# One wing

1. Jun 7, 2007

### wolram

Can an aircraft fly with just one wing? it sounds impossible but this film
shows otherwise.
And the pilot pulled out of a spin, the use of afterburner seems to have given the aircraft the extra speed to stabilise flight.
Still very odd, i can not see how aerodynamically this aircraft flew.

Last edited by a moderator: Sep 25, 2014
2. Jun 7, 2007

### ank_gl

awesome video, really unbelievable. i think it was the skill of the pilot that made it to go thru

3. Jun 7, 2007

### caslav.ilic

As they say (at least where I am :), "it's easy being a general after the battle", but I don't see much aerodynamically troublesome in this matter.

What's the problem with "one wing" (more properly, half-wing) shot off? To maintain level flight, first, the other wing has to give twice as much lift, and second, the rolling moment around the CG would have to balance out. Nothing more than that. Here is how it aerodynamically goes.

Half of the wing perishes. The sudden lack of equal and opposite balance to the rolling moment produced by the remaining wing half, make airplane start spinning. The pilot instinctively moves the stick so to counter roll, which does the right thing in this case too: raises the outboard aileron (quite powerfull on F-15) on the remaining half of the wing, and possibly counter-turning intact horizontal tailplanes (all-movable on F-15).

However, this is still not enough to balance out the rolling moment produced by the assymetric wing lift. The controls are maxed out, so the pilot cannot any longer increase counter roll moment, at the same velocity. So he speeds up (afterburner), which increases the counter moment, but also increases the moment due to lift (both roughly proportional to square of velocity). However, the pilot can now reduce the lift without reducing the counter-roll moment, by keeping controls maxed out and reducing wing's angle of attack. The airplane comes to a balance. (Any yawing motion introduced by the assymetric drag can easily be balanced by twin vertical tails, also intact.)

Unfortunately, the airplane is now quite unaerodynamic: a lot of drag due to wing rubble and control deflection, much less lift than normal. Basically, the lift is now produced only by the body and, looking at F-15's wing, roughly half of the intact wing half -- the outboard part where the aileron is raised produces downward force to counterbalance roll. So, it needs much higher speed for this little lifting performance to be enough to balance the weight. And that's precisely what the pilot says, they were landing at twice the normal landing speed. This means that the aerodynamics was spoiled so that the produced lift was only, say, one quarter to one sixth (assuming rough landing :) of the normal. This sounds quite plausible.

Now, unlike a conventional airplane configuration (general aviation, transport, airliners...), F-15-like fighters have quite stubby wings, lifting body, very high-power flight controls, and ample thrust reserve. So it had at least enough authority to conduct all the described steps, which a normal airplane would not.

On the other hand, the dynamics of transition from spinning to level flight and flight control coordination afterwards, must have been hideous (though, I'm not controls person). Perhaps this feat is more of a testament to F-15's flight control system and/or pilot's skill? I mean, aside from the fact that they actually didn't eject -- I really sometimes don't understand this thing between the pilot and the airplane :)

--
Chusslove Illich (Часлав Илић)

Last edited: Jun 7, 2007
4. Jun 7, 2007

### The_Thinker

dude!! caslav.ilic what exactly do you do again? how do you know so much? that was a really good explanation man...

oh... by the way... are pilots responsible for the planes that they fly? as in if they blow one up due to problems, are they held responsible or something?

5. Jun 7, 2007

### DaveC426913

I wanna know why they're showing pics of ancient F-100 Super Sabres and calling them A4s.

6. Jun 7, 2007

### Staff: Mentor

No, they aren't (at least not insofar as the plane being more important than the pilot). The pilot said in this case that had he realized the wing had been torn off, he would have ejected. But he couldn't see it due to the trail of fuel from the wing root.

The toughest part of the control situation is, as said, producing lift without introducing a torque that rolls the plane. The all-moving horizontal stabilizers are key there, since that isn't really possible - they counter the torque. What you end up with when the existing aeleron is all the way up is that the remaining wing produces virtually no lift at all and the plane flies as a lifting body (probably 75% of the lift) and by standing on it's afterburner (25% of the lift).

7. Jun 7, 2007

### ank_gl

yea, by the skill of pilot, i meant that he was so precisely able to balance all the forces that made that landing quite plausible. it sounded to me pretty much easy when i saw it, just balance the unbalanced forces, holla you r saved. but it is not an easy thing to do. remember pilots are not taught how to control the flight in these situations. first thing to do is to eject in this case. but the way, pilot took control, its just so much amazing.(theoretically, yes its just simple mechanics)

8. Jun 8, 2007

### Langbein

Quite an interesting and allmost unbelievable film.

When it comes to fighter airplanes one should remember that such a plane actually do not need to fly using the lift of the wings all the time.

Like for instance F15/F16 the trust of the engine(s) is approx twice the weight of an empty aircraft, so it can set the nose up and climb on the engine(s) only.

Also they are able to do some flying on their bodies, while rolling etc. (Like rockets.)

Some of the old designs like the starfigheter did not have to much wings at all, they were allmost buildt like rockets.
http://www.starfighters.nl/

9. Sep 8, 2007

### Morga

Sounds more like propoganda

10. Sep 8, 2007

### Danger

Since you obviously know so much about the subject, I had assumed that you were a pilot... specifically military. If so, you must share the feeling that the aeroplane becomes a part of the pilot. You don't fly one; you wear it.
Although I've flown only civilian craft, I would expect that military would be the same. Bailing out is a last-ditch tactic, somewhat akin to cutting your arm off to get out of a trap. Military pilots probably feel that even more, partly because of the circumstances under which the human and the machine co-exist, and partly because they're very aware of how much the plane costs.

Where the hell did that come from?

Last edited: Sep 8, 2007
11. Sep 8, 2007

### ank_gl

damn, i need to be a pilot

12. Sep 8, 2007

### caslav.ilic

Alas, no -- only an aerospace graduate.

My nearest relevant "flying" experience was armchair wrestling with virtual Slammers over Crimea, and a cold, purely intellectual challenge of afterwards landing my Flanker with various lifting surfaces missing.

In real life, I don't even have a driver's license :)

--
Chusslove Illich (Часлав Илић)

13. Sep 9, 2007

### Danger

Personal computers didn't exist when I was flying (4-function calculators were still pretty expensive). I've never tried Flight Simulator or the like because it just wouldn't be right. If you can't feel it, I can't see the joy. That would for sure be different for someone who started on them, but you'll never go back once you've had the real thing. Launching a Cessna 150 out of a cow pasture is more satisfying than ploughing through 'MiG Alley' in a Phantom on a keyboard.
The only time that I tried one was when the 'F-14' sit-down arcade game came out. At least that had a stick instead of a space-bar. Came ripping up from mid-6 on a flock of MiG's (or whatever), aimed for the one on the right, layed on the gun tit, and tromped left rudder to 'walk' the gunfire across the whole pack... only to realize that the damned thing didn't have rudder pedals; it was just a steel tube running across the front of the foot space. Flew straight up the bastard's tailpipe and got creamed. :grumpy: