What's the latest news of the V22 Osprey?
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For even more fun, see this web site for a discussion of the V-22's performance at altitude. At 10,000 feet, a Black Hawk carries more troops and goes farther (at 10% of the cost and half the gross weight):
http://webpages.charter.net/nlappos/...comparison.pdf
http://webpages.charter.net/nlappos/...comparison.pdf
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Come-on Nick, don't be a Neo-Luddite.
Darwin's 'LAW of evolution' shows that an airfoil [rotor or wing] is required for lift.
Darwin's 'LAW' also shows that an airfoil [rotor or propeller] is required for forward motion.
Intelligent Design then theorizes that there are only two logical configurations for Generation II rotorcraft.
Want to bet on the winner?
Proprotor for Hover ~ Proprotor plus Wing for Forward Flight:
Rotor for Hover ~ Rotor plus Prop for Forward Flight:
Ain't symmetry beautiful?
Darwin's 'LAW of evolution' shows that an airfoil [rotor or wing] is required for lift.
Darwin's 'LAW' also shows that an airfoil [rotor or propeller] is required for forward motion.
Intelligent Design then theorizes that there are only two logical configurations for Generation II rotorcraft.
Want to bet on the winner?
Proprotor for Hover ~ Proprotor plus Wing for Forward Flight:
Rotor for Hover ~ Rotor plus Prop for Forward Flight:
Ain't symmetry beautiful?
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Tilt-rotor efficiency
Nick
I reviewed your website above with interest. I am currently considering the tilt-prop configuration for sport personal use.
Comments on your website:
1)The fuel used per pound of payload needs to be addressed in your comparison. If you did that, it was confusing to me.
2) The chart that shows the disc size clearly gives the advantage of a helicopter in hover but I dont think the tiltrotor was intended to be efficient in hover. Does the V-22 carry each pound of payload in cruise more efficiently than a helo? If not, then the V-22 must have been poorly designed (overweight).
The basic idea of a proprotor that converts to a prop seems to be the way of the future. We simply need a more efficient and lighter configuration. Like a single tilt-rotor and tailrotor configuration is what I think might work.
slowrotor
I reviewed your website above with interest. I am currently considering the tilt-prop configuration for sport personal use.
Comments on your website:
1)The fuel used per pound of payload needs to be addressed in your comparison. If you did that, it was confusing to me.
2) The chart that shows the disc size clearly gives the advantage of a helicopter in hover but I dont think the tiltrotor was intended to be efficient in hover. Does the V-22 carry each pound of payload in cruise more efficiently than a helo? If not, then the V-22 must have been poorly designed (overweight).
The basic idea of a proprotor that converts to a prop seems to be the way of the future. We simply need a more efficient and lighter configuration. Like a single tilt-rotor and tailrotor configuration is what I think might work.
slowrotor
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slowrotor, you're right about the hover efficiency. Nick's comparison is entirely accurate, and somewhat valid as it compares the V22 to what aircraft it would replace and the roles flown by that aircraft. However, I think most of us understand that the V22 shines when time and distance are critical factors rather than cargo weight, volume, or rate.
I looked at the numbers and set up different scenarios. The V22 did become a clear winner where we would expect it to shine. Of course, for both the -53 and the V22 I had to use glossy brochures to come up with numbers.
I didn't factor cost into it at all. I have no doubt the V22 will come up high on that one. I would like to know what it will cost the US to buy one more airframe, i.e. incremental cost without the developmental costs included.
I'm a bit of a V22 supporter, but then I tend to support new technology especially when it isn't my $$ (or ££) being spent.
Matthew.
I looked at the numbers and set up different scenarios. The V22 did become a clear winner where we would expect it to shine. Of course, for both the -53 and the V22 I had to use glossy brochures to come up with numbers.
I didn't factor cost into it at all. I have no doubt the V22 will come up high on that one. I would like to know what it will cost the US to buy one more airframe, i.e. incremental cost without the developmental costs included.
I'm a bit of a V22 supporter, but then I tend to support new technology especially when it isn't my $$ (or ££) being spent.
Matthew.
