V22 Osprey discussion thread Mk II
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I wouldn't mind flying one. I can't help but compare it to the CH-47F Chinook, which is already used by the US military and can carry more troops (33), lift more cargo 21,000lbs and can go 170KTS for half the price.
I don't know the range if the 47F, it can have extended fuel tanks and mid air refuel capability. I doubt it's as far as the V-22.
I think it's an interesting aircraft and is probably well suited for CSAR and maybe some other specific missions. But I just don't buy it as a replacement as an assault platform. I spent many years in an assault unit and even the Chinook was not the preferred aircraft for the mission because it was so loud and so big. It was just a bullet magnet, and fewer LZ's were available because of size.
Maybe now that the technology is out there it will eventually get cheaper, more reliable, and more effective over time but right now I see it as adding a new capability but not replacing all the other aircraft capabilities that it has replaced.
I don't know the range if the 47F, it can have extended fuel tanks and mid air refuel capability. I doubt it's as far as the V-22.
I think it's an interesting aircraft and is probably well suited for CSAR and maybe some other specific missions. But I just don't buy it as a replacement as an assault platform. I spent many years in an assault unit and even the Chinook was not the preferred aircraft for the mission because it was so loud and so big. It was just a bullet magnet, and fewer LZ's were available because of size.
Maybe now that the technology is out there it will eventually get cheaper, more reliable, and more effective over time but right now I see it as adding a new capability but not replacing all the other aircraft capabilities that it has replaced.
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But I just don't buy it as a replacement as an assault platform.
I see it as adding a new capability but not replacing all the other aircraft capabilities that it has replaced.
Last edited by 21stCen; 12th Jul 2012 at 17:35.
Now let's add a 20-27 knot tail wind....throw in a pedal turn at the same time....out of wind to down wind....and bad things happen.
Must be all that rapid acceleration can be addictive.
It does seem counter-intuitive to have to apply aft cyclic as you accelerate by rotating the nacelles forward. It makes sense when you consider the objective is to maintain a reasonably level airframe pitch attitude during such transitions.
Nacelles are left hand (on the collective) controlled, though not per se a "collective command" while nose pitch remains R/H -Cyclic-stick. As I understand the analysis, the nacelles were over rotated for the speed. It seems to me not that he didn't maintain nose pitch so much as ran out of control authority necessary to do so.
I may have misunderstood something there, however.
How does a pilot end up in that situation?
There is the likelihood that it was a matter of learning and applying the correct monkey skills for flying a tilt rotor, which are not identical to the monkey skills for flying a helicopter.
I bet a friend of mine that the pilot at the controls was most likely a former helicopter pilot. (GIven that most Osprey pilots were transitions from rotary wing, a pretty safe bet ...)
I may be wrong.
FWIW, type/conversion training is supposed to take care of teaching the right way to fly, but some monkey skills get imbedded deeply.
Last edited by Lonewolf_50; 12th Jul 2012 at 19:32.
V-22 at Farnborough
Tcabot113 added to the video link:
"The V-22 looks pretty good here. Notice no pitch down, roll off or whatever the latest BS is."
Assuming the video link is a tape of the V-22 demo performance at the ongoing airshow, I would offer the opinion that the demo profile is so limited as to provoke asking " Why fly at Farnborough if that's all we are going to do? ". No pitch down? Absolutely. No roll off? Absolutely. But also ( to borrow from the D. Black article ) no tactical agility? Absolutely. External cargo? No. SAR/rescue hoist demo? No.
The running landingat the end was a curious way to end the demo. Landing distance was about the same ( certainly no shorter ) as the C-17 normal demo for a short field landing and at least the C-17 then backs up and does a backward taxi turn into its parking space.
Just my guess, but between the US Secretary of State offering public apologies testifying to the safety of the V-22 to the Japanese Gov't, and the present international V-22 marketing efforts that make the papers, it would be reasonable to assume that the flight demo profile was orchestrated/coordinated at very high level and based on a dictat that " there will be no incident at Farnborough ".
