V22 Osprey discussion thread Mk II
John, good points, perhaps as a result of the reports on this mishap some answers to your questions will arrive.
SAS: I figured you were aware of rotary wing formation flying.
It was almost a rhetorical question.
Back to the V-22 and how wake turbulence might have outsized effects on the tilt rotor.
I have a picture in my mind of thrust asymmetry rather than what the test pilot was addressing in discussing roll off. I don't know the Chinook well enough to think through this, but am wondering how often thrust asymmetry between the two rotors might have caused handling problems in that model, and how it accomodated that sort of problem. (Or rather, how the pilots did ...)
It seems to me that in the Chinook, a thrust asymmetry would manifest itself in pitch up / pitch down anomalies, while in the Osprey, it would do so in roll. As I sketch it out on the back of a napkin, the force in the Osprey would be generated over a longer arm, which means that the force required to counter such fluctuations would be greater, in proportion, but also that the rate of roll when encountering thrust asymmetry would likely be larger.
I'll leave it at that for the moment. Will ponder on that for a bit.
SAS: I figured you were aware of rotary wing formation flying.
It was almost a rhetorical question. Back to the V-22 and how wake turbulence might have outsized effects on the tilt rotor.
I have a picture in my mind of thrust asymmetry rather than what the test pilot was addressing in discussing roll off. I don't know the Chinook well enough to think through this, but am wondering how often thrust asymmetry between the two rotors might have caused handling problems in that model, and how it accomodated that sort of problem. (Or rather, how the pilots did ...)
It seems to me that in the Chinook, a thrust asymmetry would manifest itself in pitch up / pitch down anomalies, while in the Osprey, it would do so in roll. As I sketch it out on the back of a napkin, the force in the Osprey would be generated over a longer arm, which means that the force required to counter such fluctuations would be greater, in proportion, but also that the rate of roll when encountering thrust asymmetry would likely be larger.
I'll leave it at that for the moment. Will ponder on that for a bit.
You got it Lone.....deviations tended to be in pitch attitude....or one end having to follow the other if you "fell through" on an approach (a situation where you are leveling the aircraft and pulling a lot of Thrust (collective). As the cyclic goes forward it is reducing pitch in the forward head and increasing pitch in the aft head....all the while the Thrust lever increase (collective) is adding pitch to both heads......net effect is "less" pitch in the forward head which in an extreme situation means the nose "falls" . The good news is it is a very near ground situation.....but also bad news as it can make for a pretty abrupt landing.
Using pedal to get both heads into clean air is a trick that once mastered....can allow for take off with a much heavier load than normal aligned take offs. The Huey would give you a bit more weight capacity if you allowed it to turn to the right into the wind as you departed. Kicking the Chinook sideways right at the edge of Translational Lift Airspeed....and getting the aft head into undisturbed air worked to your benefit. It got clean air to the aft head and gave the aft head a touch more acceleration compared to the forward head. It was a finesse maneuver.
Using pedal to get both heads into clean air is a trick that once mastered....can allow for take off with a much heavier load than normal aligned take offs. The Huey would give you a bit more weight capacity if you allowed it to turn to the right into the wind as you departed. Kicking the Chinook sideways right at the edge of Translational Lift Airspeed....and getting the aft head into undisturbed air worked to your benefit. It got clean air to the aft head and gave the aft head a touch more acceleration compared to the forward head. It was a finesse maneuver.
Rt Pedal/Tandem Takeoff
SAS, in 1963 I was bootlegging an H-21 checkout at Mother Rucker and was lucky to have a recent returnee from the delta as an instructor. Taught that exact same takeoff "when you're out of ideas and the tree line is approaching" technique.
Thanks.
John Dixson
Thanks.
John Dixson
Ah yes....the good ol' days...bless'em!
The rest of the trick was to keep the ol' darling flying and accelerating no matter how slight until you could get her back into trimmed flight and still flying. Straighten her up too soon and you really had diddled the pooch!
The rest of the trick was to keep the ol' darling flying and accelerating no matter how slight until you could get her back into trimmed flight and still flying. Straighten her up too soon and you really had diddled the pooch!
Join Date: Nov 2011
Location: El Paso, Texas
Posts: 58
Likes: 0
Received 0 Likes
on
0 Posts
All,
What happens to a Chinook or CH-53 hovering low to the ground when another Chinook or 53 crosses slowly directly over that aircraft at a delta altitude of only 25 feet?
Does the aircraft above blow the aircraft below into the ground, or does the low aircraft suck the overflying aircraft into it?
TC
What happens to a Chinook or CH-53 hovering low to the ground when another Chinook or 53 crosses slowly directly over that aircraft at a delta altitude of only 25 feet?
Does the aircraft above blow the aircraft below into the ground, or does the low aircraft suck the overflying aircraft into it?
TC
Thread Starter
Typical doctrine for multiple ship operations in the H-53 called for the wingmen to get on the ground first during the landing phase. This insured, assuming landing into the wind, that the dust and crud from the leading aircraft minimally affected the wingmen. The reverse took place on takeoff. The wingmen would lift off first and gain step up prior to the leader’s lift off.
We were also trained to never fly directly over another aircraft while it was running.
We were also trained to never fly directly over another aircraft while it was running.
