On Wed, 21 Jan 2004 21:51:57 -0500, (Peter
Stickney) wrote:

It seems like a real sweet setup, as long as you're hovering. But
once you start moving, you'll be ramming more air into engine on the
advancing blade, and much less on the retreating blade, since the
rotational velocity of the rotor, and that of the helicoper moving
through the air will add. It seems to me that if you can't keep some
level of fine control on the jet's thrust levels, you're going to have
an awful time maintaining a steady (and proper) rotor speed.
How throttleable is a pulsejet? Is it throttleable at all? If you can
throttle it, how fast does it respond?

Depending on the design, pulsejets can be throttled over more than 50%
of their power range.

The problems you describe would not be an issue -- any more than the
effects of forward flight on a conventional helicopter where the
leading blade would tend to produce more lift (by virtue of its higher
airspeed) if its pitch were not reduced.

A sensible pulsejet powered helicopter (that's an oxymoron :-) would
have the air intakes placed close to the root of the rotor blade so
that the variation in ram pressure due to the combination or rotation
and forward speed would be reduced.

In reality, this extra lift produced by the leading blade would
manifest itself, not as a roll, but as a pitching motion due to the
effects of gyroscopic progression.

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