ORIGINAL: Jeff_edge540
Thanks for the excellent explanation and links on setting the CG for thermal gliders, Ed. Much appreciated.
I've noticed the main wing has several degrees of positive incidence (it also has a down-turned bottom foil - neg. camber?). I've never flown an airplane that didn't have a symmetrical or semi-symmetrical airfoil. I imagine this is what gives the Radian the excellent lift to drag ratio at lower air speeds.
However, your suggestion of putting the Radian in a 45 degree dive to check for elevator trim doesn't sound like it would apply to the 'Radian' type airfoil - would it?
We are not evaluating the wing, we are evaluating the elevator. This will work on any wing type, as far as I know.
I only have one plane that does not have an airfoil similar to this and it is a semisymetrical aerobatic glider. The flat, near flat or slightly under cambered wing is common on thermal duration gliders. Higher lift with moderate drag. Optimized for low speed flying. On a plane like this, 40 mph is really moving! It will probably do very nicely at 10 mph in calmer air. I don't clock my planes so I am guessing. But my Easy Glider, with the brushless upgrade, tops out at 45 mph and, for that plane, it is really moving.