Thermal Airfoil Questions

[garydog1]

I am going to cut some 100" or so wings for a thermal plane. I use pink foam and a home made hotwire. It may have a motor. I dont know. But I will probally use really light glass on the LE Maybe RE only

Can anybody point me to a good thermal airfoil for a home built.

Maybe mh32. But what cord.

Thanks Dan

[e-sailpilot86]

Hmm... many should be pretty good. Mh32 sounds fine, maybe a s3021, or ag sections if the wingloading is low enough. Look around at commercial products too.

[Ollie]

Pick the airfoil thickness for the strength and stiffness for the wing design.
See:
http://www.charlesriverrc.org/articles/design/joewurts_vacbaglayup.htm
http://www.charlesriverrc.org/articles/design/oliverwilson_quicksparstrengthcalc.htm

[DLD]

You might try the Quabeck 2.5/9, I found it to be one of the very best for thermalling, and it will move out when you need to. I manufactured hundreds of Saturn Sailplanes with the HQ airfoils, with many contest wins by numerous pilots. Although they work best with trailing edge control, the 2.5/9 is versatile enough to work on a poly ship very well.

Good luck,

David Layne

[Bernd Brunner]

Look at the planform of the organic http://www.airplane-model.com/organic2000sp.htm or at the Drela models. IMHO i would use a chord of 7-1/2" or 8" for a 100" glider.
Airfoil: MH32, HQW 2.5/9 or HQW 2/9 (less camber), an AG 24/25/26, or -what i have used - an modified MG06 2/9 (2%camber;9%Thickness). I wouldn´t choose the S3021 or SD7037 cause they have too much camber. I do like the more dynamic thermal flying..

Bernd

[histarter]

DLD has the correct approach for perfection. :D

Because I launch low, 2.5% MCL is just about right to yeild the airspeed I require for the weight I can build to. Because I build my wings the old woody way, I use a 8% flat bottom profile to encase that MCL (my Beachball) with a blunt entry for simplicity. To finesse flight I use turbulation or tripping (never both). Hey, it works!

To date I feel handicapped by the aging process, and realize no specialty profile is going to help me fly better - and this is true for the group of pilots I fly with (ages 50 and up). ;)

Attempting to fly centered on 400 feet of real estate, or less, one has to be a top notch builder of Light, and a pilot to match, in order to slip around at 2% MCL or less. :confused:

As I am still getting older, I am looking at 3% MCL to be able to fun fly lift. With the lightweight radio equipment available, I just may go back to flaperons to get 4% when needed. :D

[biber]

what i have used - an modified MG06 2/9 (2%camber;9%Thickness).BerndGood idea to try that. I believe that the MG 06 with slightly adapted thickness and camber is a very versatile airfoil. One will have to try things out, but the MG 06 is certainly worth a shot, no big risk of getting annoyed.
I'm a big fan of the 1.5/8 version of the MG 06 for slopers.
XFOILed the basic MG 06 and with thickness varying from 7% up to 10% and camber varying from 0 up to 3%. What I like very much is its apparent low RE-number capability.

biber

[Bernd Brunner]

Biber,

that´s exactly what i have done. And it´s working perfect!
http://www.rcgroups.com/forums/showthread.php?t=297265

Bernd