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Subject: Re: [FlyRotary] Re: Single rotor video
Date: Tue, 05 Jun 2007 10:31:44 -0400
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Rusty,
  You may be getting something that was studied with dirt bike singles=20
and narrow angle v-twins (Harleys). These engines worked well in=20
getting traction on dirt tracks due to their firing order. If I recall=20
it was called climb and retreat by the guys actually studying it. It=20
would apply to a prop very well. Your prop has at the very least some=20
flexibility in the blades. The power pulse hits and forces the blade=20
forward violently, followed by a lull. Think of it like driving a long=20
screw into wood. Every 1/2 turn you must re-position your grip. Any=20
twist in the shaft of the screwdriver is released until you start=20
turning again. The fore and aft movement might be caused by the large=20
power pulse of the single rotor. This may be a totally natural event.=20
OF course I've been wrong before, YMMV etc...
Bill Jepson


-----Original Message-----
From: Russell Duffy <rusty@radrotary.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, 5 Jun 2007 6:10 am
Subject: [FlyRotary] Re: Single rotor video


How about a freewheel unit (slipper clutch) - should prevent alt least=20
the reversal part=A0after the power-stroke...=A0

=A0

I know Rotax used those to get rid of resonant problems with their=20
912S, and=A0if I get to the point where I have to=A0custom fit some sort of=20
coupler, I'll=A0consider trying it.=A0=A0

=A0

Also, visual impact is one thing, that may have NOTHING to do with the=20
actual blade behaviour.

Unless you take a strobe and watch, you might get some "funny show" -=20
frame rate of the video, etc.=A0

=A0

This is true, but there's no optical illusion I know of that can=A0make=20
the prop move fore and aft when viewed=A0directly from the side (in the=20
arc).=A0=A0What you see is also consistent between viewing with your eyes,=20
and the camera, which is another indication that it's real.=A0 A really=20
high speed camera would be better for this=A0though.=A0

=A0

Rusty

=A0

=A0

=A0


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