Can the V-22 be used as a presidential transport helicopter?

[silkmonkey]

Can the V-22 Osprey be used as a presidential transport aircraft/helicopter and if so what would its designation be?

 

[sferrin]

Think about the direction the engine exhaust is pointing when the thing is landing or taking off. Now imagine that on the White House lawn. (This should probably be in the bar BTW.)

 

[Stargazer]

IF such a thing were possible at all, the designation would of course be VV-22...

 

[Simon666]

Can the V-22 Osprey be used as a presidential transport aircraft/helicopter and if so what would its designation be?

Why? You'd like Obama dead? ;D

 

[LowObservable]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

 

[sferrin]

CH-53K FTW. ;D

 

[Stargazer]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

How Bell has tried to sell us all the tilt-rotor concept for four decades multiplying all sorts of D-something concepts that were all attractive and seemingly viable, it is beyond me how they came up with something as complicated and unimpressive as the white elephant they call the Osprey (surely an insult to that high-flying bird!)

 

[F-14D]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

How Bell has tried to sell us all the tilt-rotor concept for four decades multiplying all sorts of D-something concepts that were all attractive and seemingly viable, it is beyond me how they came up with something as complicated and unimpressive as the white elephant they call the Osprey (surely an insult to that high-flying bird!)

Although Bell's execution may not have been all that was hoped for, nothing that's come up has been a reflection on the Tilt-Rotor concept itself.

Assault rotorcraft do tend to be hot and noisy, but insulation and VIP air conditioning are wonderful things. Witness VIP SH-3s and H-60s.

BTW, please don't go down the tired "death trap" road. The number of lives tragically lost due to accidents is directly related to the fact that the V-22 carries a lot more people than an OH-58. To draw a parallel, the fact that many hundreds died in one crash of a C-5 does not mean the C-5 is a death trap (an under achiever in the eyes of some, but not a death trap). Hundreds died in a collision of two 747s at Tenerife. That doesn't indicate that the 747 is only for the suicidal.

 

[Simon666]

BTW, please don't go down the tired "death trap" road.

How about "does not autorotate" and was that cross shafting ever actually tested?

 

[yasotay]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

How Bell has tried to sell us all the tilt-rotor concept for four decades multiplying all sorts of Something concepts that were all attractive and seemingly viable, it is beyond me how they came up with something as complicated and unimpressive as the white elephant they call the Osprey (surely an insult to that high-flying bird!)

You have to understand that the V-22 that is being operated today had to go through a significant number of modifications to make it a shipboard compatible aircraft. The original JVX was relatively simple compared (no folding and larger prop-rotors) to the MV-22.

I read and listen to all the naysayers and remember long ago when the CH-47 was still the "Boeing Body Bag" that was a leaking crate. "It's OK as long as it is leaking." was the phrase of the day. One of the prime reasons I fought naught to fly the bird. I sat around for a month waiting for a transition into Blackhawks while the Army tired to figure out why they were flipping over and exploding. I was a very unhappy Cobra driver having to become a "Crashhawk" pilot. I was in one of the first Apache Battalions and watched all of the "controlled substitution" going on to keep one of the battalions readiness rates from going through the floorboards. I remember the back up controls system failures and the oil cooler fires. The only difference? We did not have the internet to contend with.

 

[Just call me Ray]

See this is why UAV helicopters would be nice.

EDIT: It just came to me that I might need to clarify that statement: so that when the helicopters crash they don't take anybody out with them. Not meant to question aviators' abilities.

 

[yasotay]

See this is why UAV helicopters would be nice.

EDIT: It just came to me that I might need to clarify that statement: so that when the helicopters crash they don't take anybody out with them. Not meant to question aviators' abilities.

... so long as the enemy does not find the means to hack your "secure" control system. Aircraft with no conscience do not care where the bombs go.

 

[CFE]

I'm definitely in agreement that the "death trap" reputation is often connected to the number of passengers on board. The deadliest single incident for the US in Iraq was the loss on an H-53 type helicopter during a sandstorm in Jan 2005 with 31 souls on board. But that shouldn't give anybody the impression that the H-53 series is any more dangerous than any other chopper.

