commenced than gasoline?

Neither of the processes to produce diesel or petrol in industrial quantities is really developed when you can get supply cheap from crude.​

 

[marathag]

The APUs would've made sense in the big & heavy tanks/AFVs. One can keep the batteries full with them, as well as the crew compartment, without the need for intermittent starting of the main engine. A much more elegant solution than lightning the fires under the engine, too.

Germans were _so_ close.
The Mk IV had a small 500cc two stroke made by Auto-Union for running a 2kw generator the electric turret traverse, but it wasn't set to charge batteries or run the radio. Just Traverse. I believe this was originally for one of the engines used by the tiny DKW cars

Th Sherman had a slightly smaller 1.5kw two stroke/generator combo made by Homelite, but was made to charge batteries with a max voltage of 30V.
There was a heat exchanger of sorts, to warm the engine and the crew compartment when desired

It was electric start, but if the batteries were flat, there was a backup rope starter.

 

[Shortround6]

Nobody said that they need to wait until mid-war to develop the new engines, nor that they need to replace ALL of the types of gasoline engines with diesels. They could've started out by the time the 15-20 to tanks were mooted, so that after a few years the workable types can be put in series production.

Germans have had far less problems in making this or that engine, than it was a problem for them to gain the access to the fuel quantity required.

Germans were short sighted, but for the the supply officers, it was often a question of one fuel for all (or most) vehicles or trying to supply two different types of fuel.
They could had designed one or two or even 3 different diesel engines for their tanks. They could have used one or two of these in some of the 1/2 tracks and/or some trucks.
But they still had tens of thousands of trucks (either foreign or domestic commandeered) or needing new engines for some some trucks. Germans don't even get to an engine the size of the Pz II engine until they get to the 8 ton 1/2 track.
Most of the German 4.5 ton diesel trucks used engines of 100-112hp. Maybe the higher torque is enough to make up for the slightly lower power in a light tank? Or maybe you just run them a few hundred rpm faster and accept the shorter life.
The Germans needed to start this rationalization of the engine/transport plan in the middle of the 1930s. In History they were just trying to increase motor vehicle manufacture in large numbers by any means possible. From Wiki so...................

"The collapse of the global economy during the Great Depression in the early 1930s plunged Germany's auto industry into a severe crisis. While eighty-six auto companies had existed in Germany during the 1920s, barely twelve survived the depression, including Daimler-Benz, Opel and Ford's factory in Cologne. Four of the country's major car manufacturers — Horch, Dampf Kraft Wagen (DKW), Wanderer and Audi — formed a joint venture known as the Auto Union in 1932, which would play a leading role in Germany's comeback from the depression"

Not all auto makers made trucks and not all truck makers made autos. The economy for most nations didn't turn around until the mid to late 30s.
The German Ford trucks used the standard Ford flat head V-8 of around 85-95hp (3.6-3.9 l). The Opel used a GM 6 cylinder car engine of 3.6 liters/75hp. These were cheap engines to make once you had the tooling. Mercedes truck diesels may have been nice engines but cheap?
Germans could not afford to make driven front axles for all wheel drive in sufficient numbers.

 

[don4331]

Mercedes truck diesels also use pre combustion chambers, which doesn't play nice with ether making cold starting doubly difficult.

USA had >475 auto manufacturers consolidating to <50 (and the big 3 controlled >90% of market share; GM almost 1/2 of that), that's just industry consolidation. Auto manufacturing is a very capital intensive industry - if you're not making enough money to invest in the required machinery, you're quickly out of business.

 

[marathag]

Moving materiel by rail in way more efficient (barge is even more efficient), but if you have the resources...

Hot Take:

Should have used the U-Boat MAN 2100hp Diesels, and their fuel, for US style Locomotives instead of sub warfare for moving things around central Europe and parts East.

No Water stops: long range, work great in freezing weather. far higher speed for similar tractive effort. Move that freight fast. 100mph vs 50

 

[Shortround6]

Not all factories had the same manufacturing capacity.
As has been noted before, especially in the US, many small auto manufactures bought their engines either from another auto company or from a specialty engine manufacturer who did make the rest of the automobile/truck.

However to show what the rest of the world was up against.
1939 top eight US manufacturers that year.

Chevrolet	577,278
Ford	487,031
Plymouth	423,850
Buick	208,259
Dodge	186,474
Pontiac	144,340
Oldsmobile	137,249
Studebaker	85,834

Please note that 1939 was not a good year, back in 1936 Ford and Chevrolet had combined to make just under 1,850,000 cars between them. Granted these are cars and not trucks
Could they have done better with better planning and more consolidation? Yes, but enough to really change anything?
The Allies sent more trucks to Russian than the Germans made during the entire war. Germans could have increased production (unlimited steel/labor?) by almost 20% and still not equaled that the Soviets received from Lend Lease.

 

[SaparotRob]

How is the Krupp Protze different from say a Dodge WC-62
View attachment 812464
..

The Dodge is way cooler. No brag. Just fact.

 

[z42]

There were several cold weather 'layers' where the German forces were expected to operate. Winters in better part of Germany, France, Balkans etc. were not as harsh as the winters in the Soviet Union. Winters in the Med basin were milder still. So having the diesel engines dominating there would've provided a lot of fuel saving without the troubles and risks associated with the dieselised force needed in the SU.
Germans have had years to test and tweak the diesels for the use in harsh conditions, and then apply that knowledge.



The APUs would've made sense in the big & heavy tanks/AFVs. One can keep the batteries full with them, as well as the crew compartment, without the need for intermittent starting of the main engine. A much more elegant solution than lightning the fires under the engine, too.


