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View Full Version : aerodynamics, anyone?

mosta
03-02-2006, 03:11 AM
okay, so a plane flies because a wing is longer on the top side than the bottom side causing the air to go faster on the top and have less pressure, right? well then why can planes fly upside down?

and then how about sailboats? I read a book on sailing and the theory of sails. it wasn't an engineering book, but it claimed to be up to date on the state of scientific knowledge at the time (in the eighties). so with a sail you have the same theory of a long side and a short side, but actually because a sail is flat the outside and the inside are in fact the same length. so can anyone tell me how sails work, too?
BruceZ
03-02-2006, 04:50 AM
[ QUOTE ]
okay, so a plane flies because a wing is longer on the top side than the bottom side causing the air to go faster on the top and have less pressure, right? well then why can planes fly upside down?

and then how about sailboats? I read a book on sailing and the theory of sails. it wasn't an engineering book, but it claimed to be up to date on the state of scientific knowledge at the time (in the eighties). so with a sail you have the same theory of a long side and a short side, but actually because a sail is flat the outside and the inside are in fact the same length. so can anyone tell me how sails work, too?

[/ QUOTE ]

This article (http://travel.howstuffworks.com/airplane6.htm) gives an excellent explanation of these things.
Go Blue
03-02-2006, 05:46 AM
Yes, that is a good article to explain flight. It is kind of confusing what it being said there, but to sum it up, planes do not fly because the top wing surface is longer than the bottom. Even though this is the explanation used in most textbooks and such, it does not take into account several factors, one of which is upside down flight, as you mentioned. A better explanation is that the angle of the wing relative to its direction of motion, by the property of the Coanda effect, deflects the oncoming airstream downward and due to Newton's 3rd Law of Motion, the wing in effect moves up. In addition to the howstuffworks.com article, I think that this one gives a really good description of what actually takes place: http://www.aa.washington.edu/faculty/eberhardt/lift.htm