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9/22/2017 12:11:25 AM
Posted: 9/16/2005 4:43:27 PM EDT
US Army awards five agreements for Concept Design & Analysis of Joint Heavy Lift (JHL) rotorcraft

The US Army, in cooperation with its Joint Service and NASA partners, announces the award of five agreements/contracts for the Concept Design and Analysis (CDA) of a Vertical Takeoff and Landing (VTOL) Joint Heavy Lift, (JHL) rotorcraft.

The purpose of the CDA activity is to define the “art of the possible”, the “science of the probable” and the “design of the affordable” for a JHL VTOL rotorcraft that enables future joint concepts of operations (CONOPS). These include such things as conducting mounted and dismounted vertical envelopment; executing operational maneuver and sustainment operations at extended ranges simultaneously into unprepared, complex terrain locations under extreme environmental conditions, 24/7; and overcoming enemy anti-access strategies from land and sea bases as part of joint expeditionary operations.

The CDA is part of the overall multi-year (FY05-07) JHL Concept Refinement effort. It is primarily focused on supporting the joint requirements definition process. The CDA is the technical pillar of activity designed to inform the joint requirements analysis with credible rotorcraft design concepts and performance projections that can reasonably be matured to a Technology Readiness Level (TRL) 6 by 2012.

The five CDA awards, made under the Army’s Aviation Applied Technology Directorate (AATD) Broad Agency Announcement (BAA) W911W6-05-R-0004, are for the conceptual/preliminary design of a baseline aircraft, and specific design excursions, to identify the impact of variations in payload, range, environmental conditions, and shipboard compatibility on aircraft size, performance, operational suitability, cost, schedule, and development risk.

The baseline design specification is to maneuver an FCS/Stryker/LAV Vehicle over a 250 nautical mile (nm) radius, under 4000 foot density altitude and 950 Fahrenheit (4k95) conditions, from/to land or sea bases and operating areas. Eight specific excursions to these conditions will also be investigated that include lighter and heavier cargo (16 – 26 tons), shorter and longer mission radii (210 – 500 nm), more extreme environmental conditions (6k95), and full compatibility with a future ship. These design variations populate the desired trade space in the joint requirements process.

The five concept vehicles chosen for this effort, listed in order of their design cruise speeds, are:
(1) Sikorsky X2C, X2 Technology Crane – coaxial rotor (165 knots);
(2) Boeing ATRH, Advanced Tandem Rotor Helicopter (165 knots);
(3) Sikorsky X2HSL, X2 Technology High Speed Lifter – advancing blade compound (245 knots);
(4) Bell Boeing QTR, Quad Tilt Rotor (275 knots); and
(5) Frontier Aircraft OSTR, Optimum Speed Tilt Rotor (310 knots).

These awards are for eighteen months and represent over $30M of Government and Industry contribution. They include the delivery of the designs with substantiating data, a specification document, a technology development strategy, and cost/schedule estimates for a Component and Technology Demonstration phase to achieve TRL 6 in an appropriately large-scale flight vehicle. Award of any future JHL development activity, should it occur, is separate and independent of this BAA .

Link Posted: 9/26/2005 2:53:59 PM EDT
Couple of pics

Bell/Boeing quad rotor concept...


Tandem rotor concept...
Link Posted: 9/26/2005 2:56:48 PM EDT
Another pic of the Quad rotor concept...
Link Posted: 9/27/2005 3:40:20 AM EDT
Great! Twice as many sensors and limit switches to fail/go out of adjustment! Have't tilt wing A/C killed enough people? I love helis, and I love airplanes-but these things are just too dangerous to be fucking with until and unless they can get the Osprey squared away.

Dave
Link Posted: 9/27/2005 5:07:25 AM EDT
Maybe they should just order a shitload of the UH-2's . . .


CMOS
Link Posted: 9/27/2005 6:25:18 AM EDT

Originally Posted By TheOtherDave:
Great! Twice as many sensors and limit switches to fail/go out of adjustment! Have't tilt wing A/C killed enough people? I love helis, and I love airplanes-but these things are just too dangerous to be fucking with until and unless they can get the Osprey squared away.

Dave



You mean the Osprey that just passed OpEval with flying colors and is about to get the go-ahead for full-rate production? It took forever and a year, but it's here. However, looking at the time and money involved in the V-22, I don't expect the QTR to make it very far.
Link Posted: 9/27/2005 6:26:40 AM EDT
Cool, one step closer to the drop ship from Aliens.
Link Posted: 9/27/2005 6:37:32 AM EDT
950 Farenheit?? Flying on Mercury or Venus anyone?



My money is on the new boeing Shithook
Link Posted: 9/27/2005 6:40:14 AM EDT
Time to resurrect the old Fairley Rotodyne. The compound helicopter has long been figured out. Westland had the rights I believe.
Link Posted: 9/27/2005 6:52:01 AM EDT

Originally Posted By Planerench:
Time to resurrect the old Fairley Rotodyne. The compound helicopter has long been figured out. Westland had the rights I believe.



VX-1 did some testing with a compound H-60 variant a few years back. Compound helicopters have some limitations - as with all machines you have to make engineering trade-offs.

A compound helo uses a fixed wing to augment main rotor lift at high speeds. Ducted tail thrust or a pusher-prop augment main rotor thrust. The idea being that by lightening the load on the main rotor by using a fixed wing for supplemental lift, you can decrease the main rotor blade angle of attack and the occurence of retreating blade stall.

