German logistics, purchase programs and war booty, reality and alternatives 1935-43 (2 Viewers)

[tomo pauk]

Many times we discuss the Axis, and Germany in particular, the conclusions were being made on how thin their logistical support was, how late they were about picking the low-hanging fruits, or how they have spread their resources (both material and manpower) and time thin, etc. Some of the decisions were a product of the expectations that the war will be short and relatively limited war, mostly focused against Poland and France. Sometimes, IMO, they tried to gold-plate stuff (like a V12-powered all-metal trainer); the aero engine companies were often allowed to do half a dozen of engine projects despite their engineers and technicians being conscripted in hundreds into the field army etc.

So here it is: a place where we can hump on the Nazi Germany leadership wrt. their mistakes in the field of logistics, purchase programs and usage of the captured stuff (both finished products and the actual factories), and suggest the changes. 'Logistics' include alternatives to the fuel used.

To start the ball rolling: The Ju 52/3m, that IMO was not the best way to invest 3 engines, propellers and the fuel required, while getting less than what other people were getting with jut two engines invested. It also used light alloys. So my suggestion is that a new transport aircraft is developed, widebody, high wing, with two or three engines, that will be no worse that the Bristol Bombay or the Italian 3-motors, respectively. Main materials being steel, wood and canvas.
On the back burner, have the Ju 52 tested with just two and one engine, and with greater incluson of not-light alloy materials; cunning plan is that the Ju 52/1m is the monoplane equivalent of the An-2 Colt (or, a more powerful version of this).

 

[tomo pauk]

Fuel (that might use a thread of it's own):
- as noted by the fellow members, steam powered machines - both big and small trucks and tractors - as well as producer gas powered ones (small trucks, cars); point of this is to leave as much of the 'normal' fuel (gasoline, diesel) for the vehicles that are the the tip of the spear
- a more concentrated effort towards dieselisation, especially wrt. the heavy stuff that uses huge amounts of fuel, like the tanks
- alcohol fuels
- diesel fuel made from the waste oils, including the used edible oils

Stumbling on the coal slurry idea would've improved the fuel logistic of the Axis greatly.

 

[Shortround6]

The Ju 52 was a pretty low hanging fruit.

Granted it used higher powered engines that Ju 52 but the cost of making a 925hp 9 cylinder radial can't be that different than making a 725hp 9 cylinder radial of about the same displacement (later Ju 52s got 830hp engines).
Feel free to use better streamlining, fewer struts, etc.
As noted by Tomo, the Italians could have shown the Germans something (or several somethings) with wider bodied transports.

A lot of US and European nations had transports in the 6-12 seat range that used low powered engines.

2 crew, 8 passengers three 260hp engines. Also not high fruit. You could also built three aircraft each with a single 260hp engine that would hold a pilot and 4-5 passengers.

Or Germans build a factory that just makes powered, steerable front axles for 3-6 ton trucks at the rated of 1000 axles a month to be supplied to various truck companies and does in in 1940.

 

[yulzari]

https://historyoflight.wordpress.com/wp-content/uploads/2011/01/cf-arm.jpg

 

[tomo pauk]

A lot of US and European nations had transports in the 6-12 seat range that used low powered engines.

A single-engined Norseman will be my go-to light aircraft as a pattern - nothing fancy, but does great on modest engine power: 10+1, on a single 600 HP engine.

Another thing that Germans went overboard were, IMO, the Arado trainers. Light alloy as a material, V12 engine in the nose. Most of other countries used less fancy materials and small radial engines to do the same. They basically need a 'baby Hurricane', not a 'baby Spitfire', structure-wise. Engine - make the 'German Mercury', if not a bespoke 7 cyl radial, talk half of a BMW 139 sans fuel injection? Or perhaps one half of the DB 600 (ie. no fuel injection, just a 1-speed S/C drive)? Aim for 400-450 HP on the 80 oct A2 fuel (a bit more with the 'Mercury').

