1943 Chromium use for German aircraft engines

Discussion in 'Engines' started by davebender, Dec 19, 2010.

  1. davebender

    davebender Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    6,418
    Likes Received:
    64
    Trophy Points:
    48
    Location:
    Michigan, USA
    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.
     
  2. Milosh

    Milosh Well-Known Member

    Joined:
    Aug 10, 2009
    Messages:
    1,918
    Likes Received:
    96
    Trophy Points:
    48
    So DB is going to stop engine production so Jumo 004A engines can be produced?
     
  3. davebender

    davebender Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    6,418
    Likes Received:
    64
    Trophy Points:
    48
    Location:
    Michigan, USA
    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.
     
  4. Jabberwocky

    Jabberwocky Active Member

    Joined:
    Jul 24, 2005
    Messages:
    1,090
    Likes Received:
    16
    Trophy Points:
    38
    Occupation:
    Teacher
    Location:
    Japan
    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.
     
  5. riacrato

    riacrato Member

    Joined:
    Oct 17, 2009
    Messages:
    669
    Likes Received:
    4
    Trophy Points:
    18
    Occupation:
    Project Manager in FADEC industrialization
    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.
     
  6. davebender

    davebender Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    6,418
    Likes Received:
    64
    Trophy Points:
    48
    Location:
    Michigan, USA
    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.
     
  7. delcyros

    delcyros Well-Known Member

    Joined:
    Mar 2, 2005
    Messages:
    2,037
    Likes Received:
    27
    Trophy Points:
    48
    Location:
    Berlin (Kreuzberg)
    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.
     
  8. davebender

    davebender Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    6,418
    Likes Received:
    64
    Trophy Points:
    48
    Location:
    Michigan, USA
    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.
     
  9. Jabberwocky

    Jabberwocky Active Member

    Joined:
    Jul 24, 2005
    Messages:
    1,090
    Likes Received:
    16
    Trophy Points:
    38
    Occupation:
    Teacher
    Location:
    Japan
    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.
     
  10. davebender

    davebender Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    6,418
    Likes Received:
    64
    Trophy Points:
    48
    Location:
    Michigan, USA
    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.
     
  11. Milosh

    Milosh Well-Known Member

    Joined:
    Aug 10, 2009
    Messages:
    1,918
    Likes Received:
    96
    Trophy Points:
    48
    These metals were used in more than just a/c engines.
     
Loading...

Share This Page