The V-22 has had both its share of real early design flaws and a rash of bad luck to boot. But the biggest obstacle the Osprey has had to over come is a flood of out of date, distorted and down right untruths spread by individuals with special interests.
Supposed aviation experts also continue to apply their helicopter rules of flight to the V-22. Well the V-22 is not a helicopter, it is a Tiltrotor. And Tiltrotors have capabilities provided by their wings and tilting nacelles that when used properly eliminate most of the problems you quoted.
1. Ring vortex once entered is very difficult if not impossible to recover from.
Vortex Ring State or as it is commonly known setteling under power affects all helicopters both tandem and tail rotor when they drop to rapidly over one spot. In a tandem CH
-46 VRS induces pitch and the condition is relieved. In tail rotors you keep dropping. In Tiltrotors VRS can induce roll, but if you rotate the nacelles slightly forward VRS is relieved. V-22 pilots are now trained in this maneuver.
2. Massive downwash produces white brown or black outs depending on the terrain at upto 100ft in the hover.
This problem affects all rotor craft. V-22 pilots have developed a technique however that reduces the problem to a level much better that CH
-46 it replaces. During final approach the nacelles are rotated slightly forward while using the cyclic to reduce forward speed. This blows the dust behind their field of view.
2. Autorotation is unobtainable in any true sense of the term.
As a consequence of this double engine failure is unsurvivable. Unless your on the ramp. (Contaminated fuel is the number one cause of double engine failures in shipborne rotorcraft.. a not so rare occurrence)
Based on the V-22s rotor diameter and inertia, analysis predicts that a pure autorotation would be iffy at best. But guess what! The V-22 has a wing with huge flaps! Any degree of forward speed provides substantial lift. To provide directional stability in autorotation and select a landing spot helicopters hardly ever autorotate straight down. V-22 Pilots are trained to maintain required forward speed for autorotation landings.
4. Single engine failure is problematic the aircraft is sensitive in the hover even using two and susceptible to PIO at all times in this phase.
Pilot Induced oscillations in earlier aircraft were related to the Fly-by-Wire flight control system issues, not single engine power. These problems have been corrected. The V-22 also has sufficient power to climb with one engine.
5. Imagine taking this aircraft into combat getting shot at, (no means of self defense fitted !) and then sustaining Battle damage and then having to make a single engine approach in bad wex, possibly overweight....etc
All flight critical V-22 systems and components are either redundant or designed and tested for ballistic tolerance. The ballistic tolerance requirements imposed on the V-22 are higher that ANY existing fielded helicopter.
If by no means of self defense you infer no way to shoot back with bullets, you are (currently) correct. However the V-22 is the best equipped vertical lift aircraft known to deal with IR
and radar guided missiles. I am not referring to chaff and flares (although it has them). Some of those strange bumps you see on the V-22 are radar guided lasers.
The V-22 also has both an IR
and radar signature much smaller than any similar payload helicopter.
Finally, it flys further and faster (even with just one engine).
By the way. In answer to the original question. The V-22 has completed OPEVAL, and although the results will not be formally announced until Sept., all reports indicate it will be approve for full production. Currently approximately 40 V-22s have been delivered to the Marines/Navy.