HI,

I am currently interested in building an A-10 in 1/10 scale, this would be the same size as the new Freewing model which I am led to believe will be available April onwards this year.
Now most of the A10 video's in the smaller scale's seem to be way over speed. and do not look convincing when compared to full size.
Just to put some numbers in ::

Full size wingspan 57' 6", wing area 506 ft^2 root aerofoil Naca 6716, wingtip Naca 6713, cruise speed 340 mph, max speed 440 mph
Model wingspan 69" , wing area 5.06 ft^2, root aerofoil ? wingtip aerofoil ? cruise speed 34 mph, max speed 44 mph.

I would like to produce a "sport type design" what I mean by that is simplification , i.e. electric power via either a single pusher prop on fuselage tail or 2 pushers located in the turbine pods i.e. not a D.F approach. In other word by dropping a D.F. system gain more practability / increased efficiency, the resulting prop/ props would hardly be visible in the air. Ideally I would prefer to omit wing flaps so choice of aerofoils must be made on basis of no wing flaps for a quicker building wing and less weight.
I have done some calcs, and then there is some guess work,
Known quantities are wing Aspect ratio at ~ 6.53, taper ratio 0.68, wing tip chord 8.2 ", max chord 12.04", mean chord 10. 84" Reynauld's no's at 20mph are wing tip 127560, mean chord 169000, root 188000.
The guesswork is the final weight, now with a light build (some use of Depron) 8 to 9 lbs all up weight should be feasible , this results in a wing loading range of 25.3 to 28.5 ozs/ft^2.
I cannot find any aerofoil polars for the above Naca foils so cannot just trust to luck with them, should I use Clark y at root and tip with 1 or 2 ' of washout or does any body have a better suggestion please ?

Henry