Assertion: airfoil's lift | /r/CapableOf | keep airplane flying
Facets:
Source sentences:
text: There are so called "laminar airfoils" that do have a much reduced drag when airborne, but are sensible to things as cleanliness of surface, above a dirty surface the air no longer flows in a laminar way, and when above an airfoil flow becomes turbulent, big losses in efficiency of wing result, (the air in the upper part of wings flows faster than in the lower part, thus producing a decrease in pressure in the upper part of wing, and an increase in pressure in the lower part, this is the reason why wings do produce lift to keep the airplane flying), if in the upper part of airfoil the air flow changes from laminar to turbulent, after the transition point, an increase in pressure results, the wing loses lifting power, and the drag of moving the wing thru the air sharply increases.