US Joint Heavy Lift

[F-14D]

Amen. Reminds me of the design specifications for the C-5. It was given this complicated, heavy landing gear design under the assumption of austere fields operations. Guess how many times the C-5 operated that way...

An austere airfield to the Air Force... well I do know you will not get anything larger than a C-130 to land at an "austere airfield" without a full up crash rescue service.
[/quote]

...and, don't forget, an O Club and a golf course

 

[yasotay]

I think it's more a case of "if we absolutely have to we'd like to be able to" and avoiding the mentality of "hey let's flush airframe hours down the toilet by landing on dirt runways just because we can".

I can understand not landing in the dirt for no reason, but landing at a hardened former IrAF base (in this case Mosul) to deliver materials is another thing. Army could get an occasional C-130 to bring stuff in, but the USAF refused to fly C-17 into Mosul without full up crash rescue, etc. Wonder how much FEDEX charges.

 

[flateric]

Not sure if it's related to JHL, but here goes interesting stealthy crane chopper patent filed in 2004 by Sikorsky.
http://www.google.com/patents/pdf/VTOL_aircraft_external_load_drag_reducti.pdf?id=LVh3AAAAEBAJ&output=pdf&sig=ACfU3U0v9vPhMF8xyi90TRPcOOsk6ggpSA

 

[flateric]

Bell/Boeing Quad Tiltrotor employment concept - 2004 video courtesy Al Huber (Yasotay)

http://www.youtube.com/watch?v=zjYFhQA8mYs

 

[hesham]

Hi,

http://128.102.216.35/factsheets/category.php

 

[yasotay]

Both of those concepts are products of the NASA Runway Independent Aircraft efforts from earlier in the decade. Interestingly the program is still alive.

 

[hesham]

Hi,

the HLH X.
http://www.aerodyndesign.com/HLHX/HLH_X.htm

 

[Orionblamblam]

Hi,

the HLH X.

No... not "the" HLX, just "a" HLX. As scribbled by some college students.

 

[yasotay]

Interesting.... um? Anti-torque? Anyone? ;D

 

[Jemiba]

From the link:

"The concept is a coaxial compound helicopter. Coaxial meaning 2 counter
rotating rotors aligned axial for moment cancellation."

 

[Orionblamblam]

From the link:

"The concept is a coaxial compound helicopter. Coaxial meaning 2 counter
rotating rotors aligned axial for moment cancellation."

Those blades are *real* close to each other. Wouldn't take much deflection for the rotor disks to intersect.

As I said: student designs. Apart from the occasional bit of artistry, such designs can almost always be dismissed. I shudder when I think back to *mine.* Bleah.

 

[yasotay]

From the link:

"The concept is a coaxial compound helicopter. Coaxial meaning 2 counter
rotating rotors aligned axial for moment cancellation."

Those blades are *real* close to each other. Wouldn't take much deflection for the rotor disks to intersect.

As I said: student designs. Apart from the occasional bit of artistry, such designs can almost always be dismissed. I shudder when I think back to *mine.* Bleah.

So close in fact I completely missed the co-axialness... guess I should read.

 

[fightingirish]