TCabot, I agree that the machine looks good ( it has always " looked good " to me ), but the timidity of the flight demonstration profile, 23 years after first flight, conveys a different assessment.
Thanks,
John Dixson
"The V-22 looks pretty good here. Notice no pitch down, roll off or whatever the latest BS is."
Assuming the video link is a tape of the V-22 demo performance at the ongoing airshow, I would offer the opinion that the demo profile is so limited as to provoke asking " Why fly at Farnborough if that's all we are going to do? ". No pitch down? Absolutely. No roll off? Absolutely. But also ( to borrow from the D. Black article ) no tactical agility? Absolutely. External cargo? No. SAR/rescue hoist demo? No.
The running landingat the end was a curious way to end the demo. Landing distance was about the same ( certainly no shorter ) as the C-17 normal demo for a short field landing and at least the C-17 then backs up and does a backward taxi turn into its parking space.
Just my guess, but between the US Secretary of State offering public apologies testifying to the safety of the V-22 to the Japanese Gov't, and the present international V-22 marketing efforts that make the papers, it would be reasonable to assume that the flight demo profile was orchestrated/coordinated at very high level and based on a dictat that " there will be no incident at Farnborough ".
TCabot, I agree that the machine looks good ( it has always " looked good " to me ), but the timidity of the flight demonstration profile, 23 years after first flight, conveys a different assessment.
Thanks,
John Dixson
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JD
When you have something that is so beyond the performance of helicopters you do not have to take it to extremes. A 275 kt fly over after a vertical takeoff is impressive enough. As to the long roll that is just to show the vehicle to the attendees on the display line.
TC
When you have something that is so beyond the performance of helicopters you do not have to take it to extremes. A 275 kt fly over after a vertical takeoff is impressive enough. As to the long roll that is just to show the vehicle to the attendees on the display line.
TC
Lone,
The Osprey does not like relative winds other than from head on....and if you read the posts made by Osprey pilots and accident reports that are quoted....they note a nose down pitching moment when cross winds are encountered. Add that to over rotation of the nacelles by the pilot which generates a nose down pitch movement, a forward shift in CG, and then combine that with a nose down pitch movement caused by the tail wind....that is why I suggest all this culminated in the pilot losing longitudinal pitch control of the aircraft.
A helicopter does not react in that manner....quartering winds don't necessarily result in nose down pitch moments, over rotating in pitch attitude does not result in a shift in CG....in some aircraft a tail wind can get under synch elevators or similar devices but not in all helicopters to the extent it affects the Osprey.
Likewise....helicopters pitch nose down with cyclic movement....and that is how they accelerate. In the Osprey...pilots are trained to apply aft cyclic while accelerating by rotation of the nacelles....which is exactly opposite of the way helicopters are made to accelerate. That makes the Osprey control inputs opposite of a helicopter in that part of its flight profile. I would assume that during landing....and decelerating....the cyclic is moved forward to keep the nose down and the nacelles are beeped aft....again just the opposite of a helicopter. Unlearning Monkey Memory is harder than learning new Monkey Memory items. I seem to recall there are warnings in the NATOPs about mixing pitch, roll, and yaw inputs at a hover or in the transition to forward airplane flight as the mix can result in control issues. That is exactly the mix the Morocco crash Pilot was doing when it all went egg shaped.
The Osprey does not like relative winds other than from head on....and if you read the posts made by Osprey pilots and accident reports that are quoted....they note a nose down pitching moment when cross winds are encountered. Add that to over rotation of the nacelles by the pilot which generates a nose down pitch movement, a forward shift in CG, and then combine that with a nose down pitch movement caused by the tail wind....that is why I suggest all this culminated in the pilot losing longitudinal pitch control of the aircraft.
A helicopter does not react in that manner....quartering winds don't necessarily result in nose down pitch moments, over rotating in pitch attitude does not result in a shift in CG....in some aircraft a tail wind can get under synch elevators or similar devices but not in all helicopters to the extent it affects the Osprey.
