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I just have seen a video of a demonstration of an Osprey V-22. While this is an impressive aircraft I wonder whether this might land with failing engines (with the large "propellers" probably hinder proper gliding).

What would a pilot do in the following cases:

  • one engine failed
  • both engines failed
  • tilt mechanism stuck
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Welcome to AviationStackExchange and to provide a short answer to your question, yes there are autorotation measures that are similar to those featured on helicopters. The basis for most of my answers pertain the unique drive shaft system, which allows for redundancy between proprotors, something other twin-engine fixed wing aircraft usually lack, so here's a diagram for some reference:

a little blurry but really illustrates the complex system

As for the detailed answer, I'll split it into three parts: One engine failure, total engine failure, and a stuck rotation mechanism.

  1. The two RR T406 type engines of the V-22 are connected by a driveshaft, which means that if one engine loses power, the other, provided that it is in good working order can deliver power to both proprotors through said shaft. It lacks the power to actually hover on that one engine though, so it has to be glided down, and protocol presumably dictates a powered glide to somewhere safe.

  2. When both engines fail, autorotation just as on a helicopter is instructed, however, due to the fact that the proprotors are about a third of the diameter of conventional rotors means its low rotational inertia results no autorotation will significantly reduce the impact from a total failure. In other words, it can't really glide like a plane and won't autorotate like a helicopter. It's getting the best and worst of both worlds.

  3. As long as the engines are working, the V-22 can land and take off in both configurations. However, there's an approximately 18-20% (Wikipedia quotes 18, Boeing claims 20) increase in flight efficiency in the turboprop aircraft configuration over the VTOL setting. I can only imagine that number goes higher by 10-15% during takeoff and landing. Planes are simply more efficient this way.

So, yeah.

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  • $\begingroup$ By 'rotation mechanism' I actually meant the ability to tilt the nacelles, for change between the plane/helicopter configurations. $\endgroup$
    – hitchhiker
    Commented Feb 16, 2019 at 21:35
  • $\begingroup$ That makes more sense. Anyways, it's my 3 (alternate) one so i'll probably just delete the former. Thanks for clarifying! $\endgroup$
    – Jihyun
    Commented Feb 17, 2019 at 2:51
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    $\begingroup$ I'm wondering how a V-22 would take off in turboprop mode, given that its proprotors extend further down than its wheels do... $\endgroup$
    – Vikki
    Commented Feb 17, 2019 at 3:48
  • $\begingroup$ I suppose you're right on that count. Though, the actual toggle for the nacelle rotation also can be adjusted manually, so if it comes to it, and there is no available repair then I suppose they could put it somewhere half-way? Talking to some seniors of my afrotc det a lot of emergency procedure they go through includes last-ditch adjustments, especially for landing protocol so hopefully this issue wouldn't completely render a V-22 useless lol. $\endgroup$
    – Jihyun
    Commented Feb 17, 2019 at 5:14

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