Join Date: Nov 2011
Location: El Paso, Texas
Posts: 58
Likes: 0
Received 0 Likes
on
0 Posts
V-22 Looks Pretty Good
Came across the linked article. The UH-60 appears to have had a number of crashes and lives lost between Y81 to 84: 15 crashes, 22 dead,and with two fatal in 40 days. Not sure how many of these were the crashes in Grenada in a formation landing. And this is now a revered (though old tech) helicopter.
On Grenada: Wake turbulence? Suck down? Some Sikorsky guy could answer.
As to what caused the grounding. In flight breakup: Tut-Tut!
TC
The Pittsburgh Press - Google News Archive Search
On Grenada: Wake turbulence? Suck down? Some Sikorsky guy could answer.
As to what caused the grounding. In flight breakup: Tut-Tut!
TC
The Pittsburgh Press - Google News Archive Search
Some people seem to make the mistake of thinking that the Chinook rotors act independantly of each other all the time. This is not...I think...the case. They overlap by, what, 30%? Not only that, the masts are at different angles with respect to each other. Even in a hover the Chinook rotors are interacting with each other.
Not so the V-22. SAS says that it's neither a helicopter nor an airplane and that's incorrect. In a hover the V-22 is most definitely a helicopter...*two* helicopters, actually, connected by a stick, with a WHOLE LOT MORE lateral polar inertia than a Chinook has longitudinal polar inertia (think majorette's baton). How many Chinooks and Sea Knights over the years have done a forward or rearward somersault and crashed inverted because one of their rotors got into VRS and other didn't?
The proprotors on a V-22 do act individually...and need to act individually because it has been discovered that when they interact with each other (as in the shipboard testing) the results can be nearly disastrous. Or have we forgotten that for the sake of convenience? Apparently the Air Force didn't read or listen to what the Navy discovered about proprotor downwash interaction.
We don't know enough about the recent Eglin crash yet to know whether it really was "roll off" or what. Maybe Maj. Luce can enlighten us if he has any recollection of *this* crash. (Personally I wouldn't bet on it. If not, he may go down in history as the most forgetful pilot ever since my 80 year-old Uncle Ned, from whom we finally had to take the keys to his Cessna 140 away after he landed, parked, tied it down and walked away from it while it was still running! We were, like, "Uhh Ned, did you lock your plane?" Then he started patting his pockets for the nonexistent keys.)
But whether the Eglin crash was the result of "A-VRS roll off" or "wingtip vortice roll off" makes no difference. The aircraft rolled over and crashed (we know at least that much) which strongly hints at unequal lift on one side. It still strengthens my point that the tiltrotor concept is DEFECTIVE. When one proprotor loses lift that piece of crap flips over on its back and crashes. It is only a miracle that anyone on the Eglin aircraft survived. (And don't give me that BS about "See how survivable a tiltrotor crash is!")
I've said this all along. And some of you nitwits blather on and on about how, "All you have to do is beep the nacelles forward and fly out of it!" Piece of cake! And now it happens again (maybe?) and the same nitwits are saying, "Oh no, loss of lift on one side of the V-22 is NOT THE SAME as A-VRS!" Yeah, right. Asymmetric loss of lift is asymmetric loss of lift. Why don't you guys just admit it? Okay, geniuses, what's the EP for "Roll-Off That You Think Might Not Be Caused By A-VRS?" And how do you differentiate between the two when you're down close to the ground and the thing starts to flip over on its back? And don't give me that Henny Youngman line: "Don't do this." Do not tell me that the crews should merely avoid any flight regime that *might* cause roll-off.
So what's next? "Let's not do formation flying with them." (And you KNOW that's coming...but...we learned that after Marana and the shipboard trials, didn't we? I guess not.) "Let's not use them for gunnery." (It was never intended to have a gun. There was never a V-22 gunship model proposed.) Let's just keep whittling down what the V-22 *cannot* do until we find what's left that it *can* do safely. Which in my book is nothing.
"Fatal Flaw." I'm telling you. Watch for it soon.
Not so the V-22. SAS says that it's neither a helicopter nor an airplane and that's incorrect. In a hover the V-22 is most definitely a helicopter...*two* helicopters, actually, connected by a stick, with a WHOLE LOT MORE lateral polar inertia than a Chinook has longitudinal polar inertia (think majorette's baton). How many Chinooks and Sea Knights over the years have done a forward or rearward somersault and crashed inverted because one of their rotors got into VRS and other didn't?
The proprotors on a V-22 do act individually...and need to act individually because it has been discovered that when they interact with each other (as in the shipboard testing) the results can be nearly disastrous. Or have we forgotten that for the sake of convenience? Apparently the Air Force didn't read or listen to what the Navy discovered about proprotor downwash interaction.
We don't know enough about the recent Eglin crash yet to know whether it really was "roll off" or what. Maybe Maj. Luce can enlighten us if he has any recollection of *this* crash. (Personally I wouldn't bet on it. If not, he may go down in history as the most forgetful pilot ever since my 80 year-old Uncle Ned, from whom we finally had to take the keys to his Cessna 140 away after he landed, parked, tied it down and walked away from it while it was still running! We were, like, "Uhh Ned, did you lock your plane?" Then he started patting his pockets for the nonexistent keys.)
