Need a big glider airfoil
 

I plan on scratch building an EPP sailplane, 4.3 meter wingspan. So far I am thinking about using a sd7037 or s3021 airfoil, but Im not sure which is better suited to a plane of this size. I expect the final weight to be around 90 - 100 oz's. Could anyone suggest some preliminary wing parameters (chord, thickness, root). Also, the wing will be built as 2 pieces... where each half is composed of 2 panels. So, its possible to maybe use a different airfoil at the tip panel.

Mainly, I dont really know much about bigger planes, so any advice would help alot.

Thx in advance

RE: Need a big glider airfoil
 

I don't konw what kind of your sailplane?
It is a powered sail or no-power?

I plan make a electric sailplane, wingspan is 200 inchs.
root airfoil is RG15
http://www.nasg.com/afdb/afshow.phtm...dat&name1=RG15
tip airfoil is NACA23012
http://www.nasg.com/afdb/afshow.phtm...ame1=NACA23012
or NACA 8H12
weight/area about is 3kg/sqm

RE: Need a big glider airfoil
 

EPP doesn't have a lot of it's own strength. To help things along without needing to get into complex spar systems that sort of defeats the simplicity of the EPP concept I would suggest a thicker airfoil at least for the center panes. Something like a Selig 4233 at 12% would be a good choice.

Actually any sailplane of this sort of span is going to require a complex and well designed spar system. The span alone means you're going to put a big load on the wing in higher G loaded turns and pullups. And if you want to make it a fairly high aspect ratio so it sort of looks scale like then you'll need a rigid skin on the wing to support it from torsional twisting as well.

At this size it's not a Cut N' Chuck project. Structural details to support the flight loads need to be carefully evaluated and planned for.

RE: Need a big glider airfoil
 

Hi Mike.

Wingsection : you could use a HQW 2,5 12 or if you want a wing a little big thicker you might consider HQW 2,5 14. 2,5 stand for the chamberline and 12 and 14 for the thickness in relations to width of wing

I could suggest a rootcord f 300 mm and a tipcord of 200 mm.

These sections from mr. Helmuth Quabeck a very good and they respond admirably to flaps. Make these 22 % of wingcord.

and make the wing with 2 or ( better ) 3 flaps and ailerons in each wing.

Use a modern computerradio and have your pride and joy towed aloft by a competent pilot.

look into : www.gliders.dk
www.f3j.dk
www.iggnorge.com
www.igg-sverige.se


Kind regards,

hld - OY - 9901