DerGiLLster
Airman
- 70
- May 1, 2015
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The official man-time-between-overhaul (MTBO) was either 25 hours or somewhat higher. 10 hours is related more to anecdotal evidence from pilots. There's a lot of information on this scattered around the forum. If noone else manages to point them out, I'll try to dig them up eventually.I think an interesting follow-up question might also be, given the dire state of German manufacturing in late 44 1945, how much of what they were producing was unfit for purpose or manifestly sub-standard.
I have seen stories of aircraft supposedly made to 'standard' specs having to be, where possible, refinished (by hand), Me262's with issues, poor welding on tanks and so on.
A Jumo 004 with 'book' service life of 10 - 25hrs might often have a lot less (and ditto any improved later versions), no?
Did the Type XXI use some of the same alloys as the 004A? I could certainly see it using tons of stainless steel alloys, but those weren't the limiting factor for the 004A. I'm sure there were a good amount of 'common' stainless steel components (I suspect a large portion of the combustion chambers and exhaust) but some of the key components like the turbine and turbine stator used more exotic high temperature alloys that, as I understand, were not available in quantities suitable for mass production.I suspect this had an impact. Type XXI submarine program was massive, top priority and happened around same time that Germany might have ordered Jumo 004A engine into mass production.
Most of the German quality problems related to unskilled labour, often working with inadequate tooling in some production lines and the reality that it can take a few months to sort out production issues
naturally detractors focus on these.
The clue is big variations in say service life: some engines lasting hundreds of hours and others only dozens. That's indication of a variation control problem.
You will often find quality issues on allied equipment as well. The AZON bomb had around a 40% dud rate. A lot of folks were learning mass production, one reason new types were introduced only slowly.
I had meant that materials normally used for machine tools were being used IN the turbine components themselves. Molybdenum and cobalt alloys in the ENGINES rather than just in the machines making them.Submarine machine tools required the same alloys as aircraft machine tools. Same goes for concrete and labor required for factory construction. That's the issue during fall 1942 / spring 1943 when Germany might have been tooling up for mass production of Jumo 004A engine and Me-262 airframe beginning fall 1943.
The German transportation network and overall logistical resource management/directing was already problematic pre-war, so those added stresses would have further complicated matters there. That was my point regarding 'getting engines, airframes, and fuel all in the right place at the right time' but it applies on the broader 'materials, components, engines in need of overhaul, etc' as well.No worse then anyone else. However late war Germany had an additional problem which is rarely mentioned.
Component production was widely dispersed in order to mitigate effects of British and USA bombing. This made quality control much more difficult. Even the top priority Type XXI submarine had problems with prefabricated sections which had to be corrected before the boat became operational.
No worse then anyone else.
27.41kg. DB605. Oct 1943.
19.01kg. DB605. Oct 1944.
21lbs. Jumo004A.
7lbs. Jumo004B. Early variants.
5lbs. Jumo004B. Late variants.