The V-22 Osprey

Helicopters and tilt-rotor aircraft
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Gums

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Unread post29 Sep 2007, 04:12

Salute!

Someplace around here I have a XV-22 (or whatever they called it) flight manual. It's about 12 or 13 years old, but damned neat.

We were working up the stores management system for the Special Ops version. Were using our design for the Commanche and USMC Super Cobra upgrade.

I'll keep searching, as "she who must be obeyed" frequntly "cleans up" my war room.

*****

Lemme tellya, that thing looked really neat here at Eglin during the climatic hangar drill. Having the flight manual helped explain a lot of what we saw when it taxied, hovered and transitioned.

I truly believe I could fly the thing, given the FLCS and controls. To wit:

- a slide switch on the equivalent of the cyclic that commanded horizontal translation. Neat, as no rudder/stick input required. If you wanted to turn the nose, use rudder at same time and you rotated while moving sideways. Once in horizontal flight the rudder pedals commanded no sierra rudder, but not when in the "helo" mode.

- The nacelle pitch used a dedicated switch, not a lever like the 'vaark or Tomcat. So you could "beep" the nacelles a bit at a time until moving along like a real plane

- the FLCS made for neat transitions to hover. The thing would zoom in at a hundred feet, not change pitch attitude, but nacelles were tilting the whole way. It would slow until in a hover and the nose never rose a degree (look at helos when they come to a hover on ingress). Sucker looked like it was on a wire.

- once in hover, the thing was rock solid due to the FLCS. Kinda spooky. And pilot didn't have to do anything, just like the Viper when you relax pressure on the stick.

******

I'll search for the manual and report back

Gums sends .....
Gums
Viper pilot '79
"God in your guts, good men at your back, wings that stay on - and Tally Ho!"
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Roscoe

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Unread post29 Sep 2007, 22:43

Gums, I have no doubt you could fly it. I had the opportunity to fly it in the Sim at Kirtland, and with minimal coaching I was able to take off, convert to forward flight around the flag pole, convert back to hover and land.

If this ham-fisted engineer can do it...

That said, the airplane is pretty limited in what it can do. Quite frankly, it was a mistake to buy. Can't carry the payloads required, can't auto-rotate worth a damn, can't hover when one rotor is in ground effect and the other isn't (picture the standard lateral approach into a carrier or onto a helipad on a tall building, or laterally slide over the edge of a cliff) without the bird getting into a violent lateral oscillation, can't effectively hoist or fast rope due to the horrendous downwash (thanks to the world's highest disk loading), etc...
Roscoe

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flames

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Unread post29 Sep 2007, 22:53

Thanks for the info.
Trouble in the air is very rare. It is hitting the ground that causes it.
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elp

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Unread post29 Sep 2007, 22:57

Roscoe wrote:can't hover when one rotor is in ground effect and the other isn't (picture the standard lateral approach into a carrier or onto a helipad on a tall building, or laterally slide over the edge of a cliff) ...


Damn. That statement there by you just put it all into some perspective for the layperson.
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elp

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Unread post29 Sep 2007, 23:00

Roscoe wrote:... can't effectively hoist or fast rope due to the horrendous downwash (thanks to the world's highest disk loading), etc...



Someone told me that this when it was tested instantly knocked it out of the ability for USAF to use it for rescue in the situation where it would be hovering over a PJ in the water. The down-wash was just too excessive to work around.
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Unread post01 Oct 2007, 06:09

Yup, that is why the CSAR community went with a classical helicopter design.
Roscoe

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Lawman

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Unread post17 Jun 2009, 01:33

Roscoe wrote:
That said, the airplane is pretty limited in what it can do. Quite frankly, it was a mistake to buy. Can't carry the payloads required, can't auto-rotate worth a damn, can't hover when one rotor is in ground effect and the other isn't (picture the standard lateral approach into a carrier or onto a helipad on a tall building, or laterally slide over the edge of a cliff) without the bird getting into a violent lateral oscillation, can't effectively hoist or fast rope due to the horrendous downwash (thanks to the world's highest disk loading), etc...


Have you ever seen the autorotational profile of any of our currant utility/assault helicopters? How about when they are loaded up around Max Gross as is typical with operations? How about when they are in the high density altitudes typical to the currant AO which greatly reduces available hover torque?

Ive heard the auto aurgument again and again. I dont even have a dog in this race, Im in the Army. But putting your faith in Autorotations like its some mysterious black magic that will prevent the helo from coming out of the air like a comet is a mistake. Fact of the matter is the Osprey is actually more survivable under the same fire as a Hawk or Phrog as its engines are so much further apart. Not to mention the fact that the a pilot is never as proffecient at autorotation in his career as he is when he graduates primary in flight school. Hell the Navy/Marines dont even do theirs all the way to the ground and there are loads of differences between auto'ing a clean, 2900lbs 206 than a fat loaded heavy helo. And Ive watched Marines fast rope out of it. They go out the ramp.

