quick questin about ailerons
 

Hi, i have a hangar 9 Piper Cherokee which i flew for the first time today. It flew nice but comes in too fast for landings. I set the CG as far back as i could and used an 11x6 prop, to try and compensate for the problem, but still too fast for me. My question is, what would happen if i adjusted both ailerons, so they are both in the sligtly down position at the same time(almost like flaperons) Could this help to slow the plane or just make it fly awful. The ailerons use only one servo, so i couldnt use flaperons. This isnt my first low wing, but i had a hard time landing it. Should i give it a try ? thanks
-Jamie

RE: quick questin about ailerons
 

I would say no -- this is similar to adding positive incidence to the wing -- it will compromise the entire flight envelope. Your plane will want to climb with speed & you will have to trim nose down, but the trim change will be speed dependent -- a real pain. Plus there will be more drag & it won't want to fly inverted at all. It will also tend to balloon on approaches if you have to make a slight nose-up correction. Better if you actually learn to land it as-is.

A better alternative is to go whole hog & actually add flapperons, then the entire flight envelope won't be compromised & you can practice using the flapperons at a safe altitude before you actually try them out in a real approach.

RE: quick questin about ailerons
 

"My question is, what would happen if i adjusted both ailerons, so they are both in the sligtly down position at the same time(almost like flaperons) Could this help to slow the plane or just make it fly awful. "
"...what would happen..."
Tip stall.
Highly unrecommended.
Move the c.g. forward, and go for a lower pitch prop

RE: quick questin about ailerons
 

ok...i didnt think it would work to good, just an idea... I was also thinking of adding another servo for flaperons. My concern with that is, are flaperons actually that effectve on an approach? I mean, ailerons return to neutral position as soon as you hit the stick, and on an approach your constantly making corrections using ailerons, would they even be in the down position enough to slow the plane. i also have to consider i would have to cut another slot in the wing, and the little extra weight of a servo...i dont know though... would it be worth it ? let me know what ya think..thanks

RE: quick questin about ailerons
 

I played with flaperons on a glider in the past and tried it a few years later with an ARF shoulder wing sport model. Up to about 10 degrees down helps the lift a lot on the glider and a touch on the ARF with it's narrow strip ailerons compared to the glider. Niether model showed any sign of tip stalling (Sorry Paul). Assuming your model uses strip ailerons there is no problem at all with using the clevis links to adjust in some droop. All you're doing is adding camber to the airfoil. Don't go more than 10 degrees though or you'll find you have too much adverse yaw to enter turns smoothly without using rudder coordinated in with the ailerons. 5 to 7 is probably the best bang for the buck all 'round.

But if this is conventional outboard ailerons then don't do it. Tips stalls will almost certainly occur.

RE: quick questin about ailerons
 

My first try would be an 11x4 prop or an APC 11.5x4. After ten or twenty flights you may feel more comfortable with the faster landing speed and work back upto the 11x6. I did this to learn to fly my Kaos. Be careful about getting too slow on the landing approach[&o].

Losing some weight can be a big help. A four ounce change in a 40 size plane is fairly significant. Foam wheels, wood prop, physically smaller NIMH battery, mini throttle servo, arranging items to get rid of balance weight, etc.

A turn or two on the aileron clevises shouldn't drastically effect the performance of the plane.

Flaperons don't go back to nuetral when you excerise the ailerons.

Carl

RE: quick questin about ailerons
 

The main factor affecting landing speed is wing loading. If the airplane isn’t too heavy, you just need to make a flatter approach. Try slowing the airplane down at a safe altitude and see how slow it will go before stalling. You will likely see it fly pretty slow but with the nose held a little higher than some other airplanes you have flown. Use that higher nose attitude on approach and fly a flatter approach angle and I believe you will see a much slower approach speed.

As for the dire consequences predicted by drooping the flaps slightly, the net effect will be about the same as if you had built the wing with a cambered (or flat bottom) airfoil. It won’t produce greater tendency to tip stall. That is mostly affected by wing planform and loading. It won’t create a tendency to balloon, and change trim with speed. That is primarily affected by cg position. It will cause inverted flight to be at a more nose up attitude. Moving the cg aft won’t affect approach speed, it will just make the airplane less stable in pitch.

Using a flatter pitch prop is usually appropriate only if you can’t get a low enough idle. It will allow a slightly steeper approach angle but really won’t affect stall speed, which is what actually determines approach speed.

Practice slow nose high glides at altitude until you have a good feel for the normal glide. Learn to trim the airplane in this condition for approach, and I think you will find that the problem will simply go away.

RE: quick questin about ailerons
 

There's another option here too. I wonder if you're not adding enough up trim to slow the model down. If you just let it settle into whatever glide speed it's happy with as set by your cruise speed trim then it's quite possible that it's gliding fast for that reason.

So many of us forget that the elevator trim function is actually a PRIMARY control in full sized aircraft. The idea is to set the glide in a level or slightly nose high position that is about 1/2 way from the cruise to stall speed or a bit slower and then let the drag of making all that lift at a lower speed settle the airplane down to the ground in a flat manner.

This method was pressed home to me a few years back when I flew a Quickie 500 as a sport model. With its racing heritage it was clean and would glide forever if I put the nose down at all and let it have some speed. The only way to ensure it would land decently was to hang it up like above and let it settle in. I used to use a steep banked turn to bleed off the speed at the end of the landing approach and make sure it came out of that turn nose high and set up for the mushy approach.

You'll be playing with the stall of course so practice this at first with the standard "2 mistakes worth" of altitude under your model to get the hang of it.

Because I use the elevator trim so much I've added a 3/4 inch 2-56 screw set into the knob so I can find and use the trim quickly and easily.

RE: quick questin about ailerons
 

New planes always seem to land too fast. It takes a little while for you to get used to the plane and learn how to slow fly it. Chances are, given time, you will learn to slow it down without any modifications. That is just my experience.

RE: quick questin about ailerons
 

One caution on using flaperons (both ailerons trimmed down) as it will increase the tendency to tip stall if you get the speed to low, especially on that last final turn. Other than that, it should help.

RE: quick questin about ailerons
 

This is only true if the wing has outboard ailerons (barn door). Trimming down full span ailerons has the same effect as using a cambered (or flat bottom) airfoil and does nothing to aggravate tip stall.

RE: quick questin about ailerons
 

I must agree with Bruce and his comment about full sized landings. Modelers tend to forget about using the throttle when landing. I have had quite a few planes that would let me trim them nose high on the approach and then control the sink rate with throttle. Drag is what you want for slow landings.