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Message
Greetings,
Thanks for
all the comments, but I do think some of you are getting a bit ahead of me on
this :-) The following are mostly random thoughts.
The
phenomenon is really amazing to me, but until more combinations are tested, I'm
not sure if it's even a problem. My gut feeling is that it happens to some
extent with any flexible prop, and requires some instability in thrust to set it
off. Low rpms and changing speeds seem to set it off for
sure. IVO props are more flexible, and have an even worse problem,
but the only caution is to allow 5" clearance at the tips of the IVO so it
won't hit anything. Even with that clearance, my old IVO on the Kolb
hit the back of the fuselage cage on startup one day. They flex
a LOT.
Common sense
would dictate that too much of this flexing is clearly not good, and a line
will have to be drawn before prop, or engine damage is done, but who can
say where that line needs to be without a ton of
testing?
A single
rotor Mazda (without a flywheel) has to be about the worst case,
because it's got a big powerful combustion chamber. Rotax
had plenty of single cylinder engines, but at most, they were half the size
of the single Mazda chamber. By the time any "normal" engine gets to
the displacement of the single rotor Mazda, it's got at least two cylinders to
help smooth things out. Clearly, what we need is a 2 or 3 rotor engine
that's sized to make an easy 100 HP.
My goal will
be to re-video the current configuration, perhaps with a yardstick or some other
markings in the picture for scale. I'll zoom it more to get just the
engine and prop, for more detail. I might even use the real video camera
instead of my Cannon PowerShot 3 :-) I'll video set rpms from about 2000
to maybe 5000, depending on how brave I feel about my trailer
stand. Not sure when this will happen, as I'll be out of town
for a few days getting dual in a similar gyro (nice try Lynn
<g>).
I smell
fajitas, and my beer is empty. Gotta go :-)
Rusty
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