ORIGINAL: gkaraolides
Greetings all,
ORIGINAL: pjwright
Another factoid I discovered had to do with tapered wings and their tendency toward tip stall. Since a pattern plane doesn't want to use washout to counter tip stall, the early designers did two things: made the wingtip leading edge slightly more blunt, and/or used a slightly thicker airfoil towards the tip to add lift. For example, a NACA 0015 enlarged to a NACA 0017 at the tip.
Apropos of the above, I've always wondered why in all designs I've seen, tailplanes use thinner sections than wings. Does anyone have an explanation for this?
My guess is that, since the airflow is already deflected by the wing, the effective angle of attack on the tailplane remains within a narrower range than that on the wing. So a thicker section would only add drag, and offer nothing in return. But this is only my own guess. I have never read about this or seen it discussed anywhere. I'd be glad to hear from anyone who knows for sure.Best regards,
George
You are right George and this is known by aiplane designers of course.
See the picture I did make a few month's ago.
Even modelers not always want believe this, but the design of the pattern plane is depending of this phenomenon.
The "cotton thread downwash" is showing downwas still also below and after elevator bending upwards as result of up deflection of the elevator.
Glidepath is horizontal and the Taurus is flying at highest possible angle of attack.
Cees