I am new to RC and am wondering when flaps are extended when landing. Everytime I extend them, the plane shoots up and stalls, even at low speed. How (incerments or full) and when do I extend the flaps? Also do I use flaps on takeoff? I fly the Cessna 182.

Thank you

TCR, What you describe is normal. Flaps do two things. At low deflection angles (roughly less than 30 degrees) they increase lift, after that the increas drag. From a straight and level flight if you lower the flaps the full way you have a huge increase in lift, and the plane balloons upward. In a full scale 182 you milk the flaps down, 10 deg on downwind, 20 through the turn to base 30 through the turn to final and the rest of them if you need to steepen the decent angle. Some radios will mix in down elevator as you add flaps. Otherwise just hold what ever down elevator you need to hold to keep the nose from climbing.

HTH
Tom

For takeoff... you want a small amount of flaps . 5 deg to 7 deg deflection (about 1/4 inch on a typical .40 size plane) The idea is to make the effective angle of attack at the root higher than at the tips and reduce the chance of a wing-tip stalling befor the root.

For landing... you slowly dial in more flaps, don't just dump them down. If you dump them down with airspeed too high you get the baloon effect every time... an have a higher chance of ripping off a flap. (ripping them off is not a big concern with most models... its a huge concern full scale) Most planes need some up elevator to keep the nose up with the flaps deployed.(after the initial ballooning) Some need some down elevator to prevent the nose from rising. Its rare that one would need neither. Cessnas tend to need the up elevator.

The full scale Cessna will have a mechanism that can not deploy the flaps fast enough to violently effect the aircraft such as you describe IF the flaps are deployed within specified speed range. If you find the air speed indicator in a full scale plane, you will find it has several colored arcs on it (if its a mechanical analog dial. Newer stuff?). The main green one is normal speed range with no flaps. There will be one or more arcs that are for flap operating speeds. the top speed for flaps will be within appx 1/3 or less of the main speed arc, and the bottom flap speed will be somewhat lower than the bottom of the main arc.

The main purpose of high deflection flaps (on a light aircraft) is to allow a steeper approach without building up airspeed. They also allow you to fly slower before stalling. (how much slower is dependant on if you are trying to maintain altitude or making use of the increased sink rate...)
On a jet airliner the main purpose of flaps at any deflection is the lower required flying speed. They can nearly double the wing area with the multi-stage Fowler flaps.

When you flair for touchdown with flaps down and have the wheels touch just as the plane stalls you can end up with an extremely short roll-out. I've seen a full scale C-182 have under 100 ft roll-out on grass in light winds. (he darn near drug the tail when he touched)

They always increase drag. (Basically, ANYTHING that increases lift will also increase drag)

And in my experience, most planes (RC anyway) require down elevator when the flaps are extended, including Cessnas.

You definitely need to bring them in slowly, but if you have a two or threee position switch that's not possible, so be ready to feed in some down elevator, either with the stick or the trim lever.
Dennis-