Problems include increased main rotor vibration. Once you unload that rotor head it tends to flap more, increasing stress on dynamic components. This is what led to the demise of the Cheyenne. Advanced materials and engineering (vibration reduction) can mitigate this problem.

A second problem is the higher power required to hover in a compound helo. Rotor wash (this is all of your lift in a hover) blows on the fixed wing and the helo pushes itself down. This seems to be the main problem with this type of aircraft presently. If the mission is heavy lift, possibly at high DA, the problem is even more critical.

If an easy answer existed to this problem, it would have been employed already.
Link Posted: 9/27/2005 7:17:47 AM EDT

Originally Posted By SnoopisTDI:

Originally Posted By TheOtherDave:
Great! Twice as many sensors and limit switches to fail/go out of adjustment! Have't tilt wing A/C killed enough people? I love helis, and I love airplanes-but these things are just too dangerous to be fucking with until and unless they can get the Osprey squared away.

Dave



You mean the Osprey that just passed OpEval with flying colors and is about to get the go-ahead for full-rate production? It took forever and a year, but it's here. However, looking at the time and money involved in the V-22, I don't expect the QTR to make it very far.



Pilot error was the cause for most if not all Osprey crashes IIRC. The press just beat it to death...it's funny how they can fuck the military so bad by pretending to just care for the troops. We all know they (most) are full of shit but people still buy it. Amazing really. I'll be damned if I want to Washington Press Corps deciding what equipment our military needs.
Link Posted: 9/28/2005 3:26:55 AM EDT
The Sikorsky offerings are:
1) A Skycrane-type with co-axial rotors and no tail rotor, so 100% of power goes to lift. "X2" is Sikorsky's term for the old "ABC" or advancing blade concept. One rotor above another, both going opposite directions. Likely powered by a CH-53X powertrain.

2) A High Speed Lifter, which will combine the "X2" (ABC) with a pusher (jet or prop). I think it's supposed to have a normal fuselage with a big cabin. Picture a CH-53X with co-axial rotors and a pusher prop instead of a tail rotor and you get the idea.

The three conventional helos represent low risk options. The tilt-rotors are high risk options. By high-risk I mean in the procurment sense. There's more risk that a tilt-rotor will run into problems, overruns, take longer, etc. because of technology.

There's some debate as to just what the Army really wants out of this, and how it's going to time into the FCS procurment. If this is supposed to fly the FCS around, then it has to be ready soon enough to do that. The CH-47F is incapable of doing this, so even though this is supposed to replace the CH-47F, it has much more to do with the weight-gain of the FCS. The FCS contractors have stated there's no way they can get the FCS under 26 tons, so the heavy-lift helo will have to move at least that. This weight increase is why the FCS', and even the Stryker's, original "C-130 transportable" requirement has changed to "C-17"

These contracts are to find out from the indusrty just what can be done, then there will be some more work on what to do. Anyway you cut it, the more complicated options (i.e. tilt-rotor) are going to take 15-20 years to complete. There's a definate timing problem here the Army is having. There's some political problems with the big tilt's as well. Some people at the USAF are starting to get edgy about the Army pushing into the cargo plane arena with the twin-prop FCA. A C-130 size aircraft will be seen as a stab at taking over theater level air cargo. It might not be too far off of the Army's intentions either.

One of the "off-the-shelf" ideas that has been floated as a cheap option to any of this crap is the Mi-26. It's actually capable of meeting the requriements now and has been in production forever. Essentially a zero-risk, low cost option, but with limited growth potential, and the obvious political problems.

I personally like the 'Crane proposal. The old CH-54 had alot of flexibility that the Army just never really put to good use. Those flexible features would be useful today.
Link Posted: 9/28/2005 3:45:45 AM EDT

Originally Posted By H46Driver:

Originally Posted By Planerench:
Time to resurrect the old Fairley Rotodyne. The compound helicopter has long been figured out. Westland had the rights I believe.



VX-1 did some testing with a compound H-60 variant a few years back. Compound helicopters have some limitations - as with all machines you have to make engineering trade-offs.

A compound helo uses a fixed wing to augment main rotor lift at high speeds. Ducted tail thrust or a pusher-prop augment main rotor thrust. The idea being that by lightening the load on the main rotor by using a fixed wing for supplemental lift, you can decrease the main rotor blade angle of attack and the occurence of retreating blade stall.

Problems include increased main rotor vibration. Once you unload that rotor head it tends to flap more, increasing stress on dynamic components. This is what led to the demise of the Cheyenne. Advanced materials and engineering (vibration reduction) can mitigate this problem.

A second problem is the higher power required to hover in a compound helo. Rotor wash (this is all of your lift in a hover) blows on the fixed wing and the helo pushes itself down. This seems to be the main problem with this type of aircraft presently. If the mission is heavy lift, possibly at high DA, the problem is even more critical.

If an easy answer existed to this problem, it would have been employed already.



The only problem with the Rotodyne was noise. By the end of the test program they had that under control but the stigma of the thing being loud stuck and killed the project. With modern engineering and materials the only trade off compared with tilt rotor designs is top end speed but the safety of the configuration would seem to offset that. Planerench
Link Posted: 9/28/2005 2:26:00 PM EDT
The Rorotdyne had alot more problems than noise. The Army tested tip-jets before the Rotordyne. The Rotodyne solved alot of the problems the Army had, but some you just can get around. Tip-jets was an interesting path to explore, but an evolutionary dead-end as far as military helos goes.

They're simply way too maintenance intensive and way too inefficient for military use. For what it was desgined for, the Rotordyne would have worked well, but there wasn't much military application for it for a combat aircraft.

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