RE: OV-10 Bronco 81"
Nice, slotted flap hinges. Have you shaped the flap's top surface with an airfoil curve? What about extending the top skin of the wing back to form a slot lip?
Ooops, wait. I'm looking closely at your setup, and you actually want to reverse the hinges, so the hinge point (axle) is under the flap. That will give the flaps the correct motion to open the slot.
If you do those things, you'll have a decent slotted flap setup. With slotted flaps being blown in the propblast, you'll develop an unbelieveable amount of lift. The thing will float like a foamy. If it flies slow enough, you might even need ailerons & elevator on high rate to get enough control power.
You can do a search on slotted flaps in the Aero forum and get plenty of info and diagrams on good setup.
Anyway, good luck with that. Good Stuff.