But whether the Eglin crash was the result of "A-VRS roll off" or "wingtip vortice roll off" makes no difference. The aircraft rolled over and crashed (we know at least that much) which strongly hints at unequal lift on one side. It still strengthens my point that the tiltrotor concept is DEFECTIVE. When one proprotor loses lift that piece of crap flips over on its back and crashes. It is only a miracle that anyone on the Eglin aircraft survived. (And don't give me that BS about "See how survivable a tiltrotor crash is!")
I've said this all along. And some of you nitwits blather on and on about how, "All you have to do is beep the nacelles forward and fly out of it!" Piece of cake! And now it happens again (maybe?) and the same nitwits are saying, "Oh no, loss of lift on one side of the V-22 is NOT THE SAME as A-VRS!" Yeah, right. Asymmetric loss of lift is asymmetric loss of lift. Why don't you guys just admit it? Okay, geniuses, what's the EP for "Roll-Off That You Think Might Not Be Caused By A-VRS?" And how do you differentiate between the two when you're down close to the ground and the thing starts to flip over on its back? And don't give me that Henny Youngman line: "Don't do this." Do not tell me that the crews should merely avoid any flight regime that *might* cause roll-off.
So what's next? "Let's not do formation flying with them." (And you KNOW that's coming...but...we learned that after Marana and the shipboard trials, didn't we? I guess not.) "Let's not use them for gunnery." (It was never intended to have a gun. There was never a V-22 gunship model proposed.) Let's just keep whittling down what the V-22 *cannot* do until we find what's left that it *can* do safely. Which in my book is nothing.
"Fatal Flaw." I'm telling you. Watch for it soon.
"Nitwits!".....just who do you refer as "Nitwits"?
Come on now FH....surely you are trying to be humorous and unfortunately failed.....you were being funny right?
Come on now FH....surely you are trying to be humorous and unfortunately failed.....you were being funny right?
Join Date: May 2006
Location: stateside
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
I heard the blackhawk Grenada crashes ( where #3 landed too close to #2 and #4 hit them both) were from the guys just coming in too hot.
It was a quote from one of the pilots behind them who aborted and while screaming back to the airport was told to slow down by the C&C bird that had seen the whole crash sequence happen and assumed that was the cause.
Could be wrong, it was a History Channel program!
I put the AVRS/lift differential or whatever you call it I'm the same category as twin engine props losing an engine after take off. How many mishandled it and rolled in. We haven't stopped flying King Airs because of it.
It was a quote from one of the pilots behind them who aborted and while screaming back to the airport was told to slow down by the C&C bird that had seen the whole crash sequence happen and assumed that was the cause.
Could be wrong, it was a History Channel program!
I put the AVRS/lift differential or whatever you call it I'm the same category as twin engine props losing an engine after take off. How many mishandled it and rolled in. We haven't stopped flying King Airs because of it.
FH, do you consider Mast Bumping to be a fatal flaw of the Huey? Just curious. It is a feature that comes with the rotor system and head, as designed. It can kill you, if you don't account for it in your handling of the aircraft.
For some reason, I get the idea that this has been discussed before, possibly even in this very thread.
No, I don't think so.
That is irrelevant to the point that you can end up with thrust asymmetry if the forward rotor and the aft rotor are rotating in different quality air. Thats aero 101, but depending upon the magnitude of the difference, may not create a substantial handling problem.
A scenario: landing on the back of a ship, like a destroyer, that has a tall hangar. The mini-version of the Chinook, CH-46, has to account for this during approach to land. If you are making an "up the rear" approach, you may find, as you move forward over the deck, that the front rotor disk will begin to hit the turbulent air that swirls off of the superstructure before the rear rotor does. Typically, it isn't of sufficient magnitude to make controllability a problem, but you will find in the NATOPS wind limits for such approaches. As with most transitional maneuvers, there is an adjustment to be made, depending upon the wind and aspect.
Your point is well made, however, that the distance between the centers of thrust are proportionally greater when comparing the V-22 to the Chinook or its baby brother. That is what has the gears churning in my brain.
Indeed, they are not the same as the tandem rotors in the Phrog or Chinook.
It might to whomever is writing the NATOPS manual, or the Dash 1, as there may need to be a change in guidance for handling.
You are being redundant there. Unequal lift in a system that produces lift from two sources requires, by definition, that one side's lift production isn't equal to the other.
I don't think your point is supported by the evidence of the thousands of hours of successful operation.
I am not so sure that's right, in terms of design. As I understand the design, if one of the engines fails, or some of the subsystems fail, you will have torque asymmery and thus transient uncommanded rolling moments. (Best translation from the NATOPS (old) that I have access to).
In other words, not every asymmetry in thrust / torque causes a roll to inverted state, but the risk is there. The handling issues are both addressed and as I understand it, part of the training program: just as you or I would be aware of how to deal with stuck pedals in a Jet Ranger or a Huey. The handling is a bit more difficult, and if not done quite right can result in a wreck, but if done right can result in a safe landing.
Critical engine and rudder in twins, fixed wing, anyone?
Not buying your argument here. Are you aware of the significant efforts the Army went to in order to upgrade crashworthiness and crash survivability for the Blackhawk versus the Huey? That isn't the only aircrft to have benefited from the work they did.
