Wing tip designs
03-11-2006, 11:04 AM
#1
Wing tip designs
Wing tips
In general for a new light plane design, which type of wing tip design is acceptable?
1, a full round design like in a Piper Tri-pacer
2, a vertical and squared off end like on a Mooney M-20
3, the lopped off and rounded design like on a Cessna high wing.
I see certain types used on certain types of models and wondered if this was simply the choice of the designer in each situation or based upon a bias or simplicity of construction.
The #1 was used on aerobatic designs of the 1960's, then #3 was used during the 1970's and #2 was used in the 1990's.
Lastly, does whatever goes on with the main wing, apply to the hoz-stab also? I notice many, many designs using some sort of a #1 there.
Wm.
In general for a new light plane design, which type of wing tip design is acceptable?
1, a full round design like in a Piper Tri-pacer
2, a vertical and squared off end like on a Mooney M-20
3, the lopped off and rounded design like on a Cessna high wing.
I see certain types used on certain types of models and wondered if this was simply the choice of the designer in each situation or based upon a bias or simplicity of construction.
The #1 was used on aerobatic designs of the 1960's, then #3 was used during the 1970's and #2 was used in the 1990's.
Lastly, does whatever goes on with the main wing, apply to the hoz-stab also? I notice many, many designs using some sort of a #1 there.
Wm.
03-11-2006, 01:17 PM
#2
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RE: Wing tip designs
On gliders the raked back Schumann or cresent shape combined with some local tip washout can reduce the draggy tip vortices. And some of the folks here have great things to say about tip plates for reducing tip stalling tendencies or just to delay the stall. You also see that same cresent shape in racers these days as it helps control the vortices in the high drag, high G pylon turns.
But outside of these particular uses it's more about aesthetics than any real need for efficiency in our models.
On some of my recent CAD doodles where I seem to be doing a lot of 3 channels stuff I've been using a stretched version of the actual airfoil shape as an angled up wingtip. The angle and stretch being matched so the outline of the tip is even with the top surface of the wing. This provides an upward angled "slash" cut sort of tip. The idea being that it adds to the dihedral effect to better roll the wing into the turn as well as providing a nice look to the top covering at the tips.
I suspect that this same minimal dihedral effect could be used on a low wing model with no actual dihedral to help counter the adverse rudder rolling effect when in knife edge but it would need to be tuned to do so.
As for matching the tail surfaces that's simply for looks. The tail doesn't care if it's the same shape or not.
But outside of these particular uses it's more about aesthetics than any real need for efficiency in our models.
On some of my recent CAD doodles where I seem to be doing a lot of 3 channels stuff I've been using a stretched version of the actual airfoil shape as an angled up wingtip. The angle and stretch being matched so the outline of the tip is even with the top surface of the wing. This provides an upward angled "slash" cut sort of tip. The idea being that it adds to the dihedral effect to better roll the wing into the turn as well as providing a nice look to the top covering at the tips.
I suspect that this same minimal dihedral effect could be used on a low wing model with no actual dihedral to help counter the adverse rudder rolling effect when in knife edge but it would need to be tuned to do so.
As for matching the tail surfaces that's simply for looks. The tail doesn't care if it's the same shape or not.