Speed Agile - a Glimpse of Boeing's Super-STOL Airlifter
Posted by Graham Warwick at 1/9/2009 2:44 PM CST
A couple of recent NASA research papers give a glimpse of the "super-STOL" tactical transport concept Boeing is working on under the U.S. Air Force's Advanced Joint Air Combat System (AJACS) studies. Boeing last year won the Air Force Research Laboratory's Speed Agile demonstration contract to conduct low- and high-speed windtunnel testing of a possible C-130 replacement that could take off and land in 1,500-2,000ft, yet cruise efficiently above Mach 0.80.
[See now first picture]
This photograph of an 8ft-span low-speed model tested early in 2008 in NASA Langley's 14 x 22ft windtunnel shows an earlier iteration of Boeing's Speed Agile concept. It has a hybrid wing/body design with embedded engines for stealth, and a V-tail with ruddervators for low-speed controllability. For high lift, the design uses upper-surface blowing of the inboard flaps, active flow control on Fowler-motion flaps on the outboard wing, and leading-edge slats.
Since this model was tested, Boeing says, the design has been updated to meet AFRL's latest AJACS requirements, which include a heavier payload and larger payload box - almost identical to the Airbus A400M's - to carry the Army's ever-larger and heavier Future Combat Systems vehicles.
The Air Force-backed AJACS is the fixed-wing STOL candidate for the emerging Joint Future Theater Lift (JFTL) program - the Army-supported Joint Heavy Lift tiltrotor is the VTOL candidate. We have seen Northrop Grumman's all-wing STOL design for AJACS before, but here are a couple of images from recent NASA presentations that give a better idea of the concept.
[See second picture]
Look carefully and you can see the drawing above shows the ducting that routes engine fan air to the inboard and outboard blown flaps, which can be deflected downwards to 90deg and upwards to 30deg. There are also leading-edge slats on the outboard wing sections.
[See third picture]
Northrop says a flying wing provides low wing loading for relatively short take-off and landing distances and so minimizes the amount of additional lift required for STOL. The centerbody provides a third of the total lift, it says, while the wings with blown flaps provide the remaining two thirds. The company, which has a lot of experience with this planform, also believes it can control the aircraft at low speed without a tail.

 

[AeroFranz]

VERY interesting pictures.
The Boeing design seems to use fairly well-understood blown high-lift devices. on the other hand, Northrop must be doing something really spiffy with their flying wing.
A big issue with STOL transports is that the high lift coefficients (CL) required usually imply large nose-down pitching moments (negative Cm). That's why YC-14 and the likes have ENORMOUS horizontal tails to trim the Cm, as well as huge vertical tails for adequate low speed yaw control.
Granted, their flying wing will be designed for lower wingloading, so CL requirements are lower, but without a tail their bird will be VERY sensitive to pitching moment. I'd be curious to see what they use for yaw control, I doubt split brakes could be made big enough for their low-speed needs.
Their design probably flies unstable, which allows you to generate higher CL and still trim the aircraft, but that does scary things to your allowable CG range. And allowable CG range is extremely important for an aircraft that is expected to airdrop tens of thousands of pounds of payload.
So unless I am missing something, Northrop has a clever high-lift device that gets them the high CL without too much nose down moment. Does anyone have more info on the Northrop design?

 

[sferrin]

So what we have here is a $1 billion tactical airlifter? Wonder what a dirt takeoff will do to the stealth goodies.

 

[donnage99]

So what we have here is a $1 billion tactical airlifter? Wonder what a dirt takeoff will do to the stealth goodies.

No more damage to its stealth than the f-35B. If stealth can already be made to withstand the ever changing temperatures while switching from high to low altitude, as well as withstanding supersonic speed like the f-22, I think it's not a huge leap to strengthen it to take a few cloud of dirt.

 

[sferrin]

So what we have here is a $1 billion tactical airlifter? Wonder what a dirt takeoff will do to the stealth goodies.

No more damage to its stealth than the f-35B. If stealth can already be made to withstand the ever changing temperatures while switching from high to low altitude, as well as withstanding supersonic speed like the f-22, I think it's not a huge leap to strengthen it to take a few cloud of dirt.

They don't plan on flying the F-35 off dirt runways to my knowledge. C-130s do.

 

[donnage99]

So what we have here is a $1 billion tactical airlifter? Wonder what a dirt takeoff will do to the stealth goodies.

No more damage to its stealth than the f-35B. If stealth can already be made to withstand the ever changing temperatures while switching from high to low altitude, as well as withstanding supersonic speed like the f-22, I think it's not a huge leap to strengthen it to take a few cloud of dirt.

They don't plan on flying the F-35 off dirt runways to my knowledge. C-130s do.

f-35b, not just f-35. To my knowledge, isn't the point of STOVL or VTOL for marines is to have a versatility in the runways the aircraft can operate? Isn't that what the harriers have been doing with the marines for the past decades?

