Michealvalentinsmith
Well-Known Member
I'm interested in designing a plank style flying wing with some taper. I've managed to find all the info I need on CofG location and airfoil selection but I can't get much on the twist.
A few of the articles say a properly designed plank style wing doesn't need twist (so what is properly?). Some have said with effective forward sweep of a straight LE you actually need washin.
One article says that with a straight or forward swept foil you don't want the tips to stall after the root because it causes pitch up with the lift ahead of the CofG somewhat like a canard
What I can't figure is how such a wing can have adequate stall characteristics. Seems to me with washin or no twist you'd get tip stalls and spins but they claim such wings are resistant to such.
So far I'm leaning towards low sweepback angle of about 10 degrees (it fits the construction method I want with minimal spar torsion) with slightly positive Cm foils and 5 degrees geometric twist so I can use the same foil section root to tip but I'd like to understand how plank style wings work with zero twist or washin.
Any help would be appreciated.
A few of the articles say a properly designed plank style wing doesn't need twist (so what is properly?). Some have said with effective forward sweep of a straight LE you actually need washin.
One article says that with a straight or forward swept foil you don't want the tips to stall after the root because it causes pitch up with the lift ahead of the CofG somewhat like a canard
What I can't figure is how such a wing can have adequate stall characteristics. Seems to me with washin or no twist you'd get tip stalls and spins but they claim such wings are resistant to such.
So far I'm leaning towards low sweepback angle of about 10 degrees (it fits the construction method I want with minimal spar torsion) with slightly positive Cm foils and 5 degrees geometric twist so I can use the same foil section root to tip but I'd like to understand how plank style wings work with zero twist or washin.
Any help would be appreciated.