 

[GrauGeist]

Siebel had two smaller twin engined transports, also used as trainers, which used non-strategic engines.
The Fh104 used two Hirth HM508D v-8s and the Si204D used two Argus As411 V-12 engines.

 

[Shortround6]

Siebel had two smaller twin engined transports, also used as trainers, which used non-strategic engines.
The Fh104 used two Hirth HM508D v-8s and the Si204D used two Argus As411 V-12 engines.

They made about 46 of the Fh 104 and starting in 1940-42 (took that long for 3 prototypes) for the Si 204. Most production was farmed out to SNCAN in France starting in late spring of 1942 followed by CKD and Aero in Czechoslovakia and by BMM (parent of CKD) in Germany. About 1216 built by Jan 1945.
Early ones were all metal with wooden wings and tail parts coming in late 1944 (?).

The Germans took a long time to simplify even the 200-500hp engines. They were small and light (the Argus V-12 was only 12 liters) so actual cost can be argued. Using 12 cylinder to make the same power as the Americans were getting out 16 liter 9 cylinder engines takes a rather thorough examination. Perhaps using a larger V-8 instead of a small V-12 would show some advantage but I don't think it is going to be huge.
I would note that the Germans tended to use two basic sizes of cylinders on their small engines. Either 105 X 115 mm on the 4, 6, 8 and 12 cylinder Hirths and the V-12 Argus's or 120 x 140 cylinders used in the Argus V-8s
Hirths tended to be expensive due to the multi-piece crankshafts running in roller bearings.
I would note that the British Cirrus Major 4 cylinder engine used 120 x 140 mm cylinders and the DH air cooled engines, once you got passed the Gypsy-Minor all used 118 x 140 mm cylinders for the 4, 6 and 12 cylinder engines.
French and Italian air cooled inline engines tended to use either the 120 x 140 mm size (Renault) or the 118 X 140mm size (Alfa).

I am not sure when Lycoming got into the larger flat 4 & 6 market if it was before Sept 1939 or after. I think the Stinson L-5 Sentinel of 1942 was the first plane to use the Lycoming O-435 flat 6. Lycoming was making their small under 85hp flat fours and their 9 cylinder R-680 radials as fast as they could during WW II.

 

[z42]

Maybe a couple of small 7 or 9 cylinder radials would have been cheaper and lighter than the Argus V-8 and V-12 engines for similar power level, but in the grand scheme of things a pretty marginal improvement. Perhaps when BMW licensed the P&W R-1690 Hornet (which eventually was developed into the BMW 132) they should also have licensed the R-985 and R-1340 as well?

But in general, maybe Germany would have needed a series of cheap and reliable radials in different size classes. An engine a step up from the BMW 132 could have been a nice transport and bomber engine, replacing the Jumo 211. Use single-point fuel injection to keep cost and complexity down. Maybe license something from Japan? BMW 801 was ok-ish, but somewhat heavy and apparently very expensive.

 

[z42]

the aero engine companies were often allowed to do half a dozen of engine projects despite their engineers and technicians being conscripted in hundreds into the field army etc.

Indeed. In retrospect it's easy to say they should have killed anything that isn't a liquid-cooled V-12, an air-cooled radial, or a turbine engine. And even after that, for the piston engines at least, focus on improving existing models rather than starting from scratch. But maybe not so obvious at the time; it wasn't clear if jets were going to deliver on their promises anytime soon.

To start the ball rolling: The Ju 52/3m, that IMO was not the best way to invest 3 engines, propellers and the fuel required, while getting less than what other people were getting with jut two engines invested. It also used light alloys. So my suggestion is that a new transport aircraft is developed, widebody, high wing, with two or three engines, that will be no worse that the Bristol Bombay or the Italian 3-motors, respectively. Main materials being steel, wood and canvas.

Yes, anything which isn't a high performance combat aircraft should be constructed from steel tubes, (ply)wood, and fabric.

