Wing Shapes and differences

[tsanalp]

Hi there,

Is there an important difference between these wing shapes?
which is best for sailplanes? Or it depends?
Drag and lift, Low and high speed comparision granted.

Regards,


http://img171.imageshack.us/img171/9756/kanatturevlerigs0.jpg

[Jurgen Heilig]

My gutt feeling tells me, that 5) is the best solution. ;)

:) Jürgen

[Brandano]

5 might have a tad too much dihedral, though. As far a s lift is concerned, all other things being equal, 1, 2 and 3 are equivalent. 2 and 3 are slightly more draggy than 1 because of the way the wingtips are aligned to the airstream. 4 and 5 have less wing surface, and therefore a higher wing loading/higher stall speed. However, they are closer to an elliptical planform and are both less draggy than 1,2 and 3. This comes at the expense of a more twitchy plane, perhaps prone to tip stalling, which would force to add washout and lose some of the wing planform benefits...
I'd go with either 4, or 5 with less dihedral. In any case, some of the best planes were designed using the tried and tested "TLAR" method. Legend has it that the P51 Mustang started his life as a sketch on a paper napkin

[Jurgen Heilig]

5 might have a tad too much dihedral, though....

The dihedral of 5) is the same as 1) to 4).

:) Jürgen

[mnowell129]

Current theory says 5 is the best for induced drag, this of course ignoring any twist.
5 will have more effective dihedral due to the LE sweep.

[HugePanic]

according to the sketches, the profile thickness stays the same.
so the %-thickness increases at 4 & 5. i don't think that this is "good" solution.
(tipstalls might get worse, don't they??)

[Jurgen Heilig]

according to the sketches, the profile thickness stays the same.
so the %-thickness increases at 4 & 5. i don't think that this is "good" solution.
(tipstalls might get worse, don't they??)

There was no question concerning the impact on flight characteristics. ;)

The relative increase in airfoil thickness in the outer wing panels should not cause too much of an issue, but the lower Reynold's Numbers need to be considered.

:) Jürgen

[Brandano]

At the same camber and profile thinner wings stall earlier.

[MCarlton]

At the same camber and profile thinner wings stall earlier.

Thinking that through.

For a tapered wing with narrow tips.

How about the tip sections havign a transitional section from moderate camber at the root to high camber at the tip, coupled with a bit of washout.

It "feels" like that would even out the lift distribution across the tip, but thats just a gut feeling.

[nmasters]

pretty smart gut you have there ;)

[MCarlton]

Its been well nourished!!

;)