McDD/Northrop/BAe ASTOVL/MRF/JAST/JSF studies

[Abraham Gubler]

much more cool drawings are in full-text document

Almost got configuration overload, almost.... Great find, thanks for sharing.

 

[hesham]

Hi,

http://www.flightglobal.com/pdfarchive/view/1996/1996%20-%201664.html

 

[elmayerle]

When I was at LM-Ft. Worth, an aerodynamicst I worked with mentioned that tehy'd always seen McDD as their main competitor and were surprised by their downselect. He was not especially impressed by Boeing's X-32 aerodynamics, considering them but thought highly of the MCDD proposal. It's a shame that McDD's efforts on the GCLF didn't work, though it's not totally surprising considering that earlier efforts (XV-5) were not as efficient as expected nor have other gas-coupled efforts (XV-12A with augmentor flaps) proven successful. I rather suspect there are some inherent inefficiencies that make a gas-coupled approach unlikely to work.

 

[Sundog]

Of course the question of flight idle descent is raised, not to mention engine-out. One would think that B-2 style split ailerons methods are more useful.

Actually, split ailerons wouldn't be as effective as you think due to the small lever arm. The B-2 has much greater leverage due to it's much higher aspect ratio. Besides, they can get the same effect by using differential displacement of the flight controls on the wing, such as up aileron, down flaperon, to create higher drag on one side without inducing a rolling or pitching moment and without the complexity and weight of a split aileron. In fact, that's what many of the tail less UAVs and UCAVs do, however, I don't know if they do that for just stability, as in using the control surfaces for stability and thrust vectoring in yaw for control, or using the trailing edge surfaces for stability and control. Although, I think the X-31's wingspan is too small to have too much of an effect, unless they were doing that to aid stability. Of course, that increases the drag. The question is whether or not it increases the drag as much as having a vertical tail would or possibly even higher. Then it becomes a trade study in terms of is it worth it for the weight saving. As such, it's most likely LO which is the driver. Then again, it may be a win-win situation all around. I don't have the exact numbers and they don't seem to be sharing that with me. ;D

 

[CFE]

It's a shame that McDD's efforts on the GCLF didn't work

It would seem that the Lift Plus Lift-Cruise option wasn't the wisest choice for McDD, possibly used as a fallback after GCLF didn't work out. Would runway erosion have been a concern with the McDD STOVL aircraft?

 

[elmayerle]

It's a shame that McDD's efforts on the GCLF didn't work

It would seem that the Lift Plus Lift-Cruise option wasn't the wisest choice for McDD, possibly used as a fallback after GCLF didn't work out. Would runway erosion have been a concern with the McDD STOVL aircraft?

For LPLC? I'd reckon it likely. That's one of the advantages of the approach Lockheed took.

 

[Abraham Gubler]

It would seem that the Lift Plus Lift-Cruise option wasn't the wisest choice for McDD, possibly used as a fallback after GCLF didn't work out. Would runway erosion have been a concern with the McDD STOVL aircraft?

From a commercial sense in that it’s not what the customer wanted maybe. From a program sense L+L/C is not so bad. Most significantly L+L/C does not place any further burden on the cruise engine to generate lift by and/or via additional nozzles and powered fans. Could the “McNorbrit” STOVL JSF have flown with the off the shelf F119 engine? Yes. Would the program have insisted on a new, higher bypass JSF engine? Probably, but with only half the lift to generate that engine could have been a lot simpler than our F135/F136.

While the L+L/C had the most weight penalty of all the STOVL designs it was by far the easiest to field. It also provided a significant survivability benefit with a ‘get me home’ capability in case the main engine failed. While in peacetime one engine out in modern fighters is hugely overrated by various proponents it is better than nothing and very nice to have if you must spend some time below the trash fire line.

 

[Stargazer]

Ever since the days of the Bell X-14, runway erosion has always been a major worry with ducted fan VTOL aircraft; development the BAe Harrier and the Russian Yak-36 and -38 aircraft proved it could be a nightmare, especially for aircraft carriers. Likely it must have been considered a major issue when weighing the pros and cons of L+L/C.

 

[Colonial-Marine]

Are there any more information on the "multiplane thrust vectoring nozzle" featured on design studies prior to the final JSF submission asymmetric configuration? I am having a difficult time visualizing the operation of this nozzle based on it's shaping. Did the JAST 9C (one of my favorite concepts) use this configuration?