No kidding. I hear an Israeli F-15 flew home missing a good portion of a wing. I've flown fixed wing in split flap condition (annoying as hell) due to a system failure. I didn't roll inverted.
Methinks you overstate the case.
For some reason, I get the idea that this has been discussed before, possibly even in this very thread.
Some people seem to make the mistake of thinking that the Chinook rotors act independantly of each other all the time.
This is not...I think...the case. They overlap by, what, 30%? Not only that, the masts are at different angles with respect to each other. Even in a hover the Chinook rotors are interacting with each other.
A scenario: landing on the back of a ship, like a destroyer, that has a tall hangar. The mini-version of the Chinook, CH-46, has to account for this during approach to land. If you are making an "up the rear" approach, you may find, as you move forward over the deck, that the front rotor disk will begin to hit the turbulent air that swirls off of the superstructure before the rear rotor does. Typically, it isn't of sufficient magnitude to make controllability a problem, but you will find in the NATOPS wind limits for such approaches. As with most transitional maneuvers, there is an adjustment to be made, depending upon the wind and aspect.
Your point is well made, however, that the distance between the centers of thrust are proportionally greater when comparing the V-22 to the Chinook or its baby brother. That is what has the gears churning in my brain.
The proprotors on a V-22 do act individually...and need to act individually because it has been discovered that when they interact with each other (as in the shipboard testing) the results can be nearly disastrous.
But whether the Eglin crash was the result of "A-VRS roll off" or "wingtip vortice roll off" makes no difference.
The aircraft rolled over and crashed (we know at least that much) which strongly hints at unequal lift on one side.
It still strengthens my point that the tiltrotor concept is DEFECTIVE.
When one proprotor loses lift that piece of crap flips over on its back and crashes.
In other words, not every asymmetry in thrust / torque causes a roll to inverted state, but the risk is there. The handling issues are both addressed and as I understand it, part of the training program: just as you or I would be aware of how to deal with stuck pedals in a Jet Ranger or a Huey. The handling is a bit more difficult, and if not done quite right can result in a wreck, but if done right can result in a safe landing.
Critical engine and rudder in twins, fixed wing, anyone?
It is only a miracle that anyone on the Eglin aircraft survived. (And don't give me that BS about "See how survivable a tiltrotor crash is!")
Asymmetric loss of lift is asymmetric loss of lift.
Let's just keep whittling down what the V-22 *cannot* do until we find what's left that it *can* do safely. Which in my book is nothing. "Fatal Flaw." I'm telling you. Watch for it soon.
Tuk-Tuk weighs in:
Tut-tut, Tuk-Tuk, WRONG!
The King Air pilot you desribe has a couple of things going for him. 1) For one thing, there's a big "ENGINE OUT" caption up on the panel in front of him to warn him about what's going on. 2) Most King Airs I've flown also have this thing called "AUTOFEATHER" which takes the load off of the prop that's not being driven by its engine anymore.
The V-22 pilot HAS NO SUCH DEVICES. An "A-VRS Detector" has not been invented yet. So when a wing of a V-22 drops on approach, the pilot has no idea whether this is just an errant gust of wind, A-VRS or "roll-off caused by some other reason," all of which may have different responses required of him.
Definitely NOT the same as an engine failure in a twin-engine plane.
And see, that's what I'm getting at here. Some of you people THINK you "know" a lot about a V-22. You make these asinine and irrelevant comparisons to airplanes or helicopters, without fully understanding what we're dealing with here. And what we're dealing with is an aircraft with an inherently defective design.
Lone, rather than debate all of your inane statements point by point, let me just address one:
Asymmetric thrust and asymmetric torque are two different things. As you should probably know, a single engine failure (asymmetric torque) will not cause asymmetric *thrust* as the proprotors are shaft-connected together.
Asymmetric *thrust* WILL cause the V-22 to want to roll over and dive for the ground. Only split-second detection and proper reaction on the part of the flight crew can even hope to save the day.
Your analogies about fighters losing wings and split-flap situations in fixed-wing are amusing but irrelevant to a discussion about asymmetric lift/thrust in a tiltrotor aircraft. (Oh, and by the way, the fighter pilot can eject if his a/c departs controlled flight due to loss of a wing. The hapless passengers of a V-22 can do nothing but enjoy the brief-but-exciting roller-coaster ride to their doom.
I put the AVRS/lift differential or whatever you call it I'm the same category as twin engine props losing an engine after take off. How many mishandled it and rolled in. We haven't stopped flying King Airs because of it.
The King Air pilot you desribe has a couple of things going for him. 1) For one thing, there's a big "ENGINE OUT" caption up on the panel in front of him to warn him about what's going on. 2) Most King Airs I've flown also have this thing called "AUTOFEATHER" which takes the load off of the prop that's not being driven by its engine anymore.
The V-22 pilot HAS NO SUCH DEVICES. An "A-VRS Detector" has not been invented yet. So when a wing of a V-22 drops on approach, the pilot has no idea whether this is just an errant gust of wind, A-VRS or "roll-off caused by some other reason," all of which may have different responses required of him.
Definitely NOT the same as an engine failure in a twin-engine plane.
And see, that's what I'm getting at here. Some of you people THINK you "know" a lot about a V-22. You make these asinine and irrelevant comparisons to airplanes or helicopters, without fully understanding what we're dealing with here. And what we're dealing with is an aircraft with an inherently defective design.
