NASA funds sexy, stealthy, sideways supersonic flying wing NASA has awarded $100,000 in funding for a unique four-pointed flying wing that rotates mid-flight to transition between super and subsonic flight, thus increasing efficiency and eliminating sonic booms. The proposed Supersonic Bi-Directional Flying Wing (SBiDir-FW) aircraft, by Florida State University aerospace engineer Ge- …
Wings generate lift when airflow passes over them. They tend not to generate lift moving sideways through the air. When the cockpit becomes the wing and the wing becomes the front of the aircraft it will present asymmetrical flight surfaces. The wing is of course not a perfect symetrical shape in cross section.
It would also loose lift in transition where neither wing produces lift, if anyone has stalled or spun an aircraft will agree, it's fun, but might not be a great passenger experience.
This would probably necessitate a computer modifying pilot input like the steal fighter which is unflyable without it.
This will result in asymmetrical airflow and drag making it inefficient, a passenger aircraft needs to make money. Concorde stopped flying because it lost money. It never made a profit.
As a design concept it is fun, but in practice it is a dead end money pit. As an example for those Blue Peter fans at home try making a paper airplane that can fly on both axis?
You can make a wing symmetrical. Its not ideal but it will work. And at supersonic speeds it may actually work quite well
Rotating the engines is not hard either. After all rotating the wings on variable geometry planes works and they carry the whole aircraft weight.
And is a far better way anyway to get a wide speed envelope. Essentially have a high speed plane - at Mach 2 the fuselage alone is enough to keep the thing up with a few flattish surfaces - and then extend a low speed wing for landing and takeoff. .
But the last point that its probably not financially viable outside the military, is good.
Airliners are essentially high altitude high speed sail-planes aerodynamically. Because that is how you get the best compromise between fuel cost and journey times. Going supersonic makes for better journey times but costs escalate.
Despite claims to the contrary, BA were able to turn a profit on Concorde...
Also consider how old the technology is, with some modernisation Concorde would not only be cheaper to run, but could also have an extended range... Cutting the journey time across the Atlantic was good, but imagine having an aircraft capable of flying to Asia or Australia in less than half the time. With so much business being done in China these days, such an aircraft could do well.
Depends how you do the accounting. BA may have been able to turn a profit, however I recall that was only because they were given the aircraft for something like £1 because the airlines couldn't afford to buy them. Turning a profit when all you have to pay for is running costs is quite different to making a profit when you had to purchase the aircraft as well.
Red herring, no, but the whole concept goes against the laws of physics. The thing will create more drag than a concrete wall, use too much fuel to overcome the lift, thrust, drag formula and be uneconomical. Uneconomical aircraft die a death, unless they are for military purposes. Remember the Lightening, without the drop tanks it had a full power duration of 15 minutes but it could climb supersonic.
"Remember the Lightening, without the drop tanks it had a full power duration of 15 minutes but it could climb supersonic."
That was kind of it's point, as an interceptor.
Personally, I think it's just a horribly over-engineered design, with ten thousand over-complex things needed to make it work.
Just make a wing which changes geometry via extendy-bits. Surely that'd be easier than rotating a 'plane mid-flight?
First of all, the idea is not as bonkers as it seems. Quite a good one actually.
1. It really needs to be efficient only in hypersonic mode. Subsonic is a matter of "getting there" and "getting back". Symmetric shapes are very reasonable in hypersonic flight.
2. Who said it has to be symmetric in the first place. It has 2 operating orientations, not 4. So it does _NOT_ need to be symmetric at all. It is not that difficult to do an asymmetric shape which flies well. Scaled composites ARES is a good example. It is as asymmetric as assymmetric gets and it flies very well :)
3. Subsonic efficiency especially at low speed can be improved considerably through wing mechanization - slats, etc. That is besides the fact it may not be necessary as the wing shape does not need to be symmetric in the first place.
4. Most of hypersonic lift in the more efficient designs is generated by deflecting sonic boom reflections from the engine intakes off the wings and the fuselage. So engines are probably in the wrong place - they need to be on top, not on bottom. However, for subsonic some of the problems may be solved by going Coanda like An-72. Dunno, without running tunnel tests hard to say.
5. Transition is the most difficult part here (not any symmetric/asymmetric arguments). Even if it is 100% done by the computer there will be loss of lift and loss of control during the process. To put it bluntly, to satisfy basic safety requirements the designers will have to design a shape which allows the aircraft to successfully enter and exit what is effectively a flat spin at will. AFAIK that is yet to be accomplished by any aircraft.
If the 2 engines were staggered w.r.t. each other around the central axis then this might help as there would be a point of torque allowing more controllable rotation (possibly!?). Also, as the engines themselfes can rotate (out of necessity) then there will be additional thrust vectoring availabe.
I once saw a program where the fighter plane autopilot lernt to fly the plane with only one wing. Possibly the autopilot could be successfuly trained to accomplish the flat spin recover mannouver?
Having flown on a number of RAF aircraft in the past I do recall that we used to sit facing backwards. This has been proven to be a safer in the event of an aircrash, far safer allowing the rear of the seat to take the impact rather than bending over and impaling your head on the seat tray in front and the lap belt cutting you in half.
Civilian aircraft passenger seats all face forwards, simply because the passenger doesn't like flying backwards. Eventhough facing backwards gives a better survivability rate.
Imagine being told to brace for impact...... Sideways! Each passenger smashing into the one on the side of them. Like not wearing a seatbelt.
The chances are passengers will object to flying sideways, which will probably increase bouts of airsickness as out balance responses work better in the forward plane. It was always a relief to get out and into the fresh air on the end of a parachute after being bounced around sitting sideways.
Hmmm, yeah but what about going for mile-high club membership?
Tricky enough in a hammock on solid (unmoving; unless you live in Christchurch, NZ) ground I think, let alone in a hammock on a plane that'll roll and sometimes jump around in turbulence. Could be interesting though, I admit.
Paris because if anyone would try (re-?) joining the mile-high club in a hammock on an airplane I reckon she would.
"Civilian aircraft passenger seats all face forwards, simply because the passenger doesn't like flying backwards"
AC, you clearly do not get around much on civilian airplanes. 50% of the Passengers in BA Club World travel backwards, and passengers in business class in Air New Zealand, Cathay Pacific and many other airlines sit at a 45 degree angle in a "herringbone" configuration. Personally, I always chose a backwards facing seat on BA, as it is safer and more comfortable during takeoff and landing.
How is a backwards facing seat more comfortable on takeoff *and* landing? I'd agree it's safer on both and more comfortable on landing because the deceleration pushes you back into your seat. But on takeoff, the aircraft is accelerating, and you get pushed out of your seats, against your seatbelt. That's the same sensation you'd have on takeoff with a forward-facing seat.
That accounts for about 30 passengers out of 200?
Most airlines do not, purely because passengers don't like it. Rear facing has been tried by airlines but was not a success. Flying on the RAF Bristol Britannias was my first taste of going backwards and I have always preferred it.
"Most airlines do not, purely because passengers don't like it. Rear facing has been tried by airlines but was not a success."
Nope, rear seats were unsuccessful purely because you get less of them in a commercial jet. The bulk you'd need behind them to brace on impact means you'd lose space. For the business and 1st class seats that recline to a bed, you lose it anyway so it's negligible. For cattle class, the front facers are the most economical.
THis ties in nicely with research done a number of years back in travelling horses by road. Traditionally horses were placed facing forwards in the horsebox, then later it was worked out you could have more horses per vehicle facing sideways. People werent' sure the horses would like this, so a study was done allowing the animals to travel loose in the box with no partitions to see which position they adopted. The majority of the horses preferred standing in a backwards herringbone position, i.e. facing diagonally across the box towards a rear corner.
Any particular reason it has to be bisymmetrical? If the thing's constantly being trimmed by computer anyway, just wondering why not create a single wing with the appropriate edge profiles and make the transition from take off speed to supersonic a gradual one. Why the five second, 90 degree rotate business?
I cannot speak from experience of the TSA, never having been to the States, but if they are anything like their UK counterparts then they won't need to go into overtime to have a negative effect on journey time reductions.
Four hours against fifteen, that's 27%. Unhappily, here, in the UK, you need to report for an international flight at least two hours before takeoff, and if you can get out of your destination airfield in less than one hour you are doing well. So that's us up to seven hours, 47%, and that's before you take into account how long it takes to get to and from your airfields of choice. And they have just put body scanners on-line at my nearest international airfields !
Chris Cosgrove
I think you may be correct that it can't be totally eliminated, but it can be reduced to the point at which it's essentially inaudible. NASA have been experimenting for years with this problem - one method is a long probe which generates a small shock wave ahead of the main parts of the aircraft.
The other parts of research have been into directing most of the boom upwards and flattening the boom profile so it's nowhere near as objectionable
The testbeds F5Es looked quite strange, like flat bottomed kayaks.
See page 15 of https://www.faa.gov/about/office_org/headquarters_offices/apl/noise_emissions/supersonic_aircraft_noise/media/NASA%20Presentation.pdf
There are plenty of other pictures around. This wasn't a secret project.
"In addition, the improvements in fuel efficiency would lead to longer loiter times over targets."
I'm having a hard time getting my head around this. If the object is to loiter a long time, how can you save fuel by using more efficient supersonic travel? Surely, low speeds will always be more fuel-efficient for loitering. If the concern is to get your plane to its target loiter area quickly, just have lots of cheap drones widely distributed, ready to go from relatively nearby. Which brings me to my second point....
