LHX Program

[yasotay]

Given that it was based on the XV-15 I suspect that it would have been at least a viable flying machine. With the advantage of knowing what happened with LHX it is anyone's guess if it would have made a more viable scout attack aircraft. It had the added difficulty of going up against the "horse cavalry" mentality of Army Aviation at the time (i.e. it is very different than what they know).

 

[Dynoman]

BAT comparison to Cobra and a concept for two versions of the BAT, a small recon/anti armor version and a utility version.

 

[RAP]

...

 

[hesham]

From the book; Attack Helicopters

 

[F-14D]

It was part of the LHX project, and looks very nice, but it neve rmoved beyond mockup.


So my question, given how many projects were actually unfeasible at the time, was the BAT a feasible project, or was it something that was behond the tech of the time?

Although we'll never know whether the BAT would have achieved all its promises, what happened wasn't due to technical issues.

Originally, the LHX requirements were for an aircraft with more performance and capability than what the final solicitation specified. It was to these requirement that the BAT concept was designed.

However, at an intermediate point in the process, the Army essentially "dumbed down what they wanted the LHX aircraft to do. They lowered speed and range requirements down to the level that could be reachable by and advanced conventional rotorcraft. They also indicated they were not willing to give much credit for performance significantly beyond this. Now a Tilt-Rotor could easily exceed the Army's requirements, but it would cost more than a conventional helo. Since Army had stated that it wouldn't give credit for that extra performance when analyzing the price of the competitors, that pretty much insured that a Tilt-Rotor would not have much of a chance.

In addition, Army specified a new maximum empty/loaded weight, and also the max power of the engine. Both of these were below than what a Til-Rotor would need (although ironically the restrictions later got relaxed because Comanche ended up needing more of both).

It didn't take a genius to read the writing on the wall, so Bell dropped pursuing a Tilt-Rotor design. BTW, before the "dumbing", there were indications that another potential bidder was considering offering a Tilt-Rotor, but with the revised requirements that died as well.

 

[Yellow Palace]

They also indicated they were not willing to give much credit for performance significantly beyond this. Now a Tilt-Rotor could easily exceed the Army's requirements, but it would cost more than a conventional helo. Since Army had stated that it wouldn't give credit for that extra performance when analyzing the price of the competitors, that pretty much insured that a Tilt-Rotor would not have much of a chance.

And to be honest, it's hard to fault them for that. The logic is likely to have been along the lines of: we need X number of aircraft to fill out our order of battle, and can afford to pay Y dollars, therefore the cost of the aircraft cannot exceed Z, regardless of capability.

Depending on the operating environment, 'extra credit' for additional performance may not be relevant either. When looking for a new family car, you don't give a minibus extra credit because it has more space for passengers and cargo than a small hatchback, or a grand tourer extra credit because it's capable of driving at twice the speed. Same logic with military procurement - if your concept of operations doesn't need more than a certain level of performance, it doesn't normally make sense to strongly reward exceeding that performance.

 

[F-14D]

And to be honest, it's hard to fault them for that. The logic is likely to have been along the lines of: we need X number of aircraft to fill out our order of battle, and can afford to pay Y dollars, therefore the cost of the aircraft cannot exceed Z, regardless of capability.

Depending on the operating environment, 'extra credit' for additional performance may not be relevant either. When looking for a new family car, you don't give a minibus extra credit because it has more space for passengers and cargo than a small hatchback, or a grand tourer extra credit because it's capable of driving at twice the speed. Same logic with military procurement - if your concept of operations doesn't need more than a certain level of performance, it doesn't normally make sense to strongly reward exceeding that performance.

Sorry, must disagree. They had the projected budget to get something that would meet the original requirements (remember, this was during the height of the Cold War). Also it was quite interesting that they changed the weight and power limits down to something less that what a Tilt-Rotor (and probably other advanced rotorcraft concepts had there been any) needed. If it were just a cost thing, they could of just let that alone and tell the bidders that the Not To Exceed cost was Z, and let them make the design choices.