 

[Triton]

Bill Sweetman believes that this artist's impression of a McDonnell Douglas ASTOVL design concept released in 1994 may have been censored by adding tails because the X-36 was still secret at the time. Note the separate two-dimensional cruise nozzle, an indicator of the degree of stealth that McDonnell Douglas planned for the design.

Source: Sweetman, Bill. Ultimate Fighter: Lockheed Martin F-35 Joint Strike Fighter Zenith Press 2004 p. 39.

 

[donnage99]

Anyone knows how to get the original video in link working? The video was posted in 2006 and has a segment about mcdonnell proposal. The title as well as the still image is still there, but the content of the video itself has been replaced. Anyone knows how to get the old file?

EDIT: found the video. Sadly, it did not have the mcdonnell douglas entry as i thought.

 

[donnage99]

Was gonna post over at the lockheed entry, but after observing the shaping of the nose, I think it belongs here:

 

[Triton]

Artist's impression of Northrop Grumman CALF Tri-Service Commonality (TSC)-1 concept

Image source: http://www.jsf.mil/gallery/gal_photo_ce.htm

Concept identified in From JAST to JSF: The Evolution of the Joint Strike Fighter by Ian Maddock, Military Systems Analyst, Analytic Services, Inc.
http://www.secretprojects.co.uk/forum/index.php/topic,3368.msg130070.html#msg130070

 

[Triton]

Artist's impression of Northrop Grumman JAST TSC-3A STOVL Preferred Weapon System Concept (PWSC).

Image source: http://sistemadearmas.sites.uol.com.br/ge/furt19quargeracaojsf1.html

Concept identified in From JAST to JSF: The Evolution of the Joint Strike Fighter by Ian Maddock, Military Systems Analyst, Analytic Services, Inc.

Hesham previously identified this artist's impression as a Boeing JSF concept in the following post:
http://www.secretprojects.co.uk/forum/index.php/topic,2121.msg47124.html#msg47124

 

[Matej]

Artist's impression of BAe Systems ASTOVL concept.

Source: http://sistemadearmas.sites.uol.com.br/ge/furt19quargeracaojsf1.html

Hesham previously identified this artist's impression as a Boeing JSF concept in the following post:
http://www.secretprojects.co.uk/forum/index.php/topic,2121.msg47124.html#msg47124

And in fact it is Northrop's VSTOL version of the JAST. All pictures on that page are taken from my web and some of them are misinterpreted.

 

[donnage99]

i wonder what the stealth requirement back then was. With canards and 1 verticle stablizer, it should be very bad for stealth.

 

[BAROBA]

i wonder what the stealth requirement back then was. With canards and 1 verticle stablizer, it should be very bad for stealth.

I have read somewhere on this forum that 1 vertical stabilizer is not bad for stealthiness of a plane.
The tail can be make transparent for radar, so it doesn't reflect anything back to base.
And I imagine the same can be done for the canards.

Correct me if I am wrong,

Rob

 

[AeroFranz]

One of my coworkers was saying that even the best composite RF-transparent material is only 90% permeable. That's still too much reflection from the side. Anyone can confirm?

 

[donnage99]

I have read somewhere on this forum that 1 vertical stabilizer is not bad for stealthiness of a plane.
The tail can be make transparent for radar, so it doesn't reflect anything back to base.
And I imagine the same can be done for the canards.

Correct me if I am wrong,

Rob

If I'm not wrong, the notion came from the German Lampyridae, which is a project that explored stealthy facets, but with a verticle tail. However, the verticle tail on the Lampyridae might have been a compromise for stealth to get the aircraft flyable, and there's nothing to garantee that its developers solved the problem with the RCS disadvantages of verticle tail.

 

[flateric]

...

 

[Matej]

MDD PIANO (Propulsion Integration for Aerocontrol Nozzle) http://crgis.ndc.nasa.gov/historic/Test_446:_PIANO_(Propulsion_Integration_for_Aerocontrol_Nozzle)

 

[donnage99]

Inlet Phase II Test (1996)

 

[donnage99]

http://aaac.larc.nasa.gov/tsab/tetruss/mac/apps.html

This image shows TetrUSS results from the CFD simulation of an advanced tailless fighter aircraft. Pressure coefficient contours and volume streamribbons are shown. The goal of this work was to look at various advanced control effector concepts (a control effector is any type of device that provides maneuvering control on an aircraft). Conventional (mechanical) control effectors include flaps, ailerons, elevators, and rudders.

