Greetings,
I decided it was time to prove what I thought I knew about the single rotor prop resonance. When I went from the shore 60 damper to the shore 50, it seemed much better, so I decided to hack the shore 60 into something even softer than the shore 50 to test the theory further.
I started by drilling a couple 3/8" holes through the six faces of the damper. It seemed much better at home, but when I compared it to the shore 50, it was still harder. I then tried drilling holes perpendicular to the original holes, but it didn't make much difference. Finally, I just hacked out a notch on the inside of each segment. This is certainly softer than the shore 50, though not by as much as you'd imagine. Clearly I'd never fly it like this.
What I found was that I could run the engine as low as 2000 rpm, and the fore/aft prop movement was almost non-existent. It's an absolute night and day difference from what I had with even the shore 50 damper. There's some of the engine vibration you'd expect from having no flywheel, but it's still smoother than the Rotax 582 on my gyro.
Bottom line is that the engine should be perfectly usable if I can come up with a soft, but strong damper. I'm thinking RV-12, maybe on floats in honor of my new ASES rating :-)
Cheers,
Rusty (spending too much time on R/C stuff)