The V-22 is a very complex aircraft that sacrifices simplicity for a unique combination of capabilities. It's subjective to say whether those unique capabilities are justified by the added risk of a critical system failure.

One of those tradeoffs is the loss of autorotation. But I have to ask whether it's possible to dead-stick a V-22 to a horizontal crash landing as an alternative during situations where an engine is lost.

 

[F-14D]

I'm definitely in agreement that the "death trap" reputation is often connected to the number of passengers on board. The deadliest single incident for the US in Iraq was the loss on an H-53 type helicopter during a sandstorm in Jan 2005 with 31 souls on board. But that shouldn't give anybody the impression that the H-53 series is any more dangerous than any other chopper.

The V-22 is a very complex aircraft that sacrifices simplicity for a unique combination of capabilities. It's subjective to say whether those unique capabilities are justified by the added risk of a critical system failure.

One of those tradeoffs is the loss of autorotation. But I have to ask whether it's possible to dead-stick a V-22 to a horizontal crash landing as an alternative during situations where an engine is lost.

The autorotation issue has been talked about elsewhere, but to briefly (for me) synopsize:

There was never an absolute regiment for autorotation. The requirement was that the JVX had to be able to make a survivable landing following total engine loss either through autorotation or by gliding. Helos get less able to do autorotation as they get larger (although even in small helos, the operation is usually expected to result in the loss of the aircraft). Large transport helos (which is basically what the V-22 is) do very poorly in autorotation. In the case of the Osprey, there is the option of gliding a fair distance to a run-on landing, something not open to a conventional large rotorcraft, and they chose to go that way.

 

[F-14D]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

How Bell has tried to sell us all the tilt-rotor concept for four decades multiplying all sorts of Something concepts that were all attractive and seemingly viable, it is beyond me how they came up with something as complicated and unimpressive as the white elephant they call the Osprey (surely an insult to that high-flying bird!)

You have to understand that the V-22 that is being operated today had to go through a significant number of modifications to make it a shipboard compatible aircraft. The original JVX was relatively simple compared (no folding and larger prop-rotors) to the MV-22.

Just for historical information, the original Marine program was HXM (which did not specify a Tilt-Rotor, BTW). It was designed around the assault requirement. It would have been lighter, but not as versatile and would have had less range. It was a DoD decision to expand the program into a multi-service program which became JVX. Folding wings and the size of the proprotors are dictated by the requirement to be able to be stored and operated from Marine assault ships, and always were in there. The fact that the proprotor size is less than optimum for an aircraft of the V-22's size and weight is a direct result of being designed to operate from aboard ships and needing to be able to operate abeam the island. The stillborne Army version would have had a larger rotor disc, to my recollection, and those may have been adopted for the AF version if history had turned out differently.

 

[yasotay]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

How Bell has tried to sell us all the tilt-rotor concept for four decades multiplying all sorts of Something concepts that were all attractive and seemingly viable, it is beyond me how they came up with something as complicated and unimpressive as the white elephant they call the Osprey (surely an insult to that high-flying bird!)

You have to understand that the V-22 that is being operated today had to go through a significant number of modifications to make it a shipboard compatible aircraft. The original JVX was relatively simple compared (no folding and larger prop-rotors) to the MV-22.

Just for historical information, the original Marine program was HXM (which did not specify a Tilt-Rotor, BTW). It was designed around the assault requirement. It would have been lighter, but not as versatile and would have had less range. It was a DoD decision to expand the program into a multi-service program which became JVX. Folding wings and the size of the proprotors are dictated by the requirement to be able to be stored and operated from Marine assault ships, and always were in there. The fact that the proprotor size is less than optimum for an aircraft of the V-22's size and weight is a direct result of being designed to operate from aboard ships and needing to be able to operate abeam the island. The stillborne Army version would have had a larger rotor disc, to my recollection, and those may have been adopted for the AF version if history had turned out differently.

I believe the Army JVX was to have a larger wing that did not fold and larger prop-rotors. Less weight, simpler hydraulics and lower disk loading. Sad that the Army was focused across the German Plain at the time and went for a "Simple Scout" helicopter... something they have yet to accomplish.

