Bruce,

I did experiment with low deflection angles on the flaps with the gottingen 501, and at low deflection angles it was fiarly easy to fly. The model was impressive... it would takeoff in about 50 feet with an 8lb lead weight on board... power was a K&B .65 Sportster, altitude was 5,200 ft. I found that the flaps were useful with the payload... I would put them down to a medium deflection to help on takeoff... and all the way down to 40 degrees for landing... but whithout the payload the flaps were useless... it's hard to tell the difference between an 6 ft takeoff roll and a 5 ft takeoff roll. Where they were kind of fun was slow flight into the wind.. the model could come to a hover in the slightest winds... and as long as you didn't have to turn it was easy to control.

The eaglet I talked about could only be set to full flaps at 50 degrees. The reason I didn't like adding flaps to that airplane was because even with the flaps up that extra servo and structure weight detracted from the flying qualities.

In full size design Flaps are used to minimise the wing area needed, or in other words to maximise wing loading. The higher the wing loading the better the range, cruise speed, ect... In my experience with models and high lift devices I think that light models with good airfoils like the Gottingen or Selig 1223 are more fun to fly then ones with complicated high lift devices. For me the fun with high lift devices on models was more in the design and construction then in the flying... the only high lift model I put a lot of hours on had the leading edge slots.. that was fun because it was virtually stall proof, it was so easy to fly low and slow with no worry about stalling and or spinning.

This is pretty wordy, but I have done a lot of experiments on high lift devices... both on models and in the wind tunnels at school.

Ty