On a plane, the highest airflow
is at the root, from the prop. And it is the dirtiest there too, lots
of P factor. On a boat the highest airflow is at the top and it is
cleanest there too. Planes design twist in the wing so that it stalls at
the root first, they don't want to drop a wing.
Lift mostly comes from the curvature, not just the surface area. So more camber means more lift. So I need to reduce camber towards the tip.
The tip will have the highest wind, and largest AOA variations so I am almost forced to make it a thick camber, otherwise it is always going to stall....
correct, however they need to maintain aileron control,
tip stall is very dangerous and precipitates involuntary spins with no control to counter
the twist is another corrective measure to maintain aileron control in a narrowing wing plan
remember the airflow propagating at the root has a component of transverse flow both aft and towards the tip. And over the tip on the suction side again moves back toward the root, thus generating the tip vortice in the wake.
tip stall is very dangerous and precipitates involuntary spins with no control to counter
the twist is another corrective measure to maintain aileron control in a narrowing wing plan
remember the airflow propagating at the root has a component of transverse flow both aft and towards the tip. And over the tip on the suction side again moves back toward the root, thus generating the tip vortice in the wake.
Lift mostly comes from the curvature, not just the surface area. So more camber means more lift. So I need to reduce camber towards the tip.
as i see it, a cambered foil cannot operate both ways on a proa in the way a symmetric foil can
The tip will have the highest wind, and largest AOA variations so I am almost forced to make it a thick camber, otherwise it is always going to stall....
interestingly, the foils that cope with greater AoA changes and designed to stall after the mainplane are tails, and in contemporary low speed aircraft almost always thin wing symmetric profiles like NACA 0009. or 9% symmetric
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Posted by: robriley@rocketmail.com
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