Steve Pierce
BENEFACTOR
Graham, TX
How about the tufted tip pictures Jerry posted years ago? Looked like from that the the droop tip wing had the air flowing over the aileron and the tip bow wing had it spilling off the end of the tip.I have wanted to stay out of this, but I guess I am not.
For a straight wing aircraft the wingtip for the most part does not matter.
If you read allot of Hoerner's design theory, and follow this with the work of Mike Arnold and Burt Rutan. Keep in mind Burt has had many very able minded people in his employ.
Look at Arnold's AR5 and the AR6, look at the tips used on two of the lowest drag planes ever made. Simple rounded tips.
Arnold's AR5 did not even run a spinner. It has been proven the stagnant air around the prop hub has little to no effect on drag. They are pretty and they can make a good profit.
Even Hoerner, late in life published papers that once there was true data on his various tip designs, they made little to no difference.
Where a wingtip can make a difference is on a swept wing. Not only do the sell seats, but they save a few pounds of fuel, less than the few hundred pounds of seats sold. Freighters have little need for real fancy tips. A simple upturn will do. Freight dosen't care.
Just wait till you see what my plane will have
The wing tip essentially does not matter. Companies offering droop or upswept tips make their best money if they hire very good marketing people.