Editing 803: Airfoil
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[[File:Karman trefftz.gif]] | [[File:Karman trefftz.gif]] | ||
| − | Lift may be more usefully described as resulting from the deflection of air, although this explanation still does not explain how symmetrical wings will work (at least, absent effects caused by a change in the "angle of attack") nor how a plane may fly upside down. The Wikipedia article on {{w|lift (force)|lift}} provides a more detailed explanation. It in fact gives an explanation as to these two issues. It explains that with zero angle of attack, a symmetrical wing will not generate lift (though it is possible that other factors may generate other slight upward force, such as updrafts, the shape of the plane, and the angle of the engine relative to the wings | + | Lift may be more usefully described as resulting from the deflection of air, although this explanation still does not explain how symmetrical wings will work (at least, absent effects caused by a change in the "angle of attack") nor how a plane may fly upside down. The Wikipedia article on {{w|lift (force)|lift}} provides a more detailed explanation. It in fact gives an explanation as to these two issues. It explains that with zero angle of attack, a symmetrical wing will not generate lift (though it is possible that other factors may generate other slight upward force, such as updrafts, the shape of the plane, and the angle of the engine relative to the wings. It also explains that an asymmetrical (or "cambered") wing may adjust angle of attack to compensate and still generate lift. |
Finally, to answer the question in the second panel in a general sense: most planes ''can't'' fly upside down for an extended period of time. While many aerobatic aircraft can sustain inverted flight with negative g forces, some others can achieve an inverted attitude only momentarily, and are experiencing positive g forces. Usually the reason for this is not the wings, which function perfectly fine upside down (albeit sometimes at lower efficiency), but the engines, which may not get fuel or oil under such conditions. It has to also be noted that if angle of attack were ignored, movable control surfaces would be useless. Almost any airplane can do a {{w|barrel roll}} or {{w|Aileron roll}}, given sufficient altitude (a {{w|Boeing 707#Model 367-80 origins|Boeing 707}} prototype [https://www.youtube.com/watch?v=AaA7kPfC5Hk once did this], and so did the Concorde in a demonstration). | Finally, to answer the question in the second panel in a general sense: most planes ''can't'' fly upside down for an extended period of time. While many aerobatic aircraft can sustain inverted flight with negative g forces, some others can achieve an inverted attitude only momentarily, and are experiencing positive g forces. Usually the reason for this is not the wings, which function perfectly fine upside down (albeit sometimes at lower efficiency), but the engines, which may not get fuel or oil under such conditions. It has to also be noted that if angle of attack were ignored, movable control surfaces would be useless. Almost any airplane can do a {{w|barrel roll}} or {{w|Aileron roll}}, given sufficient altitude (a {{w|Boeing 707#Model 367-80 origins|Boeing 707}} prototype [https://www.youtube.com/watch?v=AaA7kPfC5Hk once did this], and so did the Concorde in a demonstration). | ||