For 3-motors, I suspect an issue is that with a big and wide fuselage, a non-trivial fraction of the propeller thrust is wasted pushing air around the fuselage and generating turbulence. Particularly if the surface is corrugated rather than smooth. So depending on the size of engines available and the size of the aircraft, either 2 or then 4 engines.

Perhaps something like a wood/steel/fabric version of the Ar 234B, with 4 Bramo 323 (or BMW 132's?)?

 

[z42]

Fuel (that might use a thread of it's own):
- as noted by the fellow members, steam powered machines - both big and small trucks and tractors - as well as producer gas powered ones (small trucks, cars); point of this is to leave as much of the 'normal' fuel (gasoline, diesel) for the vehicles that are the the tip of the spear

Agricultural mechanization with coal (steam or coal gas) as well as replacing horses for transport with trucks would have increased food production and improved the productivity of the economy in general. But that would realistically have been a multi-decade project, and Hitler wanted his war ASAP, and thus the focus was on rearmament.

- a more concentrated effort towards dieselisation, especially wrt. the heavy stuff that uses huge amounts of fuel, like the tanks

Yes. To nitpick, do we have any figures of how many % of Wehrmacht fuel was used by tanks? Tanks gulp a lot of fuel, yes, but they are also massively outnumbered by other vehicles. At least if Germany would have mechanized their army.

- alcohol fuels

Produced from, what? If edible crops, towards the end of the war the Germans already had huge problems with food production due to so many men and farm animals having been drafted.

- diesel fuel made from the waste oils, including the used edible oils

Yes, but just like today, marginal in the grand scheme of things.

Stumbling on the coal slurry idea would've improved the fuel logistic of the Axis greatly.

It could have been useful for steamships. Say, warships could have used CWS for cruising and then switched to fuel oil for high-speed operation. But would have required larger fuel tanks due to lower energy density.

Otherwise, not seeing a huge role for it? Slower transport ships, barges, locomotives, house heating, electricity production, the above mentioned steam/coal gas powered vehicles etc. could just keep using lump coal? (Later experiments with using CWS directly in diesel engines ran into problems with ash formation and abrasion, IIRC, so that's probably not workable..)

 

[tomo pauk]

Perhaps when BMW licensed the P&W R-1690 Hornet (which eventually was developed into the BMW 132) they should also have licensed the R-985 and R-1340 as well?

Good idea.

But in general, maybe Germany would have needed a series of cheap and reliable radials in different size classes. An engine a step up from the BMW 132 could have been a nice transport and bomber engine, replacing the Jumo 211. Use single-point fuel injection to keep cost and complexity down. Maybe license something from Japan? BMW 801 was ok-ish, but somewhat heavy and apparently very expensive.

A BMW 132 with a 2-speed S/C is already an improvement vs. the 'normal' 132. To their detriment, neither the BMW nor Bramo were good in making modern superchargers until well into ww2; retrofit of a better S/C on either the 132 or 323 would've gave them perhaps another 100 HP between S/L and, say, 4km?
Germans made a ... curious choice when they decided what to get from the G&R. Seems like the most popular engine was the least capable one, the 14M, that meant one needed two of such in order to make an aircraft acceptable. Focusing on the 14N instead would've netted them more, IMO. Let alone on the 14R. It is not a long shot for them to be getting the 14N already in 1940 (= engines already made + what can be produced), and make a switch to the 14R by the winter of 1941/42. If the Hs 129 is cancelled (preferably even before it took 1st flight), the captured 14M can be used on the transports.
This is perhaps where the 'how they could've used better the war booty' part starts.

For 3-motors, I suspect an issue is that with a big and wide fuselage, a non-trivial fraction of the propeller thrust is wasted pushing air around the fuselage and generating turbulence. Particularly if the surface is corrugated rather than smooth. So depending on the size of engines available and the size of the aircraft, either 2 or then 4 engines.

Perhaps something like a wood/steel/fabric version of the Ar 234B, with 4 Bramo 323 (or BMW 132's?)?

