Quad design questions

[p23brian]

43 minutes ago, riffclown said:

Crossfires are more dependent on what we call apparent wind and like to stay moving forward no matter what.

All kites (and other airfoils) respond to apparent wind.  The topic probably doesn't come up much with kites, because the people flying them are usually more or less stationary.  Sailing is all about apparent wind.  Some (very) high performance sailboats and all iceboats can sail faster than the speed of true wind.

Definition of apparent wind is the vector sum of headwind and true wind.  E.g. if the true wind speed is zero and you're in a car going 10 mph and you stick your hand out the window your hand will feel 10 mph wind.  If the same car is driving 10 mph directly into a 10 mph true wind, your hand will feel 20 mph wind.  If the car is driving 10 mph and there's a 10 mph tailwind, your hand will feel zero wind.  Same principles apply if the wind is coming from a direction other than straight ahead or straight behind.  If the wind is light and you jump backwards, tug on the kite lines, etc. to fill the sail you are momentarily increasing apparent wind.

[riffclown]

.....self correction. I should have said "responsive to" instead of "dependent on"

@p23brian

Great point and that's why high aspect ratio kites like the HQ Prodigy or PL Vapor are so desirable but not for static flying. . The tack is also a huge factor..