Thanks for that info. I can imagine myself visiting someday, Czech aviation would be nice to experience in person. I was intrigued when visiting the Kbely museum in Prague a few years ago.
The OHC design is really something else, reminiscent of high class 1920s and early 30’s automotive practice. Some designs live on for a very long time – I have a 1980 motorcycle with bevel gear and tower shaft drive OHC, they kept using that design until only about 35 years ago. For a low speed aircraft engine it wouldn’t seem to make a lot of sense versus hydraulic tappets, pushrods and a cam driven by one gear set… but who knows what factors and constraints may have been in the designers mind.
Silvaire wrote:
The OHC design is really something else, reminiscent of high class 1920s and early 30’s automotive practice. Some designs live on for a very long time – I have a 1980 motorcycle with bevel gear and tower shaft drive OHC, they kept using that design until only about 35 years ago.
The M137/337/332 series dates back to 1956, when it was still Walter. Since then, several modifications have been introduced (aerobatic oil system, adaptations to specific airframes, and a higher power rating) but the core design remains unchanged.
Allison dohc V 12 :
DB 605 camshaft, one cam each for inlet and exhaust, four valves :
DB 605 cam:
DB 605 and RR Merlin right:
@Ultranomad. I just did some research on the Zlin 526A (and engine configuration) that a friend here owned for 15 years in the 80s and 90s. He got it to ‘one up’ the 80’s Chipmunk crowd here, and what got my attention was that it was imported to the US in 1971 by Harold Krier, who is (was?) a legendary figure in early US aerobatics. That’s about the same era as CZ motorcycles and a few other nice Czech machines were also making their their way west 
After Krier was killed, it was taken over by a lady who installed 200 HP O-360 power, which is how my friend eventually got it. Apparently it was built for a Walter engine but imported to the US originally without any engine installed. Not originally a 526L, but it ended up that way. I have no idea if it’s still flying – it would be fun to figure that out.
This from an old 1973 monthly newsletter
