What's the latest on tilt rotors?
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mriya225 asked:
When are the engineers going to tackle the problem of adding armor?
The modern way to approach this is to design in "ballistic tolerance" so that the shots that can take the aircraft down are quite improbable. For example, a set views of the airframe are made (long before design is frozen) and analysis of the components that are exposed is made. Several design software tools are available for this. redundant systems, and physical separation of critical components are used to help drop the vulnerability. Critical components designed with multiple load paths to allow strength after impacts. The parts are tested with actual bullet and cannon hits, and the remaining strength is assessed. Often, fatigue tests are run with the damaged parts to judge how much flying time remains after the damage. Multiple electric, flight control and hydraulic systems are used. Armor is used sparingly usually around critical engine and aircraft parts, and around the crew. US Army crews wear ballistic helmets and shields ("chicken plates") across thier chests to round out the ensemble.
The actual "vulnerable area" of a modern combat helicopter might be only a square meter or less for 23mm cannon, and might be zero for typical hand held 7.62 mm weapons. This is typical of Apache, Black Hawk and Osprey.
Considered this way, the V-22 is quite robust, and was judged in the OT&E reports that I read to be very much up to par.
Nick Lappos
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When are the engineers going to tackle the problem of adding armor?
The modern way to approach this is to design in "ballistic tolerance" so that the shots that can take the aircraft down are quite improbable. For example, a set views of the airframe are made (long before design is frozen) and analysis of the components that are exposed is made. Several design software tools are available for this. redundant systems, and physical separation of critical components are used to help drop the vulnerability. Critical components designed with multiple load paths to allow strength after impacts. The parts are tested with actual bullet and cannon hits, and the remaining strength is assessed. Often, fatigue tests are run with the damaged parts to judge how much flying time remains after the damage. Multiple electric, flight control and hydraulic systems are used. Armor is used sparingly usually around critical engine and aircraft parts, and around the crew. US Army crews wear ballistic helmets and shields ("chicken plates") across thier chests to round out the ensemble.
The actual "vulnerable area" of a modern combat helicopter might be only a square meter or less for 23mm cannon, and might be zero for typical hand held 7.62 mm weapons. This is typical of Apache, Black Hawk and Osprey.
Considered this way, the V-22 is quite robust, and was judged in the OT&E reports that I read to be very much up to par.
Nick Lappos
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To: Nick Lappos
On the Apache they ran a vulnerability analysis and found that through placement of different equipments and black boxes they could protect the pilots but only from small arms and ground based machine gun fire. The impact energy was dissipated because in the analysis the round was assumed to be tumbling and would make initial impact not pointy end first but hit flat on its' side. All bullets do not tumble with the exception of 7.62 MM. Bigger rounds like 50 Cal. hit pointy end first and in doing so have much deeper penetration than a tumbling round. Also, the Apache had frangible armor that was mounted inside of the skin and each piece of armor was spring mounted to absorb the impact energy. In absorbing this energy the armor plate would jam into the engine and flight controls. 23MM rounds are another story. It is true that tests were performed to demonstrate the resiliency but only one round was used.
This is an excerpt from a letter I sent to John Persinos the editor of Rotor & Wing.
It was directed to the AH-64 but it also applies to the V-22 and Comanche as well.
The Army also lied to the pilots of the Apache relative to its’ invulnerability to the ZSU 23-4 weapons system. This was the primary weapon that would be used against the Apache if it were to attack a group of Warsaw Pact tanks.
This weapon was also being supplied to all of the governments that were in league with the Warsaw Pact. The U S Army commissioned a study by a so-called”Think Tank” to study the effectiveness of the ZSU 23-4 against the Apache. It was their considered opinion that the ZSU 23-4 was inaccurate, It had a low degree of reliability and that if the ZSU 23-4 did hit the Apache with one round, the pilot would have sufficient time to evade any further hits by dropping below the tree line. The uninitiated reader should understand that the ZSU 23-4 has a rate of fire of 1200 rounds per minute and that if one bullet hit its’ mark, there would be forty or fifty rounds right behind the first round. When the writer was on contract with Agusta helicopters he took a two-week holiday in Yugoslavia. While there, the writer watched a T V program, which was describing the weaponry of the Warsaw Pact. One of the weapons demonstrated was the ZSU 23-4. In the demonstration the weapon was pointed on a line parallel to a stand of trees. A helicopter popped up from behind the trees and in an instant the weapon acquired the helicopter and was pointed directly at it. The helicopter then dropped below the treetops and at that time the gun was turned off. The helicopter was allowed to fly away and the gun was turned on. It immediately started to fire and it swept an arc approximately 30 to 45 degrees on either side of center. The trees started to explode. It looked like there were hundreds of chain saw wielding loggers in the tree stand felling trees as fast as they could. It appeared to the writer that if a hail of 23mm bullets didn’t hit the helicopter, a falling tree would destroy it.
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The Cat
[This message has been edited by Lu Zuckerman (edited 06 June 2001).]
On the Apache they ran a vulnerability analysis and found that through placement of different equipments and black boxes they could protect the pilots but only from small arms and ground based machine gun fire. The impact energy was dissipated because in the analysis the round was assumed to be tumbling and would make initial impact not pointy end first but hit flat on its' side. All bullets do not tumble with the exception of 7.62 MM. Bigger rounds like 50 Cal. hit pointy end first and in doing so have much deeper penetration than a tumbling round. Also, the Apache had frangible armor that was mounted inside of the skin and each piece of armor was spring mounted to absorb the impact energy. In absorbing this energy the armor plate would jam into the engine and flight controls. 23MM rounds are another story. It is true that tests were performed to demonstrate the resiliency but only one round was used.
