enginehistory.org

[rinkol]

I noted with interest the recent article on the Jumo 222. I recall a report that the Soviets continued the development under a team of interned German personnel. However, AFAIK, there does not appear to have been any significant outcome.

Can anyone else shed further light on this?

One thing that is curious about the Jumo 222 development is that versions with three different sets of cylinder dimensions were developed, and moreover, there seemed to be parallel developments with different sized cylinders. I would have thought that the priority would have been on resolving the reliability issues. Can anyone comment as to the severity of these issues and the progress made on them?

Robert

[pshort]

Robert,
I have a book "Junkers Aircraft and Engines 1913-1945" by Antony L Kay (Putnam, 2004) which has a pretty brief glance at the various Junkers engines.
The engines mentioned in regard to later work by the Soviets were the Jumo 223 and 224 - large diesel engines in a square or cruciform layout. No more info given about the Russians except to say these large engines were overtaken by the jet age.

I can't make much sense out of the info given in this book about the Jumo 222. There is one page given to the the various models of Jumo 222, but the author confuses me by saying "the bore and stroke (of the E/F series) was less than the C/D series but the capacity was increased"?? Later says "bore and stroke of the G and H models reverted to that of the A and B models but capacity was greatly increased"!! Maybe this meant the latter were 36 cylinders, but this isn't mentioned.
The Jumo 225 is mentioned as a projected development of the 222G/H using 36 cylinders (six banks of six cylinders).

I suspect there is better information in "Junkers Flugtriebewerke", but I can't decipher much of it! Hoping for an English translation of this nice book.

[kmccutcheon]

[rinkol]

The motivation for the increases in cylinder size would seem to be to squeeze out more power. The primary application, at least to start out with, was the Ju 288, and this in turn went though increases in size and weight to meet changing specifications.

In highly political bureaucracies, there is often a temptation to keep making promises, some of which result from a need to make amends for the failure to make good on previous promises, no matter how unrealistic they are, because to not to do so would effectively be an admission of the unmentionable, namely that things have gone terribly wrong.

FWIW, Irving's book on Milch reports that Koppenberg, the head of Junkers, was dismissed on the spot after Milch decided his promises for Ju 288 production were not credible. The book goes on to say that shortly afterwards, reports indicated that there were fundamental problems with the Jumo 222 piston rod bearings and cylinder heads, but that mass-production was envisaged in August 1942. It also states that Milch was given permission to cancel the Jumo 222 engine contract, though it appears that development continued.

Robert

[pshort]

There is a little bit about these engines in "Russian Piston Aero Engines" by Vladimir Kotelnikov, pages 236-237.

The author says there was great interest in the Jumo 222, and that two engines were taken to Moscow. Apparently there were preliminary projects prepared for long-range bombers using both 222 and 224. The Jumo 222 was re-designated the M-222.

It was the Jumo 224 that he says a little more about though - how the Russians went about getting the engine re-drawn (drawings and engines were destroyed before the Russians arrived) and how a group of Germans were taken to the Soviet Union to work on this engine design. Work on this design (M-224) stopped in June 1948. Apparently V.M. Yakolev slowed down work before this, believing his M-501 diesel engine would be better for long-range bombers. Apparently this engine went on into series production for marine work - seven blocks in radial, 42 cylinders. Sounds like another very interesting design!

[mmotley]

There is mention of a follow on development in 1949: Dobrynin WD-4K also a 6 Bank, 4 Row Inline Radial about to be used ,but replaced by a lighter Turboprop.