Just got my new futaba 6ex tx, what is a good starting point for expo and aileron-rudder mix settings for my 52 size J-3? from research I came up with around 15% expo and 25% mix. How do these # sound? also, I have not flown the decathlon yet, what is a good starting point for that plane? I have seperate servos on my ailerons on both planes, would they benifit from flaperons? I would really like to the cub to be a stol plane, or will flaperons just make it more difficult to fly than its worth? As always, thanks in advance!

I flew my Decathlon with no expo or mixes to start. It's pretty graceful in the air and I don't think it needs much. Mixes I guess are up to you, but I like using my thumbs to coordinate turns on such planes.

Combination tools alway come at a cost of function. One tool designed to do one job is the best.

It's like that with flaperons. When you apply the flapperons, you loose some effeciency in the aileron area, and along with the flaps deployed, a little to much aileron stick will result in a pile of parts. What happens is with flaps, you are flying near stall speed, When you kick in a bit of aileron, you are deploying more flap on one side and less on the other. Tip stall soon to follow.

There are only a few planes I've seen that could benifit from flaps, and all were heavy pattern planes, war birds, or jets. Nothing in the trainer to third or fourth plane needs flaps. Also a newer pilot usually isn't ready for that complexity yet.

Don

I fully concur with Campgems above in fact if one had to list the worst possible choices for the use of Flaperons then the Cub Would be at the top of the list. Flaperons should never be used with an airplane having only barn door ailerons and no dedicated flaps This is just asking for low speed approach tip stalls. I would only ever consider flaperon use with an airplane equiped with strip ailerons.

Aileron to rudder mix is a mix that can be useful in many cubs to minimise adverse yaw however I suggest 25% is a bit much and would only try perhaps 10 percent intially. kIf your cub is a goldberg aniversery cub then no the mix is not advisable or needed since that design had ofset aileron horns to induce aileron differential which also minimizes adverse yaw. Most modern Arf however do not have that set up.

John

Mixing rudder with ailerons could be useful, but I would fly without it. The reason is that rudder and ailerons should (in my opinion) be controlled individually. When entering a turn with the Cub, both ailerons and rudder is necessary to make a coordinated turn. During the turn, release the aileron and hold rudder. If mixed, it will be difficult to keep the tail up during the turn, although it will help when entering the turn. Crosswind takeoffs and landings could be a problem with ail/rud-mix. Quite often cross-control is necessary to keep the Cub in one piece .

Flaperons: No. Cubs are known for dropping a wing when they stall. Some do, and some don't. Flaperons increase the risk of this, and you need quite a bit of altitude to recover.

Flaps: Yes. There is a huge difference between flaperons and flaps. Flaps are usually inboard towards the center of the wing. With flaps down, the center of the wing stalls first, and when the plane starts to drop, the wing is likely to be level. Flaps stabilize the plane during slow flight and stalls, whereas flaperons increase the risk of tip stall (one wing drops).

I agree with campgems that flaps are not necessary for a beginner. It is more important to learn to control airspeed with the elevator and descent rate with the throttle. That being said, when the basics are mastered, flaps can be great fun.

Correct me if I am wrong, but I believe that with rudder mixed w/ailerons, you will hold the ailerons through the turn because the rudder is trying to pull it back the opposite direction. I think I remember RCKen saying something about this.

Rudder is used in normal level turns to correct adverse yaw. Adverse yaw is caused by the downward moving aileron producing more drag than the upward moving aileron. This causes a yaw (about the vertical axis) away from the direction of the bank and intended turn. In other words an intended turn and bank to the left will cause the nose to swing to the right.

Normally in full scale for coordinated flight the aileron and rudder is used together in the same direction to compensate for this yaw. Aileron differential applied either mechanically or electronically which lets the upward moving aileron move further up than the downward moving aileron moves down will help to minimise the adverse yaw.

Aileron 'to' rudder mix in which when the ailerons are moved will move the rudder also with a smaller percentage of throw will help to coordinate the turns. Note this mixing in full scale aircraft is common indeed and the fact is most modern general aviation aircraft does have some form of aileron to rudder mix. Usually done in the form of springs mechanically. Taxi most modern general aviation aircraft with the pedals and hand off the column and watch the ailerons respond when making sharp turns with your feet. Yep that is the mechanical mix.

John

Expo, I start at about 40% and work from there, I like a soft center. I have only mixed in the aileron and rudder on one plane, a Giant Bipe. I had it on a switch and only used it at shows to help smooth out my turns without doing any of that thinking stuff, I had 10 or 12%mixed in, that's not a lot but it worked fine. Before that I had learned years before to use my rudder so it wasn't really a must do thing. Nix the idea of the flaperons, not needed on a Cub.