As far as extra credit goes, that's a very useful tool. You can use it to determine the cost/benefit best value to meet your needs and also allows you to priortize various characteristics, as opposed to going strictly with lowest cost. Example: Let's say there are two finalists for F/A-XX. Both bid a price below the NTE limit. Performance objectives have been specified. In addition, it is said that a 1 % benefit will be allowed for each .1 Mach over the supercruise objective up to a maximum of 5%. Similarly, a 2% credit will be given for each 100nm combat radius over the objective up to a maximum of 10%,. Plus there would be credit for each 10% reduction of mmh/fh below the gov't estimate. A meets all the threshold and objective requirements. B also at least meets every objective requirement, but using advances in technology that it developed on its own and using a more efficient engine, offers a design that supercruises .45 Mach faster and exceeds the combat radius requirement by 400nm, while requiring 30% less maintenance. Only thing is, its flyaway cost is 5% more. What that extra credit does is allow the gov't to select a much more capable aircraft that will do more for the Navy even though it isn't the lowest bidder.

In LHX the revised specifications gave no credit for anything exceeding what a conventional helicopter could do, no matter how good or little extra it might cost.

 

[yasotay]

In LHX the revised specifications gave no credit for anything exceeding what a conventional helicopter could do, no matter how good or little extra it might cost.

Never underestimate the human side of the equation. The Army Aviators at the time were very much disinclined toward anything different. They were concerned with the risks associated with the new technologies and the potential for delays because of this. As mentioned it was the height of the cold war, so they wanted something fast. Also recall originally they wanted something very light. The Aviators were mostly Vietnam veterans who expected scout aircraft to be lost at a significant rate, so they wanted relatively simple as well. Rather ironic that over time ALL of the original logic for LHX went out the window.

 

[VTOLicious]

Interresting, but I doubt such a folding concept would be feasable, and if feasable, survivable on a modern battlefield.

Actually the fold TR concept has been demonstrated with a scaled run in the NASA Langley Wind Tunnel about a decade ago. I would certainly be interested in why you think it not feasible today, although this is not the correct forum for it.

Cammnut I want to add my thanks for the great picks from Sikorsky on some of their TR work. Today it is taboo at Sikorsky to talk TR. They have also done a lot of work with tilt-wing work. Here is a stealthy tilt-wing from the mid-nineties that they worked on for the Army After Next efforts for the U.S.Army.

@yasotay
Do you know the source of that picture? Could it be a SOFTA proposal?

BR Michael

 

[F-14D]

In LHX the revised specifications gave no credit for anything exceeding what a conventional helicopter could do, no matter how good or little extra it might cost.

Never underestimate the human side of the equation. The Army Aviators at the time were very much disinclined toward anything different. They were concerned with the risks associated with the new technologies and the potential for delays because of this. As mentioned it was the height of the cold war, so they wanted something fast. Also recall originally they wanted something very light. The Aviators were mostly Vietnam veterans who expected scout aircraft to be lost at a significant rate, so they wanted relatively simple as well. Rather ironic that over time ALL of the original logic for LHX went out the window.

Army aviators were the ones who pushed for the original specifications, concerned about vulnerability of conventional helos, the large area they would have to cover in Europe and elsewhere, and expected future threats. Also given the limited numbers of vehicles that could be available ar a given place at a given time, they felt the need for more than what a regular 'coper of the time could do. One other benefit was that Congress, seeing this as a chance to advance American VTOL technology relative to what was coning up in Europe and elsewhere, was very supportive of the LHX program. The sudden dumbing down after all the encouragement by the Army to industry for advanced capabilities caught almost everyone flat-footed. Congress felt it had been subjected to a bait and switch and support went from advocacy to skepticism, something the program never overcame and one of the sources of the sniping against RAH-66, which of course did have delays that weren't so well tolerated because it really wasn't that much of a push airframe-wise.