Likewise....helicopters pitch nose down with cyclic movement....and that is how they accelerate. In the Osprey...pilots are trained to apply aft cyclic while accelerating by rotation of the nacelles....which is exactly opposite of the way helicopters are made to accelerate. That makes the Osprey control inputs opposite of a helicopter in that part of its flight profile. I would assume that during landing....and decelerating....the cyclic is moved forward to keep the nose down and the nacelles are beeped aft....again just the opposite of a helicopter. Unlearning Monkey Memory is harder than learning new Monkey Memory items. I seem to recall there are warnings in the NATOPs about mixing pitch, roll, and yaw inputs at a hover or in the transition to forward airplane flight as the mix can result in control issues. That is exactly the mix the Morocco crash Pilot was doing when it all went egg shaped.
SAS, we appear to be in violent agreement.
Nacelle posit was explained to me, some years ago, by a Pax River test pilot as "the new monkey skill" but not the only change he had to deal with in translating his flying skills to Osprey flying.
Nacelle posit was explained to me, some years ago, by a Pax River test pilot as "the new monkey skill" but not the only change he had to deal with in translating his flying skills to Osprey flying.
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Sas/Lone,
Yes, the descriptions of basic tiltrotor handling described above are correct as some on this thread can explain far better than I could.
I was fortunate enough many years ago (late 90s) to have been invited to a couple of tiltrotor trial studies in the VMS (vertical motion simulator) at NASA Ames (capable of pulling positive and negative Gs). Before my first ride an Army Major who flew Blackhawks flew the sim that was configured as an XV-15. In the control room there was a computer display that showed what the a/c would look like from the outside as it maneuvered. The display showed what I thought was a smooth acceleration and take off. The room burst into laughter with the comment being made, "typical helicopter pilot!" I sat quietly for a while, then whispered to the NASA gentleman who invited me who was very experienced in the XV-15, "what did he do wrong?!"
He explained that a helicopter pilot uses forward cyclic to lower the nose during a normal acceleration for takeoff as the Major did, whereas a tiltrotor pilot rotates the nacelles forward and holds the fuselage level with the cyclic as SOP.
Pilots who had the experience have said that they did not have difficulties moving back and forth between helicopters and tiltrotors, but of course during periods requiring immediate reaction, the 'monkey skills' from previous experience can come back in the form of negative transfer.
Having said that, a helicopter pilot transitioning to a tiltrotor will still be a better option (IMO) than a fixed wing pilot who will not have the same amount of positive transfer gained from the similarities between helicopters and tiltrotors when they are operated in the helicopter mode.
Yes, the descriptions of basic tiltrotor handling described above are correct as some on this thread can explain far better than I could.
I was fortunate enough many years ago (late 90s) to have been invited to a couple of tiltrotor trial studies in the VMS (vertical motion simulator) at NASA Ames (capable of pulling positive and negative Gs). Before my first ride an Army Major who flew Blackhawks flew the sim that was configured as an XV-15. In the control room there was a computer display that showed what the a/c would look like from the outside as it maneuvered. The display showed what I thought was a smooth acceleration and take off. The room burst into laughter with the comment being made, "typical helicopter pilot!" I sat quietly for a while, then whispered to the NASA gentleman who invited me who was very experienced in the XV-15, "what did he do wrong?!"
He explained that a helicopter pilot uses forward cyclic to lower the nose during a normal acceleration for takeoff as the Major did, whereas a tiltrotor pilot rotates the nacelles forward and holds the fuselage level with the cyclic as SOP.
Pilots who had the experience have said that they did not have difficulties moving back and forth between helicopters and tiltrotors, but of course during periods requiring immediate reaction, the 'monkey skills' from previous experience can come back in the form of negative transfer.
Having said that, a helicopter pilot transitioning to a tiltrotor will still be a better option (IMO) than a fixed wing pilot who will not have the same amount of positive transfer gained from the similarities between helicopters and tiltrotors when they are operated in the helicopter mode.
