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Old 27th May 2011, 16:07
  #97 (permalink)  
Join Date: Jun 2009
Location: florida
Age: 76
Posts: 1,072

Wow! Super answers, and the Garage guy's reference is outstanding. Hell, I'm almost ready to try to fly the beast after a few more hours of study, heh heh. As a TV ad says, " it's so easy that a caveman can do it".

I raised the runaway trim issue, as many of us were taught to roll the plane if we had runaway nose up trim. The technique was intended to maintain a reasonable pitch attitude. For nose down, the idea was to reduce power/slow down in order to overcome the elevator trim. Of course those procedures were for "elevators" and not the horizontal stab.

As we try to digest the data and maybe cry a bit, I'll ad lib and add a war story about horizontal stabs. JT Moderator can delete if appropriate, but it explains a few things about many planes' horizontal stab designs.

So first few months at Hill we had all kindsa celebrities drop by the first Viper unit in the world. One was Chuck Yeager. And we all assembled in the main briefing room and he sat on the stage, feet on the floor, and told us war stories and answered questions. Was a magic moment, I tellya.

He got to the part about the first supersonic flight and a bit of advice from a Bell technician/aero dude. He told Yeager that once supersonic or even close to the mach that they were worried about losing elevator control due to the shock waves. So they had a manual wheel to 'trim" the horizontal stab. He told Yeager that if all else failed, to use that sucker and he might gain pitch control.

Sure enough, above the mach the elevators didn't work very well, if at all. So Yeager cranks the wheel back and forth and regains pitch control. Back below the mach all was "normal". He told us that this discovery was why North American and other folks developing the new jets went to the one-piece horizontal stab. Moving the entire thing as one piece changes the shock wave pressures and the thing acts like a "normal" jet.

Gotta love it!

We now return to our regular hypothesizing and second-guessing, heh heh
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