 

[F-14D]

Call it the Flying Term Limit. It's also hot, noisy and cramped.

How Bell has tried to sell us all the tilt-rotor concept for four decades multiplying all sorts of Something concepts that were all attractive and seemingly viable, it is beyond me how they came up with something as complicated and unimpressive as the white elephant they call the Osprey (surely an insult to that high-flying bird!)

You have to understand that the V-22 that is being operated today had to go through a significant number of modifications to make it a shipboard compatible aircraft. The original JVX was relatively simple compared (no folding and larger prop-rotors) to the MV-22.

Just for historical information, the original Marine program was HXM (which did not specify a Tilt-Rotor, BTW). It was designed around the assault requirement. It would have been lighter, but not as versatile and would have had less range. It was a DoD decision to expand the program into a multi-service program which became JVX. Folding wings and the size of the proprotors are dictated by the requirement to be able to be stored and operated from Marine assault ships, and always were in there. The fact that the proprotor size is less than optimum for an aircraft of the V-22's size and weight is a direct result of being designed to operate from aboard ships and needing to be able to operate abeam the island. The stillborne Army version would have had a larger rotor disc, to my recollection, and those may have been adopted for the AF version if history had turned out differently.

I believe the Army JVX was to have a larger wing that did not fold and larger prop-rotors. Less weight, simpler hydraulics and lower disk loading. Sad that the Army was focused across the German Plain at the time and went for a "Simple Scout" helicopter... something they have yet to accomplish.

Among the Army-unique features of its version were a pressurized front end and different proprotors. In its role as a Special Equipment Missions Aircraft, it would be able to cruise at 30,000 feet, something of no use to the Marines' mission. AF, though, strongly objected to Army having something that looked like a fixed-wing aircraft that could fly that high and lobbied strongly against it. This was one of the reasons the Army dropped out (They could also make use of the Marines' design for other Army missions, but since that was going to be built anyway, why spend Army money on its development? use that money to go off and develop LHX. They could always buy some of the Maine version if they chose to.).

I don't think a decision had been made on whether or not the wings would have the folding mechanism in place. Deleting it would save weight and reduce maintenance costs even if was was never used. On the other hand, there would be the question of whether or not that would be enough to offset the increased design and development costs of developing a new non-folding hub and wing carry-through. A parallel example would be the retention of folding wings on USAF F-4s and A-7s.

 

[luedo34]

Okay, there are many people out there who think the V-22 is crap, it can´t autorotate, it´s expensive, complicated and was involded in a number of tragic accidents. Any other reasons for hateing the bird? ;D
But that is true for many other airplnes as well, isn´t it? Weren´t a lot of designs plagued with severe difficulties at the beginning of their career?

 

[AeroFranz]

Okay, there are many people out there who think the V-22 is crap, it can´t autorotate, it´s expensive, complicated and was involded in a number of tragic accidents. Any other reasons for hateing the bird? ;D
But that is true for many other airplnes as well, isn´t it? Weren´t a lot of designs plagued with severe difficulties at the beginning of their career?

I don't have a definitive idea on the merits of the V-22, but to some degree you answered your own question. It doesn't matter how much operational experience will be gained, it still won't autorotate, be expensive, and complicated.

 

[Woody]

There are many more reasons for hating the the V-22 than just the lack of autorotation.

I recently had the experience of explaining to a girlfriend how a Westland Wessex, on display at the Sydney maritime museum, worked. After struggling to explaining about the free flying rotor, swash-plate controls and the necessity of an anti-torque rotor, I became, in equal parts, amazed that Sikorsky came up with it and that after 70 years this is supposedly the best idea we've had.

There have been hundreds of alternative to the helicopter proposed but few have been as slow, as massive on radar, as incapable of flying through treetops or surviving a minor mechanical problem as the V-22 series. At least the many tilt wing/duct/jet designs could land horizontally (without further damage) if the mechanism jammed.

A blind man could see that a blended delta with an embedded fan in each wing would be cheaper and higher performing in every respect. They just need to have the fans shaft driven with normal hub controlled variable pitch instead of dodgy gas drive, And turbine gas supplied thrusters for pitch and yaw instead of louvers!?!?.