Lone, rather than debate all of your inane statements point by point, let me just address one:
In other words, not every asymmetry in thrust / torque causes a roll to inverted state, but the risk is there.
Asymmetric *thrust* WILL cause the V-22 to want to roll over and dive for the ground. Only split-second detection and proper reaction on the part of the flight crew can even hope to save the day.
Your analogies about fighters losing wings and split-flap situations in fixed-wing are amusing but irrelevant to a discussion about asymmetric lift/thrust in a tiltrotor aircraft. (Oh, and by the way, the fighter pilot can eject if his a/c departs controlled flight due to loss of a wing. The hapless passengers of a V-22 can do nothing but enjoy the brief-but-exciting roller-coaster ride to their doom.
Grenada etc.
Tcabot,
Not sure I recall the accidents in their proper chronological order, but two Army accidents from that exact period stuck in my mind, and one that occurred at Sikorsky.
One occurred at Hooper stage field within the Ft Rucker complex, with all fatally injured, and was caused by a main rotor servo failure. This failure resulted from "hydrogen embrittlement " of the main rotor servo material, a phenomena which markedly reduced the fatigue strength of the servo. Main rotor servos had severe ballistic survivability requirements and Hydraulic Research Co had used a mfg process which led to the embrittlement proble.
Another occurred at Ft Bragg, where two A models were flying low level, next to one another, with the infantry troops waving at one another, when one simply nosed over and went in upside down, with all fatally injured. They were going pretty fast, so the rotor, control system etc, wound up all over the place and some of it buried fairly deep. Of course the media and rumor mill immediately pronounced the cause as the stabilator failing full down. That investigation took six months before we found the cause. Maintenance records were available, and we knew the control mixing unit had been worked on, but subsequent flying had produced no flight gripes. It took some months before we found all the parts, and found a bolt in the longitudinal mixer control missing a nut, then found the non-safetied nut with damage marks which fit some curious indentation marks in the longitudinal control limiter within the mixer.
Think I've mentioned this previously, but the only stabilator caused accident was the test aircraft at SA, which was caused by two separate human errors. But scuttlebutt can be a powerful influence, and it turned out that we at SA learned, after the Grenada assault, that with the Ft Bragg units, they were putting the stabilator in manual, zero degrees incidence, when they started in on the approach, ensuring that the pitch attitude would be far higher than normal when the main rotor down wash impinged upon the tail. BTW, did I ever mention that when I first got a close look at an AH-64, and looked at their stabilator installation, the actuator part number began with: 70-xxx-xxx, I.e., it was a UH-60 part! This was awhile ago, of course.
Thanks,
John Dixson
Not sure I recall the accidents in their proper chronological order, but two Army accidents from that exact period stuck in my mind, and one that occurred at Sikorsky.
One occurred at Hooper stage field within the Ft Rucker complex, with all fatally injured, and was caused by a main rotor servo failure. This failure resulted from "hydrogen embrittlement " of the main rotor servo material, a phenomena which markedly reduced the fatigue strength of the servo. Main rotor servos had severe ballistic survivability requirements and Hydraulic Research Co had used a mfg process which led to the embrittlement proble.
Another occurred at Ft Bragg, where two A models were flying low level, next to one another, with the infantry troops waving at one another, when one simply nosed over and went in upside down, with all fatally injured. They were going pretty fast, so the rotor, control system etc, wound up all over the place and some of it buried fairly deep. Of course the media and rumor mill immediately pronounced the cause as the stabilator failing full down. That investigation took six months before we found the cause. Maintenance records were available, and we knew the control mixing unit had been worked on, but subsequent flying had produced no flight gripes. It took some months before we found all the parts, and found a bolt in the longitudinal mixer control missing a nut, then found the non-safetied nut with damage marks which fit some curious indentation marks in the longitudinal control limiter within the mixer.
Think I've mentioned this previously, but the only stabilator caused accident was the test aircraft at SA, which was caused by two separate human errors. But scuttlebutt can be a powerful influence, and it turned out that we at SA learned, after the Grenada assault, that with the Ft Bragg units, they were putting the stabilator in manual, zero degrees incidence, when they started in on the approach, ensuring that the pitch attitude would be far higher than normal when the main rotor down wash impinged upon the tail. BTW, did I ever mention that when I first got a close look at an AH-64, and looked at their stabilator installation, the actuator part number began with: 70-xxx-xxx, I.e., it was a UH-60 part! This was awhile ago, of course.
Thanks,
John Dixson
I've said this all along. And some of you nitwits blather on and on about how, "All you have to do is beep the nacelles forward and fly out of it!" Piece of cake! And now it happens again (maybe?) and the same nitwits are saying, "Oh no, loss of lift on one side of the V-22 is NOT THE SAME as A-VRS!" Yeah, right. Asymmetric loss of lift is asymmetric loss of lift. Why don't you guys just admit it? Okay, geniuses, what's the EP for "Roll-Off That You Think Might Not Be Caused By A-VRS?" And how do you differentiate between the two when you're down close to the ground and the thing starts to flip over on its back? And don't give me that Henny Youngman line: "Don't do this." Do not tell me that the crews should merely avoid any flight regime that *might* cause roll-off.
