> All of these problems are workable - as was demonstrated by the Jet
> Gyrodyne
>
> http://www.gyropilot.co.uk/downloads/Rotodyne%%202%%20RTF%%20Mod.pdf
>
> Here an engine, designed to operate efficiently at subsonic speeds
> produces a jet of super charged air that is directed through a rotor
> to tip jets -here the noise is abated, due to the rotor itself acting
> like a tuned muffler, and night visibility is not a problem - due to
> the temperatures of the exhaust at that point.
>
Both the Gyrodyne and follow-on Rotodyne suffered from high tip jet
noise problems; in fact, it was the noise that the Rotodyne's supersonic
exhaust tip jets generated that led to its cancellation - it was
intended to takeoff and land from pads in the interior of cities, but
the noise level was so high that the airlines that looked at it found it
unacceptable because of this...and it's still a problem with rotor-tip
jet propulsion: http://www.rotaryforum.com/forum/showthread.php?t=15533
