Tiago1973 wrote:Peter_Frank wrote: Just like an airplane is never symmetrical - it will never be very performing if it was
think some they are - those acrobatic airplanes that need to fly invertedPeter_Frank wrote: The foils are not "plain straight" either - most have changing AOA out during the foil section (wash out), just like airplanes, for stability and agility.
from memory wash out main purpose is to control lif distribution across the span to reduce drag - the closer the lift distribution is to an elipse the lower induced drag you will have
for the same effect maybe it´s just easier to start with a wing with an eliptic shape platform, think spitfire, instead of choosing a different shape and then having to play with the AoA along the span (something that would require a CFD program to know what one would be doing..)
NACA has numerous foils optimized to operate at certain Reynolds (function of velocity and viscosity if I remenber right), but I do not know enough to just go there and pick 1 that would make sense for you guys
Think you need Spork jumping into this topic..
Peter_Frank wrote:A spitfire with its elliptical wings is VERY prone to tipstalling, thus it was one of the first to use a lot of washout in order to avoid this.
Washout has three purposes in fact.
The major is IMO to avoid tipstalling.
You can also use it to reduce induced drag, at low AR wings, yes.
And last but not least - if you have a swept wing, washout will add stability - and you could in fact ride without any tail wing if you wanted.
Not as performing though....
Bille wrote:Everyone told Me that i should learn on a Low AR foil ; so
i need plans for one of Those.
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