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.
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