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Nick,
I realized I was setting myself up for your question. I did that a few years ago and posted the results. I'll look and see if I still have those numbers. For now, unfortunately, all I can offer is my word.
Matthew.
I realized I was setting myself up for your question. I did that a few years ago and posted the results. I'll look and see if I still have those numbers. For now, unfortunately, all I can offer is my word.
Matthew.
As is Matthew, I am also a big fan of new technology. Having said that, I am no fan of the V-22 tiltrotor. (And yes, it is strange standing on the same side of this particular fence as N.L.)
The V-22 is the wrong answer to the wrong questions. And in fact it is not "new technology." At least, not if you look at it's development track. I see a lot of literature referring to the V-22 as "in development since 1986..." which is more than a little misleading. Yes, that particular, specific make and model has been in development since the mid-1980's. But the V-22 is just an outgrowth of the XV-15 (1970's) which itself can trace it's roots directly back to the XV-3 which had it's genesis in...ready?...1953.
"New technology?" My arse. Bell has been working on this concept for over fifty years! and still hasn't been able to perfect it, despite what the V-22 lovers claim. It is a concept fraught with technical difficulties, and the V-22's capabilities could easily and more efficiently be equalled with more conventional VTOL designs. Right, Nick? Right, Dave?
But for some reason, the tiltrotor concept simply has this incredible momentum that inexplicably keeps it alive. And by now we've put so much time, money and effort into the thing that it would just seem irresponsible for the government to cancel it. Too embarassing to admit that we were- well, no other way to say it- wrong.
I think back to the original Lockheed Electras, and how one of those turboprop engines would get a-vibrating in a way that fed on itself until the wings cracked and flew off like those of a seaplane that's had too many rough-water landings. Of course we know more about vibration and how to deal with it now, but still I can envision numerous and awful scenarios for those proprotors on the V-22. I don't think the tiltrotor has shown us all of it's bad sides yet.
But maybe it's all worth it. Maybe the ability to send a speedy, unarmed aircraft with a squad of Marines (and a Growler!) off to a covert insertion in a remote "hot-spot," is the wave of the future. Maybe it'll be worth the half a century of development and billions of dollars invested. And maybe it'll keep the U.S. Marines in existence. Which, come to think of it, is probably the V-22's raison d'etre all by itself.
The V-22 is the wrong answer to the wrong questions. And in fact it is not "new technology." At least, not if you look at it's development track. I see a lot of literature referring to the V-22 as "in development since 1986..." which is more than a little misleading. Yes, that particular, specific make and model has been in development since the mid-1980's. But the V-22 is just an outgrowth of the XV-15 (1970's) which itself can trace it's roots directly back to the XV-3 which had it's genesis in...ready?...1953.
"New technology?" My arse. Bell has been working on this concept for over fifty years! and still hasn't been able to perfect it, despite what the V-22 lovers claim. It is a concept fraught with technical difficulties, and the V-22's capabilities could easily and more efficiently be equalled with more conventional VTOL designs. Right, Nick? Right, Dave?
But for some reason, the tiltrotor concept simply has this incredible momentum that inexplicably keeps it alive. And by now we've put so much time, money and effort into the thing that it would just seem irresponsible for the government to cancel it. Too embarassing to admit that we were- well, no other way to say it- wrong.
I think back to the original Lockheed Electras, and how one of those turboprop engines would get a-vibrating in a way that fed on itself until the wings cracked and flew off like those of a seaplane that's had too many rough-water landings. Of course we know more about vibration and how to deal with it now, but still I can envision numerous and awful scenarios for those proprotors on the V-22. I don't think the tiltrotor has shown us all of it's bad sides yet.
But maybe it's all worth it. Maybe the ability to send a speedy, unarmed aircraft with a squad of Marines (and a Growler!) off to a covert insertion in a remote "hot-spot," is the wave of the future. Maybe it'll be worth the half a century of development and billions of dollars invested. And maybe it'll keep the U.S. Marines in existence. Which, come to think of it, is probably the V-22's raison d'etre all by itself.
