Over on the Kolb list there's currently a lively discussion on wingtip shapes. One of the members posted a link to this 1923 NACA report on swept wingtips. The results are interesting, though not dramatic, and the shape would visually suit the ultralight biplane I'm designing (evocative of a pre-WWI pusher biplane, though not a historical replica).
However, I wonder that the effect would be on stall? I'd hate to build a plane with any nasty tendencies to tip stalling, as swept or sharply tapered wings tend to be prone to, I'm using a 23012 airfoil... not known for the gentlest stall in the first place, but it does quite well on many aircraft with rectangular wings (e.g. Taylorcraft). Actually I want a clean stall for snap rolls and spins, and the aerobatic purpose of this design rules out any washout.
Interestingly, the same concept has been successsfully applied to propellers. I made a similar mod to one of my paramotor, and saw a minor improvement in fuel consumption.
-Dana
Most politicians aren't crooks, but the ones that are sure are making the other 10 percent look bad.
However, I wonder that the effect would be on stall? I'd hate to build a plane with any nasty tendencies to tip stalling, as swept or sharply tapered wings tend to be prone to, I'm using a 23012 airfoil... not known for the gentlest stall in the first place, but it does quite well on many aircraft with rectangular wings (e.g. Taylorcraft). Actually I want a clean stall for snap rolls and spins, and the aerobatic purpose of this design rules out any washout.
Interestingly, the same concept has been successsfully applied to propellers. I made a similar mod to one of my paramotor, and saw a minor improvement in fuel consumption.
-Dana
Most politicians aren't crooks, but the ones that are sure are making the other 10 percent look bad.
