In the 1950s when the USAF first started flying the F-100 Super Sabre, a lot of guys were killing themselves in the jet. It had a nasty level of adverse yaw that had never previously been encountered. The swept wing jet obeyed the laws of aerodynamics but to a different extreme than most pilots have ever seen. Everyone knew that adverse yaw was caused by the downward deflected aileron creating more drag than the upward deflected one. When you move the control stick to roll left, the right aileron goes down and the left one comes up. Result should be left wing driven downward and right wing rising to roll to the left.
But, adverse yaw causes the nose to swing to the right. In most aircraft it was a simple matter to step on some rudder in the direction of roll to "coordinate" the turn. In the F-100 the adverse yaw was extreme and vicious. Aileron deflection at low speeds and high angles of attack cause rapid violent rolls in the opposite direction. Pilots were afraid of the jet.
North American Aviation needed a salesman to convince the customer he didn't want his money back. That was where Bob Hoover came in. He traveled the country from F-100 base to base giving lectures and demonstrations of what the aircraft was capable of when flown properly. His skill and expertise essentially translated into training for a couple of thousand guys around the world who would learn to fly and employ the F-100 effectively.
Was he good? Well, for quite a long time he demo'd the North American/Rockwell Aero Commander, a small business aircraft. Wanna ride along?
One of his most famous feats was pouring a glass of water during a roll of the aircraft without spilling a drop or upsetting the glass.
6 comments:
Some liberal editing there (landed engines off, parked engines running), but still a wonderful demonstration from a legendary pilot.
That was inspiring. He obviously knew his platform.
A heckuva guy.
Ed:
Are you and Bob friends?
Ed:
You wrote about flying the F-4 without aileron deflection because of adverse yaw characteristics. Since reading about that, I've wondered how one could quickly maneuver in a dogfight without aileron deflection.
Was AY a problem at fighting airspeeds? With or without high angle of attack at fighting speed?
How did you manage to get a good roll rate without aileron?Did you use front pressure to dip the nose slightly and then apply back pressure with rudder?
When you've got back-pressure on the stick, you avoid aileron input in a hard-wing F-4. The jet will roll quite briskly with rudder. If you don't have back-pressure, i.e. the stick is neutral, then aileron deflection is fine.
It is simply a matter of flying a given airplane with recognition of its characteristics. Trouble comes from people who think that all high-performance aircraft fly the same.
When the F-4 got modded with LES (leading edge slats), the adverse yaw characteristic was largely eliminated. Modern flight control systems allow computers to adjust resulting control deflections to compensate for AOA characteristics.
When I was at Sheppard last month and got into the T-38C sim, I found that they've tweaked the rudder roll a bit and it actually rudder-rolls much more quickly than it did when I was flying the AT-38 version. The IP said they still have folks who recommend flying the jet with feet flat on the floor. You don't get everything out of it that way, but at least you can't hurt yourself.
We're almost out of those guys. Pilots like Tex Johnson, Tony Levier and those like them, ones that sold airplanes by flying them, not talking them up on a computer screen or in a simulator.
I may have only been a lowly wrench, but I could recognize an artist in the air.
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