Just wondering what you guys do,that have built Diamond Dust's , with the trailing edge of the control surfaces, do you sharpen them to a fine edge or leave them as they are? or is it indifferent?..if you do sharpen them down , whats the best way to keep the taper even from L.E of surface to T.E

I've flown both tapered and blunt TE elevons, and can't tell any difference at 120-130 mph. So you could say that the blunt flap gets into the airstream quicker, making the model either more responsive or more twitchy, whichever way you want to look at that. The tapered TE goes into the airstream more gradually. In practice, I haven't been able to tell the difference. Maybe if I tried to fly the C/L STUNT pattern over asphalt with a fast delta, then the difference in handling would be more obvious?

To taper the flaps, get a fine line roller tip pen and draw a center line on the trailing edge. Then take a MASTER AIRSCREW razor plane [the Xacto plane is garbage] and go to town, until you get within a 1/16" of your C/L mark, then finish up with sanding blocks until you get down to a 1/16" thick TE. If you try to go to a point, it gets alot trickier and isn't worth the effort on a sport plane. Some guys inlay a strip of 1/64" ply to define the edge, before any shaping is done. Blunt TEs look hokey, a compromise is to use pre shaped aileron stock and "call it a day".