Now since you wondered what I thought happened (you did wonder, didn't you?), I'm a bit of a cynic about this. There definitely were some cautious people at the top of the Army, but I'm of the opinion there was more. Because of some screwups with teh way things were awarded, especially some of the sole-source stuff done during the war, the mantra was maximum competition. It got to the point that competition became not nearly a means to an end, but an end in itself. Now at the time, there were really only two companies that had experience with a technology that had a reasonably low risk chance of delivering, Bell and Boeing. Bell was one with Tilt-Rotor, and the other was Boeing, who was also considering a Tilt-Rotor. That in and of itself meant there wouldn't be that much competition, given the multiple manufacturers there were then. What made the situation worse was what if the two companies teamed like they did on JVX? Even if they were the best choice, there wouldn't be "competition", and that might be considered unacceptable. Also, what the Army was asking for might be viewed by USAF as infringing on their "roles and missions" and they'd start lobbying against it (a concern I have for FLRAA if it goes forward), something Army definitely didn't want given how much they wanted to replace the OH-58.. So, in order to preserve the chance they'd get something they lowered the requirements to what a conventional helicopter could do and insured that a higher performance aircraft had no chance. Ironically, they ended up allowing Comanche more weight and power than what they directed in the solicitation.

So here we are, four failed attempts to replace the OH-58 later, still not having anything to show for it.

Or so my twisted logic goes.

 

[Yellow Palace]

In LHX the revised specifications gave no credit for anything exceeding what a conventional helicopter could do, no matter how good or little extra it might cost.

Never underestimate the human side of the equation. The Army Aviators at the time were very much disinclined toward anything different. They were concerned with the risks associated with the new technologies and the potential for delays because of this. As mentioned it was the height of the cold war, so they wanted something fast. Also recall originally they wanted something very light. The Aviators were mostly Vietnam veterans who expected scout aircraft to be lost at a significant rate, so they wanted relatively simple as well. Rather ironic that over time ALL of the original logic for LHX went out the window.

That helps make sense: they wanted a certain capability to be able to do the job, and they wanted it cheaply because they'd drop like flies.

Whether that analysis was correct is clearly arguable. But defence procurement isn't done by moustache-twirling officers who'll do anything to defeat a technology they oppose. It's done by people who want to do what's best for the service, and sometimes they make mistakes.

 

[yasotay]

In LHX the revised specifications gave no credit for anything exceeding what a conventional helicopter could do, no matter how good or little extra it might cost.

Never underestimate the human side of the equation. The Army Aviators at the time were very much disinclined toward anything different. They were concerned with the risks associated with the new technologies and the potential for delays because of this. As mentioned it was the height of the cold war, so they wanted something fast. Also recall originally they wanted something very light. The Aviators were mostly Vietnam veterans who expected scout aircraft to be lost at a significant rate, so they wanted relatively simple as well. Rather ironic that over time ALL of the original logic for LHX went out the window.

So here we are, four failed attempts to replace the OH-58 later, still not having anything to show for it.

Or so my twisted logic goes.

To be clear I agree that it was Aviators who pressed for the advanced technology. Unfortunately, those Aviators were not the ones in the Pentagon who dealt with OSD, nor the SASC and HASC. The adventuresome Aviators in St. Louis, Fort Eustis, and Ames Research Facility, were all about pressing the envelope and skipping forward. The Aviators in the Pentagon (remember Aviation was not a branch within the Army yet) had to keep an eye on a dwindling budget and other priorities. The Big Six was still very new. The Fourth Estate within the Pentagon are as risk adverse as any other part. LHX/Comanche could replace the Bradley Fighting Vehicle in the movie "Pentagon Wars" and still remained the black comedy historical movie that it is.

 

[Colonial-Marine]

LHX changed a lot over time but I don't think the final configuration of the RAH-66 was necessarily a mistake for the European battlefield it was originally designed for. Against an enemy with the sort of air defenses the Soviets/Russians had and have scouting would have been all about using the terrain and sensors to detect the enemy first. Of course the increased speed would have been useful in flying from the FARP to the battlefield but wouldn't greater signature reduction and (in-theory) a lower price tag be a better option in this scenario.

The V-22 also had such a long painful history before becoming the aircraft that it is today that it's entirely possible a tilt-rotor LHX would have been cancelled sooner. The V-22 had a lot of backing while Army aviation always seems to be short of money.

I admit a tilt-rotor LHX would have been very useful in Afghanistan and all the United States' other Middle Eastern adventures.

 

[Bgray]

Interresting, but I doubt such a folding concept would be feasable, and if feasable, survivable on a modern battlefield.