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V22 Osprey
http://www.g2mil.com/Duma.htm
I took note that "Aviation Week" had run several very negative letters about the V-22 in recent weeks. As you all may know, they depend on the defense industry for advertising money, so they rarely mention anything negative about any major program. I knew they had read my recent article, so maybe this is their way of getting the word out. It must have angered Bell-Boeing, so it looks like they cut a deal. The 1-02-06 "Aviation Week" has a very unusual 16 full-page advertisement about the great V-22, it must have cost Bell-Boeing a million dollars, oh I mean American taxpayers. What is strange is that it is written as an article, but according to very small print at the bottom of the first pay, and only the first page, it notes this is a special advertising section.
That section quotes the head of Marine Aviation, General Michael Hough, about what he told all Marines about the second operational evaluation: Hough stated: "And we have to do things in such a way that we can show unequivocally that this capability is safe." As a result, Hough should be fired and possibly arrested for criminal conspiracy. He doesn't understand or doesn't care if it is truly safe, which is why he put out the word that "we have to do things in such a way." He should have stated that we will have to see if the contractor has built a safe aircraft that meets the performance they promised. However, he is quoted several times saying about what "we" needed to prove. He sounds likes someone working for Bell-Boeing because they are the ones who needed to prove the V-22 to the Marine Corps. So Marines followed orders and did things "in such a way" like skipping tests and having a loyal "friend" at DOT&E falsify the results.
All the evidence is here for a criminal indictment: http://www.g2mil.com/Duma.htm The reaction I get from many people who read it that it cannot be true because it is so blatant. In addition to safety, the performance just didn't fail to meet goals, it only demonstrated half the payload and range promised. That advertising section shows that Bell-Boeing is going all out to keep this undercover, making sure Aviation Week knows who pays their salaries, indirectly at least. They know the V-22 is unsafe, why else would they substitute sandbags to simulate Marines grunts for most of their "demonstrations" during OPEVAL? Why else would they skip important tests, but state they know it is safe? Why else would they run a 16-page advertisement disguised as an article in a respected aviation magazine?
Carlton Meyer
I took note that "Aviation Week" had run several very negative letters about the V-22 in recent weeks. As you all may know, they depend on the defense industry for advertising money, so they rarely mention anything negative about any major program. I knew they had read my recent article, so maybe this is their way of getting the word out. It must have angered Bell-Boeing, so it looks like they cut a deal. The 1-02-06 "Aviation Week" has a very unusual 16 full-page advertisement about the great V-22, it must have cost Bell-Boeing a million dollars, oh I mean American taxpayers. What is strange is that it is written as an article, but according to very small print at the bottom of the first pay, and only the first page, it notes this is a special advertising section.
That section quotes the head of Marine Aviation, General Michael Hough, about what he told all Marines about the second operational evaluation: Hough stated: "And we have to do things in such a way that we can show unequivocally that this capability is safe." As a result, Hough should be fired and possibly arrested for criminal conspiracy. He doesn't understand or doesn't care if it is truly safe, which is why he put out the word that "we have to do things in such a way." He should have stated that we will have to see if the contractor has built a safe aircraft that meets the performance they promised. However, he is quoted several times saying about what "we" needed to prove. He sounds likes someone working for Bell-Boeing because they are the ones who needed to prove the V-22 to the Marine Corps. So Marines followed orders and did things "in such a way" like skipping tests and having a loyal "friend" at DOT&E falsify the results.
All the evidence is here for a criminal indictment: http://www.g2mil.com/Duma.htm The reaction I get from many people who read it that it cannot be true because it is so blatant. In addition to safety, the performance just didn't fail to meet goals, it only demonstrated half the payload and range promised. That advertising section shows that Bell-Boeing is going all out to keep this undercover, making sure Aviation Week knows who pays their salaries, indirectly at least. They know the V-22 is unsafe, why else would they substitute sandbags to simulate Marines grunts for most of their "demonstrations" during OPEVAL? Why else would they skip important tests, but state they know it is safe? Why else would they run a 16-page advertisement disguised as an article in a respected aviation magazine?