This is an excerpt from a letter I sent to John Persinos the editor of Rotor & Wing.
It was directed to the AH-64 but it also applies to the V-22 and Comanche as well.
The Army also lied to the pilots of the Apache relative to its’ invulnerability to the ZSU 23-4 weapons system. This was the primary weapon that would be used against the Apache if it were to attack a group of Warsaw Pact tanks.
This weapon was also being supplied to all of the governments that were in league with the Warsaw Pact. The U S Army commissioned a study by a so-called”Think Tank” to study the effectiveness of the ZSU 23-4 against the Apache. It was their considered opinion that the ZSU 23-4 was inaccurate, It had a low degree of reliability and that if the ZSU 23-4 did hit the Apache with one round, the pilot would have sufficient time to evade any further hits by dropping below the tree line. The uninitiated reader should understand that the ZSU 23-4 has a rate of fire of 1200 rounds per minute and that if one bullet hit its’ mark, there would be forty or fifty rounds right behind the first round. When the writer was on contract with Agusta helicopters he took a two-week holiday in Yugoslavia. While there, the writer watched a T V program, which was describing the weaponry of the Warsaw Pact. One of the weapons demonstrated was the ZSU 23-4. In the demonstration the weapon was pointed on a line parallel to a stand of trees. A helicopter popped up from behind the trees and in an instant the weapon acquired the helicopter and was pointed directly at it. The helicopter then dropped below the treetops and at that time the gun was turned off. The helicopter was allowed to fly away and the gun was turned on. It immediately started to fire and it swept an arc approximately 30 to 45 degrees on either side of center. The trees started to explode. It looked like there were hundreds of chain saw wielding loggers in the tree stand felling trees as fast as they could. It appeared to the writer that if a hail of 23mm bullets didn’t hit the helicopter, a falling tree would destroy it.
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The Cat
[This message has been edited by Lu Zuckerman (edited 06 June 2001).]
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to Lu Zuckerman:
Wow! Don't be shy, Lu! Tell us what you feel.
I think you are saying that folks lie about ballistic tolerance, and that lots of trees have been killed by 23mm shells. OK.
I have never seen anyone say that any of the aircraft you mention are invulnerable to large caliber fire. The concept of minimizing the vulnerable area is to specifically allow some items to be vulnerable. By making the exposed area small, the probabilities of being shot down are acceptably low, and mission survivability is at or above required levels.
The way to survive in combat is captured by 4 basic rules: Don't be seen, don't be engaged, don't be hit, and don't be killed. A balance of factors to control each rule allow survivability.
I also believe that when you accuse some other professional person or organization of perpetuating lies, my "Flake Alarm" goes off, and most of the rest you have to say gets drowned out by the ensuing Bull---t alarm.
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Wow! Don't be shy, Lu! Tell us what you feel.
I think you are saying that folks lie about ballistic tolerance, and that lots of trees have been killed by 23mm shells. OK.
I have never seen anyone say that any of the aircraft you mention are invulnerable to large caliber fire. The concept of minimizing the vulnerable area is to specifically allow some items to be vulnerable. By making the exposed area small, the probabilities of being shot down are acceptably low, and mission survivability is at or above required levels.
The way to survive in combat is captured by 4 basic rules: Don't be seen, don't be engaged, don't be hit, and don't be killed. A balance of factors to control each rule allow survivability.
I also believe that when you accuse some other professional person or organization of perpetuating lies, my "Flake Alarm" goes off, and most of the rest you have to say gets drowned out by the ensuing Bull---t alarm.
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To: Nick Lappos
I stand by what I said about the Apache and by extension the V-22. In your post you stated the following:
“The way to survive in combat is captured by 4 basic rules: Don't be seen, don't be engaged, don't be hit, and don't be killed. A balance of factors to control each rule allow survivability”.
If you remember the pictures of the Apaches’ in Desert Storm none of them engaged the troops and armor on the ground as they were intended to. They fired their cannons and Hellfire missiles from a long way from the actual targets because the Army was afraid of loosing too many of them if they engaged excessive ground fire. In the Balkans the Army would not allow the Apaches to engage ground troops because of the possibility of high losses.
In order to apply the four rules stated above the V-22 would have to remain on the hangar deck of the LHA. The V-22 by the nature of its’ mission is required to get down and dirty. There are no trees to hide behind very few hills to hide behind and in order to avoid ground fire they will have to make a big hole approach and shift into helicopter mode and when they do, I pity the crews on those aircraft as IMHO they will be cut to pieces no mater how many vulnerability studies were made.
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The Cat
I stand by what I said about the Apache and by extension the V-22. In your post you stated the following:
“The way to survive in combat is captured by 4 basic rules: Don't be seen, don't be engaged, don't be hit, and don't be killed. A balance of factors to control each rule allow survivability”.
If you remember the pictures of the Apaches’ in Desert Storm none of them engaged the troops and armor on the ground as they were intended to. They fired their cannons and Hellfire missiles from a long way from the actual targets because the Army was afraid of loosing too many of them if they engaged excessive ground fire. In the Balkans the Army would not allow the Apaches to engage ground troops because of the possibility of high losses.
