From: Spike Jones (spike66@attglobal.net)
Date: Fri Jan 12 2001 - 22:06:14 MST
"Michael S. Lorrey" wrote:
> Here are links to various pics of assorted little known VTOL aircraft,
> including several that takeoff and land on their tails...
Cool! Thanks Mike. I fooled with designs for several years
for VTOL aircraft. I am in the Society of Aerospace Weight
Engineers. At the conferences, the latest VTOL and STOVL
concepts are the most common topic of discussion.
I messed around for years with the idea of a pivoting single
engine single rotor craft within a lifting surface. It kinda
looked like a flying saucer of sorts, but I never could figure out
a practical way to cancel the torque. Consequently the only
convincing small VTOL craft designs are dual rotor and end
up looking a lot like a scaled down version of the V22 {thus
my personal interest in the Osprey}.
My calcs show that a scaled down version of a V22 could be
built large enough to haul one person, however it has some
pretty severe practicality and safety related compromises, such as:
1) The two rotors are not geared together as in the V22, thus
if either engine fails, the probability of survival is low. If one
pays the weight penalty for variable pitch rotors, then there
remains some possibility of surviving an engine-out landing,
at the expense of a large fraction of the payload capacity.
2) The range is short since the fuel hauling capacity is not high,
and the engines large and thirsty.
3) The short legged landing gear necessitated by weight
constraints makes a conventional landing impossible for
two reasons: the wheels are very small and also the rotors
would strike the ground).
4) If I calculated correctly (and its possible I didn't) then
if one were to go full throttle in horizontal flight mode
the wings could tear off. This one Im not at all sure about.
5) As with the V22, the transition between horizontal to
vertical flight modes is very do-wrongable, even with an
experienced pilot.
The most convincing looking design is that dual rotor
air-cowboy thing those two local guys are working on.
spike
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