To me, the Tilt-fold looks more like it's designed for something that is expected to spend most of its time acting like an aircraft, rather than a helicopter, (although art is always dfangerous to go on, due to the divide between art/engineering, the art for their TF designs seems to be doing more ah, "attack aircraft" stuff than helicopter stuff. ), As such, it would seem too expensive and complex to be worth it on something like the LHX.

 

[youROKer]

Bell LHX. From "Army", March 1984.

 

[yasotay]

Oh the grand arguments about single pilot attack helicopters that ran around the Aviation community for a few years. Finally the "conservative" folks won out. Good thing they did as the bold Russian adventure with Ka-50 seems to have demonstrated it was/is not easy to fly and push buttons at <10 meters at the same time.

 

[Jason Dykstra (Wyvern)]

I have a book about helicopters written by Bill Gunston where it describes in brief the future of helicopter design through the LHX program and also included some speculation about the Kamov "Hokum" (Ka-50). I shall post some information later when I get a chance. I remember that there was a picture of a guy with a special helmet that projected a 3D model of the landscape in front of him. It was pretty interesting. I shall send more information later.

 

[Dynoman]

Single pilot cockpit management is challenging at altitude, let alone in a combat environment flying NOE, I would imagine. Single pilot LHX preliminary designers must have believed automation technologies in the 1990's would materialize much faster than they did, or possibly their marketing departments got ahead of their engineering departments.

 

[yasotay]

Single pilot cockpit management is challenging at altitude, let alone in a combat environment flying NOE, I would imagine. Single pilot LHX preliminary designers must have believed automation technologies in the 1990's would materialize much faster than they did, or possibly their marketing departments got ahead of their engineering departments.

There was an incredible amount of faith in automation improvement coming about.

 

[Archibald]

Oh the grand arguments about single pilot attack helicopters that ran around the Aviation community for a few years. Finally the "conservative" folks won out. Good thing they did as the bold Russian adventure with Ka-50 seems to have demonstrated it was/is not easy to fly and push buttons at <10 meters at the same time.

Well for a start, the Mirage III-E / F-105 already proved this fact in the 60's... and they flew thrice faster than any chopper.

 

[yasotay]

Oh the grand arguments about single pilot attack helicopters that ran around the Aviation community for a few years. Finally the "conservative" folks won out. Good thing they did as the bold Russian adventure with Ka-50 seems to have demonstrated it was/is not easy to fly and push buttons at <10 meters at the same time.

Well for a start, the Mirage III-E / F-105 already proved this fact in the 60's... and they flew thrice faster than any chopper.

@Archibald - No doubt it was already known. I should have been more clear to state: "Oh the grand arguments about single pilot attack helicopters that ran around the Aviation helicopter community..." However the fixed wing communities (especially the fast jets) and the helicopter communities have always looked on each other as completely different environments. There was, until recently, very little professional cross-communications in either the engineering or military venue. While fast jets were indeed far faster and had a great operational environment, they only operated in the ecosystem of the helicopter regularly at stall speed and lined up for landing, not their tactical strong suit. Helicopters only went to the stratospheric heights of 10,000 feet to set records and flew at airspeeds that did not even show up on airborne radar. With the elixir of technology to come, a hand wave was given to overcoming the the pilot workload issues of the 60's and 70's (with "AI" before we called it that).

 

[Archibald]

Oh, no problem, really. Shame these two didn't talked much to each others, since the issues were somewhat similar - piloting in a CAS mission while fighting one's way across manpads, flak guns, SAMs...
The one machine that could have broken the deadlock you mention, was the AH-56 Cheyenne. Alas, the Army and USAF chose to ignore each others.
I often think, by 1972, were in competition
- AH-56
- YAH-63
- AH-64 (the winner)
- S-67
- Bell 309
- A-10
- YA-9
And one could add, AV-8A and A-7E for CAS.

Jack Real famously said (about the Army rejecting AH-56, S-67 and Bell 309 and starting anew from zero) "they were like kids in a candy shop". Could apply to USAF, too.

 

[apparition13]

Well for a start, the Mirage III-E / F-105 already proved this fact in the 60's... and they flew thrice faster than any chopper.

I don't know about that. P-47, F4U, A-1, A-4, A-7, AV-8, A-10, Su-25, etc. are all single pilot and good CAS platforms.