And the one rotor in one rotor out is crap. If that were true we wouldnt be able to do pinnicle landings with the tandem helos we have today. Yes they have more cyclic autority than the Osprey does lateral but if when you were saying were true they never would have survived sea trials.
Drew
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TC

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Unread post17 Jun 2009, 02:47

If it comes down to auto-rotation in ANY chopper, it would be wise to assume the position and kiss your @$$ goodbye. Maybe you make it. Maybe you don't. Maybe the Rams move back to L.A. this year. At any rate, I don't want to take my chances.

If it spins to fly, it sucks to fly.
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Unread post17 Jun 2009, 03:00

TC wrote:If it comes down to auto-rotation in ANY chopper, it would be wise to assume the position and kiss your @$$ goodbye. Maybe you make it. Maybe you don't. Maybe the Rams move back to L.A. this year. At any rate, I don't want to take my chances.

If it spins to fly, it sucks to fly.


In a loaded Apache, the theory is to throw a rock out the window and attempt to fly to the ground at a steeper angle than it does. If you attempt to follow the rock with all the drag on the pylons, you'll loose to much rotor RPM.
Drew
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Unread post18 Jun 2009, 01:45

Lawman wrote:And the one rotor in one rotor out is crap. If that were true we wouldnt be able to do pinnicle landings with the tandem helos we have today. Yes they have more cyclic autority than the Osprey does lateral but if when you were saying were true they never would have survived sea trials.


It's not the twin rotors that's the issue, it's the flight control computer.
Roscoe

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Lawman

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Unread post18 Jun 2009, 01:56

Ok... so it managed to do all those lateral slide shipboard landings how exactly? If it cant handle the differencial of ground effect the solution is pretty simple, ground effect goes away once you get above the altitude of your rotor disk span, and theirs is significantly smaller than that of a Phrog or Huey. Talking with some of my boat helo bretherin about shipboard ops the only time you even notice the effect is on the big boats during the last 5 feet or so of decent. So you make your approach 10 feet higher than usual, allow the aircraft to slide right until over your spot, decend to land. If you can control a hover at 50 feet AGL, its nothing to do it at 60.
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Unread post08 Dec 2009, 00:43

"The technical challenge of rotating an airplane's wings and engines in midair led to delays, which in turn led to an ever higher price tag."

That's from the article the CNN/Time article. The wings don't rotate in midair. This leads me to believe the author doesn't know what he's talking about. I discontinued reading after that sentence.
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Unread post09 Dec 2009, 18:31

discofishing wrote:"The technical challenge of rotating an airplane's wings and engines in midair led to delays, which in turn led to an ever higher price tag."

That's from the article the CNN/Time article. The wings don't rotate in midair. This leads me to believe the author doesn't know what he's talking about. I discontinued reading after that sentence.


Check that DF... CNN/Time are correct just not how you're thinking.

The wing rotates to fold, the props needed to fold as well for storage.

You may be thinking about the "Tilt-Wing" test aircraft used prior to "Tilt-Rotor" designs.

Don't just think about flight conditions when talking about military aircraft, they often have 'special needs' for military service.

One of the C-5's biggest hurtles was 'kneeling' to load/unload cargo. Specifications for the aircraft said it needed to load/unload without any support equipment. (Loaders or external docks/ramps) Lockheed developed the kneeling landing gear to shorten the stance of the aircraft; which still has the occasional problems yet today. Has nothing to do with flight, but without it the Boeing 747 may have been our largest cargo aircraft. It could carry more cargo, further, faster than the C-5 but wasn't 'self-loading'

Likewise without the folding wing the V-22 wouldn't have been suited for USN or USMC use. I highly doubt it would have seen service without a full multi-service commitment.

Keep 'em flyin' :thumb:
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V-22_Osprey_wing_rotated.jpg
Looks like the wing has rotated to me?
[Airplanes are] near perfect, all they lack is the ability to forgive.
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Roscoe

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Unread post10 Dec 2009, 06:29

The author was talking about rotating the engine nacelles in flight, not folding the wings.
Roscoe

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Unread post17 Dec 2009, 18:28

Roscoe wrote:The author was talking about rotating the engine nacelles in flight, not folding the wings.


So if one of the most redundently designed hydraulic systems ever put on an aircraft fails theres and issue.... Wow insightful.

You know the Bell 206B, the most common and "safest" helicopter per flight our in the world has major issues with its hydraulic system. There's even an emergency proceedure for it called "Uncommanded Flight Control Movement." Ive seen video of one have an incedent while hovering into a hot pit for refuel... the thing literally went from a flat level 3 foot hover to standing on its face in less than 2 seconds with no imput from the pilot. 8 million dollars of Bell Helicopters money says the problem doesnt exist but they have a reputation to maintain.
Drew
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