Originally Posted by
Dave_Jackson
It was mentioned by IMFU, in a different thread, that Sikorsky's new X2 coaxial ABC will have multiple-speed rotors, as did its predecessor, the XH-59A ABC.
However, the possibility of using single-speed, low-rpm rotors with wide chord blades (large
solidity ratio) for tomorrow's high speed rotorcraft appears to have significant advantages.
I found this Nick Lappos quote:
It pulled 2.5 G's at 25,000 feet and cruised at over 250 mph, as the thrust engines pushed it along in autorotation (it was an autogyro at high speed!) Not too shabby.
You can find that quote in the middle of this page:
http://www.synchrolite.com/0891.html
And, as Nick said earlier in the thread:
Originally Posted by NickLappos
A turbine helo has way too much blade chord for hover (it throws away power) because it needs that chord for higher speed forward flight.
So, if the S69 was an autogyro, its main rotor was not absorbing much power. So what would wide chord blades do to to help it speed along?
Then again maybe it gets solidity ratio through sheer number of blades rather than chord.
-- IFMU (not IMFU, that's my evil twin)