Genuine question, is piloting a helicopter so much more difficult than fixed wing that piloting and targeting become impossible?

Oh, no problem, really. Shame these two didn't talked much to each others, since the issues were somewhat similar - piloting in a CAS mission while fighting one's way across manpads, flak guns, SAMs...
The one machine that could have broken the deadlock you mention, was the AH-56 Cheyenne. Alas, the Army and USAF chose to ignore each others.
I often think, by 1972, were in competition
- AH-56
- YAH-63
- AH-64 (the winner)
- S-67
- Bell 309
- A-10
- YA-9
And one could add, AV-8A and A-7E for CAS.

Jack Real famously said (about the Army rejecting AH-56, S-67 and Bell 309 and starting anew from zero) "they were like kids in a candy shop". Could apply to USAF, too.

If by "kids in a candy shop" he meant kids who wind up going home with nothing because they can't make up their minds he might be right. The Army had to wait 15 years longer than it should have for its attack helicopter, while the Air Force is the kid who takes the licorice stick they don't really like or want (the A-10) just to keep the kid who does like licorice from having any (the AH-56).

 

[Archibald]

I don't know about that. P-47, F4U, A-1, A-4, A-7, AV-8, A-10, Su-24, etc. are all single pilot and good CAS platforms.

The subtle difference ssentially boils down to "clear weather CAS" vs "long range strike at night or in adverse weather".
A-6, Buccaneer, F-111, Phantoms, Mirage 2000D, TSR-2, Mirage IV (and countless others) were all two seaters. F-105 and Mirage III-E tried the same mission with a lone pilot and... it was difficult.
That was the point I was trying to make.

Genuine question, is piloting a helicopter so much more difficult than fixed wing that piloting and targeting become impossible?

Helicopters are notoriously harder to pilot. Remember the motto "they don't fly: they beat the air into submission".

If by "kids in a candy shop" he meant kids who wind up going home with nothing because they can't make up their minds he might be right. The Army had to wait 15 years longer than it should have for its attack helicopter, while the Air Force is the kid who takes the licorice stick they don't really like or want (the A-10) just to keep the kid who does like licorice from having any (the AH-56).

Spot on, right on, bingo.

 

[yasotay]

Until AH-64 and UH-60 (for the US) helicopters were completely mechanical and relied on the pilot to deal with the associated physics. With the new helo's of the late 70's there were both mechanical and electronic assistance to deal with some of the basic physics associated with helicopters. With the advent of fly by wire for rotorcraft, many of the old challenges are now dealt with by the computers onboard.

We shall soon see if the kids grew up enough to pick candy ... and share.

 

[Dynoman]

Even working in a highly automated cockpit, LHX researchers found in trade-studies that the single-pilot crew member's cognition would become easily saturated with a variety of stimuli operating within the a low-level environment, especially in NOE, at night, and in combat conditions. Hence, two crew members for LHX. The study below even indicated that single-seat fighter aircraft that took advantage of automation (e.g. F-15, F-16, F/A-18) needed two-crewed aircraft to accomplish the low-level, all weather, attack mission effectively, which are now accomplished by two-seat F-15E, F-16D, and F/A-18D/F.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a158076.pdf

 

[yasotay]

At least with FVL the Army is not trying to make a single pilot rotorcraft. Although they do indicate it "could" be operated single pilot or autonomously.

 

[ZacYates]

Boeing Sikorsky LHX mock-up.

http://www.arcforums.com/forums/air/lofiversion/index.php?t202161.html

So I think I know the answer to this (based on the lack of photos or info appearing over the years), but was a SuperTeam mock-up ever built?

 

[trajan]

1. BELL=B
BOEVING—VERTOL=BV
HUGHES=H
SIKORSKY=S


2. CE/Dstage&PD pictures(1983—1987/88)

S:
B:

H：

BV：

 

[trajan]

 

[trajan]

View attachment 659601

in 1987 LHX—U cancelled because of rapidly climbed prices

 

[trajan]

In 1988 LHX passed DSARC I. Came to the CD/E stage.
Now B-S made "First team"=Ft

Boeing and Bell made "Super team"=St

 

[trajan]

St photos:

 

[flateric]

Try to use forum search before posting in wrong threads and posting low-quality images that already here in much better quality please

 

[overscan (PaulMM)]

Yep, tolerance level is low today.