Carlton Meyer
Re: V22 Osprey fails OPEVAL
This is a twenty year old story. The V-22 has been and a will continue to be suspect as long as the USMC continues to champion it without regard for the truth. Technology has been pushed to and past the limits of reasonableness. Fatal accidents aside, the V-22 has never clearly met most of its design goals. Clear technical issues have been side stepped in favor of a public relations push. As a former Marine, Test Pilot and an H-53 pilot, I have witnessed this first hand over the past twenty years. Gen Blot blocked a long range demonstration flight of a CH-53E in the 1990’s stating that he would not allow the CH-53E demonstate anything that may comprise or make the V-22 look bad. The V-22 has always been compared to the CH-46. With 12,300 ESHP and a gross weight approaching 60,000 the V-22 actually exceeds the gross weight of the CH-53D and approaches that of the CH-53E. Comparing the V-22 to the CH-53 line would have closed the gap and made the program less viable if not totally unworthy. I invite Nick Lappos, Shawn Coyle and anyone else with real perspectives on the technical issues that have been unreported to date and enter into a real discussion of topics (i.e. disc loading, power loading, OEI power loading, actual conversion envelope, HV development ….) concerning the V-22.
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Re: V22 Osprey fails OPEVAL
At the risk of being made the target of a US Marine corps-level attack, the problem is that the Marines are so good at working with what they've been given that they have to make it work.
There is no independent evaluation process for US military equipment - by an organization that is not concerned with whether the particular service needs it or not, but whether the equipment meets something equivalent to the civil certification requirements. Failure effects are an example - civil requirements are pretty strict on this, but the military can accept the risk and make work-arounds on something the civil world wouldn't accept.
And this is nothing against the US Marines - one of the world's finest military (non-special forces) organizations. They are simply doing what they need to do to work with the equipment that has been procured for them.
And there have been lots of other military aircraft that were bought for more political than military reasons - the Tornado comes to mind - didn't meet the range or payload requirements, but that didn't stop it being bought and used.
Is the V-22 perfect? Certainly not. It was conceived, designed and made by humans.
Do we need to go through this process to further the development of vertical flight aircraft? Certainly. I know of no other way to make things better.
Again, the Tornado comes to mind. Developments of the avionics, radar and weapons systems were flown in different versions of the Bucaneer, but were never all put together in one Bucaneer, because it would have been obvious that the Bucaneer, old as it was, could have carried more bombs farther and faster than the Tornado, (at least that's what I've been told).
So, while the V-22 isn't perfect, it's a necessary step on the way to getting something much better.
Carry on Marines.
There is no independent evaluation process for US military equipment - by an organization that is not concerned with whether the particular service needs it or not, but whether the equipment meets something equivalent to the civil certification requirements. Failure effects are an example - civil requirements are pretty strict on this, but the military can accept the risk and make work-arounds on something the civil world wouldn't accept.
And this is nothing against the US Marines - one of the world's finest military (non-special forces) organizations. They are simply doing what they need to do to work with the equipment that has been procured for them.
And there have been lots of other military aircraft that were bought for more political than military reasons - the Tornado comes to mind - didn't meet the range or payload requirements, but that didn't stop it being bought and used.
Is the V-22 perfect? Certainly not. It was conceived, designed and made by humans.
Do we need to go through this process to further the development of vertical flight aircraft? Certainly. I know of no other way to make things better.
Again, the Tornado comes to mind. Developments of the avionics, radar and weapons systems were flown in different versions of the Bucaneer, but were never all put together in one Bucaneer, because it would have been obvious that the Bucaneer, old as it was, could have carried more bombs farther and faster than the Tornado, (at least that's what I've been told).
So, while the V-22 isn't perfect, it's a necessary step on the way to getting something much better.
Carry on Marines.
Re: V22 Osprey fails OPEVAL
Unc,
I see your still full of $hit. V-22 passed Op-eval and is in full rate production. Just because you hate looking the fool you are, don't hat the player.
The Sultan
I see your still full of $hit. V-22 passed Op-eval and is in full rate production. Just because you hate looking the fool you are, don't hat the player.