Lets throw you a bone and make a hypothetical case that the V22 is extremely sensitive to asymmetrical thrust in hover, which is the argument you are trying to make if I understand your rambling, mostly incoherent posts. If that actually was the case, then the V22 would have doubtlessly encountered these roll-off events numerous times in its operations, and was successfully recovered in ALL BUT ONE OF THEM!
The reality is, and you seem hellbent on ignoring this, that the V22 is not as sensitive as you love to believe, as it knocks down your strawman. In addition, I have heard recovery from rare roll-off events does and has indeed happened in operation without incident.
Basically, your constant yammering on about how it actually isn't so simple to detect, react, and recover from an asymmetrical thrust event is directly countered when you ignore both the hard facts of 150,000 hours of operation with 1 crash SPECULATED due to this phenomenon, and your complete lack of knowledge regarding successful recoveries to date.
You cant have it both ways!
The evidence at hand proves either the V22 isn't the over-sensitive unstable top that you claim, or recovery is as easy and routine as others have suggested. And then there's the third option, which is mostly supported by our friend Occam and his razor, that the V22 is both largely stable and recoverable.
BTW, did I ever mention that when I first got a close look at an AH-64, and looked at their stabilator installation, the actuator part number began with: 70-xxx-xxx, I.e., it was a UH-60 part! This was awhile ago, of course
I cant imagine how in the world a Sikorsky part would end up on a Hughes
FH, I don't think you understand what terms are being used here, nor their relationship. "Inane" would apply to a few of your comments in this discussion.
If you are in helo mode, the torque on your proprotor, be it on the right or the left, is an indication of the thrust you are producing in the vertical direction. A change in torque will be an indication of a change in thrust.
Let's talk about something you know well: a helicopter.
Case 1 is hover at Gross Weight X, with 70 % Torque required to hover.
Case 2 is hover at Gross Weight Y, with 77 % Torque required to hover.
Which hover requires more thrust? Thrust is a vector. Your torque is indicated in the cockpit, hence the thrust / torque in my discussion, since there isn't a THRUST gauge in the cockpit.
A pilot would know this, right?
For John: thanks for further enlightenment on Blackhawk stab failures, and others. A point that might be related to the V-22 mishaps may be germane: control authority. If that linkage broke, so much for flight control authority.
Aside: we were warned in the Seahawk about the limits in pitch authority with the stab at various angles of 'down." There was a placard in the cockpit, and as well as typical NATOPS test questions on airspeed limts for various stab down positions. Loss of control authority in the pitch channel can be fatal. (Related note: If you check the news from last year, the Navy lost a T-45 due to loss in pitch control authority, pilot bailed out. Appears to be a cause similar to the hardware issue found in the Bragg crash.)
We had cautions in the Huey NATOPS about tail rotor control authority limits (IIRC due to the chain / sprocket) such that on a hot day, at the bottom of an auto, IIRC the TH-1E, you could hit the stops and not have the control authority you had expected. Jack Carson and I discussed this a while back, I think he remembers it better than I.
Might the Osprey team want to look at control authority limits?
I am not sure.
It's not like the control linkage to an aileron or a tail rotor control linkage.
From the AF 447 threads, I have learned that control laws in some modern planes limit the control authority, or the "throw" you can achieve with a max deflection. There was a passenger liner near New York that lost its Vertical Stab due to what I think was exceeding design stength via over control, or excessive control authority.
FBW systems have plenty of limiting features.
IIRC, V-22 has an FBW, or FBW type system. Is there enough control authority for the operating environment?
That's a hard question. See the airliner above. If you increase control authority X amount, you may risk Y or Z damage or fatigue in a given control channel.
Interesting point to ponder.
If you are in helo mode, the torque on your proprotor, be it on the right or the left, is an indication of the thrust you are producing in the vertical direction. A change in torque will be an indication of a change in thrust.
Let's talk about something you know well: a helicopter.
Case 1 is hover at Gross Weight X, with 70 % Torque required to hover.
Case 2 is hover at Gross Weight Y, with 77 % Torque required to hover.
Which hover requires more thrust? Thrust is a vector. Your torque is indicated in the cockpit, hence the thrust / torque in my discussion, since there isn't a THRUST gauge in the cockpit.
A pilot would know this, right?
For John: thanks for further enlightenment on Blackhawk stab failures, and others. A point that might be related to the V-22 mishaps may be germane: control authority. If that linkage broke, so much for flight control authority.
Aside: we were warned in the Seahawk about the limits in pitch authority with the stab at various angles of 'down." There was a placard in the cockpit, and as well as typical NATOPS test questions on airspeed limts for various stab down positions. Loss of control authority in the pitch channel can be fatal. (Related note: If you check the news from last year, the Navy lost a T-45 due to loss in pitch control authority, pilot bailed out. Appears to be a cause similar to the hardware issue found in the Bragg crash.)
We had cautions in the Huey NATOPS about tail rotor control authority limits (IIRC due to the chain / sprocket) such that on a hot day, at the bottom of an auto, IIRC the TH-1E, you could hit the stops and not have the control authority you had expected. Jack Carson and I discussed this a while back, I think he remembers it better than I.
Might the Osprey team want to look at control authority limits?
I am not sure.
It's not like the control linkage to an aileron or a tail rotor control linkage.
