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LHX Program

overscan

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More Bell/McDonnell team

All the above pics found on the internet, sources unknown.
 

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overscan

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First, an early Bell configuration, then a later Boeing/Sikorsky LHX configuration.

Sources:

Bill Gunston, Warplanes of the Future, Salamander 1986
Roy Braybrook, Attack Aircraft Foulis 1990
 

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overscan

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Some interesting info from USAF, 1985:

LHX/LOA requirements

  • Highly agile, manouverable, single seat conventional rotorcraft
  • Armament 4 Hellfire, 2 Stinger, 1 gun
  • Self deployable 1250 nm
  • 500fpm climb, 170kts (SCAT), 160kts (Utility) in hot & high conditions (4000ft, 95degF)
  • Transportable in C-5, C-17, C-141
  • Crashworthy design, wheel landing gear, NBC protection
  • Twin T800 turboshafts
  • 6 seats in utility version (space for eight)
  • Integrated targeting system
  • wide field-of-view optics
  • 8000lb +-500lb target mission gross weight for SCAT
  • Unit flyaway cost $6 million (SCAT), $4 million (Utility) in 1984 dollars
  • 70% commonality between SCAT and utility versions
  • 40-50% reduction in support and operating costs
 

Archibald

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overscan said:
More Bell/McDonnell team
This pic figured in Science&vie HS Aviation 1987. There was another pic of an LHX firing at a Mi-24 Hind :)
I suppose the LHX was the forerunner of the comanche :)
 

hesham

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Hallo,

there were anther projects to LHX program,such as:
-Boeing-Vertol project in SCAT role,and was different in design
from a pictures to dear overscan.
-Boeing-Vertol :single seat with computer cockpit.
-McDD project for NOTAR a supersonic jet helicopter/fighter.
-Sikorsky S-76 with a new single-place cockpit in the nose.

unfortunately I have not a scanner now.
 

flateric

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Boeing/Sikorsky team
McDD project for NOTAR a supersonic jet helicopter/fighter.
 

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Antonio

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McDD project for NOTAR a supersonic jet helicopter/fighter.
I knew this pic but I ignored it was a supersonic helo. How it works? It is possible to attain supersonic flight with the rotor "on"?. Anybody knows about which was its max speed?
 

overscan

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I don't believe it was supersonic.
 

yasotay

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I remember going up to the Boeing booth at the 1986 Army Aviation Association meeting and looking at a model that appeared to be a frog tadpole with a rotor system on its back. As I stood there looking at it a elderly gentleman came up and asked if I had any questions. I asked, "Where is the cockpit?". He replied "Right where it is supposed to be." I asked "Where is the canopy?" He said "There isn't one." I said "I won't fly it!" He smiled and said "No but your son will." He then went on to explain that future battlefields would be ugly with lasers and other bad things that cause pilots not to fly well. I thought him daft and moved on. A day later I got to sit in the full scale mock up of the Bell BAT tilt-rotor at their planet. It reminded me of a World War 2 fighter and I wanted one bad. I had visions of commanding a battalion of LHX. Twenty years later I have neither. Having spent time assisting with the Comanche effort I am left to wonder how we might have faired with some of the other aircraft concepts.
 

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USAF? For an Army helo project? Or was the LX intended for USAF use as well?


overscan said:
Some interesting info from USAF, 1985:

LHX/LOA requirements

  • Highly agile, manouverable, single seat conventional rotorcraft
  • Armament 4 Hellfire, 2 Stinger, 1 gun
  • Self deployable 1250 nm
  • 500fpm climb, 170kts (SCAT), 160kts (Utility) in hot & high conditions (4000ft, 95degF)
  • Transportable in C-5, C-17, C-141
  • Crashworthy design, wheel landing gear, NBC protection
  • Twin T800 turboshafts
  • 6 seats in utility version (space for eight)
  • Integrated targeting system
  • wide field-of-view optics
  • 8000lb +-500lb target mission gross weight for SCAT
  • Unit flyaway cost $6 million (SCAT), $4 million (Utility) in 1984 dollars
  • 70% commonality between SCAT and utility versions
  • 40-50% reduction in support and operating costs
 

overscan

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Sorry, my mistake. It was an Army project.
 

hesham

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My dears,

in anther book for Bill Gunston he suggested that the McDD design
was supersonic jet helicopter/fighter, I agree with him because
in anther book and about X-wing helicopter program,the Sikorsky
submitted serveral proposals, one of them the Auther Michael Taylor
spoke about it ,it could have a speed more than 800 km/h and
it was a normal helicopter design.
conclusion:-
if a normal design can attain 800 km/h, the unconventional
design to McDD can reach more.
 

