DARPA/Northrop Grumman Oblique Flying Wing program

sferrin

sferrin

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flateric said:
BTW, vstol.org backbone man is here, but he was rather surprised with low reaction on his post of a program he involved right now (DARPA/NG OFW), so he decided to stay a spectator so far.

And, guys, stop posting VTOL stuff in helicopter section. You are free to create new dedicated one any time.
Click to expand...

What is "DARPA/NG OFW"? ???
 
Northrop Grumman's OFW concept - DARPA was going to call the programme Switchblade, but changed its mind. Pity
 

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And here is the original R T Jones oblique flying wing design - NASA Ames artwork from way back when
 

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From the 100+ Meg video linked in the "SR-72" thread. No further data on this...
 

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...And the authors are among us - vtol and boxkite.
 
Wow, that's an outstanding report guys. I just skimmed through it. I'll be printing it off and reading it in it's entirety this weekend. :)
 
Orionblamblam said:
From the 100+ Meg video linked in the "SR-72" thread. No further data on this...
Click to expand...

So where does the landing gear go? :eek:
 
No - it's a "taildragger". Main gear is mounted forward between the engine pods, with a tailwheel aft. It takes off and lands with the wing unswept. The engines are J85s from the F-5E, by the way
 
CammNut said:
No - it's a "taildragger". Main gear is mounted forward between the engine pods, with a tailwheel aft. It takes off and lands with the wing unswept.
Click to expand...

Something like this...
 

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Found in shockwave tab at NG IS site...operational OFW concept?
 

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apart from AD-1 and the Switch blade. hmmm,

just for good measure
http://www.desktopaero.com/obliquewing/library/whitepaper/
 
What role would this plane probably be used for? Recon, Air Superiority, etc...
 
Northrop Grumman tests oblique flying wing X-plan in windtunnel
Flight International 10/09/2007
Northrop Grumman is beginning high-speed windtunnel testing of the oblique flying wing
X-plane it is designing for the US Defense Advanced Research Projects Agency. If built,
the OFW technology demonstrator will be the first supersonic, tailless, variable-sweep
flying wing.
The high-fidelity model will be tested at speeds up to Mach 1.3 in a tunnel at Calspan in
Buffalo, New York as a step toward possible flight tests of the unmanned demonstrator
around 2011. Low-speed windtunnel testing was conducted in January, achieving
"excellent correlation" with computational fluid dynamics analyses, says programme
manager Joe Pawlowski.
Northrop is working under a 25-month contract, awarded in March last year, to complete
preliminary design of the X-plane. The preliminary design review is planned for Mach
2008, leading to a decision whether to proceed into Phase 2 and construction and flight
test of the subscale demonstrator.
Studied since the 1950s, the variable-sweep oblique flying wing promises aerodynamic
efficiency at both low and high speeds, but poses challenges with aeroelasticity and
controllability. The goal of the X-plane is to prove the OFW concept is feasible, but not
to characterise its performance, says chief engineer Gary Tiebens.
Previous oblique wing aircraft have all been subsonic - and tailed - and the X-plane is
focused on proving that a tailless OFW can transition to supersonic speed. The benefit
of a variable-sweep oblique flying wing is that airflow normal to the leading edge stays
subsonic, keeping the drag rise low as the aircraft goes supersonic.
The flying wing has a span of 17m (56ft) unswept and sweeps between 0º and 65º,
measured at the trailing edge. The X-plane will take off and land with the wing at 0º, the
sweep increasing linearly with speed until it reaches 65º before going transonic. "It will
be fully swept before the transition, to reduce risk," says Tiebens.
The X-plane is powered by two General Electric J85-21 afterburning engines (from
Northrop's F-5E). In a change to the original design the previously paired engines are
now in separate pods, one moving forward and one aft as the wing sweeps, to improve
area ruling and reduce wave drag at the design maximum speed of M1.2.
The demonstrator has "taildragger" landing gear, with the main gear mounted forward
between the engine nacelles and a castoring tailwheel, says Tiebens. The nacelles and
flight control surfaces embedded in the wing and along the trailing edge are all
electrically driven.
Sweep is varied aerodynamically by yawing the wing using the outermost control
surfaces - "like a rudder kick to produce sideslip", says Tiebens - then retrimming in all
axes to maintain the yawed condition. The engine nacelles rotate to face into the
airflow. "They do not rotate fast enough to use as a control device," he says.
Aeroservoelasticity - the interaction of aerodynamic, structural and control responses -
is the "Achilles heel" of the OFW, says Tiebens. All three axes - pitch, roll and yaw - are
coupled and wing bending caused by manoeuvres or gusts effects stability in all three.
The flight control system must be able to decouple the responses.
The configuration's assymetry, its sensitivity to roll moment and the coupling of roll and
pitch instability at high oblique sweep angles are among the factors the control system
has to alleviate. But the demonstrator's instability is within the range of Northrop's
experience with the B-2, Tiebens says.
"The X-plane is not performance-driven. The big push is the control algorithms," says
Pawlowski. "The objective is to open up the design space for future aircraft. We want to
prove we can fly a tailless, supersonic oblique flying wing with subsonic leading edge
and address the aeroservoelastics."
A future operational OFW, envisioned for beyond 2025, could combine efficient
subsonic loiter and supersonic dash capability to perform military reconnaissance and
strike missions requiring rapid deployment, long range and long endurance, DARPA
believes.
Click to expand...
 
