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Radical bi-directional flying wing design gets NASA funding


September 4, 2012

The supersonic bi-directional flying wing (SBiDir-FW) aircraft in high-speed configuration (Image: University of Miami)

The supersonic bi-directional flying wing (SBiDir-FW) aircraft in high-speed configuration (Image: University of Miami)

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A team that has created a supersonic jet design resembling a flying shuriken has been awarded a US$100, 000 grant from NASA’s Innovative Advanced Concepts (NIAC) program to continue development of the aircraft. Aside from looking suitably futuristic, the concept plane’s four-pointed star design serves a practical purpose. By rotating in mid air, the plane can transition between broad-wing subsonic and shorter wingspan supersonic configurations.

Aircraft design is usually a compromise between subsonic and supersonic performance. At low speeds, broad wings provide more lift and help minimize takeoff distance, while swept back wings with a smaller profile enhance performance at high speeds. Variable-sweep wing (or swing wing) aircraft, such as the F-14 Tomcat and B-1 Lancer, get around this with wings that are spread broadly at takeoff and low speeds and can be swept back while in flight for improved performance at high speeds.

The supersonic bi-directional flying wing (SBiDir-FW) aircraft tackles the problem in a different way. It would take off in one orientation with broader wings, before rotating 90 degrees in flight to transition to high-speed mode with a shorter wing span.

“No matter how fast a supersonic plane can fly, it needs to take off and land at very low speed, which severely hurts the high-speed supersonic performance for a conventional airplane,” said Ge-Chen Zha, a professor in the University of Miami’s College of Engineering and principal investigator of the project. “The SBiDir-FW removes this performance conflict by rotating the airplane to fly in two different directions at subsonic and supersonic. Such rotation enables the SBiDir-FW to achieve superior performance at both supersonic and subsonic speeds.”

While conventional commercial aircraft consist of a tube-shaped fuselage attached to two wings that responsible for generating lift, as a flying wing, the entire surface of the SBiDir-FW is used to generate lift. Passengers and cargo would be contained within the wide span, thick, rounded airfoil used at low speeds, while the high-speed wing would have a shorter span and a thin-sharp-edged airfoil to reduce drag at supersonic speed.

The aircraft would rotate into supersonic configuration by folding winglets attached to the end of the wings in subsonic configuration. Folding them up again would see the aircraft rotate back again to subsonic orientation once again. The engine pod on the back of the aircraft would also be rotated when switching modes.

Zha hopes his SBiDir-FW will produce no sonic boom, have low supersonic wave drag, and low fuel consumption. A preliminary computational fluid dynamics (CFD) simulation for a SBiDir-FW business jet indicates that at speeds of Mach 1.6 to 2.0, there is no sonic boom.

“I am hoping to develop an environmentally friendly and economically viable airplane for supersonic civil transport in the next 20 to 30 years,” said Zha. “Imagine flying from New York to Tokyo in four hours instead of 15 hours.”

The $100,000 NIAC grant is intended to help the research team refine the aircraft design using CFD, examine the feasibility of the design, and conduct wind tunnel testing to verify the aircraft’s performance at supersonic speeds and its sonic boom signature. If all goes well, the team will be eligible for an addition $500,000 to continue development of the aircraft.

Sources: NASA, University of Miami via Dvice

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Love the concept, will watch with interest to see how this develops. Great to see the weird and occasionally wacky ideas can still get funding.

Jules Tipler

I do not see a reason that this could not work but the design can not be modified to add or remove a few rows of seats without redesigning the whole airplane. Boeing saved a lot of money by using the same nose, cockpit, and fuselage components in the 727 and 737 that they designed for the 707.

I prefer a tube with a delta wing and a tail like a Mig 21. However if retractable canards like the Tu-144Ds can provide enough elevator control to allow the full use of high-lift devices on the main wings I would gladly forgo the horizontal tail wing assuming it is demonstrated that the plane can land safely without deploying the canards.


A $100,000 grant?? It looks like NASA is feeling the economic crisis too :)

Airsoft-World Scotland

I think it is a neat idea, although true the funding seems low, but times are what they are. I dont understand why it seems they just tacked the engines on top, and not incorporated them into the plane design. They could have developed a flattened dome incorporated in the structure which could rotate to provide thrust in whatever direction they wanted.


I saw this wing configuration 30 years ago. The rotating engines look novel. Hope it flies.


That thing is going to have some serious stability problems. But at least now I know how low the bar is to get research grant money from Nasa, maybe I should submit a few of my own designs?


Like the rotational idea, but how exactly do the engines spin? In the two smaller renderings, they look to be on the port side of the fuselage, but in the larger one (over the water and island) they seem to be more centered.

Bob Fately

Congrats to the University of Miami for managing to coax money out of NASA for an academic exercise. No wonder our aero research effort is is trouble.

You can look at the supersonic capabilities all you want. The transition from subsonic to supersonic and back again is dubious and should be looked at first.

How'd you like to be flying this thing during the transition--hang onto your drinks etc!! Do you pivot the seats or is everyone flying sideways? How do you land the thing if there's a systems failure, etc, etc, etc.


It looks like some of the Gamilas ships from Space Battleship Yamato. That's the original anime series from 1974, not the 2010 movie.

Gregg Eshelman

You can see an animation of the SBIDIR-FW on the U of Miami website. And, if you want to hear more details, then watch 40 minutes of video presentations by Dr Gecheng Zha.



I am not some hippy moron, but I do think that good design will be similar to nature.

I am trying to think of a fish or a bird with a bi-directional shape and I am stumped.

It is a neat idea. It could be great but would it just be easier make a plane with a high speed configuration that has wings that grow, or rotate or what not like. Maybe like the f-14 and f-111.

I would think rotating an entire plane in the air would be so much more complicated then adding surface area to wing.

In some ways I hope they can do it, because its a very interesting idea.

Michael Mantion

re; yinfu99

Your dome would cause much greater drag. ...........................................................................

re; Bob Fately

the engines share a pivot point that is not centered in both directions. It looks unsound to me If I were to try something like this I would have the engines mounted on independent pivots on opposite sides of the passenger compartment and one ahead of the other so when the airplane changes flight configuration which engine is in the lead changes as well so that the thrust remains symmetrical. Like I said before it might work but I do not think it is a good idea.


The flight animation skips the rotating transition. Looks like the designers themselves couldn't visualize that either.

Joe Acerbic

A 90 degree rotation at near supersonic speeds would be an "interesting" experience. Many people have issues with normal take off and landing, imagine facing sideways on takeoff and as you accelerate, a quick wrenching turn where you are facing forward or vice versa. Such great speeds could create all kinds of stability issues as it slices sideways. Because it looks like a shuriken, I suppose it will be easy to "stick" a landing.


PeetEngineer, you are right about stability. When I was shown a similar wing design in the 1980's I was told it had low drag, but no pilot could fly it. Now they don't have to. Like the B2 bomber, it can be controlled by computer. But for this design, stability is not the only problem. Propulsion will be difficult, too.


An interesting concept. As a pilot and a long time model airplane aficionado, the first thing he needs to do is to build a working scale flying model to see if the darn thing will fly. I could build a bunch of model aircraft with $100,000. Nowadays model helicopters have tiny stability gyros that could greatly enhance the chances of success. I hope this guy is acquainted with all of the advances within the model airplane community and doesn't try to "re-invent the wheel". I've seen this phenomenon happen when the government tries to develop new stuff. They throw around tons of money and are unaware of hobbyists that can achieve the same results on a shoestring budget.


I have to agree with the critics who say this thing will never fly.

