![]() ![]() It had tip rudders only for control however and used weight shift for pitch. #CENTER OF PRESSURE AIRFOIL FULL#I've built and flown a full scale bi-wing flying wing pusher and it was very stable due to the angle difference between the wings plus it's sweep, washout and dihedral. I've resigned myself to adding elevons aka IFO except detached and all flying, more like a tandem wing actually. I'm wanting to make a flat version without the pre-formed ribs for better stunts but this opens a big can of worms since the camber/twist give it all it's yaw/roll/pitch stability. In my case it's much more complicated since I'm starting with a swept flying wing (see avatar) with undercambered single surface wing using washout for stability and wing-warping for control. ![]() The more cambered the airfoil's mean line, the bigger the difference in incidence needs to be for similar force arrangements comared to a flat plate of the same aspect ratio and area. ![]() In other words, the cambered airfoil has to be set at a more negative incidence than the flat plate for equivalent force arrangements. Perhaps you should be working with the zero lift angles of attack of the two airfoils in question. Generally speaking, the more mean line camber, the more negative the zero lift angle of attack will be. The only difference is that flat plates have zero lift at zero angle of attack and cambered airfoils have zero lift at negative angles of attack. The graph of coefficent of lift versus angle of attack is a more or less straight line between positive and negative stalls and the slope of the line is about the same for all airfoils. You probably won't be able to find any published data on wind tunnel measurements of airfoils using the old system of measurements that were taken after the mid 1930's. Since the late 1920's or early 1930's aerodynamicists have been using the lift coefficient, drag coefficient and moment coefficient to describe airfoil behavior rather than the lift, drag and center of pressure system. The nose down pitching moment is accounted for by a pitching moment coefficient while the lift and drag vectors remain stationary in the modern system of describing airfoil behavior.īTW, the aerodynamic center is defined as the point about which the pitching moment coefficient is constant over the range of angles of attack between positive and negative stalls. The flat plate's center of pressure is very nearly stationary for angles if attack between positive and negative stalls and is located very near 25% of the mean aerodynamic chord.įor airfoils with mean line camber the aerodynamic center is still very near 25% of the mean aerodynamic chord. The center of pressure for a flat plate or any symmetrical airfoil is at the aerodynamic center. ![]()
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