Eleavons

[Mike]

Do semi- symmetrical wings need a horizontal stab?
Also for eleavons, elevator up is still control throw up, correct.
If anybody could help I'd apprecate it.:confused:

[Dave Robelen]

H Mike,
It sounds like you are talking about a flying wing setup. Assuming that is the case, yes up elevon will be nose up control. The basic shape of the airfoil can be anything from undercambered to full symetrical. The main thing that will be affected is the CG position and the amount of up rigged into the elevons at neutral. Usually a flying wing with a semi symetrical section will do fine with about 5 deg. of up in the elevons at neutral and the CG set at about 15%.
Twisting in washout in the wing will be a big help in acheiving a stable setup. I hope this is some help.
Regars, Dave Robelen

[Dave Robelen]

Hi Mike,
After reading your question again and my resonse, I realized that I did not directly answer the issue. The answer to the first part is no, a semi symetrical wing does not need a horizontal stab. For that matter, any airfoil can be setup to fly without a stab. See the first response.
Regards, Dave Robelen

[Mike]

Thanks Dave for the info I'll be reconfiguring the CG this weekend.:)

[genebond]

I've seen a plane somewhere (EAM, maybe?) called the Tilde, that has a tail with just a Vstab. I have it on FMS, and it is different to fly. Also, the Elipse series from NES is basically this way.