I have been tempted to launch a giant flying wing for some time for various reason, and need some input:

I have a design loosely based upon Brian Shaw's El Condor from 1994, enlarged quite a bit. I am aiming for a 6m span (ap. 240 inches), and might keep the polyhedral design from El Condor. A few questions: My target is a 6,250 - 9,000 sq inch. area, and a weight around 20-25 lb, with a WL of 8-11 ounces/sq ft. somewhere. Probably go electric on a 1,200 - 1,500 watt power system.

What airfoil is recommended? Used for Thermal duration only.
Should I keep the stock reflex?
Can I thin the airfoil a bit and count on higher Rn to support a lower drag airfoil, with constant stability, lift coeff, and CG?
Can I keep the CG stock, around the 16% mark or should I move it due to scaling of the size?

Construction in mind is CF round LE, Foam ribs, D-tube setup, leave the inner section one piece at 2m, and two tips at 2m each. Probabaly remove the sheeting on the outer two sections. I just bought a Rebelove, and got some serious apprecitaion for how light, and strong a non-sheeted wing can be.

Four servo wing, each one driving a section of the TE.

Is there a better original to scale up?

Thanks in advance,

Anders

6m span

Wow! Isn't that larger than "legally" acceptable - like, doesn't that violate some sort of FAA (or equiv.) rule or something?

I sure want to see this thing if you ever get it going. Six meters? Wow, very cool!

I have found this site a great source of information on flying wings.
http://www.b2streamlines.com/

I am building a 2.5m x 0.45m wing for Thermal duration flying..its loosely modelled after the R2 wing described. I use the BW 05 02 09 airfoil described there.

You might want to try Martin Hepperle's website for more info.

Shane

PS I might do a 4m wing after this one is built but 6m....wow, thats going to be monster!

I would choose a selig foil shape, but first i recomend you post this in the modeling Science forum.

Ok, I don't know how to move this. I copied/paste, but there must be another better way.

The Selig S5010 is a very good airfoil, I have used it on a two meter wing and it flew very well.

Also check in with Bill and Bunny at B2 Streamlines they are extremely helpful to folks needing useful info concerning flying wings.

Mike

Anders. I thought there would be much more enthusiasim in MS than you have recieved so far. Give them some time though, there is a pool of knowledge that hangs out there thats huge. Back t the foil shape. MikeC has brought to the table the S5010 foil shape. I think hes given great advice here with this shape. the S5020 has a slight less drag but its your final decision on all the comprimises of higher lift vs lower drag. To be honest, it sounds like your already headed the right direction. Do you have profili? if not i would recomend you get it, its free and you can visual compare the foil shapes. I think you know what your looking for and this might help you compare.

6 Meters? What's the weight, including the saddle?

More info on flying wing airfoils (both swept and planks) here:

http://www.aerodesign.de/english/profile/profile_s.htm