« Morning Smoke: GAO Finds Deficiencies in Interior's Ability to Monitor Oil and Gas Production on Federal Leases | Main | Classification Data -- The Tale of the Tape »

Apr 15, 2010



Its seems ITP has been following this scandal from the info at G2mil http://www.g2mil.com/scandal.htm

That has details on everything wrong with this program

A.A. Cunningham

"The counter rotating rotors of the V-22 have an even worse ring vortex state than your typical helicopter."

Fortunately we have objective data which refutes this oft repeated, yet very wrong, specious claim perpetuated by the ignorant.

"In August 2003, the V–22 Integrated Test Team completed a thorough investigation of the V–22’s low-speed / HROD flight characteristics. Testing defined an operational envelope for the aircraft and demonstrated flight regimes free from vortex ringstate (VRS). Tests also probed deeply into fully developed VRS to determine precise flight conditions where it may be encountered, and to confirm the ability of the V–22 to recover from the condition. The ability to tilt the nacelles proved to be a powerful and (in every case) reliable means for rapidly regaining aerodynamic function of the rotors, even when operating in VRS beyond the point of having sufficient controllability. Results for steady-state HROD conditions are presented and the methods for testing are described. In an operational sense, the test results show that the V–22 has a significantly higher rate of descent margin for avoiding VRS with respect to the published NATOPS limitation than conventional low disk-loading helicopters. Furthermore, dynamic maneuver testing of the V–22 showed that VRS cannot be initiated outside the steady-state VRS boundary. Simple engineering analysis is used to show that the V–22’s steady-state VRS boundary is predictable by simple methods that work for conventional helicopters. High blade twist, and the side-by-side rotor configuration of theV–22 do not play a significant role in defining the VRS boundary."



I used to have a book on VTOL aircraft. It said one of the lessons Bell Aerospace learned in their early work was never to use rotors or ducted fans on the wings. When you do you create a situation where the flow from the fans merges and diverts fore and aft under the fuselage of the aircraft. This flow will suck the airplane to the ground.

The counter rotating rotors of the V-22 have an even worse ring vortex state than your typical helicopter. Because of the twist of the air coming out of the rotors they create a big wash of air under the fuselage going aft. Much more of the impinging flow from the rotors goes aft than forward. If this aft flowing stream of air ever impinges on a wall or anything that diverts it upward, it is possible for that stream of air to get sucked into one of the rotors and cause a loss of lift on that side.

These aircraft are fundamentally flawed. The program should be cancelled and the aircraft scrapped. If our aircraft were designed by people instead of by committees the way they used to be in the Soviet Union this vehicle would have never been designed the way it was. It often makes me wonder who really won the Cold War.

The comments to this entry are closed.