Dan wrote:
Pat Flannery wrote:


Vince wrote:

The handling of the V 22 would be even marginal except that it is
massively overpowered and overweight for the cargo load it can carry

they use brute horsepower to overcome the inefficiency of the tilt rotor

it lifts about half the load a ch 53 with 12000 hp lifts

Could be worse...could be this:
http://www.vstol.org/wheel/VSTOLWheel/KamovKa-22.htm
That didn't look right, and it didn't fly right either.

Pat

Interesting layout. I assume the rotors would be used in autorotation
during horizontal flight. If this were done full time it wouldn't be
able to take off vertically, but would make one big autogyro.

Dan, U.S. Air Force, retired

the v-22 cannot safely auto rotate

1. LACK OF AUTOROTATION CAPABILITY

Although it was initially believed that V-22 would have a full
autorotation capability, it is now generally agreed that the V-22 cannot
autorotate in any practical sense. Although the V-22 has performed an
autorotation in a technical sense, the test procedure was carefully
structured to allow for a safe entry (the engine power was slowly
removed to allow the aircraft to establish a stable autorotation.) In a
practical autorotation, the aircraft must be able to enter a stable
autorotative state following an abrupt power interruption. Although an
abrupt removal of engine power in V-22 has never been done, such an
event would probably result in loss of control because of the inability
to maintain rotor RPM. This is especially true if the failure occurs in
transition mode (60 deg nacelles)[1], the common configuration used for
“slinging” external loads.

The single autorotation test in V-22 also demonstrated that the attempt
to recover from autorotation to a safe landing by using stored rotor
energy to arrest the rate of descent failed markedly. The test data
indicate that the aircraft would have impacted the ground at a rate of
descent of about 3700 ft/min (61.7 ft/sec) ¾ a fatal rate-of-descent.
Authoritative proponents, e.g., the NASA Review Team, have argued that
autorotation is not a needed capability for the V-22 due to the low
probability of a two-engine failure. My analysis of Navy safety data
shows that the Navy/USMC experiences a dual engine failure in a
helicopter about once every 3 to 4 years due to fuel contamination
onboard a ship. Historically, such accidents have usually been
survivable because the helicopter autorotates into the water and the
crew and passengers quickly scramble out. If such an event were to
occur in V-22, it will probably be fatal to crew and passengers because
the aircraft will not smoothly enter autorotation, but most probably
depart from controlled flight, and because the cabin is too cramped for
a rapid egress.
http://www.g2mil.com/V-22safety.htm