 

[yasotay]

These pictures are great stuff. They add tremendous credence to the USAF claims that a VTOL aircraft is far to expensive to develop and field; that a VTOL aircraft is way to expensive per unit cost for a tactical lifter; that even though you can simultaneously land five or more VTOL into the same landing area as one stealthy STOL platform, fixed wing is more combat effective given the fact that we live in the information age where the amount of time you need to off-load a force is not very important anyway.

I think these pictures may have been released because the USAF is shying away from stealthy transports. Cost being one of the reasons. They need stealthy fighters and bombers more, so I think they will get by with a few 130J every year and wait until this VTOL hoopla has played out.

 

[Orionblamblam]

A couple of recent NASA research papers...

Which are not called out. Grr. However, I've guessing he means these (and maybe others)

http://ntrs.nasa.gov/search.jsp?R=648741&id=7&qs=Ntt%3Dflaps%26Ntk%3Dall%26Ntx%3Dmode%2520matchall%26N%3D0%26Ns%3DPublicationYear%257c1
Wind Tunnel Testing of Powered Lift, All-Wing STOL Model
Abstract: Short take-off and landing (STOL) systems can offer significant capabilities to warfighters and, for civil operators thriving on maximizing efficiencies they can improve airspace use while containing noise within airport environments. In order to provide data for next generation systems, a wind tunnel test of an all-wing cruise efficient, short take-off and landing (CE STOL) configuration was conducted in the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) 14- by 22-foot Subsonic Wind Tunnel. The test s purpose was to mature the aerodynamic aspects of an integrated powered lift system within an advanced mobility configuration capable of CE STOL. The full-span model made use of steady flap blowing and a lifting centerbody to achieve high lift coefficients. The test occurred during April through June of 2007 and included objectives for advancing the state-of-the-art of powered lift testing through gathering force and moment data, on-body pressure data, and off-body flow field measurements during automatically controlled blowing conditions. Data were obtained for variations in model configuration, angles of attack and sideslip, blowing coefficient, and height above ground. The database produced by this effort is being used to advance design techniques and computational tools for developing systems with integrated powered lift technologies.


and

http://ntrs.nasa.gov/search.jsp?R=364025&id=9&qs=Ntt%3Dflaps%26Ntk%3Dall%26Ntx%3Dmode%2520matchall%26N%3D0%26Ns%3DPublicationYear%257c1
Flow-Field Measurement of a Hybrid Wing Body Model with Blown Flaps
Abstract: In this paper we describe flow-field measurements obtained in the wake of a full-span Hybrid Wing Body model with internally blown flaps. The test was performed at the NASA Langley 14 x 22 Foot Subsonic Tunnel at low speeds. Off-body measurements were obtained with a 7-hole probe rake survey system. Three model configurations were investigated. At 0deg angle of attack the surveys were completed with 0deg and 60deg flap deflections. At 10deg angle of attack the wake surveys were completed with a slat and a 60deg flap deflection. The 7-hole probe results further quantified two known swirling regions (downstream of the outboard flap edge and the inboard/outboard flap juncture) for the 60deg flap cases with blowing. Flow-field results and the general trends are very similar for the two blowing cases at nozzle pressure ratios of 1.37 and 1.56. High downwash velocities correlated with the enhanced lift for the 60deg flap cases with blowing. Jet-induced effects are the largest at the most inboard station for all (three) velocity components due in part to the larger inboard slot height. The experimental data are being used to improve computational tools for high-lift wings with integrated powered-lift technologies.

These are, irritatingly, not available for download from the NTRS site. They were presented at the International Powered Lift Conference in London last July. You can buy the proceedings here: http://www.aerosociety.com/conference/iplc.html for the low, low price of £175.00.



Let me know how that goes.

 

[sferrin]

So what we have here is a $1 billion tactical airlifter? Wonder what a dirt takeoff will do to the stealth goodies.

No more damage to its stealth than the f-35B. If stealth can already be made to withstand the ever changing temperatures while switching from high to low altitude, as well as withstanding supersonic speed like the f-22, I think it's not a huge leap to strengthen it to take a few cloud of dirt.