The Sultan
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Re: V22 Osprey fails OPEVAL
Sultan did you read the light bulb thread ? I am in this case one of the syntax police that is talked about . His what is full of $hit ? and I have never heard hat used as a verb before. Anyway keep up the well reasoned discussions.
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Re: V22 Osprey fails OPEVAL
From an aviation point of view, it's nice to see the boundaries being pressed, especially when someone else is paying the bills.
But the thing that always has confused me with the V22 is the doctrine. How do the USMC use the improved cycle time of this aircraft when all of the heavy equipment is being moved by CH53, LCAC and conventional landing craft? Regardless of the distance from ship to LZ/beachhead, surely this results in more troops on the ground in a given time, but short of heavy equipment which will still be in the process of offloading in slowmo. Given the cost and deck impact of this large aircraft, it should be possible to deploy a (slightly) larger fleet of medium helicopters at considerably lower cost, and still get the same number of boots on the ground by the time the heavy equipment has arrived. So what is the scenario/doctrine that places such a high premium on high speed?
But the thing that always has confused me with the V22 is the doctrine. How do the USMC use the improved cycle time of this aircraft when all of the heavy equipment is being moved by CH53, LCAC and conventional landing craft? Regardless of the distance from ship to LZ/beachhead, surely this results in more troops on the ground in a given time, but short of heavy equipment which will still be in the process of offloading in slowmo. Given the cost and deck impact of this large aircraft, it should be possible to deploy a (slightly) larger fleet of medium helicopters at considerably lower cost, and still get the same number of boots on the ground by the time the heavy equipment has arrived. So what is the scenario/doctrine that places such a high premium on high speed?
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Re: V22 Osprey fails OPEVAL
Originally Posted by Shawn Coyle
So, while the V-22 isn't perfect, it's a necessary step on the way to getting something much better.
Carry on Marines.
Carry on Marines.
I am not looking forward to the first time the Osprey descends onto a field, under heavy fire, trying to unload troops. Or maybe it will be the second time, or the twentieth... But sooner or later someone's not going to be paying attention and is going to do the same thing that the experimental one did (asymmetrical VRS if I'm not mistaken), or something similar. It will cost a bunch of lives and a bunch of money.
At any rate my point is that I can't see how this is a necessary step.
dave
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Re: V22 Osprey fails OPEVAL
Nick, at face value, your presentation certainly does no favours in advancing the V22. I can’t really understand why the USMC is so hell bent on it.
Sultan, perhaps you are correct and the op-eval was signed off. But did it meet all KPP’s? Was it required to? Is the premise of Uncs original post correct?
Sultan, perhaps you are correct and the op-eval was signed off. But did it meet all KPP’s? Was it required to? Is the premise of Uncs original post correct?
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Re: V22 Osprey fails OPEVAL
Hi all,
my view on the Osprey is whatever I heard/read in the past years on it, I am not a US-taxpayer, so I am just surprised on what s**t citizens take from their government.
Nick, one question:
On your comparison.pdf - page 26, the graph puts
tilt-wing below tilt-rotor on an efficiency scale.
My uneducated opinion was, that they a pretty equal - the tiltrotor having an edge on maneuverbility as it needs a complete rotor control over a tiltwing, that might get away with a pitch control only and using flaps on the wings in the downwash - probably less effective though.
Efficiencywise I thought them equal, with the wing having an edge as the wing is streamlined with the downwash.
What's the explanation?
To the V-22:
What I don't get is that (supposedly) the V-22 should be able to go into a hot LZ WITHOUT cover, but has NOTHING to shoot forward/sideways - how is that going to work?
If it was decided that it will go in WITH cover after all, where is all the (supposed) speed-advantage, if the V-22 has to wait or slow down for its cover (Apaches or Cobras presumable), and all the rest of disadvantages hit again....
It's amazing how blatantly ignorant people are, even when the lives of their own troops are at stake!! You think the very doctrine of the Marines would put the lives of their own units before anything else - well I guess money speaks just louder.....
I guess some V-22s could be used for Special Forces ops, IF they start to rip out all the folding gear, replace it with Fast-assembly-moduls. This would save tons (literately) of weight and still keep the machines transportable to some hot spots around the world.