That way you stand a chance of getting jet type performance with payload increasing CTOL where a carrier or runway was available. A big delta would also trap downdraught in ground effect for efficient hover especially if the fan doors opened to become wing fences.

As well as all the potential helicopter replacement rolls it would be a natural for a C-2/E-2 replacement even on STOVL carriers and could even be stealthy. The wing folding could be tricky but no more so than the V-22's wing/rotor folding I'm sure.

Cheers, Woody

PS: The V-22 is also butt-ugly. ;D

 

[sferrin]

There are many more reasons for hating the the V-22 than just the lack of autorotation.

I recently had the experience of explaining to a girlfriend how a Westland Wessex, on display at the Sydney maritime museum, worked. After struggling to explaining about the free flying rotor, swash-plate controls and the necessity of an anti-torque rotor, I became, in equal parts, amazed that Sikorsky came up with it and that after 70 years this is supposedly the best idea we've had.

There have been hundreds of alternative to the helicopter proposed but few have been as slow, as massive on radar, as incapable of flying through treetops or surviving a minor mechanical problem as the V-22 series. At least the many tilt wing/duct/jet designs could land horizontally (without further damage) if the mechanism jammed.

A blind man could see that a blended delta with an embedded fan in each wing would be cheaper and higher performing in every respect. They just need to have the fans shaft driven with normal hub controlled variable pitch instead of dodgy gas drive, And turbine gas supplied thrusters for pitch and yaw instead of louvers!?!?.

That way you stand a chance of getting jet type performance with payload increasing CTOL where a carrier or runway was available. A big delta would also trap downdraught in ground effect for efficient hover especially if the fan doors opened to become wing fences.

As well as all the potential helicopter replacement rolls it would be a natural for a C-2/E-2 replacement even on STOVL carriers and could even be stealthy. The wing folding could be tricky but no more so than the V-22's wing/rotor folding I'm sure.

Cheers, Woody

PS: The V-22 is also butt-ugly. ;D

X-22 FTW

 

[Woody]

X-22 FTW

True, X-22 = nice but I'd still rather have a big conventional wing rather than those draggy duct/wing thingys for efficient fast cruise. The X-22 also has twice as many shafts to go wrong as I'm talking about but the ducts do provide horizontal thrust. I'd suggest F-35 STOVOL type powerplants (with high bypass and no afterburners).

Have we ever ever established whether the X-22 could land horizontally or glide in an emergency? The X-22 is still 10 x better IMHO than the V-22, pity about the lack of tail ramp though.

Of the 'tilters' the Grumman 698 VSTOL canard has to be the best I've seen.

http://www.secretprojects.co.uk/forum/index.php/topic,1200.0.html

Cheers, Woody

PS: FTW = Fortworth, Texas or f**k the world? ;D

 

[F-14D]

Okay, there are many people out there who think the V-22 is crap, it can´t autorotate, it´s expensive, complicated and was involded in a number of tragic accidents. Any other reasons for hateing the bird? ;D
But that is true for many other airplnes as well, isn´t it? Weren´t a lot of designs plagued with severe difficulties at the beginning of their career?

I don't have a definitive idea on the merits of the V-22, but to some degree you answered your own question. It doesn't matter how much operational experience will be gained, it still won't autorotate, be expensive, and complicated.

Uh, do you realize you've just described virtually every medium to large transport helicopter?

 

[F-14D]

There are many more reasons for hating the the V-22 than just the lack of autorotation.


There have been hundreds of alternative to the helicopter proposed but few have been as slow, as massive on radar, as incapable of flying through treetops or surviving a minor mechanical problem as the V-22 series. At least the many tilt wing/duct/jet designs could land horizontally (without further damage) if the mechanism jammed.

A blind man could see that a blended delta with an embedded fan in each wing would be cheaper and higher performing in every respect. They just need to have the fans shaft driven with normal hub controlled variable pitch instead of dodgy gas drive, And turbine gas supplied thrusters for pitch and yaw instead of louvers!?!?.

