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,

You've actually got 3 pictured that you will see used in real life. Let's talk about those 3.

BTW, all those wings have a dihedral layout that would be seen on sailplanes. None would be the first choice for other type airplanes. And like I said, two wouldn't be used, even on sailplanes.

Wings 1, 4, and 5 would all be possible choices for floater sailplanes. Why floaters? Because other types don't usually have dihedral breaks halfway out the span. And truth is, most often you'll see wings with half-span dihedral breaks also have center dihedral as well.

Wing 1's planform is often found on models where the primary consideration is ease of building.

Planform #4 isn't used much on today's designs.

#5 has become quite fashionable, and just might have only that going for it compared to #4.

Speed? Not really important to the usual application. So what do YOU want? What are you designing?

You often see 1 and 5 in use.

When you see a wing like 4, it'll probably have a leading edge sweep. Oly's are a bit like 4, but their LE is swept.

Oly's have their dihedral start at the root. A major reason to have the dihedral start at the root is there is no penalty in weight or construction to have dihedral there. You'll need extra strength there and it won't matter if the spar joiner has an angle or not.

Most gliders with dihedral breaks out the span usually have some dihedral from the root. Why? Fashion maybe. And so there will be less dihedral needed out the span. No really strong reason for that.

The reason for planforms that taper is to suit the lift to the strength requirements for the wing. The wing doesn't need to be equally strong all the way out the span. So can be weaker as it goes out. And it's not going to need equal lift at the tips, nor can it even create equal lift out there. And drag at the tips has disproportionate effect owning to the leverage the tip has. So take all those and you have an excellent case for having tapered wings. So #4 and #5 planforms have advantages over #1 planform.

I am confused .

what is the highlights of a wing design. where can find info?

What do you want the glider to do?

What do you plan to do with it?

One reason why #5 is often used these days on sailplanes is that the smaller tip chord slightly reduces the size and strength of the tip vortex. And a lot of the wing's drag comes from that vortex off the tip. The raked back Schumman style wing is supposed to be pretty much the best at reducing the size and strength of the vortex and this is why you see those raked back or even half elliptical crescent shapes on a lot of sailplanes.