Gavin really is not 100% right. Sailboats do not develop lift off their sails! Ok..technically they do, but the lift is in the wrong direction.
Sailboats develop lift by their keels/centerboards. That pulls them to "weather". The sails develop thrust. The sailboat is always slipping at a couple degrees, creating a positive angle of attack on the foil to create the lift to weather. There are few situations where "tacking" a glider is used to an advantage. The biggest problem with gliders is that there is a time vs distance. In the absence of lift, the parameters you have are: altitude, speed, wind, distance, and time. If you need either of these maximized you need to affect the others. Wind is a fixed variable...or one you cannot control. Speed, altitude, distance and time are all relative...change one and you change the others. Distance is the fixed parameter...you need to get from point a to point b. Increasing this by "tacking" only makes it longer. Straight is better in 99.9% of the time. The only time it would not be is in a varying wind due to shifts. For example, if you fly in the lee of a mountain. It may be advantageous to take a short hitch into more favorable winds due to the external influence. In that case the advantages of flying hte extra distance may be overcome by the favorable tailwind (or lack of headwind). Sailing and gliders are VERY similar...but also very different. Jason Werner > > --- In [EMAIL PROTECTED], "gavin" <[EMAIL PROTECTED]> wrote: > > > > Salboats tack back and forth against the wind, because the sail > needs to > > fill with air, forming a lift generating airfoil with a forward > componant > > that pulls the boat forward. Gliders wings generate lift, with a > forward > > componant that moves it forward, except the wing is rotated 90 > degrees, so > > if anything you would want to tack up and down. Actually it does > not really > > work that way because we have to deal with gravity as well. Best > bet is a > > staight line > > > > Gavin > > > > > Here is a scenario for you experts.... > > > > > > You find yourself way down wind and way high up with an > unballasted plane > > > and gotta head back into a moderate head wind. You can head > directly into > > > the wind on a straight line back or you can tack back and forth > like a > > > sailboat against the wind. Time is not an issue. Which > technique will > > get > > > you closer to home with minimal loss of altitude? > > > > > > (I'm going on the idea that everyone learns from experience, > ideally the > > > experience of others.) > > > > > > Cheers, > > > > > > Bill > > > > > > -- > > > There's two theories to arguin' with a woman. Neither one works. > Will > > Rogers > > > > > > Bill Johns > > > Pullman, WA > > > > > > RCSE-List facilities provided by Model Airplane News. > Send "subscribe" > > and "unsubscribe" requests to [EMAIL PROTECTED] > > > > > > > RCSE-List facilities provided by Model Airplane News. > Send "subscribe" and > > "unsubscribe" requests to [EMAIL PROTECTED] > > > > RCSE-List facilities provided by Model Airplane News. > Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
