• Hi Guest! Forum rules have been updated. All users please read here.

LHX Program

hesham

CLEARANCE: Above Top Secret
Joined
May 26, 2006
Messages
24,285
Reaction score
1,058
Hi,

 

Attachments

yasotay

CLEARANCE: Top Secret
Senior Member
Joined
Oct 19, 2006
Messages
2,031
Reaction score
106
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).
 

hesham

CLEARANCE: Above Top Secret
Joined
May 26, 2006
Messages
24,285
Reaction score
1,058
From the book; Attack Helicopters
 

Attachments

F-14D

I really did change my personal text
Senior Member
Joined
Oct 4, 2007
Messages
1,737
Reaction score
21
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.
 

RLBH

CLEARANCE: Secret
Joined
May 5, 2007
Messages
216
Reaction score
22
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

I really did change my personal text
Senior Member
Joined
Oct 4, 2007
Messages
1,737
Reaction score
21
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

CLEARANCE: Top Secret
Senior Member
Joined
Oct 19, 2006
Messages
2,031
Reaction score
106
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

CLEARANCE: Top Secret
Joined
Nov 24, 2008
Messages
507
Reaction score
54
Firefly said:
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

I really did change my personal text
Senior Member
Joined
Oct 4, 2007
Messages
1,737
Reaction score
21
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.
 

RLBH

CLEARANCE: Secret
Joined
May 5, 2007
Messages
216
Reaction score
22
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.
 
Top