Damn, they stole my idea :eek:
(But then again I stole it from darpa :p )
It is remarkable how close they are to my idea.
The design is nice, but I like my idea of using some kind of thrustvectoring better ( I am baised ofcourse)
But it is possible to use no vertical directional controlsurfaces to control the plane when it is flying "sideways".(for a lack of better word)
Impressive :)
My idea:
It was once created for a modeling contest on a 3dforum.
And they had the requirement that it could carry a shitload of bombs and stay in the air for 24 hours, and still small enough to be container and shipped in a C130. So I needed to scale down my design from (almost) realistic to a tad smaller. So the 2000 pounder bomb had to be moved under the plane, my apologies for it already..

Cheers,

Nice thread, interesting topic :)
 

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Northrop OFW is mutating...or this is proposed operational vehicle?
 

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Hi everybody

Shape-Shifting Supersonic Bomber
http://hypersonics.wordpress.com/2007/02/01/shape-shifting-supersonic-bomber/
Many greetings
 
What a news...try searching for OFW at the forum. Moreover, we even have people involved in Switchblade program here
 
flateric said:
Northrop OFW is mutating...or this is proposed operational vehicle?
Click to expand...

That was a cartoon of an operational concept.

Unfortunately, we'll never know if the X-Plane would have really worked.
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/OBLI10018.xml

DARPA Kills Oblique Flying Wing

Oct 1, 2008

By Graham Warwick graham_warwick@aviationweek.com

Northrop Grumman's Oblique Flying Wing (OFW) program will not proceed to an X-plane flight demonstrator. The U.S. Defense Advanced Research Projects Agency confirms that OFW has concluded following the preliminary design effort.

The OFW was a tailless variable-geometry flying wing designed to combine long subsonic loiter endurance with high supersonic dash speed. By increasing sweep as the aircraft accelerated, the leading edge always remained within the shock cone, reducing drag.

DARPA says the first phase built up an aerodynamic database from more than 1,000 subsonic and supersonic test runs using a dual-sting wind tunnel model to allow variable-sweep testing with force and moment balances in each of the stings, which hold up models in tunnel testing.

The proposed unmanned subscale X-plane demonstrator was to use trailing-edge and inlaid surfaces for flight control, and two afterburning J85 engines mounted in swiveling pods under the wing.

Northrop Grumman, meanwhile, has received a two-year, $5.7 million DARPA contract for the Advanced Technology Survivability Demonstrator. The research agency say it cannot provide any details on the program.
 
Well, Mike, we've already dropped some tears on OFW grave in the Blackswift thread...
Are any other images of the operational vehicle available for public?
I was wondering about the fixed intakes/exhaust position - how system would operate during take-off and landing when the OFW is perpendicular to airstream in plan view...
 