They don't plan on flying the F-35 off dirt runways to my knowledge. C-130s do.

f-35b, not just f-35. To my knowledge, isn't the point of STOVL or VTOL for marines is to have a versatility in the runways the aircraft can operate? Isn't that what the harriers have been doing with the marines for the past decades?

Not off bare dirt they don't.

 

[Orionblamblam]

f-35b, not just f-35. To my knowledge, isn't the point of STOVL or VTOL for marines is to have a versatility in the runways the aircraft can operate? Isn't that what the harriers have been doing with the marines for the past decades?

Not off bare dirt they don't.

General rules of thumb. Dirt, rocks and mud do not play well with:
1) Turbojet engines (especially those designed for high T/W for VTOL ops)
2) Relatively fragile composite skins
3) Stealthy contours that need to be kept smooth... not scratched, cracked, sandblasted or covered in mud.

 

[sferrin]

f-35b, not just f-35. To my knowledge, isn't the point of STOVL or VTOL for marines is to have a versatility in the runways the aircraft can operate? Isn't that what the harriers have been doing with the marines for the past decades?

Not off bare dirt they don't.

General rules of thumb. Dirt, rocks and mud do not play well with:
1) Turbojet engines (especially those designed for high T/W for VTOL ops)
2) Relatively fragile composite skins
3) Stealthy contours that need to be kept smooth... not scratched, cracked, sandblasted or covered in mud.

Exactly. That's what's so amusing about these billion dollar stealth tactical airlifter designs floating around.

 

[CammNut]

A couple of recent NASA research papers...

Which are not called out. Grr. However, I've guessing he means these (and maybe others)

The papers referenced on Ares were presented at the NASA Fundamental Aeronautics program meeting in November, in Atlanta. They are not available online yet, as far as I know, but they are incldued on a CD of presentations from the meeting that is available on request from NASA. I have copies if anyone wants them.

 

[donnage99]

f-35b, not just f-35. To my knowledge, isn't the point of STOVL or VTOL for marines is to have a versatility in the runways the aircraft can operate? Isn't that what the harriers have been doing with the marines for the past decades?

Not off bare dirt they don't.

General rules of thumb. Dirt, rocks and mud do not play well with:
1) Turbojet engines (especially those designed for high T/W for VTOL ops)
2) Relatively fragile composite skins
3) Stealthy contours that need to be kept smooth... not scratched, cracked, sandblasted or covered in mud.

Exactly. That's what's so amusing about these billion dollar stealth tactical airlifter designs floating around.

Then they must think that they have an approach to tackle that issue (though whether they can actually overcome it or not is another entire matter in its own). For what technological advancement is but to overcome challenges posed in the past. Back in the past, the rule of thumb for airplane design was that it must be stable. And now, all modern fighters are all designed to be unstable. I think what's amusing here is that we can think that somehow these specialists in the "elite stealth club" with decades of experience just happened to forget one of the basic principles.

 

[Orionblamblam]

.... they are incldued on a CD of presentations from the meeting that is available on request from NASA. I have copies if anyone wants them.

Yo!

 

[Orionblamblam]

I think what's amusing here is that we can think that somehow these specialists in the "elite stealth club" with decades of experience just happened to forget one of the basic principles.

A "stealthy" airlifter covered in mud would almsot certainly be stealthier than, say, a C-130 covered in mud. But it would no longer be as stealthy as it once was. I can remember Congress freaking out when it was reported that a B-2 got a lot brighter on radar when it was *wet.* A stealthy airlifter would very quickly encounter the real world, and would lose much of it's advantage, though not all.

 

[Abraham Gubler]

Exactly. That's what's so amusing about these billion dollar stealth tactical airlifter designs floating around.

A few points on this:

No one is making stealth aircraft that cost a billion $$$ a pop anymore. RAM coatings have become a lot cheaper since the first B-2s in the 80s and 90s. Also the stealth requirement for a stealthy transport is probably a degree of significance (or two) lower than a high altitude bomber. A transport with a RCS of -20 or -30 dB is going to be a lot harder to see than a C-130 with +30 dB.

