Japanese Piston Engines

[davebender]

The Sakae was probably inexpensive to mass produce. An important consideration when you are purchasing 10s of thousands of engines.

[proton45]

Originally Posted by cherry blossom

I found an interesting account of the problems of the Ha-40 engine in "The romance of engines" by Takashi Suzuki which stated on page 350

"The major problem with the DB-601 engine was excessive wear of the circumferential surface of the crankshaft pin during service (Photo 38-3).

The primary cause of the excessive wear was the inadequate hardness of the crankshaft due to poor heat treatment of the outer surface."

Also on page 362

"On the otherhand, when observing the structure of the carburized area, the German Benz crankshaft has a neat Martensite structure (indicating satisfactory quenching). The Japanese engine crankshaft shows precipitation of troostite, which indicates inadequate quenching (Photo A38-2)."

As you can imagine, there is quite a lot of additional discussion of the topic which I have not typed in!

Wasn't their something about the type of bearings that where used with the crankshaft?

[cherry blossom]

Takashi Suzuki notes that Professor Kiyoshi Tomizuka believed that roller bearings should not have been used in the crankshaft (Romance of Engines, page 333). Apparently Kawasaki planned a version with a shell bearing and Daimler-Benz also developed one. However, Suzuki did not accept that this was the problem and argued that DB was influenced by ease of production rather than crankshaft failures (page 343). I feel incompetent to assess these arguments! Perhaps the point is that a roller bearing must survive local deformation (as the balls roll around) as well as being hard. Thus a roller bearing may require better metallurgy.

[danjama]

Hi, this is my first post here, i was linked here over at some il2 sturmovik forums and have been lurking + reading, just wanted to say thanks for this thread in particular as i myself have been struggling to find decent information on japanese aero engines for some time. I plan on sticking around and hopefully learning alot from everyone here, and maybe teaching a few things!

[straighttj]

Hi there
If you go to the aero engine historical society website ( enginehistory.org ) they may have something for you on some of there engines.
I will also have a look at home & see what I have got aswell.
Hope that helps

straighttj

[mrcrazy]

The Smithsonian are working on a book on Japanese aero engines.

Japanese Aircraft Engines
Book research in progress
Robert Mawhinney, Museum Specialist, NASM