No quarrels about the 2- or 4-engined transports. These Arados were a great idea, IMO.
The Italians managed to gain much more with basically the same propulsion group as what the Ju 52/3m had (here). Or, to achieve the same with lower engine power (here).

Agricultural mechanization with coal (steam or coal gas) as well as replacing horses for transport with trucks would have increased food production and improved the productivity of the economy in general. But that would realistically have been a multi-decade project, and Hitler wanted his war ASAP, and thus the focus was on rearmament.

Hitler/Nazi Germany were also investing big in the synthetic fuel in order to reach autarky. The steam power was a mature thing, and 'selling' the idea of community-owned expensive farm equipment would've been easier in the country ruled by the mob, than it was to do it in a democratic country. The less fuel the agriculture uses, the more is for the military; the less of the land is used for the horse fodder, the more is for the food for people.

Yes. To nitpick, do we have any figures of how many % of Wehrmacht fuel was used by tanks? Tanks gulp a lot of fuel, yes, but they are also massively outnumbered by other vehicles. At least if Germany would have mechanized their army.

I have no such data, yet.

Produced from, what? If edible crops, towards the end of the war the Germans already had huge problems with food production due to so many men and farm animals having been drafted.

Changes in food and fuel production will indeed need to be made ASAP; waiting until the war starts is too late.
Earlier mechanization of agriculture means less human work is required.
Europe was making a lot of schnapps from the fruits, so there is an - cruel - idea. Also a lot of wine.

Yes, but just like today, marginal in the grand scheme of things.

It would've been interesting if someone can put out some numbers wrt. the use of waste oils to be turned into diesel back then.

It could have been useful for steamships. Say, warships could have used CWS for cruising and then switched to fuel oil for high-speed operation. But would have required larger fuel tanks due to lower energy density.

Otherwise, not seeing a huge role for it? Slower transport ships, barges, locomotives, house heating, electricity production, the above mentioned steam/coal gas powered vehicles etc. could just keep using lump coal? (Later experiments with using CWS directly in diesel engines ran into problems with ash formation and abrasion, IIRC, so that's probably not workable..)

Lump coal means the open combustion engine (ie. steam engine), and these are/were pretty inefficient (FWIW). Not an issue if one has abundance of the coal (= basically, Europe, that was mostly under the German boot in the day) and the small steam engines in mass production, but it might be an issue if the payload fraction was required to be high.
If used on steam engines, CWS might cut on the manpower required, requiring just gravity feed and no stokers.

Experimenting with mixing the diesel (or alcohol?) with the CWS might've perhaps be worthwhile?

 

[tomo pauk]

The Germans took a long time to simplify even the 200-500hp engines.

Bingo.

I would note that the Germans tended to use two basic sizes of cylinders on their small engines. Either 105 X 115 mm on the 4, 6, 8 and 12 cylinder Hirths and the V-12 Argus's or 120 x 140 cylinders used in the Argus V-8s
Hirths tended to be expensive due to the multi-piece crankshafts running in roller bearings.

Any worth in merging the Hirth with BMW, and Argus with Bramo? The respective 'pairs' were basically neighbours, there is no need to have 4 separate design & test offices, and the 'smaller' members of the pairs can be tasked with making lower-tech/low-power engines, or as the source of the parts for the more prominent engines?
Once the facilities in Czechia and Poland are captured, out-sourcing the small engines' production there might've been prudent.

 

[z42]

Any worth in merging the Hirth with BMW, and Argus with Bramo? The respective 'pairs' were basically neighbours, there is no need to have 4 separate design & test offices, and the 'smaller' members of the pairs can be tasked with making lower-tech/low-power engines, or as the source of the parts for the more prominent engines?

I suggested a 'consolidation scenario' in your 'Germany goes for radials' thread about a year ago: Radial engines more favored in Germany, 1935-45?

