1943 Chromium use for German aircraft engines

[davebender]

Supposedly the Jumo004A jet engine required 21lbs of chrome while the Jumo004B jet engine required only 7lbs of chrome. Supposedly this was the reason RLM decided not to mass produce the Jumo004A engine during 1943.


Daimler-Benz in the Third Reich - Google Books
A DB605 piston engine produced during October 1943 required 27.41kg of chrome. This declined to 19.01kg of chrome for a DB605 engine produced during October 1944. A significant material savings but the DB605 piston engine still required considerably more chrome then a Jumo004A jet engine.

So why didn't the Jumo004A jet engine enter mass production during 1943? The story about the Jumo004A jet engine requiring too much chrome and other such scarce raw materials is starting to sound unlikely.

 

[Milosh]

So DB is going to stop engine production so Jumo 004A engines can be produced?

 

[davebender]

DB is going to stop engine production so Jumo 004A engines can be produced?

Switching from one aircraft type to a newer type is not like flipping a light switch.

Germany was producing over 1,000 DB605 engines per month by January 1943 and production was rapidly increasing. You start by decreasing DB605 production by 100 engines per month. That frees up enough chrome to produce 200 Jumo004A engines per month. Enough to convert JG2 and JG26 to the Me-262 during 1943.

 

[Jabberwocky]

So why didn't the Jumo004A jet engine enter mass production during 1943? The story about the Jumo004A jet engine requiring too much chrome and other such scarce raw materials is starting to sound unlikely.

Because it wasn't just chromium that Germany was short for.

Molybdenum, cobalt, nickle and manganese were all needed for the engine as well, and were all in short supply.

Even if you get all the material problems sorted, there is still the difficulties with surging and blade design, which weren't solved until right at the end of 1943.

The engine simply wasn't fit for mass production until 1944.

 

[riacrato]

004A blades were made from Tinidur, with the following scarce materials:
30% Nickel, 15 % Chromium, 1.7 % Titanium

004B blades were made from Chromadur:
0% Nickel, 13 % Chromium, 18 % Manganese, 0.7 % Vanadium

So Nickel and Titanium were substituted, Chromium not really.

 

[davebender]

I agree. Unfortunately I don't know how much of these materials were required by a DB605 engine. However I suspect a DB605 piston engine required substantial amounts of these alloy materials for high strength components like piston rings, connecting rods, crankshafts etc.

We have Albert Speer's information concerning the German strategic resource stockpile at the end of 1943.

Manganese. 19 month reserve.
Wolframite. 10.6 month reserve.
Nickel. 10 month reserve.
Molybdenum. 7.8 month reserve.
Silicon. 6.4 month reserve.
Chromium. 5.6 month reserve.

Furthermore Albert Speer suggests Finland was mining more nickel ore then Germany needed. Hence ore was piling up near the mines for lack of transport.

I have no information concerning the German stockpile of titanium during 1943. Perhaps that really was a critical shortage. However it appears to me there was plenty of manganese, nickel and chromium for the production of Jumo004A jet engines during 1943, at least on a modest scale of a few hundred engines per month.

This leaves me thinking the Jumo004A engine was not as production ready during 1943 as some sources suggest. However finding information on the Jumo004A engine (as opposed to the Jumo004B engine) is like pulling teeth.

 

[delcyros]

The Nickel sources of Petsamo in Finnland secured the Reichs need for Nickel until 1944 when Finnland dropped out of the axis forces.
Production exceeded transportation capabilities.
A limited production of Jumo-004A turbines would have been possible in 1943. The design aim for the -B turbine was lowering the weight, the complexity and the production tolerances for a somehow workable jet turbine suited for mass production technique with unskilled workers. In this, the -B succeeded.

 

[davebender]

limited production of Jumo-004A turbines would have been possible in 1943.

So why didn't that happen?

Converting JG2 and JG26 to the Me-262A during 1943 would have provided Germany with a wealth of jet operational experience in addition to improving defenses vs American heavy bombers. Meanwhile Germany can continue development work on the Jumo004B engine.

 

[Jabberwocky]

So why didn't that happen?

Because its not just materials problems that prevented the entry of the 004A into service, but the fundamental design of the engine.

The 004A was purely an experimental design. It was built as a proof of concept without any concessions to engine weight, strategic materials use, or, most importantly, manufacturing considerations. The Junkers design team pursued a deliberately conservative strategy, because they wanted a working engine in the shortest possible time.

As the design was tested and experimented with there were blade and compressor failures from vibrations, overspeeding and other issues to deal with.

The 004B underwent a significant redesign (compressor, turbine, combustor cans and blade shape) before it went into service. It also had to be redesigned to allow ease of production, as well as account for the aforementioned material considerations.

 

[davebender]

Because its not just materials problems that prevented the entry of the 004A into service, but the fundamental design of the engine.

It appears to me that material shortages were not part of the equation at all. So either the Jumo004A engine had serious engineering problems or else RLM just didn't appreciate the Me-262 performance advantage over the Me-109G.

 

[Milosh]

We have Albert Speer's information concerning the German strategic resource stockpile at the end of 1943.

Manganese. 19 month reserve.
Wolframite. 10.6 month reserve.
Nickel. 10 month reserve.
Molybdenum. 7.8 month reserve.
Silicon. 6.4 month reserve.
Chromium. 5.6 month reserve

These metals were used in more than just a/c engines.

 

[Hetzer88]

Chromium was the key to German jet engines, and was the main reason why the turbine blades burned up. To stop this, the metallurgical engineers baked aluminum onto the turbine blades, which just about doubled their life, about 16 to 20 hours worth. If they had just used chromium, engine life would not have been a major issue, and the engines would have been ready in 1943. However, jet engine manufacturers were essentially forbidden to use the amount of chromium that was needed for one specific, and as it turns out, a useless reason. Rocket engines. Chromium was the only metal that could withstand the exhaust from a rocket engine, and it was used as a steering rudder placed directly into the rocket thrust stream to keep the rocket steady until aerodynamics on the exterior rocket fins took over. That chromium burned away too, but not before the rocket was up and away and headed on course.

The bottom line here is this. Hitler saw all of the explosive flash and power of the A-4 (V-2) rocket when it took off, and decided that was going to be his secret wonder weapon. The rockets got priority over all else for chromium use, and jet engines had to figure out alternatives, hence baking aluminum onto the turbine blades. Had Hitler understood that the real wonder weapon was a jet engine, HE-280's may have been coming off the assembly lines as early as late '41. Even then, the ME-262 with chromium turbine blades, would have been into production sometime in '43. Galland wanted them to go into production in the the spring of that year, and imagine if by late '43, 262's would have been attacking Allied bombers in force. Had chromium supplies, tech, and money been diverted to the jet engine program instead of von Brauns rockets, the ending of WW 2 becomes a bit more muddled. Let us all be grateful that it did not happen.

 

[Elmas]

Italian submarines at the Bordeaux bases were captured by the Germans in 1943 and transformed in transport submarines to try to import from Far East mainly metals like Chromium and Molybdenum , but also morphine, rubber and other raw materials, that were urgently needed.
But the Allied had Ultra...