In the Configuration Aerodynamics Branch at NASA Langley, engineers use TetrUSS to analyze and design unconventional control effector concepts: things like bumps that form on the aircraft skin, porous panels that alter surface loading, and smooth continuous control surfaces that use advanced "smart" materials. The ultimate goal is an aircraft with a continuous or fixed outer moldline, that can maneuver as well or better than an aircraft with conventional mechanical controls. The benefits are lighter weight, better performance, and positive impacts on survivability, stealth, and observability.

 

[sferrin]

One of my coworkers was saying that even the best composite RF-transparent material is only 90% permeable. That's still too much reflection from the side. Anyone can confirm?

In the Archangel to Oxcart book Kelly Johnson is quoted as saying any plastic more than a couple inches thick may as well be metal from an RCS point of view. That was back in the day of course.

 

[taildragger]

Stealth technology is constrained by physics in this regard. Anytime a wave (physical or EM) propagates from one medium to another (a medium is defined for this purpose as something with a distinct Index of Refraction - be it matter or a vacuum), there will be a reflection. Energy not reflected will be refracted into the new medium. Nothing flying through the air can be truly transparent to radar unless it has the same I of R as air (if an airframe material with an I of R matching air exists, it's secret).
As far as I know, stealth technology is limited to the following approaches:
- maximize the fraction of energy refracted into the airframe by material selection (so it can be absorbed or transmitted through).
- control the direction in which energy is reflected
- actively suppress the reflection with clever devices (speculative)

 

[Matej]

- actively suppress the reflection with clever devices (speculative)

Real. Flight tested. http://www.secretprojects.co.uk/forum/index.php/topic,7807.0/highlight,active+stealth.html

 

[donnage99]

I've always thought that composites are bad for stealth, as it is transparent to radar, and therefore, exposing the internal structure to radar.

 

[donnage99]

Excellent model from Allen Rockwell at:

https://flic.kr/p/7KKjPN

View: http://www.flickr.com/photos/allenrockwell/4433203076/in/photostream/

 

[shedofdread]

I've always thought that composites are bad for stealth, as it is transparent to radar, and therefore, exposing the internal structure to radar.

Glass fibre, yes. Carbon fibre, no. Hence why radomes tend to made from glass fibre.

 

[InvisibleDefender]

Try these as starting point...Last pic is 9C.2 four post tail configuration very close to final V-tailed except you understand what. Note one of unique McDD/Northrop/BAe JAST design know-hows that team so hoped would help them to win - 'variable' internal weapons bay adoptable for carrying various AA/AG load depending on mission.

To my sorrow, I can't post some images from my collection due to promises I've made.

Nice to see that stuff is still out there somewhere...hope you're doing well flateric

 

[Matej]

WT ASTOVL model http://grcimagenet.grc.nasa.gov/images/archive/projects/93_7355h.jpg

 

[Stargazer]

Er, Matej... what does this otherwise-great pic have to do in a Lockheed thread? Did I miss something here?

 

[Matej]

I didn't realize that its MDD. It was not what I was originally looking for. Moved.

 

[donnage99]

BAE concept.

 

[flateric]

seems that Cynthia Ann Gruensfelder of MDC's St. Louis was an idea generator for MDC/N/BAe JAST - at least expandable weapons bay is hers

Mission adaptive inlet

Complete Patent Searching Database and Patent Data Analytics Services.

www.freepatentsonline.com

Expandable aircraft section

Complete Patent Searching Database and Patent Data Analytics Services.

www.freepatentsonline.com

Auxiliary inlet for a jet engine

Complete Patent Searching Database and Patent Data Analytics Services.