I'm not against technical advances, but there is a bad tendency for the military establishment to pitch ever more expensive weapons to be produced in ever lower numbers because of their cost. There will always be advantages of having large numbers of mass-produced, relatively cheap weapons, even if you lose more of them in battle. This particularly applies to weapons like drones that don't have pilots aboard. Make them cheap and cheerful and give us large numbers of them.
It's my understanding that pilots increasingly do very, very little during an actual flight and increasingly little during take off and landing, and are mainly there for backup. We've already had one incident, iirc, where we had a crash because the pilot overrode the autopilot. By the time this thing is actually ready (further designs, costing, approval, let alone manufacturing) we'll have another half a decade to a decade of computer and software advancement.
Just have a lump of silicon, it wont mind where it sits in the plane.
You need to try that line on someone who holds an ATPL, h4rm0ny. You may get an explanation of the workload of a pilot (or you may get a busted lip, but there's always a cost to gaining knowledge).
I can't think of the incident you describe, but I can easily think of two recent incidents (the landing in the Hudson and the BA 777 into Heathrow) where the presence of a human pilot led to the survival of all on board, when pure automatics would undoubtedly have left everyone dead.
Anyway, no far-paying passenger is ready to board a plane without a human pilot. And I can't see that changing anytime soon.
$100,000 just barely pays for a year of a single PhD student's time once fees and overheads are applied, It's about 50% of a post-doc's time for a year - so either this is really early stage (i.e. pretty picture and crazy ideas) or they're just not very serious about it.
This is a variable geometry wing *without* variable geometry.
Which is *very* clever.
The *key* worry about VG is mechanical failure locking the wings in the supersonic mode and making landing impossible. Part of why Concorde flew and the Boeing thing did not. Civilian operators are *very* twitchy about active lift systems (VG, blown flaps etc) because despite *huge* benefits (blown flaps reduced the wing size of the Buccaneer wing by 50%) there is no *backup* if it fails during liftoff/landing.
Caveats.
The 100 passenger size for Concorde was *borderline* in the 1960s. IIRC current thinking is 300+ or forget about it. You know this was done by a theoretical aerodynamics guy.
"Rotating engines is routine." Outside of Barnes Wallis's "Swallow" concept name one. AFAIK all *real* VG aircraft (XB-70, F-111, F-14) have flown with engines in (or under) the *fuselage*. The closest seems to be the Fairly Rotordyne
http://en.wikipedia.org/wiki/Fairey_Rotodyne
So doable, but not common. A 90deg rotation with cabling is fairly straightforward.
As for "optical devices" err periscopes were quite popular int he M3 designs of the 1950's but I hear fly by wire is quite popular (along with remote cameras) these days and commercial aircraft are cleared for instrument landing and "autoland" systems have existed since the early 1960's.
There are a number of ways to do fuel efficient large scale supersonic flight (the asymmetric flying wing being probably the simplest but *most* counter intuitive) but while they work on paper aerospace companies have just refused to try them. Boeing seem to be having trouble just getting the blended wing concept accepted.
Which leaves the question of how exactly this thing will dock at the departure lounge?
the article didn't say what sort of engines would used but i can't imagine the concord engine (or todays variants) being particulary aerodynamic perched up top like that (and sivelling in a vectored thrust arrangement) and the shape of the fuselages to cope with the stresses would. be all wrong at the different speeds. interesting idea but the costs alone would kill it.
Barnes Wallis in the 1950s proposed that an aircraft should comprise a straight wing on which are mounted two engines at each tip, at each side one over and one under the wing. There was a one page article published in Flight.
The engines would rotate to effectively 'swing' the wing to about 75 degrees. He wrote that controls would be developed, right on.
Very tidy but I never believed it because the limited volume of a wing prevents the machine from accommodating a useful number of passengers for its size. Aircraft wing area is about three times the cabin floor.
And on the strength of this in the 80s I tried a fixed wing that can be described as swung 90 degrees, so it had a chord about five times its span. This was cardboard, with a wing made from the push out from a box of Kleenex. I threw it fast and it flew. I suspect that the way forward is with wings with two axes of symmetry that will rotate 90 deg over a cabin with engines attached.
Oh, and the idea that crashing an aircraft with passengers sitting sideways is a bad idea ignores that in this mode of flight the a/c will be flying very fast or very fast indeed, if it crashes the seat orientation is not going to make any difference at all.
Not sure how the rotating engines would work. If they rotated independently, wouldn't the rotation result in one engines output pointing directly at the others intake?
The only solution I can see is a circular center passenger section with the engines on top and the wings rotating around it.
