I just read and replied to a posting about flaperons and spoilerons. I offered my opinion on these devices and don't really use them. Now, with that said, I do have two planes with real FLAPS, but not Flaperons.

My thoughts on flaperons or spoilerons is that they are often used in landing (mostly used in landing) and by adding some level of flaps, you remove effectiveness from the ailerons because of the amount of flaps added. This happens during a most critical time, during landing. I avoid flaperons and spoilerons, but it's a personal thing.

Now the question for you is if this is a reasonable approach? Do you, in your opinion, feel that these remove effectiveness from the ailerons or am I wrong? or even partially wrong or partially right?

Your ideas, please.

Thanks.

CGr.

My CGR you are busy this morning. I have a friend that has flaperons and spoilerons on his GP-Cub. Because it is such a floater I believe it helps him stick in on the ground, but at the same time also much more ineffective if a gust of wind comes up when he is close to landing. He is a instructor for our club so he is a good flyer. Simple breakfast this morning, cereal, muffin and coffee.

If you have true flaps and not flaperons. I would say the effectiveness of the ailerons remains constant, since they are not performing two duties. Essentially the flaps when down creates drag which in turn reduces air speed whcih makes landing supposedly easier. Sometimes this can result in a stall situation if the speed is reduced too much.

I guess it would depend a lot on the plane in question. Most of the sports planes at my club have more than enough aileron travel to allow for corrections when landing even if they were using 50% or more flaperons/spoilerons.

How much do you move your aileron stick when you are landing? I certainly have never used more than 1/4 of the possible travel during landing approach, so I don't really think that the reduced aileron movement would be an issue for the majority of sports planes.

Yes, the increased drag will mean more power is required to maintain flying speed, but isn't slowing down part of the reason to have flaperons/spoilerons anyway?

CGR

I am 100% with you in this regard. Do I have any proof from an aerodynamic perspective that there a reduction in aileron effectiveness? No ... but it makes sense to me. The last thing I need in the back of my mind during landing is a nagging feeling that I have less control of the plane because I deployed flaperons. I'm a firm believer in dedicated flaps or none at all.

-MA

Depends on the plane. Flappersons can be used perfectly effectively without loss of aileron effectiveness if they are full span ailerons and are used in moderation. If you have wing tip ailerons you're just going to induce tip stall by adding wash-in to the wing, and if they are deflected too far you'll have problems such as dropping full flaps but if you use them at about 15 or 20 degrees flap, you wont have any problems on most airframes.

I have used flaps for many years and I am a big fan of using them.

With the recent trend of using two aileron servos, I was seduced into trying flapperons on two of my planes - never again.

I didn't find any less aileron FUNCTION per se, but both planes acted a bit squirrley on landing approaches, especially during the turn-to-final. In fact, I lost one of the planes when the inside wing stalled on the final turn - and I've NEVER stalled an inside wing - before or since.

I immediately stopped using them on the other plane and won't use them anymore. However, I WILL continue to use regular flaps!

It's hard to say. Because when you use flaps, you're most certainly flying slower than when ailerons are obviously effective. And when you fly slower, flaps or not, ailerons really are less effective.

One thing that is for sure.......... when you're flying slowly, you really don't want to use too much aileron if you have an alternative. Get the wing up near stall AOA and a little aileron deflection brings on the stall. And that stall is only on one side. The other side's aileron movement lessens the probability of a stall. And that gives you snap roll. It's almost always the cause of the dreaded "torque roll on takeoff" when the pilot slams the throttle, jerks the elevator and prays.... and tries to steer the plane back to the right with the ailerons.

The use of regular flaps with regular ailerons actually gives the wing washout. And works like gangbusters. I've used that on big gliders and didn't see any huge difference in how slow the sucker got before the ailerons got mushy compared to landings without the flaps deployed. So my thought is that with flaps down, ailerons don't lose effectiveness more than they do at the same airspeeds with the flaps up. It's the speed that matters. And you can go slower with flaps.

As for flaperons-with-flaps............ Only flew a couple of big birds with flaperons and didn't see anything to like. Didn't need a bit more drag than standard flaps give. And that's about all flaperons can give you that I could see in practice.

It was described to me that flaperons with flaps should be a positive. The new profile of the outboard wing when flaperons are activated has a new stall angle and it matches the new stall angle of the inner wing with it's flaps down, matches it better. Darned if it looked to me like that mattered. At least in practice, landing the suckers. There might be a benefit for big gliders with partial deployment of both when you're thermalling hard. That part of the envelope pays you back if you can suddenly create more camber on demand. And more camber outboard is just as good as inboard.

I used to fly a full scale plane with full span dual slotted flaperons and felt no degradation of control whatsoever, as long as the extension was not extreme. There was some perceived falloff at maximum extension. Just remember that you are not supposed to expect the same amount of maneuverability in this phase of flight either. You should be either taking off or landing when they are deployed and not performing aerobatics.

Afterthought: They did extend the inboard portion of the flaps/flaperons considerably further than the outboard sections on the plane I flew.

http://www.bavirtual.co.uk/ops/fleet.../twinotter.htm

The main purpose of inboard flaps (other than increasing the upper surface of the wing, thereby giving one greater lift at slower speeds) is to make sure the inboard part of the wing stalls first. When you add flaps to the wingtips (i.e. flaperons), then you are inducing added drag at the wingtips, thereby increasing the likelyhood that the tip of the wing will stall before the inboard section. This leads to a bad situation, at a very bad time. Tip stall is one of the quickest ways to crash an airplane on landing.
Remember, to stop flying one MUST stall the wing. By adding the flaps inboard, not only do you maintain full throw of the ailerons, but you also create drag which will slow the plane down, while creating more upper surface area, therefore giving you more lift at slower speeds, and (when the time is right), at an altitude of about 1 inch, you reach the stall speed, the inboard part of the wing stalls, and the plane sits straight down on the runway. Way better than the wing tip stalling, the wing dropping to one side, and the plane coming to a nice, four point cartwheel "stop."

The thread is about flaperons and spoilerons and not really flaps, two different things all together. I use flaperons A lot, at least on my fun fly planes. I use them for stunts and different contests and they work great and are A lot of fun. As mike pointed out though, if you are landing with them I have found my planes tend to want to stall A bit as the speed slows down too much and the ailerons aren't responding as fast as they would if they werent deployed. I have mine on A switch and they are the slave to my elevator so as my elevator is going up my flaperons are going down. This is A fun way to get my spot landings real close, I stall the plane right over the X while inches off the ground. In A dead stick float I get A whole bunch of hang time and on very windy days I can even fly backwards. This is on A Hots, not an Extra, Fun Fly and Having Fun Flying, not good for everything. I put real flaps on Cubs and other scale type of planes, not flaperons, they are different. A lot depends on the plane itself.

CG, I use flaperon/spoileron more as a "trick" to pull off some interesting maneuvers. I've only use it as a standard setup on funfly/3D types, of which I currently have none. But when I used it, I generally slave flaperon from elevator, so elevator changed wing camber. This caused a much more agressive pitch change and a lot of drag. Spoilerons I'd apply for landings (I'd flip a switch and disable the flaperon, enable fixed spoilerons) so I could make extremely steep approaches and still stick to the runway without bouncing. My spoileron throw was generally full up aileron, so to roll, only one aileron would go down, the other stayed full up. With this I obviously noticed a huge reduction in aileron effectiveness. But with flaperon, I'm not sure. The reduced effectiveness may have been there and I just never noticed considering what I was doing with the plane. I can envision how they could have reduced effectiveness. But I'd think any reduction in effectivness would be minor, and if it created an issue, you could set up a flaperon -> aileron volume mix to circumvent the issue.