Osprey

[Tom]

Just out of curiousity sake, I have a question regarding the Osprey. What do you do when you lose an engine? Bail out?

 

[PropStop]

There's a transfer system from one engine to the other. One engine can power the aircraft.

 

[A.Kuettel]

Does the transfer system apply when it is in hover mood, and if so how do you control it effectively?

 

[Brett327]

Does the transfer system apply when it is in hover mood, and if so how do you control it effectively?

It's probably not all that different than any other multi-engine helo. Both engine shafts feed into a transmission which drives the rotor(s). When one engine quits, it works the same - you just have less power/torque available. I seem to remember a post about the V-22 being able to hover SE, given the appropriate configuration/gross weight.

Brett

 

[Pags]

It's probably not all that different than any other multi-engine helo. Both engine shafts feed into a transmission which drives the rotor(s). When one engine quits, it works the same - you just have less power/torque available. I seem to remember a post about the V-22 being able to hover SE, given the appropriate configuration/gross weight.

Brett

I'd agree with Brett on this one. I know nothing about the Osprey, but for helos in general, there's a certain Power Required (Pr) to hover in a given condition. This Pr changes based upon weight, ambient conditions, height of the hover, and wind. Your engines produce a given Power Available (Pa) for given ambient conditions. If your Pa is greater than Pr then you can hover. If it's not, you'll settle until the Pa is equal or greater to Pr.

Flying around usually takes a lot less power than hovering unless you're trying to haul ass. So, if you're going slow and you sh!t an engine, you'll probably just keep flying and when you land you won't be able to come to a hover, you'll have to do a single engine type profile, such as a running landing to take advantage of ground effect and translational lift to keep Pr low.

 

[hscs]

There really isn't room for a transmission there -- just a shaft to connect the engines.

http://www.globalsecurity.org/military/systems/aircraft/v-22-propulsion.htm

Link explains the single engine issue...

 

[skidz]

I finally saw a V-22 in flight this past weekend while on leave, d@mn those props are huge! I know, a little late given that some of you fly the things like phrogdriver, but I just wanted to say what I thought about thing, it's a gorgeous bird.

 

[wrk]

I visited the V-22 asembly plant in Amarillo a while ago and have also talked to a pilot with over 300 hours in the V-22. Like everyone said, one engine can power both prop-rotors. In theory, the osprey can also autorotate, and it should be survivable (I think someone mentioned that no one has actually tried it though). It is also has the ability to fly a no engine PEL (though high key is at 9000 ft!!), the prop-rotors are designed to break and fly away from the fuselage should it have to land that way (since the prop-rotors would hit the ground with the nacells all the way forward).

 

[Brett327]

There really isn't room for a transmission there -- just a shaft to connect the engines.

http://www.globalsecurity.org/military/systems/aircraft/v-22-propulsion.htm

Link explains the single engine issue...

Looks an awful lot like a transmission to me.

Brett

 

[phrogdriver]

Does the transfer system apply when it is in hover mood, and if so how do you control it effectively?

"I'm in the mood to hover...simply because you're with me..."

I'm surprised by the general cogent thought that's gone into this thread.

The "transfer system" is always in motion. The Interconnecting Drive Shaft (ICDS) is turning whenever the rotors are. It also drives a group of accessories on the Midwing Gear Box (MWGB), located, oddly enough, midwing. When one engine stops, the Flight Control Computers will try to satisfy the pilot's input by doubling the power demand signal to the remaining engine until it reaches a limit. They will also tell the actuators on the proprotors to adjust pitch maintain the selected Nr (84,100,104 depending on what you're doing--a whole other story).

Controlling it effectively is merely a matter of managing the lack of power from losing one engine. The controls and control authority are still exactly the same as dual-engine. It requires less power in APLN mode, so if you have to go a ways, you'd probably transition. I'd probably consider a run-on landing to reduce power req'd (and yes, a run-on is done with the nacelles at 75-deg or more).

Single-engine, you're way better off than in most helos. With a dual failure, you'll definitely have your hands full, but it's doable. I've flown practice profiles simulating a dual failure in APLN, and it's not that bad. It's no Rutan glider, but it doesn't sink that bad. You spend 99% of a tactical flight in APLN, so that's where I'd worry the most.

 

[skidkid]

Osprey-"now we can fly you to the wrong zone in half the time"

(Smiles simulated)

 

[Malice 1]

It's probably not all that different than any other multi-engine helo. Both engine shafts feed into a transmission which drives the rotor(s). When one engine quits, it works the same - you just have less power/torque available. I seem to remember a post about the V-22 being able to hover SE, given the appropriate configuration/gross weight.

Brett

no fuel
no payload
-20*C
30.50 baro
-200 Density alt


Maybe I'm just a pesimistic
I still want to fly one though.

 

[MasterBates]

Ground effect may increase that to "Realistic" numbers.

 

[phrogdriver]

no fuel
no payload
-20*C
30.50 baro
-200 Density alt


Maybe I'm just a pesimistic
I still want to fly one though.

MV-22 NATOPS increases those numbers into the realm of reality, vice idle speculation, as well.

 

[hscs]

Brett -- thanks -- I was thinking of a large H-60 style gearbox.