Wouldn't it be simpler to design a deformable wing that can be used in a typical configuration at low speed, and flatten for supersonic flight?
Either the whole area with engines rotates or they rotate individually and one engine is mounted further forward/sideways than the other. I suspect that the latter is a lot more feasible. It makes the structural problems easier, it makes the plumbing and wiring easier, and it reduces the space requirements.
By now humanity has passed its mobility peak. Nobody cares how quickly you can cross the Atlantic since the security theatre will take more time than the flight anyhow. If people cared, the Concorde would have been a success.
If you want to talk to someone on the other side of the globe, use a telephone or rent a video conference booth.
"I can't think of the incident you describe, but I can easily think of two recent incidents (the landing in the Hudson and the BA 777 into Heathrow) where the presence of a human pilot led to the survival of all on board, when pure automatics would undoubtedly have left everyone dead."
It's even easier to think of a much bigger number of incidents where the presence of a human pilot, particularly one who refused to believe what their instruments were telling them, has lead to the unnecessary deaths of all on board.
I agree - in principle, greater automation has led to greater safety, the stats speak for themselves. I can't think of any instances where pure automation on its own has resulted in a crash, though there have certainly been instances of automation 'losing it' and human pilots rescuing the situation. And, of course, prior to the extensive use of computer automation in the cockpit, almost all accidents could be ascribed to mechanical failure and/or human error.
A hidden trap with automated systems is there tendency to deal with a deteriorating situation by applying correction until they run out of authority and then dropping out, handing an almost unflyable aircraft to the human pilots. An example of this was the Turkish 737 that crashed near Schiphol, it's true that the pilots could have spotted what was happening, but in this case, sadly, they didn't.
I've a good friend who is heavily involved with software development and fault analysis in this area (safety-critical software). I put it to him (speaking as a rank amateur) that it ought to be possible for the automation to project a current trend and give some advance warning along the lines of 'if things carry on this way, I'm going to run out of control authority in 30 seconds' or something. Of course, this has been thought of. The arguments against are too many false positives and introducing an extra layer of complexity into the software.
"I can't think of any instances where pure automation on its own has resulted in a crash"
IIRC there was an early Airbus which was flying at an air show. I *think* it was flying a low altitude high angle of attack and the pilot got in trouble. He went to an emergency pull up but fly-by-wire says no.
Made a nasty mess over the landscape.
I'm sure there have been a couple of other Airbus incidents over the years where they've been at the boundary of their normal flight envelope and things have not ended well.
Urban myth, I'm afraid (i assume you're referring to the Habsheim accident). He didn't have the engines spooled up enough to make it over the trees. The presence or absence of fly-by-wire made no difference to the outcome (though it may have lulled the pilot into a false sense of invulnerability, these were very early days as you say).
As long as it's got a "screaming infant storage kennel" (http://theoatmeal.com/comics/airplane_layout), I'm comfortable leaving the rest of the design to /people who know about aircraft design, and do aircraft design research/..
Uh? Unlike other contributors? :
"I know nothing about aircraft design, so am an expert on why this idea won't work? "
So, please go home and shut up, and leave the actual "thinking about things" to people who have studied the experimental evidence, and are researching further experimental evidence?
Instead of rotating the engines proper, you can rotate the exhausts as on the Harrier jet. Possibly also the intake vents.
I think the idea og a rotating plane makes a lot of sense. I don't think passengers will mind sitting sideways when the plane is at top speed -- the speed will be fairly steady, so you won't feel any pressure. Turbulence will throw you in random directions regardless of how you face, so that won't make any difference. Declining seats are IMO a nuisance more than a service, so I would actually prefer seating arrangement like in trains: Two rows facing each other, so you can stretch your legs if you can agree with the person opposite which way to turn. Tables can be pulled out of the arm rests, like they are in the emergency-exit seats now. If seats are made back-to-back and non-reclining, they can be made sturdier at less weight. Seat belts should, IMO, be made more like in cars with a strap over one shoulder and self-adjusting. This is also easier if seats are fixed.
<sigh>
As already stated, BA at least were able to run their fleet at an operating profit. And that's before you start accounting for its value as a marketing tool. AF too, for all I know: certainly the one that crashed was 100% full.
The development costs weren't recouped, of course. But if this is being pointed out to you by a left-pondian, then remind them that they spent even *more* than was spent on the development of Concorde - and got as far as a plywood cockpit mock-up, IIRC.
Why does transition have to mean rotation? Why can't you simply have another (possibly bigger) set of engines pointed to the side? Then transition is simply a matter of throttling back (and possibly stowing) the low-speed engines and throttling up the mains. Or you could do a ducted-thrust thing, if you can get the intakes worked out. Just take off at a right angle to your intended heading, then kick it supersonic on the correct course once you're clear.
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