I still find it amazing that not ever anybody pulled the plug on this....
Oh well, USA, the land of limitless opportunities - anything is possible!!
3top
my view on the Osprey is whatever I heard/read in the past years on it, I am not a US-taxpayer, so I am just surprised on what s**t citizens take from their government.
Nick, one question:
On your comparison.pdf - page 26, the graph puts
tilt-wing below tilt-rotor on an efficiency scale.
My uneducated opinion was, that they a pretty equal - the tiltrotor having an edge on maneuverbility as it needs a complete rotor control over a tiltwing, that might get away with a pitch control only and using flaps on the wings in the downwash - probably less effective though.
Efficiencywise I thought them equal, with the wing having an edge as the wing is streamlined with the downwash.
What's the explanation?
To the V-22:
What I don't get is that (supposedly) the V-22 should be able to go into a hot LZ WITHOUT cover, but has NOTHING to shoot forward/sideways - how is that going to work?
If it was decided that it will go in WITH cover after all, where is all the (supposed) speed-advantage, if the V-22 has to wait or slow down for its cover (Apaches or Cobras presumable), and all the rest of disadvantages hit again....
It's amazing how blatantly ignorant people are, even when the lives of their own troops are at stake!! You think the very doctrine of the Marines would put the lives of their own units before anything else - well I guess money speaks just louder.....
I guess some V-22s could be used for Special Forces ops, IF they start to rip out all the folding gear, replace it with Fast-assembly-moduls. This would save tons (literately) of weight and still keep the machines transportable to some hot spots around the world.
I still find it amazing that not ever anybody pulled the plug on this....
Oh well, USA, the land of limitless opportunities - anything is possible!!
3top
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Re: V22 Osprey fails OPEVAL
After reading Mr. Lappos's presentation I have realized today I am giving the Osprey as good use as anybody will get to, desktop ornament, I really like the way it looks on my desk.
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Re: V22 Osprey fails OPEVAL
3 top,
That plot shows purely the effects of the disk loading, where the smaller disk eats more power to create a given amount of lift, and so needs more engine power. If it were plotting total efficiency of the configuration, it might show the tilt wing and tilt rotor closer, because the large vertical drag of the tilt rotor wing (about 10% of the total aircraft weight) is much reduced in a tilt wing (where the wing is rotated around so its leading edge is aligned with the downwash.) Nonetheless, the smaller props of the tilt wing usually make its disk loading so high the reduction in vertical drag is only just cancelled.
the concepts of disk loading are so poorly understood that I made it a primary thrust in the discussion, because it is the biggest headache for VTOLs to overcome as they try to compete with helicopters. Other factors are important, but not so easily handled:
1) Stiffness of the wing requiring much heavier wing structure and lost payload. The tilt rotor has to have a very stiff wing, aeroelastic response of the wing is the biggest design effort to solving the tilt rotor problem, since a wiggly wing quickly gets excited by the rotors and a major structural failure can result. The success of the V22 is greatly due to the ability to predict and quell these vibrations, and the wing depth, chord and stiffness are not designed for cruise efficiency, they are designed to assure that it all is stiff enough to stay together without giving itself a case of the flutters. Similarly, a tilt wing must have this isolation, or it will fail. The tilt wing also has to have a very strong, slop-free pivot joint if it is to succeed, and this is a major design problem. Rotating primary structures in flight may seem easy, but the resultant designs are heavy, complex and often unsuccessful.
2) Vertical drag - the wing sits in the downwash, and "weighs" more as a result, for a tilt rotor this is at least 8% of the weight of the aircraft and can be as high as 12%. For a conventional cabin=class helo, it can be 4 to 5% of the gross weight. That means a V22 could carry 5,000 lbs more payload in a hover if that vertical drag disappears. Big factor
3) Dual controls and a tilt mechanism. The stuff that drives a twin rotor helo ina hover, and an airplane in cruise and a tilt mechanism in conversion must all be carried around all the time, and it is heavy, expensive and high maintenance stuff. The V-22 has all the parts of an F-111 and a Chinook at the same time! It has three times the number of flight critical actualtors as a helicopter.
