Just after some advice on flaperons/spoilerons. I have just finished my first build, a heavily modified Dawn Trading Hurricane 40D, which is basically a semi-symmetrical stick designed as an advanced trainer.

One of the modifications I made was dual aileron servos, and while I know the plane probably doesn't need them I want to have a play with flaperons and spoilerons since it might be handy knowledge later. I've got it all programmed into my DX7, but what I'm not sure of is initial settings. How much deflection should I put in to begin with, and should I mix in any elevator with it, or leave it till I see what it does? The plane has full length strip ailerons.

I have them, I fool around with them but A bit different, I have A Kaos with the spoilerons set to my throttle per Ed Moorman of RC Report so they come up as my throttle comes down and I have them on A Hots but as Flaperons, they are slaved to my elevator, they come down as the elevator goes up. Both are set to A switch so I can turn them on and off. Ed has writen about this/these A number of times in RCR. You may want to look it up or contact Mr. Moorman.

The main problem I have with spoilerons of flaperons is that they make the elevator less effective during the most important time.. during landing. Just figure that adding, say 15 degrees of flaps to the flaperons during landing will reduce the aileron effectiveness by 15 degrees. I'm sure that there are many opinions about this, but i've seen this in action and just avoid it. But, again, I am not a super advanced flyer, and I like things simple.

CGr.

I don't think the reduced aileron effectiveness will be an issue for me with this aircraft, as I can get over three times the recommended aileron travels if I want. I will give it a go and see what happens. The plane has a .55AX in it so I have plenty of power to abort a bad approach if needed.

First you need to differentiate between Spoilerons and Flapperons. Flapperons are ailerons that also drop down a bit as flaps, but still retain their full aileron function. Spoilerons are spoilers on the wing further forward and also act as ailerons when only one is raised. When both are raised they act as spoilers to kill lift for a faster decent.

When you start setting up you flapperons, you need to do so in slow increments if you are not sure how the plane will react. If you put too much flap action in, you could induce a tip stall tendency or inability to roll the plane (or bind a servo). I would suggest you wait until you have quite a bit of solo experience with the plane before you start messing around flapperons. When you start, add just a ¼” of flap drop and slow increase that as you start flight testing and learning the specific flight characteristics of your plane.

Hogflyer

From my experience, unless the plane has huge ailerons, the effect seen from flapperon/spoileron is very small. A trainer will not have huge ailerons, by huge, I mean funfly/3D types, i.e. full span greater than 15% chord. I don’t know what you mean by “heavily modified advanced trainer”, but I’m guessing small ailerons. While I encourage you to experiment safely, I think you will come to the same conclusion, i.e. not really effective.

But, with big ailerons, such as on funfly/3d types, you can pull off some very interesting flying with huge flapperon/spoileron throws, like on the order of 30-60 degrees of throw. But as others mentioned there are some bad side effects so start small and use a switch to enable/disable the mix incase the mix is really naughty.

John brought up something I really didn't think about, the plane itself. My Hots has very large control surfaces and the Flaperons work very well, the Kaos has long but narrow ailerons, I didn't try the flaps on it but the spoilerons work great. I can be way up there and start slowing the plane with throttle and it drops right on down for A landing approach. I don't have any of this goofy stuff on any of my better planes but these are my two most flown planes, the Hots is A true fun fly plane and the Kaos is just A fun plane to fly!!

I have used both flaperons and spoilerons often on sport type planes and have found them to work well and be helpful especially for those hot landing planes. I have not seen this mentioned in any replies I read so this is what I do. I do this on my Spectrum DX7 and have done it in past on my JR 7202. Use the long toggle switch on top left of TX. to turn them on, BUT!! also have them initiated only when switch is on and throttle comes to a predetermined point called offset. I also mix some elevator as well. The amount of each has to be determined by trial and error at high altitudes. The main reason I set it up to engage by throttle location makes it instantly returned to neutral if need to go around, no need to throw the switch.

Clint:

I agree with all comments above.

I would just add:

1) A semi-symmetrical airfoil tries to pitch the nose of the model down; the more AOA and velocity, the more pitching force, which is counteracted by the tail.
Because of that fact, you need to mix the elevator accordingly.

2) Although the action of these narrow ailerons will be weak in either function (increase lift as flaps or reduce it as spoilers), consider that the model will loose some lift suddenly when you switch from flapperons to neutral; hence, don't do it while flying too slow or too close to the ground (while aborting landing).

Regards!

Thanks for the info guys.

Tried it after a couple of flights with the new model and it made no difference on this particular plane. The plane would happily drift along at walking pace anyway, even with no wind, so the only use I got from it was from what I was incorrectly refering to as spoilerons (thanks for the correction hogflyer), when both ailerons deflect upwards. I used this once after I touched down to hold the plane on the ground as at that point we were getting some big gusts and it wanted to start flying again.