The effect of rough field landing on the outer mould line depends on how hard the landing. A relatively soft VTOL landing with high landing gear (or even an air cushion bottom) is not going to cause too much damage compared to a C-130. Any mud sprayed onto the bottom of the vehicle will quickly be removed by the air stream when in flight. Further even a few ships and bangs is not going to be in the realm of adding 20 or 30 dB to the RCS. Finally the bottom side of the vehicle is going to suffer and this is of little meaning for a low altitude penetrator.

Anyway as you can no doubt see from this post I think this is a very overblown argument.

 

[flateric]

Which are not called out. Grr. However, I've guessing he means these (and maybe others)

Scott, theck this one

Flow-Field Measurement of a Hybrid Wing Body Model with Blown Flaps

John Lin, NASA Langley Research Center, Hampton, VA; Gregory Jones, NASA Langley Research Center, Hampton, VA; Brian Allen, NASA Langley Research Center, Hampton, VA; Bryan Westra, Northrop Grumman Corporation, El Segundo, CA; Scott Collins, Northrop Grumman Corporation, El Segundo, CA; Cale Zeune, Air Force Research Laboratory, Wright-Patterson AFB, OH
AIAA-2008-6718
26th AIAA Applied Aerodynamics Conference, Honolulu, Hawaii, Aug. 18-21, 2008

 

[sferrin]

I think what's amusing here is that we can think that somehow these specialists in the "elite stealth club" with decades of experience just happened to forget one of the basic principles.

Hasn't stopped them from forgetting about the $$$$ problem though has it? :

 

[donnage99]

I think what's amusing here is that we can think that somehow these specialists in the "elite stealth club" with decades of experience just happened to forget one of the basic principles.

Hasn't stopped them from forgetting about the $$$$ problem though has it? :

that's why I said whether or not they can actually tackle them is an entirely another matter.

 

[yasotay]

I am sure that a stealthy transport is possible, but the USAF number one customers will be the ones who will make up the minds of those who hand out funds. COCOM's will be a big voice in the decisions. Given the flexibility of VTOL in the new operating environment, they are having difficulty getting anyone to believe that a stealthy transport is the best answer.

 

[flateric]

BTW, I wonder if STOL was somehow implemented in much earlier Lockheed MACK studies?

 

[hesham]

Hi,

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080047712_2008046458.pdf

 

[yasotay]

Air Force Seen Ready To Accept Army Tiltrotor Vision For New Joint Cargo Plane



By Marina Malenic
Defense Daily Network
12 January 2009
http://www.defensedaily.com/publications/dd/5265.html





The Air Force is on the verge of signing on to the Army's concept for a new inter-service cargo aircraft capable of vertical take-offs from aircraft carriers and difficult terrain, an Army official said last week.



"I know that there's been a lot of talk that the Air Force is not interested in this," said Bruce Tenney, the associate director for technology at the Army's Aviation Applied Technology Directorate. "That attitude is changing."



The Joint Future Theater Lift (JFTL) program was born a year ago when Army and Air Force chiefs agreed to combine their respective development programs for a new intratheater cargo plane, after it had become clear that development costs alone for such a system could exceed $2.5 billion. JFTL is expected to replace the Air Force's C-130 and to become the primary cargo hauler for the Army's Future Combat Systems vehicles.



The Army had been focusing its efforts on a vertical take-off/landing aircraft, dubbed Joint Heavy Left (JHL), while the Air Force was wedded to the idea of a fixed-wing, short-takeoff/landing approach.



The services are putting the finishing touches on an initial capabilities document (ICD) that combines their requirements for the plane. Tenney said "all outstanding issues" between the services have been resolved, and officials are ready to sign on to a common solution.



One of the major drivers in leading the Air Force to accept the Army's vision for a vertical take-off aircraft, according to Tenney, is the need for sea-basing, which "drives you to a vertical solution." Tenney was speaking at the Institute for Land Warfare's annual aviation conference on Jan. 9.



