![]() I'm in the initial stages of coming up with a Formula 1 design for Reno. Second, I should have preceded my post with a small bit of context. Pitching moment might be relevant to that.įirst, I appreciate the responses so far. The reference to zero lift coefficient at Vcruise might be a statement about variations in the angle of attack of a plane driven by differences in thrust. It won't say much about Vmax or climb rates. Getting back to the question asked, go to the website for Loftin's Quest for Performance (a NASA publication) I am prety sure he will point you to two variables - the zero lift coefficient and flat plate area, which is how you calculate static drag.Īs for pitching moments, they will tell you something about how the plane will manouver. Engineers tend to make fewer mistakes when there is less uncertainties about the calculations. The properties of airfoils however had to be measured in wind tunnels, that is until fast mainframe computers came along in the mid 1960s. Why? Because the aerodynamic properties of wing shape (again looking down) can very nearly be determined from paper and pencil. I am pretty sure the opposite is generally true. While it is certainly true the shape of the wing (looking down from the top) influences the ratio of lift to drag (higher aspect ratios are generally better) I don't think you can argue this is more important than the airfoil shape (the view of the wing from the side). Further more, while swinging the wing backward, the relative thickness of the airfoil decrease, while the swept wings provide a more stable flight(swept wings have a better result than the V position of not swept wings). On a wing with a smaler aspect ratio the airmasses can get shifted sideward in a better way. This provide a high aspectratio and so a high lift factor for slowspeed, but also a smal aspect ratio and swept-wings. Since the wingform, providing the best wing efficiency regading the lift, is most bad for highspeed and the other way around, modern jets often use swing-wings. The solution to gain higher critical mach´s are smaler aspectratios(He162, Me163, Spitfire), more thin airfoils(Spitfire) and/or swept-wings (Me163, Me262). Although the (semi) laminar flow wing provide a smaler drag at some speeds, the also rather limited critical mach of the P51 show that also this airfoil dont have a that high influence. Though two exceptions are the Spitfire airfoil and the P51 airfoil, where the Spit airfoil was rather thin, while the P51 Airfoil didnt provide very high max AoA´s, so mainly the max lift was not that high.įor highspeed with "normal" asymetric WWII airfoils the aspectratio and swept-wings are most important as well. In theory only on a perfect eliptical wing the "Airfoil lift coefficient" ís the same like "wing lift coefficient", other, more squary wings, with smal aspectratio, guns, not covered wheels, antennas, etc minimize the wing efficiency often down to factor 0,5.Īs result two wings with exact the same airfoil can have a very different "wing lift coefficient", while the different of the "wing lift coefficient" due to Airfoils in WWII was mainly rather smal. "Airfoil lift coefficient" is by far not the "wing lift coefficient". By far more important for the highspeed behaviour and at least as important for the lift coefficient is the wingshape(aspect ratio, trapezium or squary, the form of the wingtips, swept wings etc).
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