www.freepatentsonline.com

Cynthia A. Gruensfelder graduated from Washington University in 1990 with a Master of Science degree in mechanical engineering. She earned her Bachelor of Science degree in aeronautical and astronautical engineering from the University of Illinois. Cynthia is now a team leader for the Boeing Joint Unmanned Combat Air System (J-UCAS) Program Advanced Design Group.
In her role on the J-UCAS program, Cynthia leads a multi-disciplined engineering team in developing and evaluating all future air vehicle configurations for both the Air Force and Navy. She manages all cost, schedule, and technical performance as well as supplier development activities.
In addition to her current assignment on the J-UCAS Program, Cynthia has been privileged to support many Boeing platforms including the F/A-18, F-15, AV-8B, and Joint Strike Fighter as well as many Phantom Works development programs. In the F/A-18 Program Office, she led all systems engineering activities, including requirements, technical performance measurements, obsolescence assessments, best practice and configuration audits, trade studies, and program directives.
Early in her career, Cynthia had the opportunity to lead an aggressive Phantom Works development group in exploring revolutionary technological developments in air vehicle design. During this time, she was personally granted seven technology patents. In 2002, one of her patents, "Leading Edge for an Aircraft," was selected out of thousands of patents to receive the prestigious Boeing Special Invention Award.
Cynthia and her husband, Donn Gruensfelder, an electrical engineer, have four children: Jacob, Joshua, Hannah, and Sarah. The entire family enjoys water and snow skiing as well as many competitive sports, including soccer, baseball, golf, and swimming. Cynthia is an active volunteer in her church and her children's school. As an outlet to her creative and inventive nature, she produces numerous toy inventions, children's books, screenplays, and musical scores.

 

[Grey Havoc]

They may need to dust off those studies yet.

 

[Triton]

Vectored main engine plus lift jet.

Which killed the project, as JAST rule was clearly A SINGLE engine for all flight phases...

The use of the Gas Coupled Lift Fan (GCLF) was the reason why the McDonnell Douglas / British Aerospace / Northrop Grumman team was not selected by the JAST program office to enter the Concept Exploration phase of the program? It had nothing to do with the "near-tailless" design configuration being too radical?

 

[Triton]

Artist's impression of McDonnell Douglas / British Aerospace / Northrop Grumman team JAST 10 concept.

Image source:
http://www.militaryphotos.net/forums/showthread.php?49454-Several-western-aircraft-concepts-that-were-never-built/page3

Concept identified in From JAST to JSF: The Evolution of the Joint Strike Fighter by Ian Maddock, Military Systems Analyst, Analytic Services, Inc.

 

[Sundog]

The use of the Gas Coupled Lift Fan (GCLF) was the reason why the McDonnell Douglas / British Aerospace / Northrop Grumman team was not selected by the JAST program office to enter the Concept Exploration phase of the program? It had nothing to do with the "near-tailless" design configuration being too radical?

The tail design was proven in the YF-23. Originally, Northrop was given a contract to investigate GCLF and LM a shaft driven lift fan for research. However, once it moved into a development contract, Northrop abandoned the GCLF because they knew it wouldn't work. That's when the moved into a Lift+liftcruise engine arrangement. The Marine Corps would not accept such an arrangement.

 

[Triton]

That's when the moved into a Lift+liftcruise engine arrangement. The Marine Corps would not accept such an arrangement.

From JAST to JSF: The Evolution of the Joint Strike Fighter by Ian Maddock, Military Systems Analyst, Analytic Services, Inc. page 6:

STOVL capability was designed to be provided by a “three post” [Lift + Lift/Cruise] (L+L/C) concept. While performing vertical landings and short takeoffs, the JAST 10 would have used a combination of a single GE/Allison GEA-F320L2 lift engine and an aft lift module (ALM). The ALM consisted of two principal components, a diverter valve to switch the cruise engine between STOVL mode and cruise mode configuration, and the rear lift nozzles that would have provided the thrust and control functions when the cruise engine was operating in STOVL mode and fan duct sealing during cruise mode. In STOVL mode, the diverter valve would have closed the cruise exhaust system and opened a passageway allowing the core and fan streams to enter the rear lift nozzles. The nozzles would then control the engine operating line and vectored the thrust as required for control during STOVL activities. When in cruise flight, the engine exhaust would be directed through a yaw/pitch LO axisymmetric nozzle (Y/PLON) on all three [Preferred Weapon System Concept] (PWSC) variants.

Interestingly, the MDA/NGC/BAe team believed that the separate lift engine offered the potential for a “get home” capability in the event of a main engine loss. MDA/NGC/BAe planned to demonstrate this capability during flight-testing.

Additional design features included: off-the-shelf [Pratt & Whitney] F119 cruise engine (except for the nozzle) on all variants; General Electric/Allison lift engine design of approximately 16,000 lb thrust on STOVL variant.

Source:
http://www.secretprojects.co.uk/forum/index.php/topic,3368.msg130070.html#msg130070