Pretty interesting idea BAROBA


I do agree that a small, unmanned "bomb truck" that can fit inside a C-130 wouldn't be a bad idea. Hell, I think the U-45 and U-47, as pretty good, advanced compact unmanned aircraft as they are, are too big and complicated. Something following what I like to call a "stealth in simplicity" design philosophy, with for example a single P&W JT15 engine and a 2,000 to 4,000 lb bombload for the carriage of JDAMs, SDBs or even smaller submunitions; such an aircraft could be used for airfield denial by cratering runways, attack high-value C&C targets or disrupt logistical centers, and would use its small size, stealth, and computer autonomy to sneak in and sneak out, or be used in larger formations for area denial.

The vast majority of air support missions from the Gulf War onwards seems to suggest, to me, a capability for this type of unmanned combat aircraft.

I also posted some thoughts on civilian UAVs at What-If.
 
Thanks for the wonderful links you all sent in this topic. My favourite project among them is Jemiba's drawing of airliner with jet asymmetry. ;D
 
flateric said:
I was wondering about the fixed intakes/exhaust position - how system would operate during take-off and landing when the OFW is perpendicular to airstream in plan view...
Click to expand...

Operational OFW would use so-called 'stagnation point inlet', eliminating need for rotating engine pods - for more info on concept see p.91
http://dspace.mit.edu/bitstream/handle/1721.1/35565/73828808.pdf?sequence=1
 

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vstol (Michael Hirschberg) is co-author of excellent AIAA paper,

A Summary Of A Half-Century of Oblique Wing Research
Michael J. Hirschberg and David M. Hart
CENTRA Technology, Inc., Arlington, VA 22203 USA
Thomas J. Beutner
Defense Advanced Research Projects Agency, Arlington, VA 22203 USA

full text available here - and it's worth to look
http://www.obliqueflyingwing.com/OWhistory.pdf
 
What role would this plane probably be used for? Recon, Air Superiority, etc...
Click to expand...

I really like this whole asymmetric idea. It brings a lot of improvements in the range/speed stats.

However, such an approach will likely have very asymmetrical effects on maneuverability and therefore ANY fighter roles are of the table in my opinion. Just try consider how difficult will be to decide the position of the cockpit, and what forces the pilot will be experiencing in the different scenarios. So the less human factor the better. This also excludes airliners.

The best platform for this design will require equally endurance,speed and unmanned payload.

Re-con aircraft tend to be more efficient if they are subsonic UAV because of the rick, longevity and dullness of the mission.

Also the benefit of the Oblique Flying Wing will rise as the size of the design rises.

So in my opinion the only viable platform will be a heavy bomber like the one coming after NGLRS
 
flateric said:
Well, Mike, we've already dropped some tears on OFW grave in the Blackswift thread...
Are any other images of the operational vehicle available for public?
I was wondering about the fixed intakes/exhaust position - how system would operate during take-off and landing when the OFW is perpendicular to airstream in plan view...
Click to expand...

Same questions, are there any other screenshots or snapshots availabale of the later concept ( the one with the engines in the body. How would the intakes and exhausts have worked if the engines are fixed inside the wing? Looks very interesting though.
 
still no, and probably won't be for a long
 
Here's what I found when looking for Advanced Development Programs:

http://www.wipo.int/pctdb/en/wo.jsp?WO=2009029796&IA=US2008074795&DISPLAY=STATUS
http://www.wipo.int/pctdb/images4/PCT-PAGES/2009/102009/09029796/09029796.pdf
 

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interesting
ADVANCED PRODUCT DEVELOPMENT, LLC
1165 Bella Vista Drive, St. Louis, MO 63131

cover-up for NG patent?
 
flateric said:
full text available here - and it's worth to look
http://www.obliqueflyingwing.com/OWhistory.pdf
Click to expand...

Link is dead, can you check it again?
Thanks in advance :)

Rob
 
I don't quite understand that advantages of this configuration over "conventional" variable sweep wings.
 
The link mentioned in the thread and the website is no longer active. Anyone have additional illustrations of this machine?
 
www.popsci.com

The Supersonic Shape-Shifting Bomber

For years, the U.S. military has wanted a plane that could loiter just outside enemy territory for more than a dozen hours and, on command, hurtle toward a target faster than the speed of sound. And then level it. But aircraft that excel at subsonic flight are inefficient at Mach speeds, and...
www.popsci.com www.popsci.com
 

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