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I'd also like to congratulate Perry for his first fan-free flight. Like
everyone else, I'm sorry to see it go, but we do this for "education and entertainment", so maybe it's time to move on. Hope the drive is working well for you. Never caused me any trouble at all. Cheers,
Rusty
Thanks Rusty.
I was concerned that changing the flywheel to the counterweight would possibly introduce an imbalance in the engine. So I fired up the engine/psru with no prop. No vibration. Put the prop on and I'm getting some vibration. So there must be a small imbalance in my prop even though it was statically balanced. I've tried 4 times now to use a computerized dynamic balance system, but it won't converge on a solution. It always worked perfectly with my direct-drive fan. So it mustn't like geared engines. I'm going to trial-
and-error it by moving a fender washer (weight) from one prop bolt to the next and see if the vibration level readout increases or decreases, and try to find a minimum. I flew a short flight again this morning, climb rate hit 1500 fpm at one point, I usually don't see over 1000. In level flight I briefly ran it up to full throttle and saw 5700 RPM, which should be 2627 prop rpm and 170 mph/147 knots with my 68 inch pitch, but I didn't stay at the throttle setting long enough to let the speed build up, because the vibration was a little uncomfortable. Probably minor by Lycoming standards, but I still didn't like it.
I'm a little confused on my final approaches, as I seem to have to carry more power than with the ducted fan. But with only two landings now it's a little early to tell.
Ducted fan definitely has applications, such as gyrocopters or LSA (speed limit 120 knots). Here is a LSA based on the Rutan Solitaire sailplane I've been thinking about, rotary-powered of course (lighter duct and lighter flywheel than I've been using)...
Perry
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