I saw an artists conception of a better idea back in the 1980s. An aircraft with the ultimate expression of the oblique wing, AKA slew wing or scissor wing. Whereas oblique wing test aircraft would turn the one-piece wing from 90º at low speeds to a sharp angle at supersonic speeds, this concept had a wing that turned completely inline with the fuselage, which itself became a lifting body at high speeds. Wish I could remember which aircraft company promoted that idea.


re; grun4it

The rotation of the flight direction is best done well below the speed of sound. The takeoff/landing wings optimal flight speed is going to be less than Mach zero point 5.


there's absolutely no way you'd ever get me in one of these things as a passenger.

IMO it's an absolutely awful idea.

going through a 90 degree rotation WHILE FLYING !!!???! presumably at some speed too.

You just gotta be kidding me. So this thing has to be able to fly in any direction stably. What happens half way through the transition. At 45 degrees how does it still provide lift rather than rag-dolling through the air. It would need to be rotationally symmetric - which completely negates the whole concept.

Much simpler and cheaper and safer to just sweep the wings... oh. like they already do.

What a waste of money. I predict there will be no further funds.


More pie in the sky, yet unfortunately, it is a 100 thousand dollar piece of pie.

AnOld BlackMarble

re; Adrien

Rearswept wings come with a host of disadvantages. They perform worst at slow speeds such as for takeoffs and landings one of the problems is called the Sabre Dance from the F-86 Sabre in which it was first diagnosed but sense the most famous video is of a F-100 Super Sabre the source of the name is often mistakenly attributed to the F-100 including in the Wikipedia article. Rearswept wings tend to stall at the wing tips first this moves the center of lift forward which makes the plane tail heavy which results in a higher angle of attack which moves the center of lift forward in a nasty little negative feedback loop.

Rearswept wings are also subject to a condition know as a Dutch roll. This is a type of aircraft motion, consisting of an out-of-phase combination of "tail-wagging" and rocking from side to side. Some sources suggest the name comes from the similar motion of boats that has the same effect of triggering motion sickness is susceptible people.

Forward Swept Wings such as used by the X-29 suffer their worst performance at high speed. The wingtip tends to twist up and back until the wing falls off. This makes me believe that the SBiDir-FW will switch flight between modes at a relatively low velocity.

I don't like the design but it does solve the problem of high takeoff and landing speed in supersonic aircraft.



what about some sort of telescopic wing then. If the issue is to reduce drag at speed by making the wings smaller then.....

with the shuriken above, even rotating at just above stall speed would be awful IMO.


re; Adrien

Telescopic wing sounds heavy and would reduce fuel capacity.


I quite like the idea of bi-directional flying. I would even like the technology to be introduced into commercial passenger service in the not too distant future. However, I wonder how much longer this concept will remain futuristic. I even wonder if it will always remain futuristic. Even if it does go into service, how many will be made altogether? After all, Concorde probably intended to make hundreds of them but evidently made no more than 20 in the end, with as many as six of them not even going into commercial service.

The futuristic biplane also looks good, but won't it always remain futuristic? It's very easy to think about them, but how about actually putting them into commercial practice? Concorde's retirement in 2003 was seen as a technological step back as it seemed to have no successor.

I am very much in favour of flying cars and would even like them and flying saucers to displace the conventional aeroplanes and helicopters altogether, except perhaps for special occasions. I believe there is the website www.lightcrafttechnologies.com. I am also hopeful of this form of technology. Hopefully THEY will be able to get flying saucers going in the not too distant future. Like a helicopter, a flying saucer wouldn't need a runway as it would be able to take off and land vertically.

Jeremy Keller

if the center section is stationary and the [wing] surfaces rotate around it to change orientation and thus flight mode, i can see where it could work. but if the user experience is impacted in any way by the transition, this won't be commercially viable. lessons learned from previous similar designs must be heeded. by the way, who is this fellow that i have no idea how to pronounce his name? are we allowing american technology and education to flow to communist china now? irreconcilable, if so.