That way you stand a chance of getting jet type performance with payload increasing CTOL where a carrier or runway was available. A big delta would also trap downdraught in ground effect for efficient hover especially if the fan doors opened to become wing fences.

One has to keep a couple of things in mind in these kind of discussions. The reason Tilt-Rotor got all the glory is that with the other concepts, basically the final reports came out as, "Well, we demonstrated the concept, and though we don't have anything here that could actually go into engineering development, we're sure that with just a lot more money and time and the invention of certain other things, we have no doubt that we could probably develop something that would do what is depicted in the marketing brochures' artist concepts. Could we have another grant, please"? In the case of Tilt-Rotor technology, from the XV-15 tests essentially the final reports came out as, "OK, we did everything you wanted. Next"? The V-22 taught us that upscaling is not as easy as we thought, and also maybe the Marines' idea of a more basic machine for the first go had merit. Knowing what we know now, we'd do some things different (and have had a much tighter emphasis on Quality Control), but that happens with any new technology.

I for one would be fascinated to see medium to large transport helicopters that blithely fly through treetops. I'd also be interested in what minor mechanical problems make the V-22 unsurvivable relative to other powered lift concepts. To cite an example with conventional helos, if you lose the crosshaft on the V-22, you lose the ability to hover or make a controlled descent engineborne single engined. With both engines functioning, though, you are perfectly capable of normal wingborne flight. Lose the shaft in a twin rotor helo, or the tail rotor shaft in a single rotor helo, and you pretty much lose the aircraft immediately in all conditions, even if all engines continue to work perfectly. The V-22, or any Tilt-Rotor BTW, can land horizontally at least as well as any other powered lift vehicle.

Regarding the embedded fan delta, it seems that so far you can't get there from here. It turned out to be quite complex and heavy, and no one's really come up with a way to get rid of that for the foreseeable future. Also, those kind of vehicles are designed for a different range. They could theoretically go faster, faster actually than you need for a tactical transport, but the price you pay is that they don't do very well at very slow speeds or in a hover. That's OK for what they are intended for; as in the Harrier, the powered lift portion of the envelope is intended as a takeoff and landing area, to be gotten out of as quickly as possible.

It's sort of like Tilt-Rotor is the worst solution to the high speed sustained powered lift problem--except for everything else.

 

[yasotay]

First I think if you look at the number of helicopters (any shape or size) that have successfully autorotated you will see it is not a tremendous record. If you look at the number that succeeded from low level it will be even less. Flew for 24 years in medium weight helicopters and low level flight was usually on the wrong side of the "dead mans curve". Hovering auto's, yeah maybe, but above translational lift speed, I would put chances at less that 50%. We all know it and live with it. Yes I do know what the books say and all that but reality, tends in this case, not to have agreed with them.

All of these tired arguments are the same I heard helicopter pilots older than me throw at Chinook. I made them personally at the Blackhawk (it falls like a rock compared to an H-1 with its high inertia rotors).

I not saying that a "fan in wing" is not doable. It is very doable. I do think you will be surprised that it will be an expensive bird and will get the same tired gripes about downwash/outwash thrown at tilt-rotor. Cruising around at altitude it will be pretty efficient. Low and slow (where the bullets are) it will be as lousy as the dreaded tilt-rotor...or Blackhawk.

As F-14D said "It's sort of like Tilt-Rotor is the worst solution to the high speed sustained powered lift problem--except for everything else." You want other high-speed rotorcraft you have to make the investment to prove you have a better idea. At least in the United States ALL rotorcraft technology funding is less than the Air Force spends on engine technology alone. So good luck getting one operationally to the flight line.

 

[luedo34]

Uh, do you realize you've just described virtually every medium to large transport helicopter?
[/quote]

Really, it can´t be that bad, can it? ;D

 

[F-14D]

Uh, do you realize you've just described virtually every medium to large transport helicopter?

Really, it can´t be that bad, can it? ;D
[/quote]

Since it's my quote being referenced, let me briefly weigh in on Yasotay's point as it relates to luedo34's:

It's not that it's "bad". It's just that there's a price you pay for sustained powered lift, especially as you grow larger. That's the price.

