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Osprey question

Dugaru

Well Known Member
So I returned to my home base at New Kent (W96, Richmond, VA USA) the other day to find that a V-22 Osprey was doing touch-and-goes. Or whatever you would call it when a tilt-rotor aircraft practices landings.

The V-22 is just a flat-out amazing aircraft. I was going to join the pattern and land so that I could watch it in action, but then it occurred to me: what is the wake turbulence like from those things?!?

Fearing it might be extra nasty, I motored on for some additional sight-seeing elsewhere.

Any theories on how much room to give to a V-22?
 
So I returned to my home base at New Kent (W96, Richmond, VA USA) the other day to find that a V-22 Osprey was doing touch-and-goes. Or whatever you would call it when a tilt-rotor aircraft practices landings.

The V-22 is just a flat-out amazing aircraft. I was going to join the pattern and land so that I could watch it in action, but then it occurred to me: what is the wake turbulence like from those things?!?

Fearing it might be extra nasty, I motored on for some additional sight-seeing elsewhere.

Any theories on how much room to give to a V-22?
Without having anything scientific to base this comment on: A LOT.

IIRC I read somewhere they have quite a high disc loading, compared to a standard fling-wing. Check out this video of a Blackhawk-induced wake vortex crash in Colorado.
 
+1. To quote one of the Indiana Jones movies - You chose wisely.
I was an engineer on the V-22 program in the ?80s (yes it has been around that long). Based on its weight and disk loading give it a good amount of time. A few minutes at least.
 
+1. To quote one of the Indiana Jones movies - You chose wisely.
I was an engineer on the V-22 program in the ?80s (yes it has been around that long). Based on its weight and disk loading give it a good amount of time. A few minutes at least.
For practical purposes, wouldn't the rotor wash be pretty much proportionate to the flying weight of the aircraft? I understand disk loading, but it's really about moving air mass equal to the weight being lifted more-or-less, right? Or is there something about the tiltrotor that would make it significantly different than say, a Sea Stallion. (I'm lucky enough to see all of these things occasionally at my home field. So there's a practical side to the question.)
 
I remember the first time I came across one in horizontal flight.
Seeing the size of the props (rotors) my first thought was, "Man, I can't wait to see the landing gear come down!"
 
Treat rotorcraft with respect

The down wash from a helicopter or tilt rotor is nothing to be trifled with in an RV size aircraft. I treat the wake turbulence from a helicopter like I would that from an airplane 5 times larger. Just like airplanes the wake turbulence from a helicopter is worst when heavy and slow, i.e hovering. Anything the size of a Huey or larger needs to be given a wide berth and/or a couple of minutes after it's departure/landing for the wake to dissipate.
Cheers
Nige
 
Bad physics

For practical purposes, wouldn't the rotor wash be pretty much proportionate to the flying weight of the aircraft? I understand disk loading, but it's really about moving air mass equal to the weight being lifted more-or-less, right? )

It?s the force-momentum per second-that needs to equal the aircraft weight. This could be a large air mass moving slowly, or a smaller air mass moving quicker. Same as standing behind a jet or prop plane, when both are producing the same thrust. The jet blast can be felt much further away. Since the design constraints on an Osprey (forward propulsion) drive it toward shorter blades, one can expect significant downward air velocities when landing.
 
The V-22 is built in Amarillo, Texas and some of them occasionally come to our airport during cross country flight testing. They are really interesting to watch. The downside for us is they throw serious FOD everywhere! They seem to be worse in that regard than the heavy lift fire fighting choppers that utilize our airport, including Blackhawks and CH-47 Chinooks. Their exhaust is also very hot and can start fires in wooded areas.

The wife and I flew to Amarillo for a weekend get away several years ago and as we were flying over Palo Duro canyon we saw a strange looking aircraft at a distance. It took a minute to register what we were looking at. Later as we were taxiing to the runway at KAMA an Osprey came near us and to say the RV was rocking and rolling was an understatement. I was very concerned because I had seen on the news that several people had been injured by one when it knocked down tree limbs in a park it was flying over.

I have great respect for their rotor wash and wouldn't fly anywhere near one!

Here's a video: https://www.youtube.com/watch?v=i4iw2-n-Uzc
 
For practical purposes, wouldn't the rotor wash be pretty much proportionate to the flying weight of the aircraft?

Let me try to answer that without blowing too much smoke. To get the air to push up on the aircraft, be it wing or rotor, the aircraft has to push down on the air molecules. If if can push down on a lot of them (high airspeed, large wing span), then the push is shared by lots of molecules and those molecules aren't pushed as fast. If there's only a few molecules (slow airspeed, short span, or lift concentrated at the tips because flaps are up), those molecules will get pushed harder and move faster, i.e., more wake turbulence.

That doesn't really explain it for rotors, but the bottom line is that rotor wash can be deadly to light planes, especially small ones like RVs. And don't ever think of flying formation with a helicopter in the lead...
 
Agree with everything said. Give them or any large helicopter plenty of room. Fly above if possible. I flew CH-47s, and even that big thing does not like getting in the rotor wash of another. Watch helicopters in formation, they step up, not down, to avoid any chance of getting in rotor wash.
 
Somewhere on youtube is a video of a student pilot land a cirrus (I think) shortly after a Blackhawk chopper has flown down the runway. The airplane is flying alonf fine and then suddenly it cartwheels, like a big invisible hand reached out and swatted it. I think the v22 is heavier i.e. worse. I never would have guessed that a heli could create that level of turbulence.

The student climbs out very slowly several minutes later. If he was ok at least he was badly shaken. Watch that vid and you will have a lot of respect for vortices that hang around after a chopper has been through.
 
I was doing some avionics development work on the SH-60 Seahawk at Pax River when the V-22 first made its debut there for acceptance flight testing. Every point of observation, from standing on the ground to flying nearby, confirmed the V-22 to be in a substantially higher wake turbulence category than even a fully loaded SH-60. Maybe not the "factor of five" comparison made earlier but certainly more than "factor of two" compared to the SH-60. And they are loud when hovering.
 
+1. To quote one of the Indiana Jones movies - You chose wisely.
I was an engineer on the V-22 program in the ?80s (yes it has been around that long). Based on its weight and disk loading give it a good amount of time. A few minutes at least.

I remember the XV-3 that successfully flew in the early to mid 50s. Same basic concept.
 
As a DoD guy in the Bell plant in Fort Worth (Hurst), I worked on the V-22 program. Before that, I worked in the test squadron at Edwards that was doing the flight test of the V-22. Wake turbulence from any helicopter is something to be wary of. I cringe when I see helicopters conducting training by hovering in the infield between the runway and the parallel taxi way. Watch aircraft as they pass abeam that operation. Obviously, it gets worse as weight increases.

We bought a Marine One version of the V-22. But I can assure you it won't be landing in the rose garden next to the White House.
 
One Engine-V22

We had a V-22 parked on the ramp for months early this year due to an engine failure. He was traversing close to the airspace at night when a turbine failure occurred. To divert to KFLG the crew had to over-torque the opposing drive shaft and over heat TIT the remaining good engine. Still in a decent with crew aboard, the pucker factor was probably at max also while just making it to the runway. I'm sure the crew had a great time that night at the local Flagstaff bar!
 
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