Control reversal: Difference between revisions

Revision as of 22:07, 28 June 2010

Revision as of 22:14, 28 June 2010

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==Examples==

===BoeingWright B-47Brothers glider===

Finally theThe [[Wright Brothers]] suffered yet anothera form of control reversal, one normally referred to as [[adverse yaw]]. In their [[1902 glider]] they continued to encounter a problem where the glider would roll in one direction but yaw in the reverse direction, then spin into the ground. They eventually cured the problem by adding a movable [[rudder]] system, now found on all aircraft.

The [[Boeing B-47]] was speed limited at low altitudes because the large, flexible wings would cancel out the effect of the control surfaces under some circumstances.{{Citation needed|date=February 2007}}

The root cause of the problem was dynamic. Warping the wing did what was expected in terms of lift, thereby rolling the plane, but also had an effect on drag. The result was that the upward-moving wing was dragged backwards, yawing the glider. If this yaw was violent enough, the additional speed on the lower wing as it was driven forward would make it generate more lift, and reverse the direction of the roll.

===Supermarine Spitfire===

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This new wing was introduced in the [[Supermarine Spitfire (late Merlin powered variants)#Mk.C2.A021_.28type_356.29|Mark XXI]] and had a theoretical aileron reversal speed of {{convert|825|mi/h|km/h|abbr=on}}.{{Citation needed|date=January 2009}}

===WrightBoeing Brothers gliderB-47===

The [[Boeing B-47]] was speed limited at low altitudes because the large, flexible wings would cancel out the effect of the control surfaces under some circumstances.{{Citation needed|date=February 2007}}

Finally the [[Wright Brothers]] suffered yet another form of control reversal, one normally referred to as [[adverse yaw]]. In their [[1902 glider]] they continued to encounter a problem where the glider would roll in one direction but yaw in the reverse direction, then spin into the ground. They eventually cured the problem by adding a movable [[rudder]] system, now found on all aircraft.

The root cause of the problem was dynamic. Warping the wing did what was expected in terms of lift, thereby rolling the plane, but also had an effect on drag. The result was that the upward-moving wing was dragged backwards, yawing the glider. If this yaw was violent enough, the additional speed on the lower wing as it was driven forward would make it generate more lift, and reverse the direction of the roll.

===Gossamer Condor===

ThisControl issuereversal also affected the [[Gossamer Condor]], the [[Kremer prizes|Kremer Prize]]-winning human-powered airplane. When a wing-warping mechanism was tried as a solution to a long-running turning problem, the effect was to turn the airplane in the opposite direction to that expected by conventional airplane knowledge. When the Condor was rigged "conventionally", the inside wing slowed down so much that it settled to the ground. By employing "backwards" wired wing-warping, the inside wingtip [[angle of attack]] was increased so that the added drag slowed that wing while the added lift allowed the airfoil to stay aloft at a slower speed. The tilted canard could then complete the turn.{{Citation needed|date=February 2007}}

==External links==