Yes, the Osprey can be finicky with cross/tail winds, not too big of an issue until about 20 knots. Pitch Up with Sideslip can occur with about a 45 degree quartering headwind. I've never experienced it operationally but have had a demonstration while at Pax. It's very noticeable yet not dramatic, just something to be aware of.
Without a doubt, it is possible to "over-rotate" the nacelles and run out of longitudinal stick authority. That's exactly why the flight manual states a limit of no lower than 75 degrees until 40 KCAS. Once the wing becomes effective, it's no longer an issue. However, the nacelles can move quicker than the acceleration, hence the warning. But again, we're only talking about 10 seconds of time and 1 or 2 degrees of nose in reality.
As you transition, if you don't apply aft stick, the Osprey will descend, primarily due to the changing thrust vector and not CG. The similar situation in a helo would be to nose over without adding collective, same result, the helo will descend. It's a similar issue just using a different control to counteract the effect. Also, the Osprey flies about 5-7 degrees nose high in airplane mode due to a combination of having zero angle of incidence in the wing and the thrust line being above the centerline of the aircraft. In simple terms, this will result in a constant descent if not counteracted. BTW, the wing has zero incidence because of the requirement to fold the wing and stow it on a ship. The unfortunate results are negative aerodynamics and thus, performance with a "draggy" nose high attitude.
Without a doubt, it is possible to "over-rotate" the nacelles and run out of longitudinal stick authority. That's exactly why the flight manual states a limit of no lower than 75 degrees until 40 KCAS. Once the wing becomes effective, it's no longer an issue. However, the nacelles can move quicker than the acceleration, hence the warning. But again, we're only talking about 10 seconds of time and 1 or 2 degrees of nose in reality.
As you transition, if you don't apply aft stick, the Osprey will descend, primarily due to the changing thrust vector and not CG. The similar situation in a helo would be to nose over without adding collective, same result, the helo will descend. It's a similar issue just using a different control to counteract the effect. Also, the Osprey flies about 5-7 degrees nose high in airplane mode due to a combination of having zero angle of incidence in the wing and the thrust line being above the centerline of the aircraft. In simple terms, this will result in a constant descent if not counteracted. BTW, the wing has zero incidence because of the requirement to fold the wing and stow it on a ship. The unfortunate results are negative aerodynamics and thus, performance with a "draggy" nose high attitude.
Last edited by mckpave; 13th Jul 2012 at 17:37.
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Thanks Mckpave,
As always your input is greatly appreciated and sorely needed on this thread. Only those with firsthand experience on the V-22 can truly speak to the actual capabilities and limitations of the aircraft! And as Jeffg mentioned earlier, you guys are the ones that can comment on the true 'warts' of the a/c as you have done in your post. That helps to separate the ‘wheat from the chaff’ as all those without an agenda are keen to do. It seems that these days both sides are more ready to look at the truth and put the partisanship behind on this thread. Thanks for your participation…
21stC
As always your input is greatly appreciated and sorely needed on this thread. Only those with firsthand experience on the V-22 can truly speak to the actual capabilities and limitations of the aircraft! And as Jeffg mentioned earlier, you guys are the ones that can comment on the true 'warts' of the a/c as you have done in your post. That helps to separate the ‘wheat from the chaff’ as all those without an agenda are keen to do. It seems that these days both sides are more ready to look at the truth and put the partisanship behind on this thread. Thanks for your participation…
21stC
Thanks, mckpave! 
Assuming the video link is a tape of the V-22 demo performance at the ongoing airshow, I would offer the opinion that the demo profile is so limited as to provoke asking " Why fly at Farnborough if that's all we are going to do? ". No pitch down? Absolutely. No roll off? Absolutely. But also ( to borrow from the D. Black article ) no tactical agility? Absolutely. External cargo? No. SAR/rescue hoist demo? No.
The running landingat the end was a curious way to end the demo. Landing distance was about the same ( certainly no shorter ) as the C-17 normal demo for a short field landing and at least the C-17 then backs up and does a backward taxi turn into its parking space.