From the AF 447 threads, I have learned that control laws in some modern planes limit the control authority, or the "throw" you can achieve with a max deflection. There was a passenger liner near New York that lost its Vertical Stab due to what I think was exceeding design stength via over control, or excessive control authority.
FBW systems have plenty of limiting features.
IIRC, V-22 has an FBW, or FBW type system. Is there enough control authority for the operating environment?
That's a hard question. See the airliner above. If you increase control authority X amount, you may risk Y or Z damage or fatigue in a given control channel.
Interesting point to ponder.
Some of you people THINK you "know" a lot about a V-22. You make these asinine and irrelevant comparisons to airplanes or helicopters, without fully understanding what we're dealing with here.
OK FH......everyone here are ignorant about the Osprey.
Do explain to us why you are the only expert who can attest to the Osprey's fitness for flight!
Are you an Osprey Pilot?
Have you done any Flight Test Work on the Osprey?
Do you hold an Aeronautical Engineering degree with a specialty in Tilt Rotor flight?
Are you an accomplished Googlier even?
Please do explain your Bonafides to hold forth as you do!
You called us "Nitwits"....now back up your claim please.
What makes you the Resident Expert extant on all things Osprey?
SA Part on AH-64
Sans, remember that the stabilator was not a part of the original AH design, so when they decided on having one, the Army could quite properly ( the UH-60 design now being in the public domain, so to speak ) offer them the technology and hardware. I might have mis-remembered the p/n format, but that was a 60 stabilator actuator on that 64.
Thanks,
John Dixson
Thanks,
John Dixson
Join Date: Apr 2008
Location: UAE
Posts: 311
Likes: 0
Received 0 Likes
on
0 Posts
…Please do explain your Bonafides to hold forth as you do!
You called us "Nitwits".... now back up your claim please.
What makes you the Resident Expert extant on all things Osprey?
What makes you the Resident Expert extant on all things Osprey?
Here are just three recent examples of the unanswered comments and claims of the same dribble that he keeps repeating over and over again despite the fact that they have been responded to without any rebuttal on his part. There are many, many more prior to add to that, all with no answers when his comments are discredited.
http://www.pprune.org/rotorheads/204936-whats-latest-news-v22-osprey-71.html
http://www.pprune.org/rotorheads/456619-whats-new-civil-tiltrotor-2.html
http://www.pprune.org/rotorheads/204936-whats-latest-news-v22-osprey-82.html
This sort of monotony is why many on PPRUNE have tuned out of this thread, including the majority of those who have firsthand experience on the V-22 and tiltrotor technology. We could have real answers to the questions being raised if there was a serious discussion of the facts here instead of one or two individuals with a propensity to cling to their opinions in spite of the fact that they are based on ignorance of the technology regardless of whether it be from the pro or negative side. Very sad...
As jeffg said, Osprey pilots are more than willing to discuss the 'warts' that truly do exist with the aircraft, and we could hear more about those true problems here if we allow them to speak without drowning them out with false claims and exaggerations being put forward about the technology from those who have a personal agenda.
All of us who are serious about getting truthful answers about the technology and how the Osprey really performs should give those who fly it the opportunity to speak freely without childlike banter from those who declare others to be ‘nitwits’ when in fact they are the ones who do not have a clue.
Honest and forthright input from those who are or were with Sikorsky (aka the ‘competition’ to the V-22 in some regards) can also play a valid role in the discussion particularly if the discussions focus on the facts and not the marketing side.
21stC
Join Date: Apr 2008
Location: UAE
Posts: 311
Likes: 0
Received 0 Likes
on
0 Posts
V-22s Cleared For Okinawa And Heads To UK Air Shows
By Richard Whittle
Published: June 29, 2012
The Pentagon and the Japanese government announced early Friday that a dozen Marine Corps MV-22 Ospreys are being shipped to Japan for deployment on Okinawa but the planes won't fly until investigations into two recent crashes of the tiltrotor troop transport are complete.
The announcement – issued the same day four MV-22s were scheduled to fly from North Carolina to England to take part in two international air shows – emphasized that "Japan will be the only location worldwide where the United States will suspend MV-22 flight operations. The United States will continue uninterrupted flight operations of the MV-22 and (Air Force) CV-22 elsewhere around the world, including the continental United States."
The Marines have long had plans to deploy two squadrons of Ospreys on the island of Okinawa to replace aged CH-46E Sea Knight and CH-53D Sea Stallion helicopters based at Marine Corps Air Station Futenma. Local residents and politicians have resisted the plan, citing noise and worries about the helicopter-airplane hybrid Osprey's safety -- a concern heightened in the wake of an MV-22 crash April 11 in Morocco that killed two Marines and a CV-22 crash in Florida June 13 that injured five Air Force Special Operations Command crew members.
The DoD announcement said Japanese officials agreed the Marines could go ahead with the Osprey deployment to Okinawa after being briefed on preliminary findings of investigations into those two crashes. As AOL Defense has previously reported, aircraft malfunction has been ruled out in the Morocco crash, and the commander of AFSOC's 1st Special Operations Wing at Hurlburt Field, Fla., has said there is no evidence of any mechanical problems or design flaws in the Osprey that crashed at Eglin Air Force Base. The Osprey, a revolutionary design, tilts two large wingtip rotors up to fly like a helicopter and forward to fly like an airplane.