Jemiba

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The Sikorsky S-72X wasn't a helicopter in conventional sense, but a VSTOL design
with a stoppable rotor (it never flewwith this rotor, just as a conventional a/c).
If the MDD project really was aimed at supersonic speeds, I'm pretty sure it wasn't
intended to do so with the rotor turning. Even using the rotor as an x-wing would
be quite an aerodynamic and aeroelastic challenge at supersonic speeds, I think !
 

overscan

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Hesham, the quote you are relying on is from 1984's "Illustrated Guide to Future Fighters and Combat Aircraft"

"A slightly fanciful LHX/SCAT proposed by Hughes, naturally with NOTAR but also fitted with a swept wing. This suggestion of the supersonic jet fighter shows Hughes is on the right wavelength with SCAT, but a new form of main lifting rotor would be needed"

In the main text:

"it is doubtful swept wings and leading edge root strakes would really be features of such a vehicle"

In 1986's "Warplanes of the Future" the same design is described as "broadly conventional, except for the NOTAR design".

You are misunderstanding Gunston. He says only that it looks like a supersonic jet fighter, not that it is a supersonic design.

The rotor is the barrier to high speed flight. It needs to be stopped, like on the X-Wing designs, retracted or otherwise got out of the way. There are no signs of this on the design, and it doesn't seem to have any form of forward propulsion except the rotor.
 

GTX

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Overscan,

Thanks for posting the pick of the troop transport version. Though I knew that this was part of the original LHX program, this is the first time I've seen a pick of any of the proposed versions (everything else has focussed on the attack versions).

Regards,

Greg
 

flateric

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I've got today (and have forgoten it in the office) my copy of 1988 edition of Michael Taylor's 'Jet Warplanes: The Twenty-First Century' - there are some additional LHX concept illustrations. Will post them on Monday.
 

overscan

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I know there are! I bought a copy of it in New Zealand when I got married there, but then left it behind!

Paul.
 

hesham

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My dears,

I have that book,and it has also X-wing helicopter projects.
 

yasotay

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Gents (and ladies if there are any here), i do not recall that the X-wing was actually part of the LHX effort. I certainly could be wrong, but believe that Sikorsky focused on the ABC concept for the LHX effort. I think the X-wing effort was seperate.

A couple of interesting notes. Sikorsky is once again looking at ABC technology (now called X-2 technology). I actually got to see the XH-59 ABC demonstrator fly several times at Ft. Rucker. With those turbines it certainly had a different sound that your typical helicopter.

I'll see if I can get some pictures of the Sikorsky LHX model sitting with the other "what ifs" at work.
 

overscan

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"Superteam" (Bell/McDonnell-Douglas) proposal combined Bell's 680 rotor technology with McAir's NOTAR.

Source:

Frank Collucci, Stealthy Scout: The RAH-66 Comanche Air International July 1994
 

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flateric

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From J.Jones 'Stealth Technology: The Art Of Black Magic'
!). Modified Bell-MDC LHX configuration 3-view. This was IMHO the most sexy entry of all.
2). Boeing-Sikorsky team LHX-U (Utility), rival to Bell-MDC LXH-U variant (http://www.secretprojects.co.uk/forum/index.php?action=dlattach;topic=1062.0;attach=9154)
 

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CammNut

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And while I am on (okay, slightly off) the subject - here are two Boeing folding-tiltrotor images (or maybe it was tilt-stop-foldrotor). This was actually intended to go supersonic, unlike McDonnell Douglas's cigar-shaped LHX (no propulsion system).
 

