Airfoil for a foam flying wing sloper

[Rich_N]

I am looking for suggestions, please, for a suitable airfoil for a slope soaring flying wing I am trying to improve and would appreciate any help.

It flies well when flown gently but does not perform aerobatics well and seems to lose momentum quickly so loops, rolls etc. are difficult and it loses altitude quickly during them.

I cut the wing sections from foam and it is tape covered similar to the Zagi.

Span: 4 foot
Chord at widest point: 18 inches
Chord at first step: 9 inches
Chord at tip: 6 inches
Washout: 0.12 inches

The fin and rudder are made from 2mm Correx (coroplast) with carbon fibre spar and 2mm carbon fibre vertical reinforcing inside Correx.

I would like to rebuild it using another section airfoil while retaining the look of the plane.

I believe that the reflex needed to achieve flight may be inducing too much drag so am looking for a more suitable section and am considering using the Zagi section (8% at the widest point and 10% for the outer wing sections) to reduce drag and benefit from the natural reflex in the section.

Will this work? Is there a more suitable section?

Thanks in advance for any help!

Please see the images at: Close up (http://www.flying-models.org/Test/Splinter01.jpg) and Flying (http://www.flying-models.org/Test/Splinter02.jpg)

[surfimp]

I've heard really good things about the HS 2.0/8.0, and will be using it on an upcoming forward swept flying wing design. Maybe you'll find it interesting?

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

[Jeff Leavitt]

Hi,

I've used the MH foils with very good results. He has a few that are for flying wings. The one that looks good to me is the MH-64. You can check his site at: www.mh-aerotools.de/airfoils/index.htm. You'll find a lot of good stuff there. Good luck.... Rgds, Jeff

[Rich_N]

Thanks, all, for the replies. Since my original post I have been advised to increase the weight of the wing and move the cg back to increase airspeed and allow me to reduce the reflex.

I thus loaded 350gram of ballast and took it out in 40-plus mph winds and what a difference!

I am now waiting for slightly lower winds to enable me to see just how badly the gliding performance has suffered!

It seems that this has really helped, though, and I've since built a second one with the same airfoil but with 4 servos to allow dual elevators and ailerons to give me more options to play with and to experiment with crow-braking to reduce that higher airspeed for landings!

I'll let you all know how it flies after I get the right winds.

Thanks again for your help.

Regards
Richard