Spike Jones wrote:
>
> "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
I personally prefer in-line dual rotors to the v22 configuration.
Several years ago I designed a rotorhead for such a system which seemed
to me to be far more mechanically simple than the complex stuff I'd seen
on larger contrablade systems. My design was for a rotary engine driven
backpack chopper that utilized weight shifting for some maneuverability,
but with full cyclic pitch and collective control.
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