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Firefly 2

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

flateric

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CammNut said:
And while I am on (okay, slightly off) the subject - here are two Boeing folding-tiltrotor images (or maybe it was tilt-stop-foldrotor). This was actually intended to go supersonic, unlike McDonnell Douglas's cigar-shaped LHX (no propulsion system).
What a beautiful add-on to these murky PDF extracts
http://www.secretprojects.co.uk/forum/index.php/topic,103.msg2286.html#msg2286
CammNut, you are one of the best newbees at the forum, thank you!
 

yasotay

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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.
 

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elmayerle

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Actually, this engineer considers a tilt-wing design preferable from a reliability viewpoint to a tilt-rotor design. Really, fewer moving parts, in relation to each other, and fewer critical joints. Wonder how a design combining the best of the V-22 and the XC-142 would look?
 

Firefly 2

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yasotay said:
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.
First and foremost: I'm no engineer, just an avid enthousiast of the strange and little known.
I also have gut feelings about designs wether or not they are likely to work, especially in tactical situations.
The fold TR rotor seems like a very complex and costly ( in terms of development) design. It would take ages to get it right and makes the wingtips of the design overly complex and thus vulnerable. There's just too much to go wrong, and I doubt that the stellar performance of such a design in terms of speed at low altitude would protect it enough. By this I mean... Sheesh, just imagine one of the wingtips being damaged by a stray bullet.
So, to me, in this line of thinking, the design looks hardly feasable, and if feasable, flawed.
 

yasotay

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I think that the European TR effort is something of a hybrid in that most of the wing section rotates with the nacelle. This significantly reduces the down force impinging on the wing. The problem to date with the tilt wing efforts to date is they have all used relatively small prop/rotor diameters which increase the out wash velocities. For unimproved area operations this has led to unacceptable (at least to the U.S. Military) FOD and personnel operations challenges. The V-22 is at the upper end of the out-wash velocity curve and has become something of a "do not exceed" parameter for aircraft expected to operate in unimproved areas. This has been a challenge with the JHL effort here in the states.

I agree that tilt wing though could be less mechanically challenging.
 

yasotay

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Firefly said:
yasotay said:
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.
First and foremost: I'm no engineer, just an avid enthousiast of the strange and little known.
I also have gut feelings about designs wether or not they are likely to work, especially in tactical situations.
The fold TR rotor seems like a very complex and costly ( in terms of development) design. It would take ages to get it right and makes the wingtips of the design overly complex and thus vulnerable. There's just too much to go wrong, and I doubt that the stellar performance of such a design in terms of speed at low altitude would protect it enough. By this I mean... Sheesh, just imagine one of the wingtips being damaged by a stray bullet.
So, to me, in this line of thinking, the design looks hardly feasable, and if feasable, flawed.
While I see your point regarding complexity (look at an F-111 or a Sea King), loss of one of the wing tips ability to transition back to rotor-borne flight would mean the aircraft would have to remain in fixed wing mode and land as a CTOL aircraft vice VTOL
 

Firefly 2

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True, if there is a possibility to do so.
I still have my doubts.
 

sferrin

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elmayerle said:
Actually, this engineer considers a tilt-wing design preferable from a reliability viewpoint to a tilt-rotor design. Really, fewer moving parts, in relation to each other, and fewer critical joints. Wonder how a design combining the best of the V-22 and the XC-142 would look?
Sorta off topic but any idea why the method the X-22 used never went anywhere? They seem to have been relativly successful. ???
 

yasotay

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If you are referring to the Bell X-22A four post ducted fan aircraft that was used at Calspan for many years, it was the second longest flying VTOL concept aircraft, second only to the XV-15, I believe. I think that the biggest problem for it was timing. When it first came about war requirements kept it from progressing. By the time the war ended it was overcome by a need for aircraft for the Cold War in Europe. The Navy focused on fleet defense and the Army looked for attack helo's to kill hordes of tanks at the Fulda Gap.

Ironically as the cold war progressed the Army it focused more and more of its Rotorcraft Science and Technology on a stealthy reconnaissance attack helicopter program called the LHX, which became the RAH-66 Comanche. Even the V-22 program (which had been called the JVX) was dropped from Army leadership to focus on the recon helo.
 
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