I have a pair of 582's sitting around, and a bad idea has been haunting me for a couple years and just won't go away. Two 582 or 670 two-strokes side-by-side, perhaps one inverted to place both exhausts outside, mounted to a custom shared PSRU housing, using belt drives to provide isolation and hopefully reduce the mess of harmonics and vibration issues, independently driving coaxial propellers, at least one of them in-flight adjustable. One drivetrain would probably incorporate a pair of gears to achieve counter-rotating props. The PSRU should keep the drivetrains as separate and isolated as possible, be easily inspectable, and watched like a hawk.
The only win, balanced against numerous drawbacks, would be that it might be weight and dimensionally compatible with airplanes designed for an O-360 class opposed engine. Grab any common well-proven design and make it a unique and weird twin. Assuming two 90-hp 670's, it probably (definitely) would not yield a performance or weight win of any sort. And I think the best you could say for reliability and safety characteristics is that it would uhm "change" them in a bizarre and complicated manner.
It would sound really weird in every phase of flight, and would be good conversation starter, and might lead to all kinds of unique fame.. is "The Only Two-Stroke RV" already claimed? I suppose bigger projects have been started for worse reasons.
The only win, balanced against numerous drawbacks, would be that it might be weight and dimensionally compatible with airplanes designed for an O-360 class opposed engine. Grab any common well-proven design and make it a unique and weird twin. Assuming two 90-hp 670's, it probably (definitely) would not yield a performance or weight win of any sort. And I think the best you could say for reliability and safety characteristics is that it would uhm "change" them in a bizarre and complicated manner.
It would sound really weird in every phase of flight, and would be good conversation starter, and might lead to all kinds of unique fame.. is "The Only Two-Stroke RV" already claimed? I suppose bigger projects have been started for worse reasons.