4) Horsepower systems - The cost and weight of a flying machine is driven by the power it needs and the fuel it burns, this is what the design starts with. Since a tilt rotor needs about 50% more power for the same payload, it must spend quite a bit more on engines, and on all the power transmissions, as well as the extra weight of this stuff.
None of this makes the tilt rotor impossible, but all of it makes the explanation of why the tilt rotor carries so little with so much power. How much the customer wants to spend for the job is the real issue, of course.
That plot shows purely the effects of the disk loading, where the smaller disk eats more power to create a given amount of lift, and so needs more engine power. If it were plotting total efficiency of the configuration, it might show the tilt wing and tilt rotor closer, because the large vertical drag of the tilt rotor wing (about 10% of the total aircraft weight) is much reduced in a tilt wing (where the wing is rotated around so its leading edge is aligned with the downwash.) Nonetheless, the smaller props of the tilt wing usually make its disk loading so high the reduction in vertical drag is only just cancelled.
the concepts of disk loading are so poorly understood that I made it a primary thrust in the discussion, because it is the biggest headache for VTOLs to overcome as they try to compete with helicopters. Other factors are important, but not so easily handled:
1) Stiffness of the wing requiring much heavier wing structure and lost payload. The tilt rotor has to have a very stiff wing, aeroelastic response of the wing is the biggest design effort to solving the tilt rotor problem, since a wiggly wing quickly gets excited by the rotors and a major structural failure can result. The success of the V22 is greatly due to the ability to predict and quell these vibrations, and the wing depth, chord and stiffness are not designed for cruise efficiency, they are designed to assure that it all is stiff enough to stay together without giving itself a case of the flutters. Similarly, a tilt wing must have this isolation, or it will fail. The tilt wing also has to have a very strong, slop-free pivot joint if it is to succeed, and this is a major design problem. Rotating primary structures in flight may seem easy, but the resultant designs are heavy, complex and often unsuccessful.
2) Vertical drag - the wing sits in the downwash, and "weighs" more as a result, for a tilt rotor this is at least 8% of the weight of the aircraft and can be as high as 12%. For a conventional cabin=class helo, it can be 4 to 5% of the gross weight. That means a V22 could carry 5,000 lbs more payload in a hover if that vertical drag disappears. Big factor
3) Dual controls and a tilt mechanism. The stuff that drives a twin rotor helo ina hover, and an airplane in cruise and a tilt mechanism in conversion must all be carried around all the time, and it is heavy, expensive and high maintenance stuff. The V-22 has all the parts of an F-111 and a Chinook at the same time! It has three times the number of flight critical actualtors as a helicopter.
4) Horsepower systems - The cost and weight of a flying machine is driven by the power it needs and the fuel it burns, this is what the design starts with. Since a tilt rotor needs about 50% more power for the same payload, it must spend quite a bit more on engines, and on all the power transmissions, as well as the extra weight of this stuff.
None of this makes the tilt rotor impossible, but all of it makes the explanation of why the tilt rotor carries so little with so much power. How much the customer wants to spend for the job is the real issue, of course.
Join Date: Jul 2002
Location: mostly in the jungle...
Age: 59
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Re: V22 Osprey fails OPEVAL
Thanks Nick,
for the detailed answer!
Do you see ANY use for the V-22?
Civilian/Military/Special Forces/SAR, even with major changes, like eliminating complex folding mechanisms, eliminating the military role for eg. SAR, that should reduce weight for the lack of armor....
I know, its just fishing for ANY use....
If the project would be srapped finally, is there any new Tilt design on the horizon that would evolve/learn from the V-22 at this stage?
3top
for the detailed answer!
Do you see ANY use for the V-22?
Civilian/Military/Special Forces/SAR, even with major changes, like eliminating complex folding mechanisms, eliminating the military role for eg. SAR, that should reduce weight for the lack of armor....
I know, its just fishing for ANY use....
If the project would be srapped finally, is there any new Tilt design on the horizon that would evolve/learn from the V-22 at this stage?
3top