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In article ,
Guy Alcala writes: Emmanuel Gustin wrote: "Merlin Dorfman" wrote in message ... Did the Soviets learn about the all-flying tail from the captured F-86, and put it on their later fighters The F-86A did not have the flying tail, this feature was introduced by the F-86E. This model entered combat in Korea in September 1951. The first Soviet fighter with the flying tail appears to have been the SM-9/2 prototype of the MiG-19, which was built in 1954. So it is quite likely that the Soviets were aware of the use of a slab tailplane on the F-86E when they designed the SM-9/2. On the other hand, NASA's adoption of the 'flying tail' appears to have been inspired by British data. There's a common misconception here. The "all-flying tail" on the F-86E and F wasn't a slab, it was a movable stabilizer with separate (but linked) elevator, as developed for the XS-1 (and credited by Yeager with allowing the a/c to be controllable through the Mach). The slab came in on the F-100, IIRR. From what I recall, there'd come a Mach number when the shock wave from compressibility would make the elevator ineffective (usually leading to tuck under), but the stabilizer itself would then be forward of the shock and retain its effectiveness. So the stabilizer was made movable (i.e. trimmable like a Buff, but directly connected to the joystick instead of just the trim switch) and linked to the elevator around a center pivot. The two surfaces were geared to move in a certain relationship to each other. I don't know the specific details (whether it was based on IMN or just a pure mechanical relationship). Hopefully Mary, Pete or someone else can fill in the details. F-86D/Ls and Hs had a one-piece slab. The reason for th all-moving tails (dangit, no chalkboard again! Assume a chalkboard, and a lot of Fighter-Pilot hand talking) Think of the stabilizer/elevator combination as a wing (Wich, after all, it is) At subsonic speeds, deflecting the elevator affects the airflow over the entire surface, so that the entire are of the stabilizer is used to control pitch. As the flow over the stabilizer gets transonic, and the shockwaves form, elevator deflection begins t only effect the flow over the elevators themselves, greatly reducing effectiveness. The solution is to move the entire stab (stabilator), which lets the entire surface develop whatever lift needs to be created to counterbalance the wing. (It's early yat - I've only had 1 cuppa Coffee) Why doesn't every airplane use this? (The Wright Brothers did) The problem is that once the stabilizer had to get above a certain small size, it's danged hard to move manually, no matter how much you balance it. It took the advent of powered controls, (The electric screw jack on the XS-1, or the hydraulics on the F-86E) to make it practical. You can certainly fly a transonic or supersonic airplane without using a slab, but what happens is that your pitch authority (Ability to raise or lower the nose) decreases, and, depending on the configuration, teh airplane may not be able to be trimmed at all. (The pitchup of the F-84s, for example.) -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster |
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