OS MAX-S 35 and OS MAX-H 40

I have 2 of the 35s and used them in profile carrier about 30 years ago. I'd like to remove the carbs and install a venturi. I see a lot of messages talking about various OS engines here but quite frankly I'm not quite sure what I've got. Is there still a URL that might have some info on these particular engines? Is this still a desirable engine for modern stunt?

The 40 has a small RR right below the 40 at the bottom of the by pass. It is a front rotor engine with a large opening in the venturi. There is a crankcase pressure tap in the upper left of four screws in the backplate. I would like to set this up for stunt if it is a good engine for stunt. The 40 is a ringed engine. All the engines have very good compression.

Tom,
The 35s is a great stunt motor and the 40H is good too. E-mail Leonard the forum host. He can set you up as he sells venturi's and mufflers for both these engines. He can tell you the props and the fuel to use. He is at: [email protected]

I believe that the Max H 40 with RR stamped in the circle below the "40" was their rat race engine and has significantly different timing than the ones used for stunt. There is also an RC engine with a "P" below the "40" which designates it as the pylon racing engine, another engine timed for high speeds. The stunt motor was marked "S", but there are many more of the RC version with no mark other than the 40 which have the same or very similar timing.
Steve
The older I get, the better I used to fly!

Yep. It's not really suitable for Stunt unless completely reworked- there are Max .40Hs and then there are Max .40Hs!