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-   -   Lift Produced Where Wing Transects Fuselage (https://www.pprune.org/tech-log/457973-lift-produced-where-wing-transects-fuselage.html)

grounded27 2nd Dec 2011 03:38

As I understand as an aircraft (commercial) operates at closer to trans mach speeds the center of lift moves inboard and aft.

chrisN 2nd Dec 2011 10:50

Jane, I doubt if anyone is more careful with wing/fuselage drag minimising and (if possible) efficient lift production than high-performance glider designers.

AFAIK, they concentrate of getting lift from the wings, not at all from the fuselage, but focus greatly on fillets where the wing joins the fuselage to minimise drag. These are, of course, slender fuselage aircraft and operating at low Mach numbers.

An example of testing to show the effects is referred to at:
http://web.archive.org/web/200304190...80-1996-06.pdf

“The oil flows showed little or no signs of airflow separations on the top surface, except possibly for a suspiciously stagnant area near the fuselage at about .7 chord (see photo)”

(Dick Johnson conducted independent tests of many gliders over the years, developing carefully calibrated methods, and became a legend in gliding circles for his analyses and recommendations as to how to improve glider wing efficiency.)

By the way, I know little about airliner aerodynamics, but AIUI all conventional (not canard or flying wing type) glider tailplanes always generate DOWNWARDS lift in steady flight. It is a stability thing.

Chris N.


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