In order to apply the four rules stated above the V-22 would have to remain on the hangar deck of the LHA. The V-22 by the nature of its’ mission is required to get down and dirty. There are no trees to hide behind very few hills to hide behind and in order to avoid ground fire they will have to make a big hole approach and shift into helicopter mode and when they do, I pity the crews on those aircraft as IMHO they will be cut to pieces no mater how many vulnerability studies were made.
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The Cat
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Lu,
I guess I mostly object to your assertion that the Army lied, and therefore that the V-22 folks are, too.
The films from Desert Storm prove that the Apache was effective and deadly, and believe me (I have about 1000 hours of Attack Helicopter combat time) standing off is the right way to fight. If you are in a fair fight, you didn't plan it properly!
The vulnerability of aircraft will always be worse than tanks, and armorplating of flying machines will not replace robust systems and good tactics. Nobody I have heard or read lied about Apache or V-22 capabilities from a vulnerability standpoint.
I am in the awkward place of also agreeing with you that speed alone is a poor way to try and survive, and the V-22 will have its hands full in a contested environment.
I also do not like the way it is described as having "twice the speed, twice the payload and four times the range" of the helicopter it replaces, because I think this is often perceived to mean it is that good against any helicopter, which is not true. In reality, the V-22 has "twice the cost, half the payload, the same range and 50% more speed than a modern helicopter."
I also believe that if you start out by saying those you disagree with are liers, you will turn off those you wish to convince, and you lose automatically.
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I guess I mostly object to your assertion that the Army lied, and therefore that the V-22 folks are, too.
The films from Desert Storm prove that the Apache was effective and deadly, and believe me (I have about 1000 hours of Attack Helicopter combat time) standing off is the right way to fight. If you are in a fair fight, you didn't plan it properly!
The vulnerability of aircraft will always be worse than tanks, and armorplating of flying machines will not replace robust systems and good tactics. Nobody I have heard or read lied about Apache or V-22 capabilities from a vulnerability standpoint.
I am in the awkward place of also agreeing with you that speed alone is a poor way to try and survive, and the V-22 will have its hands full in a contested environment.
I also do not like the way it is described as having "twice the speed, twice the payload and four times the range" of the helicopter it replaces, because I think this is often perceived to mean it is that good against any helicopter, which is not true. In reality, the V-22 has "twice the cost, half the payload, the same range and 50% more speed than a modern helicopter."
I also believe that if you start out by saying those you disagree with are liers, you will turn off those you wish to convince, and you lose automatically.
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Guest
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To: Nick Lappos
Let’s turn the word lied to deceive. To tell the whole truth about the weapons system that the Apache pilots would come up against would not serve the Army very well, as fewer pilots would ask to become Apache pilots. This deception was told to me by one of the senior investigators who wrote a report for the US Congress. The report was made at the request of Les Aspin who at that time was the Chairman, Committee on Armed Services and John Dingle who at that time was Chairman, Subcommittee on Oversight and Investigations. This report (B-238876) was entitled APACHE HELICOPTER; Serious Logistical Support Problems Must Be Solved to Realize Combat Potential. During Desert Storm he spent a great deal of time incountry and monitored the Apache for reliability maintainability and combat deployment. He stated that it was decided to keep the Apaches’ from close in combat because they were afraid that they would be both vulnerable to ground fire and that with their poor reliability they would lose too many aircraft due to parts failure.
You must understand that when the Apache program was initiated NATO was planning on a major land war in 1988 with the Russians and the Warsaw Pact. The battle plan was that the Allied forces would be pushed back to Southern France and into Spain and they would have to fight their way back to Central Europe. The whole concept was that the Apache would be in a ground support roll and would become actively engaged with the tanks and other offensive weapons systems and that the ZSU-23-4 was the major defensive weapon used by the Warsaw Pact and the Russians.
The Apache dynamic systems and the rotor system were tested by being fired at by a single 23MM HE round. The testing proved that the helicopter could successfully fly for at least a half an hour or, it could make a successful autorotation.
The pilots were separated by transparent armor so that if one pilot were hit by a 23MM HEI round his guts would not fly into the adjacent cockpit. My contention is that if one round hit, the second would be right behind it.
In the case of the V-22 they may have performed an extensive vulnerability analysis and as a result, incorporated redundancies and placed less valued equipments in front of more valuable equipments in order to provide ballistic shielding but Plexiglas in the cockpit area offers minimal shielding from even 7.62 MM ground fire.
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The Cat
[This message has been edited by Lu Zuckerman (edited 10 June 2001).]
Let’s turn the word lied to deceive. To tell the whole truth about the weapons system that the Apache pilots would come up against would not serve the Army very well, as fewer pilots would ask to become Apache pilots. This deception was told to me by one of the senior investigators who wrote a report for the US Congress. The report was made at the request of Les Aspin who at that time was the Chairman, Committee on Armed Services and John Dingle who at that time was Chairman, Subcommittee on Oversight and Investigations. This report (B-238876) was entitled APACHE HELICOPTER; Serious Logistical Support Problems Must Be Solved to Realize Combat Potential. During Desert Storm he spent a great deal of time incountry and monitored the Apache for reliability maintainability and combat deployment. He stated that it was decided to keep the Apaches’ from close in combat because they were afraid that they would be both vulnerable to ground fire and that with their poor reliability they would lose too many aircraft due to parts failure.
