I believe there is a basic problem with tiltrotors. Either engine can power both rotors if one engine fails (like the Chinook). But because the rotors are on either side, if the power from the rotors gets wildly out of sync, it’s possible for the aircraft to go into an uncontrollabe roll. The so-called Vortex Ring State (VRS) is one way this can happen, and that was what caused at least one of the 3 fatal accidents that have dogged Osprey since it first flew in 1989. That - 18 years - is how long it’s been in development. 30 people died in the three accidents - and in 2000 development was grounded. The Pentagon gave two years for the programme to be sorted out. It was sorted out - basically by restricting the aircraft so that it never gets into that vulnerable corner of the flight envelope. That’s why it now has warning systems for VRS, and improved training for pilots in VRS awareness.
Osprey achieved its successful operational evaluation in June 2005, and the Pentagon approved full scale production in September 2005. Now it faces its greatest test, in operational service.
Btw, I also blinked at what nacluv quotes
The Osprey's big problem is that it risks losing lift in just one of its two engines, in which case it will flip over and begin to fall upside down.
I believe there’s an error there - the report should perhaps refer to ‘rotors’ in this sentence, rather than ‘engines’.
airsound