"In recognition of the remaining concerns of the Japanese government about the safety of the aircraft, the DoD will refrain from any flight operations of the MV-22 in Japan until the results of the investigations are presented to the Japanese government and the safety of flight operations is confirmed," the Pentagon announcement said. "The Defense Department anticipates presenting this information to the Japanese government in August."
As the debate in Japan shows, the Osprey's reputation remains marred in some quarters by three crashes during its 25-year development that killed 30 people between 1992 and 2000, including 15 Marine infantry who were taking part in an operational test. Even with its two recent crashes, though, the Osprey has been one of the safest rotorcraft in the U.S. military inventory since 2001, a period in which the armed forces have lost 414 helicopters at a cost of 606 lives. During the same period, six people have been killed in three Osprey crashes.
The Marines and the makers of the Osprey, 50-50 partnersBell Helicopter Textron Inc. andBoeing Co., have high hopes of making a first foreign sale of the V-22 sometime soon, which is why the four MV-22s are being sent to the upcoming air shows in England. From July 7-8, they'll will be used to take senior air commanders from around the world on demonstration flights during the world's largest military air show, the Royal International Air Tattoo at Royal Air Force Base Fairford, two hours northwest of London. From July 9-15, the Ospreys will offer flights to military brass and foreign VIPs during the Farnborough International Airshow, which alternates biennially with the Paris Air Show as the world's premier aviation trade fair.
An Osprey was on display last November at the Dubai Airshow, and the United Arab Emirates are thought to be the most likely first foreign buyer of Ospreys. UAE and U.S. military representatives have recently been meeting and exchanging paperwork on a possible Osprey purchase in a "very active dialog," said a government official privy to the discussions. "Looks pretty serious. Until the contract's written, though, the contract's not written."
By Richard Whittle
Published: June 29, 2012
The Pentagon and the Japanese government announced early Friday that a dozen Marine Corps MV-22 Ospreys are being shipped to Japan for deployment on Okinawa but the planes won't fly until investigations into two recent crashes of the tiltrotor troop transport are complete.
The announcement – issued the same day four MV-22s were scheduled to fly from North Carolina to England to take part in two international air shows – emphasized that "Japan will be the only location worldwide where the United States will suspend MV-22 flight operations. The United States will continue uninterrupted flight operations of the MV-22 and (Air Force) CV-22 elsewhere around the world, including the continental United States."
The Marines have long had plans to deploy two squadrons of Ospreys on the island of Okinawa to replace aged CH-46E Sea Knight and CH-53D Sea Stallion helicopters based at Marine Corps Air Station Futenma. Local residents and politicians have resisted the plan, citing noise and worries about the helicopter-airplane hybrid Osprey's safety -- a concern heightened in the wake of an MV-22 crash April 11 in Morocco that killed two Marines and a CV-22 crash in Florida June 13 that injured five Air Force Special Operations Command crew members.
The DoD announcement said Japanese officials agreed the Marines could go ahead with the Osprey deployment to Okinawa after being briefed on preliminary findings of investigations into those two crashes. As AOL Defense has previously reported, aircraft malfunction has been ruled out in the Morocco crash, and the commander of AFSOC's 1st Special Operations Wing at Hurlburt Field, Fla., has said there is no evidence of any mechanical problems or design flaws in the Osprey that crashed at Eglin Air Force Base. The Osprey, a revolutionary design, tilts two large wingtip rotors up to fly like a helicopter and forward to fly like an airplane.
"In recognition of the remaining concerns of the Japanese government about the safety of the aircraft, the DoD will refrain from any flight operations of the MV-22 in Japan until the results of the investigations are presented to the Japanese government and the safety of flight operations is confirmed," the Pentagon announcement said. "The Defense Department anticipates presenting this information to the Japanese government in August."
As the debate in Japan shows, the Osprey's reputation remains marred in some quarters by three crashes during its 25-year development that killed 30 people between 1992 and 2000, including 15 Marine infantry who were taking part in an operational test. Even with its two recent crashes, though, the Osprey has been one of the safest rotorcraft in the U.S. military inventory since 2001, a period in which the armed forces have lost 414 helicopters at a cost of 606 lives. During the same period, six people have been killed in three Osprey crashes.
The Marines and the makers of the Osprey, 50-50 partnersBell Helicopter Textron Inc. andBoeing Co., have high hopes of making a first foreign sale of the V-22 sometime soon, which is why the four MV-22s are being sent to the upcoming air shows in England. From July 7-8, they'll will be used to take senior air commanders from around the world on demonstration flights during the world's largest military air show, the Royal International Air Tattoo at Royal Air Force Base Fairford, two hours northwest of London. From July 9-15, the Ospreys will offer flights to military brass and foreign VIPs during the Farnborough International Airshow, which alternates biennially with the Paris Air Show as the world's premier aviation trade fair.
An Osprey was on display last November at the Dubai Airshow, and the United Arab Emirates are thought to be the most likely first foreign buyer of Ospreys. UAE and U.S. military representatives have recently been meeting and exchanging paperwork on a possible Osprey purchase in a "very active dialog," said a government official privy to the discussions. "Looks pretty serious. Until the contract's written, though, the contract's not written."