 

[tomo pauk]

Another pet peeve of mine wrt. the German questionable take on the logistics is the wide array of the ammo types. Eg. there was 9 different 75mm ammo types, without looking at the cartridges from the 19th century. Add the foreign 75-76mm ammo types in the wide use, and it bloats even more. The 88mm ammo situation was also curious, to say at least, with 5 different ammo types, with the caveat that Flak 18 and Tiger used different priming on an otherwise same ammo.
So as always, I'd suggest the massive reduction there. Maximum of 4 different 75mm types and 3 different 88mm types perhaps? Cunning plan is to have one 75mm gun design that can also use the Polish/French 75mm ammo, and vice-versa.

Having a common ammo type for the 37mm AT and Flak gun would've been prudent, IMO.

Make just one gun in-between the 37mm and 75mm calibre brackets. 55-57mm as a necked-down 75mm for towed AT gun for the late 1930s, no worse than the 6pdr?

The 127/128mm guns - just two 'sizes', not 4.

 

[GrauGeist]

Produced from, what?

Wood.

Wood alcahol aka Methanol burns closer to the properties of gasoline than Ethanol and it's production base does not involve food sources.

 

[Shortround6]

Any worth in merging the Hirth with BMW, and Argus with Bramo?

Not Hirth.
It was not a big company. The owner/chief designer died in 1938. The company was nationalized and by 1942 was merged/given to Heinkel for jet engine research.
As noted earlier it was sort of the RR of small aircraft engines only more complex. Using a 7 piece crankshaft for a six cylinder engine does allow for using roller bearings for each main bearing but it makes for a very expensive engine.

Air cooled engines all have something in common and that is keeping the engine cool. This gets real hard real quick as the size of the cylinders goes up. The volume of the cylinder ( amount of fuel burned per power stroke) goes up faster than the surface area of the cylinder and cylinder head. You need to increase the size of the fins.
You have three basic choices.
1. Increase the depth of the fins.
2. Increase the pitch of the fins/more fins per cm/in of cylinder length. which leads us to #3
3. Make the fins thinner so you can squeeze more in.

And then #4, make the fins out of a different material than you make the actual cylinder out of. You now have a two piece cylinder made out of different materials that have a different expansion coefficient. P&W, Wright and even Ranger all went to this two piece construction during the war.

It doesn't matter what you do for fuel, or supercharger or bearings for high rpm. That is a fundamental problem for all high powered air cooled engines.
Now the practical problem was how to make the fins using either existing tooling or with available new tooling. Wright about tripled the amount of fin area on the R-1820 engine between 1930 and 1940. Which means bigger (thicker) basic forgings, a lot more machine time machining the fins and/or ways to cut more than one grove at a time. Also means getting the thin cutting tools down into deep tightly spaced grooves. Cylinder head design was also critical for the same reasons. Trying to squeeze in a lot more fin area in a limited area required new materials, changes in casting/forging, new tools, etc.

The small engine guys never faced this problem or since their cylinders were smaller, they could adopt techniques the bigger engine makers had figured out earlier.
The small engine guys were using superchargers but they were interested in take-off power or power at 2-3000 meters. Just a little more power for cruising at altitudes that didn't require oxygen equipment.
Some of the engineers were skillful and any engineers going to a larger company beats no engineers incoming. Not saying they could not make some contribution. But I am not seeing a big one.
In the US Fairchild/Ranger did a lot of research trying to straighten out their small V-12 (chronic over-heater) and it lead to a lot of knowledge in airflow, fin spacing and baffling (and a way to "glue" sheet metal aluminum fins to a steel cylinder barrel) just in time for the war to end.

Somebody claimed that a German engineer said he knew the war was lost when he saw the P&W engine in crashed P-47. He knew what they did to make the engine, he didn't understand how they did it on a production basis.

 

[tomo pauk]

It doesn't matter what you do for fuel, or supercharger or bearings for high rpm. That is a fundamental problem for all high powered air cooled engines.

A better, more efficient S/C will be leaving more HP for the prop, though.

Somebody claimed that a German engineer said he knew the war was lost when he saw the P&W engine in crashed P-47. He knew what they did to make the engine, he didn't understand how they did it on a production basis.

You know me and the legends/stories
In case of the P-47, the part where the Americans were better/much better was the turbo, not the engine itself. Turbo and the ancillaries being fruit of the Republic/Seversky and GE, not P&W.

In the US Fairchild/Ranger did a lot of research trying to straighten out their small V-12 (chronic over-heater) and it lead to a lot of knowledge in airflow, fin spacing and baffling (and a way to "glue" sheet metal aluminum fins to a steel cylinder barrel) just in time for the war to end.

The last part kinda points out to the real problem.

 

[Shortround6]

In case of the P-47, the part where the Americans were better/much better was the turbo, not the engine itself.

The R-2800 doesn't get quite the credit it deserves as an engine. Or as a feat of manufacturing.
The US built over 82,000 R-2800s in 1941-44 compared to the Germans building 61,800 BMW 801s including 1945 (not many).
The US built over 31,000 R-2800s in 1945 but that is an unfair comparison.
R-2800 used 28% more cylinders per engine which have to be made.
The Americans figured out new ways to make things (like cylinders and cylinder heads) that made parts just as good as the old ways, if not better, and in huge quantities.

I will also point out that Just two factories (or complexes ) made over 66,000 of the R-2800s made in 1941-44. Granted they saw a lot of expansion.

Or try to flip the engines around.
Allied fighter/s with BMW 801 engines (even with allied turbos) trying to fly the distances (hours) that the P-47s flew in 1944?
Yes the Allies had better access to raw materials.

If the basic engine wasn't very good it would not have stood up to the turbos or two stage superchargers like it did.
P&W made the choice to use 155cu.in cylinders instead of the 183 cu/in cylinder that a BMW 801 used (or the 185 cu/in that the Wright R-2600 used) in part for better cooling. Using 28% more cylinders for just under 10% more displacement is a poor choice unless they got something else out of it.

Now maybe P&W was forced to use more but smaller cylinders for better cooling because their lousy supercharger/s heated the intake air so much
Apparently Wright had not figured it out.

 

[tomo pauk]

The R-2800 doesn't get quite the credit it deserves as an engine. Or as a feat of manufacturing.
The US built over 82,000 R-2800s in 1941-44 compared to the Germans building 61,800 BMW 801s including 1945 (not many).
The US built over 31,000 R-2800s in 1945 but that is an unfair comparison.
R-2800 used 28% more cylinders per engine which have to be made.
The Americans figured out new ways to make things (like cylinders and cylinder heads) that made parts just as good as the old ways, if not better, and in huge quantities.

I will also point out that Just two factories (or complexes ) made over 66,000 of the R-2800s made in 1941-44. Granted they saw a lot of expansion.

There is no doubt that the R-2800 was a great engine, and that Americans made an excellent job in making them in tens of thousands. One can just expect that Germans will make far less of the BMW 801s, even if they were not bombed.
Germans also made far less of other things than what the US made.

The point I was trying to make is that the turbo system gave the edge to the P-47. However, while the Germans were able to match about the 90% of the R-2800's power under the same circumstances, it was the turbo set-up - promising as it was - that they were not able to replicate in the required quantity.

Or try to flip the engines around.
Allied fighter/s with BMW 801 engines (even with allied turbos) trying to fly the distances (hours) that the P-47s flew in 1944?
Yes the Allies had better access to raw materials.

Stick the BMW 801 instead of the R-2800 on the P-47 in 1942-45, and it will fly just as good and just as long.

 

[z42]

P&W made the choice to use 155cu.in cylinders instead of the 183 cu/in cylinder that a BMW 801 used (or the 185 cu/in that the Wright R-2600 used) in part for better cooling. Using 28% more cylinders for just under 10% more displacement is a poor choice unless they got something else out of it.

One could argue that with lower octane gas than the Allies (C3 was what, roughly equivalent to 100/130, whereas late in the war R-2800 ran on 115/145?), and poorer valves, bearings etc., the Germans could get away with slightly more volume per cylinder before running into cooling limits due to the surface area vs volume issues you described.