Sure there are high and low lift profiles for symmetrical wings; it's a matter of how much difference there is between a straight-line path and the curved paths forced by the profile when a fluid flows over and under them, at whatever angle of attack. The lift will vary according to the angle of attack-zero lift for a symmetrical wing at zero angle, and changing as the angle changes until the profile stalls. A fatter profile, all other things being equal, will generate more lift at a given angle of attack, but may also stall earlier and will create more drag-partly due to increased wetted area, frontal profile, and the induced drag that comes with lift. And the shape of the foil is important; it's been proven that a sailboat with a bulb keel held by a flat plate is slower on VMG than one with sideways profile (aspect ratio, chord, length, etc) that has an airfoil shape.
From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, March 17, 2008 11:54 AM To: [email protected] Subject: Re: catalina27-talk: Keel Fairing One might think, that because a keel is like an symmetrical wing, which can only produce lift by altering the angle of attack, (as in a sport, aerobatic plane) that the shape of the foil would be irrelevant, aside from possibly reducing drag, which will make your boat faster.....But there is no "high" or "low" lift with a symmetrical wing....just angle of attack. Tommy, One might think... _____ It's Tax Time! Get tips, forms and <http://money.aol.com/tax?NCID=aolprf00030000000001> advice on AOL Money & Finance.