You must understand that when the Apache program was initiated NATO was planning on a major land war in 1988 with the Russians and the Warsaw Pact. The battle plan was that the Allied forces would be pushed back to Southern France and into Spain and they would have to fight their way back to Central Europe. The whole concept was that the Apache would be in a ground support roll and would become actively engaged with the tanks and other offensive weapons systems and that the ZSU-23-4 was the major defensive weapon used by the Warsaw Pact and the Russians.
The Apache dynamic systems and the rotor system were tested by being fired at by a single 23MM HE round. The testing proved that the helicopter could successfully fly for at least a half an hour or, it could make a successful autorotation.
The pilots were separated by transparent armor so that if one pilot were hit by a 23MM HEI round his guts would not fly into the adjacent cockpit. My contention is that if one round hit, the second would be right behind it.
In the case of the V-22 they may have performed an extensive vulnerability analysis and as a result, incorporated redundancies and placed less valued equipments in front of more valuable equipments in order to provide ballistic shielding but Plexiglas in the cockpit area offers minimal shielding from even 7.62 MM ground fire.
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The Cat
[This message has been edited by Lu Zuckerman (edited 10 June 2001).]
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Nick and Lu
Looks like the title of this thread about "Reprieve" needs to be changed to the real situation of Vulnerability,because of lack of Manueverabilty. If the V-22 with about 1/2+ G available in hover/slow airspeed mode cannot manuever - he is a sitting/dead duck situation, which suggests it should'nt be exposed to Comabt Assault or Combat Rescue missions. What is left is a nice but inadequate people carrier -- to where????
There is a new internal group in DOD looking at all of the real life problems. Decisions will probably be made by new DOD and SecNav in about 90 days.
[This message has been edited by hpdunn (edited 11 June 2001).]
Looks like the title of this thread about "Reprieve" needs to be changed to the real situation of Vulnerability,because of lack of Manueverabilty. If the V-22 with about 1/2+ G available in hover/slow airspeed mode cannot manuever - he is a sitting/dead duck situation, which suggests it should'nt be exposed to Comabt Assault or Combat Rescue missions. What is left is a nice but inadequate people carrier -- to where????
There is a new internal group in DOD looking at all of the real life problems. Decisions will probably be made by new DOD and SecNav in about 90 days.
[This message has been edited by hpdunn (edited 11 June 2001).]
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Many interesting issues to solve, gentlemen...
Mr. Lappos,
I appreciate your insight--thanks for your time. For the record, these concerns were passed on to me by a few of the United States Marines who'll be dependant on this technology to keep their 'six' out of the grave.
Lu,
I'd re-nick you "El Gato Magnifico", but the term of admiration is currently being used by my big black cat Madison--the most gorgeous full-on scrapper God ever did create (built like a Maine Coon and definitely not to be trifled with)! Still, you're one of my all-time faves for good reason sugar. Keep on keeping 'em on the straight & narrow.
Thanks again gentlemen, it looks like the Osprey still has a ways to go--but then, we might have known there would be the need for adjustments as the full-scale production progressed.
Mr. Lappos,
I appreciate your insight--thanks for your time. For the record, these concerns were passed on to me by a few of the United States Marines who'll be dependant on this technology to keep their 'six' out of the grave.
Lu,
I'd re-nick you "El Gato Magnifico", but the term of admiration is currently being used by my big black cat Madison--the most gorgeous full-on scrapper God ever did create (built like a Maine Coon and definitely not to be trifled with)! Still, you're one of my all-time faves for good reason sugar. Keep on keeping 'em on the straight & narrow.
Thanks again gentlemen, it looks like the Osprey still has a ways to go--but then, we might have known there would be the need for adjustments as the full-scale production progressed.
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Jamie - the Flight Yest Engineer
Have been waiting for someone from texas to discuss that little FLAW in engineering design called Ct/Sigma, and its resultant limit load factor. Perhaps you can show all of us who in Texas engineering decided to go for three blades with terrible Ct/sigma - with no manueverability, instead of 4-5 blades which might have made it workable in Combat.
PS It AINT over til the fat lady sings -- and she will NOT sing until about September -Count on it!
[This message has been edited by hpdunn (edited 15 June 2001).]
Have been waiting for someone from texas to discuss that little FLAW in engineering design called Ct/Sigma, and its resultant limit load factor. Perhaps you can show all of us who in Texas engineering decided to go for three blades with terrible Ct/sigma - with no manueverability, instead of 4-5 blades which might have made it workable in Combat.
PS It AINT over til the fat lady sings -- and she will NOT sing until about September -Count on it!
[This message has been edited by hpdunn (edited 15 June 2001).]
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to Sultan,
I may sound like a BS'er to you, that's unfortunate, but your call. What I reacted to with Lu was the assertion that the Army or Marines are lying or deceptive.
You don't have to agree with me, and you can think I'm BS'ing, just don't start spouting about how you must be right because others are lying.
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I may sound like a BS'er to you, that's unfortunate, but your call. What I reacted to with Lu was the assertion that the Army or Marines are lying or deceptive.
You don't have to agree with me, and you can think I'm BS'ing, just don't start spouting about how you must be right because others are lying.
