I don't know if it has ever been discussed but I've noticed a great deal of difference in the flying qualities of the airplane in regards to the position of the flapperons.

I have then on a rotary switch due to the minute differences it takes to make a big change.

It seems to me that the use of them will make a tail heavy aircraft fly well and the position creates all kinds of variables as to what the airplane will do.

I've only found this out on a Pizzaz and a Morris Su-Do-Khoi, I don't know if it will transfer to all types.

What kind of experiences can you share in this regard?

No one has ever experimented with the flapperons?

I doubt anyone feels flaperons can substitute for a properly trimmed plane, which uses flaperons as a manuvering aid, not a primary control.

AHH, but Tall Paul, putting the flaperons on a control knob is a great benifit in figureing out exactly where the ailerons should be trimmed. I now have a habit of reducing their total throw down to about 10% and then when flying the plane adjusting the knob slightly to see what difference it makes. If I find a setting I like then its simple to land, see where its at and then adjust the linkage to match.

Zpat, the bad thing is there is no hard a fast rule about exactly what will happen with them slightly raised or lowered. Depends on the style of the plane.

Ed M.

I have built a park flyer style electric based on a modified Wing Dragon wing. The flapperons were made by cutting loose a 40 mm wide strip of the trailing edge and hinging it with self adhesive film like the type used to cover ready to fly models. Wingspan is about 1,1 m and fuselage length 0,9 m. All up weight is 550 gram. Motor is a Speed 480 with 8 cell NiMh battery. The tailplane and fin has no moveable surfaces. Control is by flapperon and motor speed. When flying there is no obvious difference between this plane and elevator controlled aircraft in the handling or flying qualities. As this is a constant speed aircraft, motor speed control is very sensitive and needs some getting used to. To much power makes to model go into a series of uncontrolled climbs and dives.

I use flapperons on my Katana, Extra, SSE and UCD. but only for braking before landing, or in combination with a 3D maneuver like maybe coming out of a hover into a harrier, or going vertical from takeoff. When using them as an air brake, you have to mix in a little elevator to keep the plane fairly level. A little bit of flap will create lift, too much will cause drag, and that's what slows me down for my short runway. I guess it would work for take off too. The only thing about flapperons is that they decrease your aileron effectiveness.

I use flaperons on my Extreme 540, it makes for some jaw droppingly slow landings. I havent tried using at as a control aid, but it does calm down a tail heavy plane for a nice smooth landing on a windy day.

Using flaperons for pitch control is about the same as elevons on a flying wing. I have used both flaperons opposite to the elevator for more lift and tighter turns/loops and as spoilers, going the same direction as the elevator. These give some very nice elevators and elevator landings.

A few weeks back my buddy and builder were in between projects and I had this old, beat-up Extreme 330. We decided to make it into a flying wing using the ailerons as elevons. He sawed the stab off and mounted my old OS .61SF fairly far out on the mounts. You need a CG at 10%-12% back so everything has to be shoved forward. The battery and rudder servo are up under the tank. We used old servos and receiver, nothing that would be a big loss.

He was skeptical as to whether it would fly, but has has made some weird planes that I have flown so I felt he would do OK on this one. I set the elevons slightly up. Actually, I followed the under side of the airfoil. You need some reflex in the wing for pitch stability.

I lined up and added about half power for take off. It lifted off and went straight as a string. No pitch wobbles, no roll problem. Flaps (my buddy) is saying, "I don't believe it!" It was flying like a trainer. I did have the controls cut way down from 3D flying. I put in a couple of flights, proving the concept. I did get some rudder flutter on the second flight when I added full power for a vertical 8, but you can't fly a 3D plane fast so I figure that was due to the large controls and going too fast and not to being a flying wing or tailless plane.

Bottom line: the plane was really too non-eventful, very easy to fly so it was a successful project.