PPRuNe Forums - View Single Post - VTOL Research, Development and Product ~ by Wikinomics
Old 20th February 2007 | 22:53
  #23 (permalink)  
Dave_Jackson
 
Joined: Apr 2003
Posts: 1,635
Likes: 1
From: Vancouver, BC, Canada
Heliport,

Thanks.
It's looking like the 'bandwidth' usage ain't going to be too large.


Slowrotor,

I think that two, or more, recreational coaxial helicopters have rigid (no teetering or flapping) hubs with 2 blades each, as you suggest. However, I really question this approach. In addition, one of these coaxials has no ability to autorotate.

The following is a quick 'cut and past' from a UniCopter web page;
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Hiller Rigid Rotors: Hiller X-2-235, Hiller XH-44

"... the extremely rigid rotor of the Hiller lead to "Vibration problems curtailed these tests for fear of damaging the wind tunnel" When you worry about the aircraft wiping out the tunnel, you have problems! ~ Nick Lappos on RAR

Dual rotors with two blades each will result in a lateral vibration when longitudinal cyclic is applied. See: DESIGN: SynchroLite ~ Rotor - Disk - Lift Distribution re: Vibration ~ DBJ
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This submitted idea may not work and it is not intended for any of my projects. It just seems like an idea where one device might satisfy 3 or 4 requirements and be fun for a number of people to work through.


Mart,

Would you elaborate on 'hub compliance' and on 'zero-zero control loss'. Thanks.


Dave
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