mzaharis
Well-known member
- Joined
- Sep 27, 2004
- Posts
- 541
Two things:
1. Most asymmetrical wings can fly inverted, although they need to achieve a considerably greater angle of attack then when upright. Just look at the graph of lift/Angle of Attack in any aerodynamics textbook that discusses airfoil performance (Abbott and Von Doenhoff immediately comes to mind). This topic was beaten to death in this thread:
http://forums.flightinfo.com/showthread.php?t=40756
2. Despite what was stated in point 1, Tex Johnson's barrel roll in the Dash 80 (the 707 prototype mentioned by Belchfire) is not proof of much other than an airliner has enough roll authority to go inverted. He did a positive 1 G barrel roll; in other words, the wing was always generating lift in the direction in which it was designed, and a passenger would have felt (more or less) his own resting weight pulling him/her into the floor. Any fluid systems would have not had scavenge problems, either, which would probably be one of the quickest problems encountered if you rolled a 707 (or most any other airliner, including the 367-80 707 prototype) inverted with negative G's for any length of time (pretty much any aircraft that is certified as aerobatic is designed with fuel delivery and oiling systems that will work inverted). I am not certain, but I believe that most civil aircraft are tested to withstand some amount of negative G's structurally, just to ensure that they can withstand severe turbulence, so flying upside down is not an immediate guarantee that the wings will fold up.
1. Most asymmetrical wings can fly inverted, although they need to achieve a considerably greater angle of attack then when upright. Just look at the graph of lift/Angle of Attack in any aerodynamics textbook that discusses airfoil performance (Abbott and Von Doenhoff immediately comes to mind). This topic was beaten to death in this thread:
http://forums.flightinfo.com/showthread.php?t=40756
2. Despite what was stated in point 1, Tex Johnson's barrel roll in the Dash 80 (the 707 prototype mentioned by Belchfire) is not proof of much other than an airliner has enough roll authority to go inverted. He did a positive 1 G barrel roll; in other words, the wing was always generating lift in the direction in which it was designed, and a passenger would have felt (more or less) his own resting weight pulling him/her into the floor. Any fluid systems would have not had scavenge problems, either, which would probably be one of the quickest problems encountered if you rolled a 707 (or most any other airliner, including the 367-80 707 prototype) inverted with negative G's for any length of time (pretty much any aircraft that is certified as aerobatic is designed with fuel delivery and oiling systems that will work inverted). I am not certain, but I believe that most civil aircraft are tested to withstand some amount of negative G's structurally, just to ensure that they can withstand severe turbulence, so flying upside down is not an immediate guarantee that the wings will fold up.
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