For the root a 65xxxx would be fine but you'd have to either find a reflexed version or make your own because even a small pitching moment coefficient produces a strong torque on such a long chord.What your opinion on using a series 65 airfoil on a delta?
Two ways I use.Is there any paper that explains how to reflex an airfoil in a reasonable manner, to eliminate pitching moment? The 654221 has a tiny downward kink at the te.
You could read the N.A.C.A. Technical Note 122 by Max Munk: The determination of the angles of attack of zero lift and of zero moment, based on Munk's integralsberridos said:
Is there any paper that explains how to reflex an airfoil in a reasonable manner, to eliminate pitching moment? The 654221 has a tiny downward kink at the te.
You could read the N.A.C.A. Technical Note 122 by Max Munk: The determination of the angles of attack of zero lift and of zero moment, based on Munk's integralsIs there any paper that explains how to reflex an airfoil in a reasonable manner, to eliminate pitching moment? The 654221 has a tiny downward kink at the te.
This statement needs some clarification. Absolute CLmax is affected by thickness but not very much. For any given family of airfoils usable CLmax increases with thickness up to some thickness then drops off with increasing thickness. A graph of airfoil power factor shows the cl for best angle of climb and minimum sinking speed, any AoA steeper than that is on the edge of stall, and the part of the graphs beyond max power factor produced by panel codes is always optimistic and not to be trusted. I didn't have a family of NACA 6xxxxx or reflexed sections so I generated a family of 43xx sections with the NACA section generator in XFLR5 (hope you're not color blind). This shows that power factor is highest for the 13, 15 and 17% airfoil sections, which is fairly typical for other sections. Now when you get into highly laminar airfoil sections absolute thickness has similar effects but thickness distribution becomes a problem, especialy for reflexed airfoils. Reflexing a 40% laminar airfoil section works OK but a 50 or 60% laminar airfoil usually doesn't work too well.One of the problems with the NACA 6 series sections is that CLmax is low. That's a consequence of the camber not the thickness. I've also attached a center-section profile that I've been working on to illustrate that you can do better than NACA 6xxxxx.
What was the wingspan?I designed and built this model over 12 years ago, I was not flying it, most of the landings were dead stick because we couldn’t keep the engine running. You can see by the landing speed that there is vortex lift at play. I believe that it would be possible to slow an airplane like this to deliver not too fragile packages.