 

[kocovgoce]

if the war in ukraine is fought somehow the helicopters had the highest survival rate due to the possibility of landing on any terrain. And not a bad idea for a sub sonic helicopter like the one in the illustration

 

[Aeroweanie]

A story from someone who was involved in the LHX competition:

The initial Boeing Vertol design was an unequal dimeter tandem rotor design. Sikorsky had toyed with the ABC concept, but settled on a single rotor + fan-in-fin design. I think part of the reason was that there were some still-unsolved vibratory issues with the XH-59A.

I had been studying on my own time how to design rotor airfoils and two years before we had completed designing and testing a new rotor tip airfoil, the SSC-A09. I tried to get support for designing a new inboard/mid blade airfoil, but the head of aero told me that there was no need for new rotor airfoil designs.

Then, one day in early 1985, head of aero came to me in a panic - the Army wanted to have Sikorsky test their new LHX blade airfoil, but we didn't have a new LHX blade airfoil. I was given one month to design a new inboard/mid blade airfoil. Working flat-out with another guy we developed a new rotor airfoil. Tests of the resulting SC2110 airfoil showed that it was superior to the SC1095R8 airfoil used on the UH-60A and S-76 blades.

When Sikorsky teamed with Boeing Vertol, the compromise was to use the overall Sikorsky design layout, but the BV VR-12 airfoil ended up on inboard region of the blades, while the Sikorsky SSC-A09 airfoil was used on the tip. My airfoil (the SC2110) later got used on the UH-60M and S-92 blades.

I was also tasked with reviving fan-in-fin design technology at Sikorsky. One of my first actions was to track down and recover the fan-in-fin that had flown on the S-67. It had not been installed when the aircraft crashed and was stored out on the helipad at Stratford. I spent six months researching fan-in-fin design practices and wrote a document laying out how to design the device. When done, I was appointed task manager on the fan-in-fin design, but quit the two days later to move on to greener, more exciting pastures. And, while we were packing up to move, the Space Shuttle Challenger blew up, something that glued all of this in my memory.

 

[StriX]

Boeing Vertol from AWST magazine archives.

 

[overscan (PaulMM)]

Nice, useful to know which issue you found it in?

 

[overscan (PaulMM)]

A story from someone who was involved in the LHX competition:

The initial Boeing Vertol design was an unequal dimeter tandem rotor design. Sikorsky had toyed with the ABC concept, but settled on a single rotor + fan-in-fin design. I think part of the reason was that there were some still-unsolved vibratory issues with the XH-59A.

I had been studying on my own time how to design rotor airfoils and two years before we had completed designing and testing a new rotor tip airfoil, the SSC-A09. I tried to get support for designing a new inboard/mid blade airfoil, but the head of aero told me that there was no need for new rotor airfoil designs.

Then, one day in early 1985, head of aero came to me in a panic - the Army wanted to have Sikorsky test their new LHX blade airfoil, but we didn't have a new LHX blade airfoil. I was given one month to design a new inboard/mid blade airfoil. Working flat-out with another guy we developed a new rotor airfoil. Tests of the resulting SC2110 airfoil showed that it was superior to the SC1095R8 airfoil used on the UH-60A and S-76 blades.

When Sikorsky teamed with Boeing Vertol, the compromise was to use the overall Sikorsky design layout, but the BV VR-12 airfoil ended up on inboard region of the blades, while the Sikorsky SSC-A09 airfoil was used on the tip. My airfoil (the SC2110) later got used on the UH-60M and S-92 blades.

I was also tasked with reviving fan-in-fin design technology at Sikorsky. One of my first actions was to track down and recover the fan-in-fin that had flown on the S-67. It had not been installed when the aircraft crashed and was stored out on the helipad at Stratford. I spent six months researching fan-in-fin design practices and wrote a document laying out how to design the device. When done, I was appointed task manager on the fan-in-fin design, but quit the two days later to move on to greener, more exciting pastures. And, while we were packing up to move, the Space Shuttle Challenger blew up, something that glued all of this in my memory.

This is wonderful stuff, thanks for sharing.