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Guest
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Well gentle men, as someone else has said the fat ladie has sung. The death of all chopper pilots as well as choppers as we know it. I fear the worst people, I don't want it to be so. 
Whats it going to do to medevac or SAR missions?
Cody the distressed chopper pilot
Whats it going to do to medevac or SAR missions?Cody the distressed chopper pilot
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mriya225..........
the diameter of the rotor in the hover would seem to me to be very small compared to a helicopter of the same weight;- tip voticies would afect a biger % of rotor and would'nt take a lot to induce vortex ring state. is that what you mean by stalling? or is the overpitching of the blade due to weight what you mean??
the diameter of the rotor in the hover would seem to me to be very small compared to a helicopter of the same weight;- tip voticies would afect a biger % of rotor and would'nt take a lot to induce vortex ring state. is that what you mean by stalling? or is the overpitching of the blade due to weight what you mean??
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V-22 Slowdown Augurs Layoffs
ROBERT WALL/WASHINGTON and PARIS
V-22 woes are about to claim more victims, with layoffs looming as
production of the tiltrotor is slowed to allow prime contractors Bell
Helicopter Textron and Boeing to fix the many design problems that have plagued
the aircraft.
V-22 production for the next fiscal year has been cut back to 12
aircraft from the planned 20. The Air Force is procuring none of the
tiltrotors next year.
The number of layoffs and when they will occur hasn't been resolved yet.
But the goal is to "lose the minimum number of people," says Michael
Tkach, Bell Boeing V-22 program director. Boeing has about 1,500 people
employed on V-22 work, while Bell has about 2,800 employees associated
with the program.
The personnel cuts are necessary even though the production rate is
expected to remain level, with 11 aircraft built this year and 12 more
planned for next year. While design changes are being made, the V-22
program is limited to a minimum sustainment production rate that will
allow the manufacturing line to remain open but not much more. How long
that rate will be sustained depends on progress made, said the new V-22
program manager, Marine Corps Col. Dan Schultz.
However, because of lessons learned in building the first batch of
aircraft, fewer people will be needed to build a similar number in 2002,
Tkach said. Furthermore, before the program was derailed, Bell and
Boeing expected to ramp production to 20 V-22s next year.
IN THE FISCAL 2002 budget, the Air Force has no production funds for
Special Operations CV-22s, although Dov Zakheim, the Pentagon's
comptroller, said that could change in 2003. The Navy budget, under
which the Marine Corps MV-22s are bought, is $542 million for 12
aircraft. "That is our understanding of the optimal number to protect
the industrial base," Zakheim said.
The change in the number of aircraft to be bought also has forced Bell
and Boeing to scramble to alter deals made with suppliers. Purchase
orders were placed with vendors anticipating a 20-aircraft buy. Tkach
said most, if not all, of those deals were adjusted with enough time to
allow suppliers to alter their production lines.
Schultz said he's trying to avoid second-guessing what caused the
current situation and, instead, is focusing on getting the aircraft
fixed and back flying. However, he believes there were weaknesses in the
government-industry partnership. "I don't think the teaming was as solid
as it is now."
A panel convened by the Pentagon to review the program highlighted
several areas of weakness. They include problems with the flight control
system and its testing, reliability deficiencies, design shortcomings in
the hydraulics system, and a need to better understand the aircraft's
flight envelope. One of the findings in the review of the second of two
crashes last year--in which a total of 23 Marines died--was that many
software modes had not been tested. This time "our intent is to test
every failure mode on the aircraft," Schultz said.
Despite the travails, vendors so far have remained supportive of the
program. "None of them are backing away," Schultz said. For instance, he
noted that Moog Inc. used its own funds to redesign a V-22 actuator
valve that now may not require inspection.
In addition to redressing the aircraft's flaws, Schultz also is looking
for opportunities to take out weight and cost. While the V-22 has met
its flight performance requirements, it has been operating with very little
weight margin.
As part of the review process, the Pentagon is reassessing V-22
requirements. However, Marine Corps Commandant Gen. James Jones has
indicated he would like to see as few changes as possible ( AW&ST May 7,
p. 64).
Program officials are shying away from predicting when they'll have the
tiltrotor back flying or production ready. Jerry Daniels, who runs
Boeing's military aircraft and missiles programs, said at the Paris air
show that it would take 60-90 days to "do a good, solid engineering
assessment of the airplane and then lay out a program plan that makes
sense."
The most time-consuming fix is likely to be reengineering the nacelles,
said Jones. The goal is to make them more maintenance-friendly and
mitigate problems with hydraulic lines running through them.
The Marines have laid out a five-step program to salvage the V-22. The
first, trying to get the aircraft ready to resume flight testing, is
underway. The V-22s have been grounded for months while the program's
problems were investigated.
Another major thrust will be to rebuild a base of support for the
tiltrotor. "It's not that the V-22 has that many problems, but people
have certainly lost confidence," Schultz said. He hopes to restore faith in the
program by meticulously resolving the lingering questions.
Late last month, the V-22 got a measure of political support when a key
panel working on Defense Secretary Donald H. Rumsfeld's Pentagon review
endorsed the tiltrotor. "It's a program that's had trouble, obviously,
but that doesn't make it unimportant. In fact, it's extremely important
as a way to move land forces, in particular, amphibious forces," said
Rand's David C. Gompert, speaking for the Conventional Forces Study
panel.
BUT V-22 PROGRAM officials also have to brace for some more bad news.
The Pentagon's Inspector General's office is continuing its
investigation regarding the charge of maintenance data falsification.
The review was to have been completed weeks ago, but has dragged on
because it has proven more complex and more involved than first
expected, Pentagon officials say.
Another unresolved issue is V-22 funding for the current fiscal year.
The Pentagon wants to cut $475 million from production while problems
are fixed, but add $80 million to engineer the fixes. However, the
Senate and House have different opinions. The House would add $40
million to the development budget, but would further cut procurement by
$115 million. The Senate, on the other hand, would only cut the Navy's
V-22 production funds to $150 million from $235 million. The difference
will have to be resolved in a conference between the two bodies.
ROBERT WALL/WASHINGTON and PARIS
V-22 woes are about to claim more victims, with layoffs looming as
production of the tiltrotor is slowed to allow prime contractors Bell
Helicopter Textron and Boeing to fix the many design problems that have plagued
the aircraft.
V-22 production for the next fiscal year has been cut back to 12
aircraft from the planned 20. The Air Force is procuring none of the
tiltrotors next year.
The number of layoffs and when they will occur hasn't been resolved yet.
But the goal is to "lose the minimum number of people," says Michael
Tkach, Bell Boeing V-22 program director. Boeing has about 1,500 people
employed on V-22 work, while Bell has about 2,800 employees associated
with the program.
The personnel cuts are necessary even though the production rate is
expected to remain level, with 11 aircraft built this year and 12 more
planned for next year. While design changes are being made, the V-22
program is limited to a minimum sustainment production rate that will
allow the manufacturing line to remain open but not much more. How long
that rate will be sustained depends on progress made, said the new V-22
program manager, Marine Corps Col. Dan Schultz.
However, because of lessons learned in building the first batch of
aircraft, fewer people will be needed to build a similar number in 2002,
Tkach said. Furthermore, before the program was derailed, Bell and
Boeing expected to ramp production to 20 V-22s next year.
IN THE FISCAL 2002 budget, the Air Force has no production funds for
Special Operations CV-22s, although Dov Zakheim, the Pentagon's
comptroller, said that could change in 2003. The Navy budget, under
which the Marine Corps MV-22s are bought, is $542 million for 12
aircraft. "That is our understanding of the optimal number to protect
the industrial base," Zakheim said.
The change in the number of aircraft to be bought also has forced Bell
and Boeing to scramble to alter deals made with suppliers. Purchase
orders were placed with vendors anticipating a 20-aircraft buy. Tkach
said most, if not all, of those deals were adjusted with enough time to
allow suppliers to alter their production lines.
Schultz said he's trying to avoid second-guessing what caused the
current situation and, instead, is focusing on getting the aircraft
fixed and back flying. However, he believes there were weaknesses in the
government-industry partnership. "I don't think the teaming was as solid
as it is now."
A panel convened by the Pentagon to review the program highlighted
several areas of weakness. They include problems with the flight control
system and its testing, reliability deficiencies, design shortcomings in
the hydraulics system, and a need to better understand the aircraft's
flight envelope. One of the findings in the review of the second of two
crashes last year--in which a total of 23 Marines died--was that many
software modes had not been tested. This time "our intent is to test
every failure mode on the aircraft," Schultz said.
Despite the travails, vendors so far have remained supportive of the
program. "None of them are backing away," Schultz said. For instance, he
noted that Moog Inc. used its own funds to redesign a V-22 actuator
valve that now may not require inspection.
In addition to redressing the aircraft's flaws, Schultz also is looking
for opportunities to take out weight and cost. While the V-22 has met
its flight performance requirements, it has been operating with very little
weight margin.
As part of the review process, the Pentagon is reassessing V-22
requirements. However, Marine Corps Commandant Gen. James Jones has
indicated he would like to see as few changes as possible ( AW&ST May 7,
p. 64).
Program officials are shying away from predicting when they'll have the
tiltrotor back flying or production ready. Jerry Daniels, who runs
Boeing's military aircraft and missiles programs, said at the Paris air
show that it would take 60-90 days to "do a good, solid engineering
assessment of the airplane and then lay out a program plan that makes
sense."
The most time-consuming fix is likely to be reengineering the nacelles,
said Jones. The goal is to make them more maintenance-friendly and
mitigate problems with hydraulic lines running through them.
The Marines have laid out a five-step program to salvage the V-22. The
first, trying to get the aircraft ready to resume flight testing, is
underway. The V-22s have been grounded for months while the program's
problems were investigated.
Another major thrust will be to rebuild a base of support for the
tiltrotor. "It's not that the V-22 has that many problems, but people
have certainly lost confidence," Schultz said. He hopes to restore faith in the
program by meticulously resolving the lingering questions.
Late last month, the V-22 got a measure of political support when a key
panel working on Defense Secretary Donald H. Rumsfeld's Pentagon review
endorsed the tiltrotor. "It's a program that's had trouble, obviously,
but that doesn't make it unimportant. In fact, it's extremely important
as a way to move land forces, in particular, amphibious forces," said
Rand's David C. Gompert, speaking for the Conventional Forces Study
panel.
BUT V-22 PROGRAM officials also have to brace for some more bad news.
The Pentagon's Inspector General's office is continuing its
investigation regarding the charge of maintenance data falsification.
The review was to have been completed weeks ago, but has dragged on
because it has proven more complex and more involved than first
expected, Pentagon officials say.
Another unresolved issue is V-22 funding for the current fiscal year.
The Pentagon wants to cut $475 million from production while problems
are fixed, but add $80 million to engineer the fixes. However, the
Senate and House have different opinions. The House would add $40
million to the development budget, but would further cut procurement by
$115 million. The Senate, on the other hand, would only cut the Navy's
V-22 production funds to $150 million from $235 million. The difference
will have to be resolved in a conference between the two bodies.
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Tilt rotor
in a previous thead somone talked about v22 problems and it seamed to me that because of the small rotors in relation to weight they whould settle with power very easily(vortex ring state), would this be true? 
i would'nt mind gettin an indorcement one day, if they can sort'em out.
what do you's recon?
i would'nt mind gettin an indorcement one day, if they can sort'em out.
what do you's recon?
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>From: "Robert B Cox"
>To: Jim Crint
>Subject: Hello again
>Date: Wed, 08 Aug 2001 20:26:57 -0500
>
>Jim:
>
>Are you still on the V-22 trail? I suspect I know the answer and that
>it's yes.
>
>I've got a guy, retired military and aero engineering degree, who's
>bugging me incessantly about the V-22. He has sent me a diagram chart which I
>will attach, claiming it shows -- no proves -- that the V-22 is fatally
>flawed because it simply cannot maneuver. I suspect he's on to
>something, but I don't have the expertise to judge or critique it. So
>I'm passing it around. I'll attach it and the guy's comments. I'd like
>to hear what you think and any suggestions on what to do with it
>(including even throw it away). Please feel free to call if you like.
>
>Thanks.
Robert
Look carefully at a set of helo rotor-blades and note their distinctive features (wash-out, twist, aspect ratio, airfoil section etc). Then observe (statically is sufficient) the available range of cyclic and collective movement in those blades. Note the RPM at which they operate.
Look at a FW's propeller blades and comparatively note the significant physical differences (planform, sectional profile, AR, twist, taper and airfoil section) - and the operating RPM and fine/coarse pitch-change regime.
Look at the problem of physically hybridising rotors and props to become prop-rotors (even without going into the control systems and morphing of control parameters via algorithmic contortions as it changes from FW to helo and back again). It all becomes one huge compromise requiring great sacrifices in robustness of design and utility. Weight and weight distribution, FBW and fail-safe systems redundancy become hyper-critical. The fault mode effects analysis (FMEA) becomes a welter of imponderables (as we've seen). The envelope in which it can operate is similarly constrained. Unmanagageable T/R phenomena such as autorotation and Asymmetric Vortex-Ring are peculiar to the side-by-side prop-rotor configuration, the prop-rotor's lack of inertia, and its hybrid prop-rotor compromise - but both
autos and VR are a manageable acceptable fact in helos. The deadly propensity for entering asymmVR (there being no such thing as V22 symmVR) is a function of the prop-rotors - their shape and disk solidity (aka number of blades and operating RPM's), and in particular their behaviour relates to their non-rotorlike characteristics when playing that rotor role. Formation of tip and sheet vortices (and the sudden lethal amalgamation of these) can occur much earlier simply because you have an upward pointing airscrew rather than a pure helo-rotor, and the V-22 prop-rotor loadings are necessarily non-optimal. Factor in the ability to go to 95 degrees aft nacelle-tilt (i.e. project the downwash powerfully ahead into its own downward flight-path) and the high likelihood of a stressed pilot doing that as a means of slowing quickly. Add a simultaneous rolling/directional correction and some gust-factor as in the Marana accident. AsymmVR is always lurking and, once hit because of even the slightest dynamic overshoot of the VR entry parameters, is quite unforgiving and terminal. They'd not done even half of the planned testing so they were fumbling in the dark with the potentialities. They found out the hard way and then went into denial. They're now looking for a warning device to insulate pilots from crossing that deadly point of total control loss. I'm not sure that they'll find it. The dynamics of manoeuvre and low-level turbulence will always mean that a potential overshoot of the VR envelope can happen. Answer? Limit the manoeuvre even if you were able to manoeuvre more because of available airframe strength and power available. But of course power available is not part of any solution for AsymmVR. So the question becomes: "Is an Osprey that is so safety-limited in manoeuvre really a combat proposition?"
The next accident was more than likely a hiatus induced by the hydraulic failure not permitting scheduled nacelle tilt for transition (but the software going ahead anyway and telling the props that they were to become rotors). Not that they've ever been that frank about it of course. So you have the V22 stuck in FW config with the props acting as if they are rotors. If you have an understanding of the subtlety with which the control mode switches over during transition, you'll appreciate that that might have been automatically terminal (as it was).
So apart from this problem of inherent design characteristics, you want to know whether Col Harry Dunn's diagram is correct; i.e. is the V22 very restricted in manoeuvre and riding a thin red-line as far as controllability goes.. I've discussed it with him and it certainly would appear so simply because (to keep it brief and non-tech) of the aerody factors outlined above. The early onset of blade stall is simply a function of the prop-rotor design. In the combat arena it will always be a sitting duck - or verging on a lethal loss-of-control if pilots are provoked into excessive manoeuvre by ground-fire. You could say that it has built-in lethality and I predict that if it ever does enter combat service it will vie with the enemy for the dubious honour of who will kill more Marines. Apart from that of course, the Marine carrier-decks will be rapidly awash with broken Ospreys. They are not very supportable and not easily fixed. I fear the USMC got carried away with a Utopian concept and only the US Army got it right. They applied the KISS Principle - overlaid on "more is better".
The man who solves all these problems, and makes it what they want of it, will be semper fi'd into the annals of Marine Corps legend. It will be fascinating to watch it all unfold.
>To: Jim Crint
>Subject: Hello again
>Date: Wed, 08 Aug 2001 20:26:57 -0500
>
>Jim:
>
>Are you still on the V-22 trail? I suspect I know the answer and that
>it's yes.
>
>I've got a guy, retired military and aero engineering degree, who's
>bugging me incessantly about the V-22. He has sent me a diagram chart which I
>will attach, claiming it shows -- no proves -- that the V-22 is fatally
>flawed because it simply cannot maneuver. I suspect he's on to
>something, but I don't have the expertise to judge or critique it. So
>I'm passing it around. I'll attach it and the guy's comments. I'd like
>to hear what you think and any suggestions on what to do with it
>(including even throw it away). Please feel free to call if you like.
>
>Thanks.
Robert
Look carefully at a set of helo rotor-blades and note their distinctive features (wash-out, twist, aspect ratio, airfoil section etc). Then observe (statically is sufficient) the available range of cyclic and collective movement in those blades. Note the RPM at which they operate.
Look at a FW's propeller blades and comparatively note the significant physical differences (planform, sectional profile, AR, twist, taper and airfoil section) - and the operating RPM and fine/coarse pitch-change regime.
Look at the problem of physically hybridising rotors and props to become prop-rotors (even without going into the control systems and morphing of control parameters via algorithmic contortions as it changes from FW to helo and back again). It all becomes one huge compromise requiring great sacrifices in robustness of design and utility. Weight and weight distribution, FBW and fail-safe systems redundancy become hyper-critical. The fault mode effects analysis (FMEA) becomes a welter of imponderables (as we've seen). The envelope in which it can operate is similarly constrained. Unmanagageable T/R phenomena such as autorotation and Asymmetric Vortex-Ring are peculiar to the side-by-side prop-rotor configuration, the prop-rotor's lack of inertia, and its hybrid prop-rotor compromise - but both
autos and VR are a manageable acceptable fact in helos. The deadly propensity for entering asymmVR (there being no such thing as V22 symmVR) is a function of the prop-rotors - their shape and disk solidity (aka number of blades and operating RPM's), and in particular their behaviour relates to their non-rotorlike characteristics when playing that rotor role. Formation of tip and sheet vortices (and the sudden lethal amalgamation of these) can occur much earlier simply because you have an upward pointing airscrew rather than a pure helo-rotor, and the V-22 prop-rotor loadings are necessarily non-optimal. Factor in the ability to go to 95 degrees aft nacelle-tilt (i.e. project the downwash powerfully ahead into its own downward flight-path) and the high likelihood of a stressed pilot doing that as a means of slowing quickly. Add a simultaneous rolling/directional correction and some gust-factor as in the Marana accident. AsymmVR is always lurking and, once hit because of even the slightest dynamic overshoot of the VR entry parameters, is quite unforgiving and terminal. They'd not done even half of the planned testing so they were fumbling in the dark with the potentialities. They found out the hard way and then went into denial. They're now looking for a warning device to insulate pilots from crossing that deadly point of total control loss. I'm not sure that they'll find it. The dynamics of manoeuvre and low-level turbulence will always mean that a potential overshoot of the VR envelope can happen. Answer? Limit the manoeuvre even if you were able to manoeuvre more because of available airframe strength and power available. But of course power available is not part of any solution for AsymmVR. So the question becomes: "Is an Osprey that is so safety-limited in manoeuvre really a combat proposition?"
The next accident was more than likely a hiatus induced by the hydraulic failure not permitting scheduled nacelle tilt for transition (but the software going ahead anyway and telling the props that they were to become rotors). Not that they've ever been that frank about it of course. So you have the V22 stuck in FW config with the props acting as if they are rotors. If you have an understanding of the subtlety with which the control mode switches over during transition, you'll appreciate that that might have been automatically terminal (as it was).
So apart from this problem of inherent design characteristics, you want to know whether Col Harry Dunn's diagram is correct; i.e. is the V22 very restricted in manoeuvre and riding a thin red-line as far as controllability goes.. I've discussed it with him and it certainly would appear so simply because (to keep it brief and non-tech) of the aerody factors outlined above. The early onset of blade stall is simply a function of the prop-rotor design. In the combat arena it will always be a sitting duck - or verging on a lethal loss-of-control if pilots are provoked into excessive manoeuvre by ground-fire. You could say that it has built-in lethality and I predict that if it ever does enter combat service it will vie with the enemy for the dubious honour of who will kill more Marines. Apart from that of course, the Marine carrier-decks will be rapidly awash with broken Ospreys. They are not very supportable and not easily fixed. I fear the USMC got carried away with a Utopian concept and only the US Army got it right. They applied the KISS Principle - overlaid on "more is better".
The man who solves all these problems, and makes it what they want of it, will be semper fi'd into the annals of Marine Corps legend. It will be fascinating to watch it all unfold.