Joe Wesson

Nothing but hot air. This aircraft is far to complex a way to solve a simple problem that was solved back in the 70's by the Grunman F-14 fighter jet. Adjustable swept wings is a far simpler & cheaper way of achieving the same thing. I'll tell you what NASA you can purchase my idea for a mere £350k. Probably save you a few billion in development costs as it is. The answer to most development questions is simplify.

Anthony Collett

@jeffrey Yup, that happens a lot. Canyon County, Idaho recently purchased a large quadcopter drone and training from a Canadian company for more than $40,000.

They plan to use it for SAR but it only has a 15 minute flight time so it's utility for water rescue will be limited and they'll have to get permission from the FAA any time they want to fly it over 200 feet altitude.

For $40,000 they could've bought a shipping container full of little quadcopters and considered them disposable should they run out of power over a lake or river.

Gregg Eshelman

I can't imagine this design flying without a Cabin/Passenger Area that Rotates internally During transition. Not to mention the Payload distribution internally to maintain stability. Well I think i see why they need to do more research. Don't think 100k is going to cover it though.

Raymond Johnson

Uuuuummmmm, no mention of the cockpit.

Regardless of what people think of technology. No one will ever want to get into a plane without pilots. They're our psychological safety net when the "stuff" hits the fan.

If the cockpit is in the "nose" on take off & landing, does this mean the pilots will be out in a "wingtip" in cruise???

ATC to pilot "Do you have visual of traffic, at your altitude @ 1 o'clock 10 miles??" Pilot to ATC "Aaaaaahhhh.......nope"

Pie in the sky, BS design for commercial use. Too many flaws. Maybe for a military drone where there is no need for passenger comfort or a cockpit.


It would be more interesting if this bi-directional flying wing could be powered by a fusion reactor to take us beyond Earth's atmosphere at hypersonic speeds. http://youtu.be/ro5-QYqqxzM

Paul Steven

If you read their research papers, the proportions of the plane shown in their video in no way resemble what they used to produce the results claimed in the article. The paper describes a plane with a subsonic wing aspect ratio of 33 and a supersonic AR of 0.33. Basically, visualize a needle with two triangular bumps on each side. Their paper has a figure with the proper scale. A quick calculation shows that for a plane with the wing area of a G550 (about the right size for a supersonic biz jet), the wingspan would be 190' (a little less than a 777). The 'fuselage' would be just 19' long for such a configuration (a G450 is 88ft long) so I find it hard to believe you could fit even 4 passengers, 2 crew, luggage and fuel in that fuselage length. A Ford Taurus is over 16' long but only seats 4 total.

That's just for starters. Don't get me going about have no lateral or roll control authority, the co-location of the CG and CP, etc. You still have to have properly sized control surfaces to keep that thing in the air, fly-by-wire or not.

It's a paper plane and I, for one, am miffed that this gets funded when there is good research at NASA scrounging for money.


@Pikeman - Why the need for a tailplane or canard at all? Have you never heard of the only successful SST ever built to date, the Anglo-French Concorde? It was of an ogival delta configuration, capable of flying slowly due to such a planform's ability to fly safely at high angles of attack, there was more than enough pitch authority from the control surfaces at the trailing edge of the wing. The Tu-144 was in no way superior to Concorde and was far more of a rushed and botched effort.


@ Partist The separate stabilizer allows the use of high lift devices that a single delta wing design does not. This allows a lower angle of attack on takeoff and landings, and reduces the power requirements. How much weight would have been save if they did not need to lower the nose for takeoffs and landings? Compare the wings of a Mirage III and a Mig 21




If you have a problem with supersonic designs at takeoff, find another solution.

This one is whacko.

William Carr

IMHO, this must be inefficient in both directions. If you want good performance in one direction, then all your airfoils etc will have to be optimized for that direction. Which then means once direction changes, it will become a non-"optimal" liability. It seem this might outweigh many of the potential advantages. Not even talking about the additional weight for all the rotational parts there... Still, might be interesting to see where this is going.

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