 

[Woody]

Thanks F-14 and Yasotay, I generally agree with you that all powered lift aircraft are dependent on there engines and transmission not failing when in that mode. My problem with the V-22 is not it's cross shaft (though it does have to pass through 2 tilt pivots some how) or its autorotation but the bloody great rotors that stick out several meters below the airframe. Which ever way you cut it, if the engines jam in the forward positsion it's the last flight that bird's doing for quiet a while.

And yes if I was special forces being flown into enemy territory I would like to be at treetop high but not in a V-22 for the same reason as above. And if I was choosing the next generation of covert air transport I'd also want it faster and slightly less of a radar target if possible.

As far as the embedded fan wing goes, it has never been tried, as far as I know, using a delta wing, with enough area and thickness for large fans, without compromising the supercritical wing section. And the only test aircraft I've seen used some weird perimeter gas dive arrangement which never works; just ask the McDonald Douglas JSF team (sorry guys). If shaft drive was used and a more or less convention propeller hub you could control blade angle as well, without the need for swash plates etc.

By driving the fans from a gearbox attached to turbofans the vertical transmission could be completely decoupled from the 'aeroplane' drive system, leaving a clean, safe, high efficiency little jetliner unless vertical flight was needed. To say you don't need speed for tactical transport is a bit like saying you don't a metal monoplane to do a canvas biplanes work (you don't ;D).

By ducting the engine (at the rear of the aircraft) gas turbine exhaust up or down or left or right, pitch and yaw could be controlled, and roll would obviously be controlled by differentially varying wing fan pitch. Transition would be easy as the wing could have large enough area to give lift with the fan doors open and the fans stopped, once the turbofans had given enough forward speed. Then the longitudinal wing fan doors would closed and off you go. I imagine it would look like a small, fatter, high wing sonic cruiser with more of a F-16 XL plan wing.

If you can't think of an application for a regional jet type vehicle (that could refuel for a KC-135) with a capacity to hover, I bet you could it you were a thousand miles from land in a rapidly sinking ship!

Cheers, Woody

PS: What about the V-22 ring vortices?

 

[F-14D]

BTW, please don't go down the tired "death trap" road.

How about "does not autorotate" and was that cross shafting ever actually tested?

Reviewing, I just realized the 2nd part of your question was never answered. Yes, the crosshaft was tested. It's also tested whenever just one engine is running.

 

[F-14D]

Thanks F-14 and Yasotay, I generally agree with you that all powered lift aircraft are dependent on there engines and transmission not failing when in that mode. My problem with the V-22 is not it's cross shaft (though it does have to pass through 2 tilt pivots some how) or its autorotation but the bloody great rotors that stick out several meters below the airframe. Which ever way you cut it, if the engines jam in the forward positsion it's the last flight that bird's doing for quiet a while.

And yes if I was special forces being flown into enemy territory I would like to be at treetop high but not in a V-22 for the same reason as above. And if I was choosing the next generation of covert air transport I'd also want it faster and slightly less of a radar target if possible.

As far as the embedded fan wing goes, it has never been tried, as far as I know, using a delta wing, with enough area and thickness for large fans, without compromising the supercritical wing section. And the only test aircraft I've seen used some weird perimeter gas dive arrangement which never works; just ask the McDonald Douglas JSF team (sorry guys). If shaft drive was used and a more or less convention propeller hub you could control blade angle as well, without the need for swash plates etc.

By driving the fans from a gearbox attached to turbofans the vertical transmission could be completely decoupled from the 'aeroplane' drive system, leaving a clean, safe, high efficiency little jetliner unless vertical flight was needed. To say you don't need speed for tactical transport is a bit like saying you don't a metal monoplane to do a canvas biplanes work (you don't ;D).

By ducting the engine (at the rear of the aircraft) gas turbine exhaust up or down or left or right, pitch and yaw could be controlled, and roll would obviously be controlled by differentially varying wing fan pitch. Transition would be easy as the wing could have large enough area to give lift with the fan doors open and the fans stopped, once the turbofans had given enough forward speed. Then the longitudinal wing fan doors would closed and off you go. I imagine it would look like a small, fatter, high wing sonic cruiser with more of a F-16 XL plan wing.