Thinning of the diesel fuel by pouring in the gasoline was a know 'trick' IIRC even back in the 1940s.

Germans already had problems with manufacturing and supporting a zillion things rather than mass manufacturing a few proven ones. Not sure having to support both diesel and petrol variants of their vehicles would have helped.

As for an APU, maybe. OTOH one of the advantages of diesels is that they're quite fuel efficient at idle and low load.

Mixing petrol into diesel in the winter was indeed a well known trick. It's a sort of DIY equivalent to the winter diesel that is sold in the winter in colder climates. Winter diesel has a slightly lighter distillation profile, which helps prevent jellying when it gets cold.

 

[z42]

Allies needing >300k is more about the destruction of the rail infrastructure.

Also a lot of German army logistics was horse powered, whereas the Allies (at least the Western Allies, not sure about the Soviets?) were mechanized.

 

[marathag]

Also a lot of German army logistics was horse powered, whereas the Allies (at least the Western Allies, not sure about the Soviets?) were mechanized.

Job One is to get rid of these old friends

For efficiency, you're putting in Oats at 8000 BTU/lbs and Hay is similar, into these guys. Each one of those needs around 25 pounds of Hay and 20 pounds of Oats when doing work. It's not much less when not working hard, you got to feed them each day, working or not. Then 15-20 gallons of clean water for how much they are working.
That's your Dual 'One HP' engine. On a wagon, 5-7 mph, with an expected working time of 8 hours, a 40 mile trip for 45 pounds of Fodder and 18 Gallons of water for moving 1.5 tons of cargo.

If you want more weight pulled or to be slightly faster for your Wagon moved cargo, you add two or four more Horses, but for continuous heavy loads, you need Oxen, that are even slower.
Union Army used six horses to pull a limber and 12 Pounder Napoleon cannon, to be able to move the two ton gun and limber into position quickly, but four was more common at the end of the War, from shortages of decent horses, Each pair of horses would have their own driver on the Left horse.

A 124 HP Sentinel Steam wagon, using 1890s technology, uses 4.3 gallons of water and 7.4 lb. of lump lignite coal per mile. 6 ton payload Top speed 30mph(though by UK Law, limited to 8mph at times). Driver and Fireman for crew, though some lines had the Driver drop coal into the Boiler for reducing labor costs.

So to move 6 tons of cargo 40 miles, that's 175 Gallons of water, 300 pounds of coal and an hour and 20 minutes of time to get to the destination, allowing for the top speed. Loading/unloading takes more time than the transport.

The horse drawn wagons to move the same amount of cargo, thats 4 wagon loads, 8 horses, four Driver/Teamster
144 Gallons of Water, 360 pounds of Fodder, and takes 8 hours- the entire 'Normal' work day.


Fodder- a mix of grains and hay. Allows for faster feeding of horses during the day. Yes, they can graze on grass, but that takes far more time. Grazing time takes away from pulling time.

That Fodder comes from Farms, where each Farm had about 1/3rd of the acreage set aside for feeding the Draft animals.
Mechanizing the Farms frees up that acreage for growing more valuable/needed crops like people food.


Both Horses and Steamer need large quantities of clean water. Both need hours of 'maintenance' before and after that work day. Neither are 'Turn key off and walk away' like with an ICE vehicle

sure, an IC truck is far better than steam, but takes much higher precision, and a fancy transmission and pneumatic tires to produce
those better results

So my idea, use Steam to get the German Farmer and Teamster away from horses

Der Volkslastkraftwagon, a small truck/prime mover to free the many Farmers and Drovers from having to use horses.

Since this is easier to build and develop than the Beetle, it's in production at Wolfsburg before that complex is even half done, being a very simplified and smaller version of the 80hp steam truck and bus that Abner Doble helped the Henschel company develop in 1930
and was in limited production in 1934

This will be an 8hp water tube boiler(not monotube flash boiler) with less automatic controls than the Doble System, and so is less efficient, but almost anyone can run one after a short training time. 8 HP doesn't sound like a lot, but Steam HP and ICE HP aren't exactly the same.
Steam has maximum torque at 1 rpm, and stays that way to maximum. The 20HP Stanley Steamer had around 1000 ft-lbs, and as with other Steam vehicles, doesn't need a transmission to get the engine in powerband. WOT on the Stanley from a standing start, would rip the tires off the rims.

The little VLKW as it's known, is a 4WD truck, uses Steel Wheels, with bolt on solid rubber blocks for use on surfaced roads, with a basic cab with side by side seating for a driver and a fireman, though normally operated by one man.
something like this Foden from the UK, size wise

 

[tomo pauk]

sure, an IC truck is far better than steam, but takes much higher precision, and a fancy transmission and pneumatic tires to produce
those better results

ICE truck also requires that precious liquid to haul stuff around, while the steam trucks use 'fuel' that is found anywhere between the Channel and Rostov, and from North Cape to the Balkans. Need be, even firewood is a fair game.

 

[z42]

But when you're not a war, the fuel for the diesel engine costs 20% more to refine from petroleum stocks; cost here in Calgary for gas is $1.339; for diesel $1.549

Not sure you can really extrapolate from current day relative pump prices to production costs 90 years ago.

And who had the crystal ball, that said diesel was going to be easier to come by after war commenced than gasoline?

Neither of the processes to produce diesel or petrol in industrial quantities is really developed when you can get supply cheap from crude.​

I suspect they had an idea that Fischer-Tropsch could be more efficient. However, the Bergius process was invented a decade earlier than FT (1913 vs 1925), so it wouldn't surprise me if they thought FT was still too immature when they made the decision to start building large scale synthetic fuel infrastructure?