"I haven't run into too many people that think we're going to land a 250,000-pound fixed-wing aircraft on any of the ships that we've got," he said.



"There have been barriers, principally from the Air Force, in agreeing to that as a requirement," he added. "I think we're past that now."



Tenney said the sea-basing requirement will be included in the ICD, which he said is expected to be released one more time to the Army next week for "review and comment" before it goes to the Joint Requirements Oversight Council.



"The problem we've had getting the ICD to the JROC has largely been a cultural issue and has to do with the nature of how we see the use of the airplane," Tenney explained. "The land components--the Army, the Marines and the [Special Operations] community--see this as part of the maneuver forces. And so that's different than how the traditional airlift community has seen their role."



He explained that the Air Force has in the past envisioned its airlift effort as one of a "point to point delivery system, where those points are very well defined, very well controlled locations."



Tenney attributes the shift in the air service's attitude to the leadership of its new chief of staff, Gen. Norton Schwartz. In his previous position as head of Air Force Transportation Command, Schwartz "talked about delivering that 'last tactical mile' for the ground forces," Tenney explained.



"So he's brought that leadership and perspective to the Air Force--delivery to the point of need and maneuver to austere, unimproved locations," he said. "And it's beginning to resonate from the top down."



Approximately $40 million in FY '08 and '09 was budgeted for technology investigation and requirements definition for JFTL. The top five efforts include 11 contracts, some of which fund JHL concept refinement studies by Bell Helicopter Textron [TXT] Boeing [BA], a Karem Aircraft- Lockheed Martin [LMT] team and United Technologies [UTX] Sikorsky Aircraft.



Tenney said the inter-service differences on the project have now been resolved, and the Air Force is committed to the effort.



"They want to support the land component. This is just a different method of transport than they've done before," he said. "I think the official position is...the Air Force is open to the solution set, and we're going to go through a legitimate analysis and let the chips fall where the analysis says they should."

 

[hesham]

Hi,

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080047716_2008046462.pdf

 

[AeroFranz]

"I haven't run into too many people that think we're going to land a 250,000-pound fixed-wing aircraft on any of the ships that we've got," he said.

I was wondering about the seabasing of these Tiltrotors...
Can an LHD flight deck even support the ground pressure of a 250,000# aircraft, be it STOL or VTOL (by ground pressure I mean weight divided contact area of the tires)? Even a CH-53K is not going to weigh more than 90,000#, AFAIK.

Secondly, I thought one of the span/rotor limits on the Osprey was precisely the width of an LHD at the island...if that's a limiting factor for the V-22, what's that going to do to a JHL? ???

 

[yasotay]

"I haven't run into too many people that think we're going to land a 250,000-pound fixed-wing aircraft on any of the ships that we've got," he said.

I was wondering about the seabasing of these Tiltrotors...
Can an LHD flight deck even support the ground pressure of a 250,000# aircraft, be it STOL or VTOL (by ground pressure I mean weight divided contact area of the tires)? Even a CH-53K is not going to weigh more than 90,000#, AFAIK.

Secondly, I thought one of the span/rotor limits on the Osprey was precisely the width of an LHD at the island...if that's a limiting factor for the V-22, what's that going to do to a JHL? ???

TheJHL will certainly not live on any of the currently ships of the Sea Base, however you can land one on an LHD and several on a CVN. There is no vision of launching fleets of JHL from the Sea Base, I don't think. But having a capability to operate those sort of aircraft in conjunction with the Sea Base offers commanders some impressive capabilities. Just consider some of the SOF options and the ability to deliver much larger components to the Sea Base (critical aircraft component [bombs, wings, engines, fuselage...air refueling). Consider what a JHL might have done in conjunction with the CVN Task Force as part of the Tsunami relief effort. As you point out the V-22 is just able to land at the mid deck points on LHD. JHL will most likely be a rear deck only aircraft. There are a lot of questions to be worked out for sure.

 

[AeroFranz]

Thanks for clarifying. I thought I was missing something

 

[LowObservable]

I see the enemy is dropping his forces 30 km behind the battle line with a wing of giant tilt-rotors...