doug@terak.UUCP (Doug Pardee) (07/29/85)
> > Sorry, lift is created by two factors; increased air velocity over the > > upper surface, and the so-called "action = reaction" lift. The first > > factor accounts for (in normal aircraft) about 80% of the lift produced. > > > More correctly, lift is caused because the increased velocity over the > upper surface causes a decrease in air pressure on the top comared with > the bottom. Last time I heard, physicists still couldn't agree among themselves on exactly how an airfoil generates lift. I think I'll leave the arguing to them. -- Doug Pardee -- Terak Corp. -- !{ihnp4,seismo,decvax}!noao!terak!doug ^^^^^--- soon to be CalComp
dsmith@hplabsc.UUCP (David Smith) (08/13/85)
> > Sorry, lift is created by two factors; increased air velocity over the > > upper surface, and the so-called "action = reaction" lift. The first > > factor accounts for (in normal aircraft) about 80% of the lift produced. > > > More correctly, lift is caused because the increased velocity over the > upper surface causes a decrease in air pressure on the top comared with > the bottom. But the air going over the top of the wing exits the wing area with a downward velocity, unless the wing has stalled. Both airflows (top and bottom) produce "action = reaction" lift. If the top airflow is responsible for 80% of the lift, then it also must receive 80% of the momentum transfer. *** The strakes on F-16 et al. stir up vortices which delay airflow separation, raising the stall angle of attack and keeping the tail from being blanked. Stealth planes also use these vortices to keep air flowing into the top-mounted air intakes at high angles of attack. David Smith ucbvax!hplabs!dsmith