If you can't think of an application for a regional jet type vehicle (that could refuel for a KC-135) with a capacity to hover, I bet you could it you were a thousand miles from land in a rapidly sinking ship!

Cheers, Woody

PS: What about the V-22 ring vortices?

Well, the few feet the proprotor tips extend below the fuselage probably aren't going to make that much difference when you're shooting along at 240 knots or so just above the trees. Oh, wait a minute, helos can't fly 230 knots just above the trees. In any case, V-22 in conventional flight mode or with the rotors partially angled up (at which point the proprotor tips are not below the fuselage) flies NoE better than conventional transport helos. Regarding landing with the nacelles fully forward, there are two situations: If the proprotors are stopped at 12 4 and 8, they will not hit the ground. If they are turning, the landing would be a conventional wingborne landing and they are designed to hit on the outside of the arc, break away at a specific point, and be thrown clear of the aircraft so as not to damage it. Emergencies are just that.


Regarding the fan in wing, who knows? It might work better than it did last time. Of course, a vehicle with a 1000 mile radius of action (tankers aren't available on a moment's notice everywhere) that is supposed to have sustained hover on higher disc loading fan lift is certainly a design challenge, useful though it would undoubtedly be. Anyone want to pony up the billions it would take to bring such a vehicle with a 150 knot higher cruise to fruition?

Regarding the Vortex Ring State that the proudly uniformed general press likes to harp on, without turning this response into the Lord of the Rings trilogy, let me just deal with it in four points:

1. All rotorcraft are subject to VRS. If you search, you can find videos of helos going down due to VRS, including a UH-60 performing a rescue on Mt. Hood that seems to undergo a classic VRS situation.

2. Following the flight manual is usually a good idea.

3. Testing has shown that the V-22/Tilt-Rotor in general is less subject to VRS than conventional helos.

4. V-22/Tilt-Rotor recovers quicker and easier from VRS than conventional helos. Blip the nacelle angle switch forward, and you're out, without having to go through the maneuvers that a conventional helo has to perform.

 

[sferrin]

First I think if you look at the number of helicopters (any shape or size) that have successfully autorotated you will see it is not a tremendous record.

Not sure what you mean as at least in the military autorotion is practiced regularly. Even in the CH-53E.

 

[F-14D]

First I think if you look at the number of helicopters (any shape or size) that have successfully autorotated you will see it is not a tremendous record.

Not sure what you mean as at least in the military autorotation is practiced regularly. Even in the CH-53E.

Not wanting to put words into Yasotay's mouth, but the fact that autorotation is practiced regularly does not negate what he said. The process of autorotation is practiced, but it's not taken all the way to the ground. Even in basic rotorcraft training, they don't take it all the way to ground contact. Most people have the impression that an autorotation results in a gentle descent that's almost like a normal vertical landing, only quieter, the big difference being less choice as to where you can put it down. In reality, it is an emergency procedure and what I've been told (I'm not a rotorcraft rated pilot), is that you can expect to lose the aircraft.

Some helicopters do it better than others. Possibly the best one was the old Skyhook, made by Cessna. I've been told that one had such high rotor inertia that if started from sufficient height, you cloud touch down, lift back off slightly , turn 90 degrees and set back down before the blades slowed enough that you were firmly rooted. that's way beyond what other helos will do and is unique. All helicopters autorotate, the questin is how well. The larger the craft, generally the poorer it does. The V-22 can autorotate, but autorotation is just the controlled descent process. What it can't do is autorotate to ground contact and regularly meet the survivability criteria established in the specifications. It meets those by gliding and doing a run-on landing. I doubt a CH-53E will do well in a full autorotation to landing, especially if it's the result of a sudden, unplanned occurrence

 

[AeroFranz]

These are very interesting points for me...I can see how the rotor inertia plays a big role in autorotation, but i am not as sure about size (taken to mean gross weight).

Does anyone know if it's plain weight or discloading that matters? Note that large helos, like a CH-53, tend to have higher discloading than smaller ones, although that's not always necessarily the case.

example: CH-53 ~ 14 lbs/ft2
UH-60 ~ 8 lbs/ft2

 

[Woody]

Any idea what the F-35's disk loading is?

Thanks for the V-22 landing info. I didn't know the rotors could be slowed and held stopped (in a glide!!!) so as not to strike the ground on landing - hope that it can be practiced. It's still not going to take off like that - you know,in an emergency ;D.

I still think the V-22 is awkward, expensive and not significantly better than the helicopters it's replacing given that we've been performing transonic VTOL flight for more than half a century by now. It would make a good presidential transport though, if he's got the b**ls.

Cheers, Woody

 

[silkmonkey]

All I wanted to know is can this aircraft be used as a good Presidential aircraft since they are looking at getting rid of the VH-71 helicopter program?

 

[Woody]

Sorry silk monkey. I hate it too when my thred gets hijacked. But I think you can answer this question just as well as anyone else. The V-22 is a new large VTOL transport so if works as advertised if should be idea. As it is a unique product to the USA I think it would be a briliant idea if it got the endorsement and publicity only the president of the USA could give. Every world leader would be shamed into getting one.

Cheers, Woody

 

[sferrin]

What exactly is the crashed V-22 pic suppose to prove? One can find crash pictures of any kind of aircraft. If it's flown it's probably crashed at some point. I can think of many crash pics off the top of my head of the type the pres currently flies in fact.

 

[silkmonkey]

So far from what I have read the V-22 in its initial combat deployment to Iraq has done remarkably well, the problems currently regarding this aircraft now, from what I have read has been the production, the distribution and the inventory of spare parts for this aircraft. The ground crews find this aircraft easy to maintain, but spare parts to maintain this aircraft have been slow getting to forward deployed squadrons. I agree the all aircraft at one point or another crash, Qantas the world best airline in regards to safety has had a "crash" and if I remember correctly it was only a couple of years ago that it happened, yet you still see their aircraft flying and from what i have read and seen on TV, Qantas fly's the best maintained aircraft and has the best safely record of any civilian aircraft commercial aviation company on this planet! New technology takes time to get its bugs worked out so if the performance of the V-22 continues to improve then maybe what I have suggested should be looked into as a future presidential Marine-One, instead of the further procurement of the VH-71

 

[F-14D]

So far from what I have read the V-22 in its initial combat deployment to Iraq has done remarkably well, the problems currently regarding this aircraft now, from what I have read has been the production, the distribution and the inventory of spare parts for this aircraft. The ground crews find this aircraft easy to maintain, but spare parts to maintain this aircraft have been slow getting to forward deployed squadrons. I agree the all aircraft at one point or another crash, Qantas the world best airline in regards to safety has had a "crash" and if I remember correctly it was only a couple of years ago that it happened, yet you still see their aircraft flying and from what i have read and seen on TV, Qantas fly's the best maintained aircraft and has the best safely record of any civilian aircraft commercial aviation company on this planet! New technology takes time to get its bugs worked out so if the performance of the V-22 continues to improve then maybe what I have suggested should be looked into as a future presidential Marine-One, instead of the further procurement of the VH-71

What problems the V-22's has experienced in its deployments so far have not been a function of the design itself or Tilt-Rotor technology (which is exceeding expectations), but of execution, obsolete NATOPS procedures and some things that indicate certain managers need to be beaten seversly about the head and shoulders. Specifically, the engines (which were imposed on the design team by the Pentagon, a variant of what they originally wanted is going to power the CH-53K) aren't lasting as long in the sand as expected, the ice protection is not up to snuff (we know how to do ice protection, so this really annoys me, not that they ever ask my opinion) and there are some quality control issues.

Despite those issues, which are all solvable without earthshaking actions, I too believe the V-22 would make a good Presidential Transport as long as the Secret Service and other bureaucracies don't do to it what they did to the VH-71: keep adding more and more equipment and asking for more capabilities than were ever envisioned when the specs were developed.

 

[silkmonkey]

I agree with you F-14D the process of adding to a weapon system has become seriously problematic to say the least!! I think a lot of what the pentagon wants in a weapon system is beyond what the capabilities are when they use the system in combat!