In article ,
"Jim Atkins" writes:
Aren't there severe weight problems involved with separate vertical and
horizontal systems? Seems I recall things like Dornier's transport (Do 31?)
with dedicated lift jets that could just barely transport the weight of the
crew.

There are, especially in teh case of lift-jet aircraft, like the
Dornier, which had to haul around a bimnch of engines that were only
used for a short time each flight, but it's not that much of a problem
with something like the Rotodyne, or even the almost-contemporary
Lockheed AH-56. In the case of those aircraft, the rotors still
provide lift, but they're unpowered, acting as an Autogiro fotor, and
a fair chunk of the lift is taken up by the fixed wings. I guess
you'd lose a bit of hover performance becase of the extra wing area
under the rotor, but that would also accur with a tiltrotor.

I suspect that Vmax would not theoretically be as high, you'd still
have to deal with stuff like rotor tip speeds and retreating blade
stall, but it'd be a fair shot.

For the Rotodyne, noise was a severe problem. (Engine selection
wasn't - Fairey wanted to move to teh Tyne for any later developments)
If the newsreel soundtracks of teh thing I've heard are accurate, it
could only be described as that of a Huey carrying a large, running
Steam Locomotive. Consider this - Rotodyne noise was considered
objectionable during a time when acceptable noise included
unsuppressed straight-jet 707s and the just-proposed Concorde. You
gotta go some to beat them.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster