V-280 wins US ARMY FLRAA contract
A good point.
Although, the precursor to FLRAA was JMR/FVL and in the early days, it was not so much about speed and range (I believe 230kn and a combat radius of 263nm were the original JMR-Medium requirements), but about getting a solution that provided a broad range of advanced capabilities, technologies and efficiencies.
At the point of having to choose a preferred solution in late 2022, I'm not convinced either TD provided what the US Army had envisioned way back in the early days of JMR, but the move away from Europe to the Pacific, with range and speed being two key factors, certainly for any USMC solution, kinda left X2 behind.
That and Team Defiant were clearly not on the same page when it came to interpretating the requirements the way the author had intended.
JMR-Medium was initially an $80Bn program for some 4,000 machines, but it does not look like the FLRAA solution will end up anything like being that big, which for me, backs up my 2nd paragraph, but time will tell.
Although, the precursor to FLRAA was JMR/FVL and in the early days, it was not so much about speed and range (I believe 230kn and a combat radius of 263nm were the original JMR-Medium requirements), but about getting a solution that provided a broad range of advanced capabilities, technologies and efficiencies.
At the point of having to choose a preferred solution in late 2022, I'm not convinced either TD provided what the US Army had envisioned way back in the early days of JMR, but the move away from Europe to the Pacific, with range and speed being two key factors, certainly for any USMC solution, kinda left X2 behind.
That and Team Defiant were clearly not on the same page when it came to interpretating the requirements the way the author had intended.
JMR-Medium was initially an $80Bn program for some 4,000 machines, but it does not look like the FLRAA solution will end up anything like being that big, which for me, backs up my 2nd paragraph, but time will tell.
Commando Cody
Tiltrotor wins on speed and range, which is what the Army wanted. So why did Sikorsky bid what was likely to be a losing design? People rightfully questioned whether the X2 could be scaled up to a larger size. Defiant proved the answer is yes.
You are right regarding engines, the Honeywell engine on Defiant was going to be scaled up to provide 7500 hp each compared to the demonstrator 5000 hp, giving a total of 15000 hp, which would provide more lift. Given larger engines and more time, hitting 260 knots, matching the X2, seems plausible. Though fuel burn rate might be very high.
Raider is intriguing regarding its low max speed, it had plenty of engine. Maybe Boeing or Sikorsky figured out how to solve the problem for Defiant? But I don't see how they would have been able to significantly improve aerodynamics. So maybe improving vibration control was the solution?
Tiltrotor wins on speed and range, which is what the Army wanted. So why did Sikorsky bid what was likely to be a losing design? People rightfully questioned whether the X2 could be scaled up to a larger size. Defiant proved the answer is yes.
You are right regarding engines, the Honeywell engine on Defiant was going to be scaled up to provide 7500 hp each compared to the demonstrator 5000 hp, giving a total of 15000 hp, which would provide more lift. Given larger engines and more time, hitting 260 knots, matching the X2, seems plausible. Though fuel burn rate might be very high.
Raider is intriguing regarding its low max speed, it had plenty of engine. Maybe Boeing or Sikorsky figured out how to solve the problem for Defiant? But I don't see how they would have been able to significantly improve aerodynamics. So maybe improving vibration control was the solution?
You know, one of Sikorsky's complaints in filing the protest was their claim that Army had always wanted a Tilt-Rotor and this was reflected in their original requirements which they said were later changed, to allow others to compete. I take this to be referring to the original anticipated speed requirement of 250 knots which in the final specs was lowered to 235 knots. Given that Sikorsky said that on Defiant they had lots more power they hadn't yet used, I don't believe more power would have gotten them any more speed or they would have claimed that. . The X2 demonstrator briefly hit 260 knots, but was grounded after that. I think that like Bell, it was the hot and high HOGE requirement that drove ultimate power required.
Vibration control undoubtedly would have been a big factor in higher speeds, but with what we've seen so far is it fair to say that the problem was solved? They came up short in a number of other areas as well.
A good point.
Although, the precursor to FLRAA was JMR/FVL and in the early days, it was not so much about speed and range (I believe 230kn and a combat radius of 263nm were the original JMR-Medium requirements), but about getting a solution that provided a broad range of advanced capabilities, technologies and efficiencies.
At the point of having to choose a preferred solution in late 2022, I'm not convinced either TD provided what the US Army had envisioned way back in the early days of JMR, but the move away from Europe to the Pacific, with range and speed being two key factors, certainly for any USMC solution, kinda left X2 behind.
That and Team Defiant were clearly not on the same page when it came to interpretating the requirements the way the author had intended.
JMR-Medium was initially an $80Bn program for some 4,000 machines, but it does not look like the FLRAA solution will end up anything like being that big, which for me, backs up my 2nd paragraph, but time will tell.
Although, the precursor to FLRAA was JMR/FVL and in the early days, it was not so much about speed and range (I believe 230kn and a combat radius of 263nm were the original JMR-Medium requirements), but about getting a solution that provided a broad range of advanced capabilities, technologies and efficiencies.
At the point of having to choose a preferred solution in late 2022, I'm not convinced either TD provided what the US Army had envisioned way back in the early days of JMR, but the move away from Europe to the Pacific, with range and speed being two key factors, certainly for any USMC solution, kinda left X2 behind.
That and Team Defiant were clearly not on the same page when it came to interpretating the requirements the way the author had intended.
JMR-Medium was initially an $80Bn program for some 4,000 machines, but it does not look like the FLRAA solution will end up anything like being that big, which for me, backs up my 2nd paragraph, but time will tell.
Nothing is ever simple.
To my mind Sikorsky was hoping the problems that had plagued X2 so far could be worked out and at a lower cost than a Tilt-Rotor. They may also have felt that if performance of the two competitors was close, Army's familiarity with them plus their political influence would pull them through. Keep in mind X2 was all they had and they had spent some significant money on it over the years. I don't think it can be said that Defiant proved X2 technology could be scaled up to this size. At best it would have to be a profound, "Maybe".
You know, one of Sikorsky's complaints in filing the protest was their claim that Army had always wanted a Tilt-Rotor and this was reflected in their original requirements which they said were later changed, to allow others to compete. I take this to be referring to the original anticipated speed requirement of 250 knots which in the final specs was lowered to 235 knots. Given that Sikorsky said that on Defiant they had lots more power they hadn't yet used, I don't believe more power would have gotten them any more speed or they would have claimed that. . The X2 demonstrator briefly hit 260 knots, but was grounded after that. I think that like Bell, it was the hot and high HOGE requirement that drove ultimate power required.
Vibration control undoubtedly would have been a big factor in higher speeds, but with what we've seen so far is it fair to say that the problem was solved? They came up short in a number of other areas as well.
You know, one of Sikorsky's complaints in filing the protest was their claim that Army had always wanted a Tilt-Rotor and this was reflected in their original requirements which they said were later changed, to allow others to compete. I take this to be referring to the original anticipated speed requirement of 250 knots which in the final specs was lowered to 235 knots. Given that Sikorsky said that on Defiant they had lots more power they hadn't yet used, I don't believe more power would have gotten them any more speed or they would have claimed that. . The X2 demonstrator briefly hit 260 knots, but was grounded after that. I think that like Bell, it was the hot and high HOGE requirement that drove ultimate power required.
Vibration control undoubtedly would have been a big factor in higher speeds, but with what we've seen so far is it fair to say that the problem was solved? They came up short in a number of other areas as well.
Lol - Sikorsky whining the Army wanted a tiltrotor all along. Reply to Sikorsky: Is water wet? Of course dummy.
Last edited by noneofyourbusiness; 16th May 2023 at 12:35. Reason: untangling my word salad
A good point.
Although, the precursor to FLRAA was JMR/FVL and in the early days, it was not so much about speed and range (I believe 230kn and a combat radius of 263nm were the original JMR-Medium requirements), but about getting a solution that provided a broad range of advanced capabilities, technologies and efficiencies.
At the point of having to choose a preferred solution in late 2022, I'm not convinced either TD provided what the US Army had envisioned way back in the early days of JMR, but the move away from Europe to the Pacific, with range and speed being two key factors, certainly for any USMC solution, kinda left X2 behind.
That and Team Defiant were clearly not on the same page when it came to interpretating the requirements the way the author had intended.
JMR-Medium was initially an $80Bn program for some 4,000 machines, but it does not look like the FLRAA solution will end up anything like being that big, which for me, backs up my 2nd paragraph, but time will tell.
Although, the precursor to FLRAA was JMR/FVL and in the early days, it was not so much about speed and range (I believe 230kn and a combat radius of 263nm were the original JMR-Medium requirements), but about getting a solution that provided a broad range of advanced capabilities, technologies and efficiencies.
At the point of having to choose a preferred solution in late 2022, I'm not convinced either TD provided what the US Army had envisioned way back in the early days of JMR, but the move away from Europe to the Pacific, with range and speed being two key factors, certainly for any USMC solution, kinda left X2 behind.
That and Team Defiant were clearly not on the same page when it came to interpretating the requirements the way the author had intended.
JMR-Medium was initially an $80Bn program for some 4,000 machines, but it does not look like the FLRAA solution will end up anything like being that big, which for me, backs up my 2nd paragraph, but time will tell.
Last edited by noneofyourbusiness; 16th May 2023 at 12:14.
To my mind Sikorsky was hoping the problems that had plagued X2 so far could be worked out and at a lower cost than a Tilt-Rotor. They may also have felt that if performance of the two competitors was close, Army's familiarity with them plus their political influence would pull them through. Keep in mind X2 was all they had and they had spent some significant money on it over the years. I don't think it can be said that Defiant proved X2 technology could be scaled up to this size. At best it would have to be a profound, "Maybe".
You know, one of Sikorsky's complaints in filing the protest was their claim that Army had always wanted a Tilt-Rotor and this was reflected in their original requirements which they said were later changed, to allow others to compete. I take this to be referring to the original anticipated speed requirement of 250 knots which in the final specs was lowered to 235 knots. Given that Sikorsky said that on Defiant they had lots more power they hadn't yet used, I don't believe more power would have gotten them any more speed……
You know, one of Sikorsky's complaints in filing the protest was their claim that Army had always wanted a Tilt-Rotor and this was reflected in their original requirements which they said were later changed, to allow others to compete. I take this to be referring to the original anticipated speed requirement of 250 knots which in the final specs was lowered to 235 knots. Given that Sikorsky said that on Defiant they had lots more power they hadn't yet used, I don't believe more power would have gotten them any more speed……
I concur your analysis, but I believe Sikorsky had dual path to winning in their strategy.
One path, was as you stated, hope that you can work out the X-2 technology for a Defiant size aircraft adequately enough to compete. Also, Sikorsky’s and Boeing’s combined corporate ego believed Bell could not succeed in producing a viable demonstrator aircraft.
The second path, was ensuring that the FLRAA program would be either canceled, or so underfunded, it would fail to succeed. This would allow Sikorsky and Boeing to continue building their legacy aircraft as long as possible.
Following Sikorsky’s lack of success of the first path, this second path of insuring FLRAA fails is now Sikorsky’s main strategy . This is best illustrated by the following video of Connecticut senator Chris Murphy questioning the Secretary of the Army.
Last edited by CTR; 16th May 2023 at 18:03.
The V-280 was designed from inception to incorporate all the lessons learned in design and manufacturing from XV-3, XV-15, 609, and V-22. It also contained specific design details (eg straight wing) to meet cost targets that the Army specified early in the JMR programme. The maturity of tiltrotors in general is now essentially beyond reasonable question, yet senator Murphy's "parochial" interest in pushing what is pretty blatant propaganda continues.
Sikorsky strove to be second best. Pick us, we're kinda good. But it isn't about what Sikorsky wants to build, it's about what the customer wants. When Bob Lutz was at Chrysler, he saved Chrysler by replacing the fading K cars with modern cars, which were well received. Lutz said that you wouldn't sell many cars if you were everyone's second choice.
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Next up will be FARA. The Army will pick what is best for their soldiers, as their lives depend on this equipment. This will override jobs in Connecticut concerns. The clutched pusher prop on Raider X is a potential problem. Sikorsky will be very careful, most of the parts in the clutch will be flight safety parts. Still, anything mechanical can fail, even if it only happens once. Unlike a Cessna where everyone knows to stay away from the prop, people will become careless because they think the prop will never be turning on the ground, until one time it is. This is insidious.
There is no significant reason to select the underpowered Raider X unless it is substantially faster than Invictus. Even then, it depends on whether this increased speed is considered to be much of an advantage by the Army, if Invictus meets the required speed. Simplicity improves reliability, safety and maintainability, and Invictus is simpler than Raider X.
The Army probably will not go to a twin engine melt and repour. Keeping the GE engine would give us two 3000 hp engines, or 6000 hp, compared to the Apache 4000 hp. Essentially this would give us a growth Apache, not a scout helicopter. It is unlikely the Army would pull the plug on its new engine and go back to using something like two older technology T800 engines. The new GE engine is a major improvement over previous engines.
There is no significant reason to select the underpowered Raider X unless it is substantially faster than Invictus. Even then, it depends on whether this increased speed is considered to be much of an advantage by the Army, if Invictus meets the required speed. Simplicity improves reliability, safety and maintainability, and Invictus is simpler than Raider X.
The Army probably will not go to a twin engine melt and repour. Keeping the GE engine would give us two 3000 hp engines, or 6000 hp, compared to the Apache 4000 hp. Essentially this would give us a growth Apache, not a scout helicopter. It is unlikely the Army would pull the plug on its new engine and go back to using something like two older technology T800 engines. The new GE engine is a major improvement over previous engines.
The clutched pusher prop on Raider X is a potential problem. Sikorsky will be very careful, most of the parts in the clutch will be flight safety parts. Still, anything mechanical can fail, even if it only happens once. Unlike a Cessna where everyone knows to stay away from the prop, people will become careless because they think the prop will never be turning on the ground, until one time it is. This is insidious.
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Hold onto your butt.
Remember that the S-97 pusher is wet clutched so it does not stop rotating. Defiant used a dry clutch to attempt to demonstrate the safety aspect of stopping it during ground ops. Unfortunately that clutch sh*t the bed and the Army knows all about it.
Remember that the S-97 pusher is wet clutched so it does not stop rotating. Defiant used a dry clutch to attempt to demonstrate the safety aspect of stopping it during ground ops. Unfortunately that clutch sh*t the bed and the Army knows all about it.
The Sikorsky X-wing clutch design, scaled to size, would work just fine.
Last edited by noneofyourbusiness; 18th May 2023 at 22:58.
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Wet versus Dry
Another large benefit of a wet clutch over a dry clutch is more predictable coefficient of friction. The highest risk of damage in this clutch application is during engagement with the main rotors spinning and the propeller stopped. This must be achieved smoothly to prevent damage to the drive system.
With a dry clutch, the coefficient of friction is higher than on a wet clutch, and dry friction can change significantly with wear and temperature. This makes safety engaging a dry clutch in this application much more problematic.
With a dry clutch, the coefficient of friction is higher than on a wet clutch, and dry friction can change significantly with wear and temperature. This makes safety engaging a dry clutch in this application much more problematic.
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At a gas turbine company, I sometimes worked on design of high power aerospace clutches. The wet clutch is always superior to a dry clutch. It is possible to design the Raider wet clutch to be unclutched while idling on the ground, so it sounds like the Raider clutch design is a botch job. A brake would still be needed on the prop, and the clutch plates would need to have spring separators, to make sure the plates separated when the clamp force was removed.
[paragraph removed]
The Sikorsky X-wing clutch design, scaled to size, would work just fine.
[paragraph removed]
The Sikorsky X-wing clutch design, scaled to size, would work just fine.
"X-Wing"... there's a technological dead end we haven't heard of in a long, long time.
I think is more likely to be an oversight in design to let the blades keep rotating on the ground. Not sure you would get much cooling effect with a relatively slow rpm rotation of the blades. The engine would be at ground idle condition, so maybe the exhaust is relatively cool.
If Sikorsky always needed to have the clutch engaged, there would be no reason to have a clutch.
I am guessing whoever designed the clutch wasn't aware you need spring separators to "unstick" the clutch plates. And maybe Sikorsky did not want to add the weight of a brake.
If Sikorsky needed to always keep the clutch engaged, there would be no reason to have a clutch.
Last edited by noneofyourbusiness; 19th May 2023 at 13:07.
Another large benefit of a wet clutch over a dry clutch is more predictable coefficient of friction. The highest risk of damage in this clutch application is during engagement with the main rotors spinning and the propeller stopped. This must be achieved smoothly to prevent damage to the drive system.
With a dry clutch, the coefficient of friction is higher than on a wet clutch, and dry friction can change significantly with wear and temperature. This makes safety engaging a dry clutch in this application much more problematic.
With a dry clutch, the coefficient of friction is higher than on a wet clutch, and dry friction can change significantly with wear and temperature. This makes safety engaging a dry clutch in this application much more problematic.
And the clutch design was fantastic, well before my time. Comparing it to some other "modern" clutches. Does JSF ring a bell?
I think is more likely to be an oversight in design to let the blades keep rotating on the ground. Not sure you would get much cooling effect with a relatively slow rpm rotation of the blades. The engine would be at ground idle condition, so maybe the exhaust is relatively cool.
If Sikorsky always needed to have the clutch engaged, there would be no reason to have a clutch.
I am guessing whoever designed the clutch wasn't aware you need spring separators to "unstick" the clutch plates. And maybe Sikorsky did not want to add the weight of a brake.
If Sikorsky needed to always keep the clutch engaged, there would be no reason to have a clutch.
I think is more likely to be an oversight in design to let the blades keep rotating on the ground. Not sure you would get much cooling effect with a relatively slow rpm rotation of the blades. The engine would be at ground idle condition, so maybe the exhaust is relatively cool.
If Sikorsky always needed to have the clutch engaged, there would be no reason to have a clutch.
I am guessing whoever designed the clutch wasn't aware you need spring separators to "unstick" the clutch plates. And maybe Sikorsky did not want to add the weight of a brake.
If Sikorsky needed to always keep the clutch engaged, there would be no reason to have a clutch.
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With upturned exhaust on H-60 rotor blades need to be positioned on centerline to avoid “charring” during rotor brake starts. I suppose even slowly rotating the pusher prop would help, but seems to be a recipe for disaster for personnel operating around the aircraft.
I’ve heard that the pusher on Raider X is electric driven, I assume clutching of the drive system would still be required?
I used to be pretty solid in the co-axial camp but the more I hear about the challenges associated with maturing the technology the less suitable it appears.
Would be interesting to see the engineering challenges both designs face discussed in detail by some of the members that have engineering backgrounds, think I’ll start a new thread on that in a bit.
FltMech
I’ve heard that the pusher on Raider X is electric driven, I assume clutching of the drive system would still be required?
I used to be pretty solid in the co-axial camp but the more I hear about the challenges associated with maturing the technology the less suitable it appears.
Would be interesting to see the engineering challenges both designs face discussed in detail by some of the members that have engineering backgrounds, think I’ll start a new thread on that in a bit.
FltMech
“Declutching” down to a slow rpm basically eliminates the blade tip noise from the prop which, like a tail rotor, is far worse than the main rotor noise. Being low to the ground, blade tip erosion from a slow spinning prop is also improved. I think for a combat scout there are operational reasons to prefer a clutchable prop. Reduced power loss from prop profile drag as well. Is all this worth the cost/weight/complexity of a clutchable prop? Completely fair question. Raider included the technology as a demonstrator. I guess it’s possible it is eliminated on Raider-X as not being worth the penalties. We’ll have to see.
With upturned exhaust on H-60 rotor blades need to be positioned on centerline to avoid “charring” during rotor brake starts. I suppose even slowly rotating the pusher prop would help, but seems to be a recipe for disaster for personnel operating around the aircraft.
I’ve heard that the pusher on Raider X is electric driven, I assume clutching of the drive system would still be required?
I used to be pretty solid in the co-axial camp but the more I hear about the challenges associated with maturing the technology the less suitable it appears.
Would be interesting to see the engineering challenges both designs face discussed in detail by some of the members that have engineering backgrounds, think I’ll start a new thread on that in a bit.
FltMech
I’ve heard that the pusher on Raider X is electric driven, I assume clutching of the drive system would still be required?
I used to be pretty solid in the co-axial camp but the more I hear about the challenges associated with maturing the technology the less suitable it appears.
Would be interesting to see the engineering challenges both designs face discussed in detail by some of the members that have engineering backgrounds, think I’ll start a new thread on that in a bit.
FltMech
A man named "spyclip" posted this on The Drive. Seems very knowledgeable, probably a former engineering insider at Sikorsky:
Spyclip
1 July, 2022
No vibration issues? Are you serious? The vibration is the entire reason they have flown only a few dozen hours in 3 years of flight testing and only allowed a single sortie flown by Army test pilots at low speed. The AVC system approach has been a complete failure (again, just like S-97), and the dynamics of another insufficiently stiff fuselage for the propulsor drive shaft make the SB1 just as much of a paint shaker as S-97. Pilots can't even read their instruments in these designs due to the vibration. SB1 has hit absolutely ZERO of its own self imposed targets in demonstration. Sikorsky's own target was a cruise speed of 250 kt at MCP, while in the end they could only manage a momentary 247 kt at CRP (130%). Swing and a miss on drag estimates, and vibration levels at high speed put a cap on that. To date they have not demonstrated any Vector Control maneuvers despite touting it in every single mention of the technology. Go watch the videos, there is no level acceleration or deceleration - its always nose down gaining speed like a normal helicopter. And they most certainly have not shown Defiant holding nose high or nose low attitude in hover, much less any ADS-33 level 1 handling maneuvers outside of a lumbering slalom. V-280 demonstrated high rate level 1 hover pitch, roll, and yaw multiple times. Sikorsky hasn't even done a hover pedal yaw turn in Defiant because they have next to no yaw authority with differential torque and it would be embarrassingly slow.
]https://www.thedrive.com/the-war-zone/raider-x-lockheed-martin
Spyclip
1 July, 2022
No vibration issues? Are you serious? The vibration is the entire reason they have flown only a few dozen hours in 3 years of flight testing and only allowed a single sortie flown by Army test pilots at low speed. The AVC system approach has been a complete failure (again, just like S-97), and the dynamics of another insufficiently stiff fuselage for the propulsor drive shaft make the SB1 just as much of a paint shaker as S-97. Pilots can't even read their instruments in these designs due to the vibration. SB1 has hit absolutely ZERO of its own self imposed targets in demonstration. Sikorsky's own target was a cruise speed of 250 kt at MCP, while in the end they could only manage a momentary 247 kt at CRP (130%). Swing and a miss on drag estimates, and vibration levels at high speed put a cap on that. To date they have not demonstrated any Vector Control maneuvers despite touting it in every single mention of the technology. Go watch the videos, there is no level acceleration or deceleration - its always nose down gaining speed like a normal helicopter. And they most certainly have not shown Defiant holding nose high or nose low attitude in hover, much less any ADS-33 level 1 handling maneuvers outside of a lumbering slalom. V-280 demonstrated high rate level 1 hover pitch, roll, and yaw multiple times. Sikorsky hasn't even done a hover pedal yaw turn in Defiant because they have next to no yaw authority with differential torque and it would be embarrassingly slow.
]https://www.thedrive.com/the-war-zone/raider-x-lockheed-martin
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