V-22 Farnborough
Thanks for the response, McPave. I did notice that the nacelles never went aft, ( and thought that perhaps there was some sort of restriction in their use under those circumstances ) and now that you are monitoring this thread, have two questions associated with aft nacelle/aft cyclic control:
1. Can the machine be ground taxied to the rear?
2. What is the flight qualified aft hover taxi speed limit? OGE in particular.
And, if you know, an associated question: what was the determining factor in the establishment of aft nacelle angle design limit?
Thanks,
John Dixson
1. Can the machine be ground taxied to the rear?
2. What is the flight qualified aft hover taxi speed limit? OGE in particular.
And, if you know, an associated question: what was the determining factor in the establishment of aft nacelle angle design limit?
Thanks,
John Dixson
for sure the 3 days I was at SBAC, the MV-22 did a better display than RIAT
Cheers
Cheers
1. Can the machine be ground taxied to the rear?
2. What is the flight qualified aft hover taxi speed limit? OGE in particular.
And, if you know, an associated question: what was the determining factor in the establishment of aft nacelle angle design limit?
McPave
Thanks for your response.
As to the last question: what design requirement led to the final aft nacelle range put into the machine, allow me to use the original UH-60 Army RFP ( request for proposal ) requirements in a similar area:
The UTTAS ( and I am summarizing here, because I left the original documents with my successor upon retirement. This was such a " big deal" however. and generated such a number of meetings, before and during flight test, that I remember it well ) had to be able to land on some significant slopes as follows:
For the longitudinal landings, that meant, for instance, that the nose down slope landings had to be done at the most forward CG ( and vice-versa for the nose up condition ).
Those requirements pretty much established the maximum control moment capability for lateral and longitudinal control, and thus the control ranges.
So, getting back to the V-22, I am guessing that there are/were slope landing and rearward flight requirements established before contract award, and these requirements may have resulted in the 97.5 degree nacelle number. Alternatively, there might be a sideslip to longitudinal aerodynamic coupling present in the vehicle and perhaps a consideration of this, and the desire to allow pretty much heads out of the cockpit flying when converted, led to the nacelle range selected.
There is one other question that I have pondered, after reading your comment regarding the 75 degree nacelle/40 KT limit during forward transition. The question is, with a FBW control system, why not put that control law into the software, thus eliminating that error possibility?
Appreciated the background on wing incidence selection. Sure there were some "spirited" pow-wows at Bell/Boeing before that subject was finalized.
Thanks,
John Dixson
As to the last question: what design requirement led to the final aft nacelle range put into the machine, allow me to use the original UH-60 Army RFP ( request for proposal ) requirements in a similar area:
The UTTAS ( and I am summarizing here, because I left the original documents with my successor upon retirement. This was such a " big deal" however. and generated such a number of meetings, before and during flight test, that I remember it well ) had to be able to land on some significant slopes as follows:
- Laterally at slopes of 15 degrees.
- Longitudinally, at slopes of 12 degrees.
For the longitudinal landings, that meant, for instance, that the nose down slope landings had to be done at the most forward CG ( and vice-versa for the nose up condition ).
Those requirements pretty much established the maximum control moment capability for lateral and longitudinal control, and thus the control ranges.
So, getting back to the V-22, I am guessing that there are/were slope landing and rearward flight requirements established before contract award, and these requirements may have resulted in the 97.5 degree nacelle number. Alternatively, there might be a sideslip to longitudinal aerodynamic coupling present in the vehicle and perhaps a consideration of this, and the desire to allow pretty much heads out of the cockpit flying when converted, led to the nacelle range selected.
There is one other question that I have pondered, after reading your comment regarding the 75 degree nacelle/40 KT limit during forward transition. The question is, with a FBW control system, why not put that control law into the software, thus eliminating that error possibility?
Appreciated the background on wing incidence selection. Sure there were some "spirited" pow-wows at Bell/Boeing before that subject was finalized.
Thanks,
John Dixson
There is one other question that I have pondered, after reading your comment regarding the 75 degree nacelle/40 KT limit during forward transition. The question is, with a FBW control system, why not put that control law into the software, thus eliminating that error possibility?