Splitting flaperons into flaps and ailerons

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Posted

Has there ever been a modification to the flaperons to split them in the middle so that the outer portion toward the tip was aileron only and the section toward the root was flap only?

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Posted

WHY????????????

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Posted

I only have a few hours in an avid heavy hauler so this is just what I noticed while flying it. The ailerons become less effective whith the flaps down and not because of lower airspeed. There is actually less aileron throw  with the flaps down. My thinking is that if you split the flaperon into 2 sections you might  have more aileron control at lower speeds. It might be necessary to make the aileron and flap have a little longer cord. It might help with adverse yaw also. I was just thinking about it and wanted to see if anybody ever did it. I know if it aint broke don't fix it , I was just wondering.

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Posted (edited)

Cliff,

     Some of the Avid Clones have already done this in a different way that I plan to do.

I have been engineering - make that planning - to make my Foxy with 14" differential ailerons and flaps, using the tube within a tube controls like the Wittman Whirlwind.  the majority of the controls are like the Kitfoxes, but control rods go to each section separately, and don't have the complicated mixer stuff.  I cut the closed end out of the stick crosstube and used the same pivoting bellcrank setup on that end just like the original end - rods from there go to vertical bellcranks that are offset about 32 degrees and rods from there to the connections on the aileron tube.  The flaps are on a larger tube and operate off of a slotted flap handle, somewhat like the Pipers.

In order to use the original rib ends, my flaps are aprox 6 1/2 feet long, and ailerons are 6 feet long.

According to my engineering book, the ailerons should be between 8 and 12% of wing area.

Sounds complicated, but really simpler than the original controls, and should give better roll control for xwinds and more flap power since I can lower the flaps to about 40 degrees.

EDMO

Edited by Ed In Missouri
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Posted

You are doing exactly what I had in my mind. I was going to mention the crosswind landing improvement in my last post but my wife asked me to do something with her so I cut it short. I also thought that if the flap cord was increased and balanced correctly you could have them almost touch the trailing edge of the wing when fully deployed for better flap athourity. If you have any pictures of your modification please post. One of my projects is a mark 4 with speed wings, I bought a wing extension kit from airdale and thought that when I rebuild the wings I might use a split flapreon design. I also need to install a left speed wing fuel tank at rebuild time.. I just haven't had any time to work on the Avids lately. I am still in the middle of a cosmetic (paint and interior) on my cessna 206. It is taking way too long to get it finished. I have an A model that I have put Kitfox 3 wings on that is very close to being finished, I plan to get it flying next then start back on the mark 4 next winter.

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Posted (edited)

Cliff,

     I am just finishing the 2nd mod to my 2nd wing - The only pictures I have of the ailerons/flaps is mostly in my brain - I have a couple of sloppy drawings of the ribs for them, and plans in my head of the controls and hangers and bushings - I have partial aluminum ribs now, and part of the tubes and all of the skin aluminum for them - that will be the next phase after getting my wing ribs modified and my struts built.  My tubes will be aluminum, except for the leading edge tube which will be 4130 and is there for an internal balance.

My favorite balance trick is to mix lead shot with epoxy and either put it into a tube or encase it in fiberglass like the balance points on my elevators.

There were some photos of the Wittman bird controls in either Kitplanes or Sports A, a while back.  It belongs to Steve ______, the guy who owns Whirlwind props.

Where are you located?

EDMO

Edited by Ed In Missouri

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Posted

Ed,

 

Thanks for the info. It will be another year until I get to the mark 4. When you get your design finished I would be very interested to see it. Hopfully you will have yours finished and flying by then. Have you ever heard of it being done before? In my opinion the flaperon set up was a compromise to make the folding wing easier to engineer. Giving up better flight characteristics for simplicity of design. I am not a flight engineer or an expert in design. I have just looked at all the other airplanes that I have flown and none had flaperons and non lost alieron throw with the flaps down. Thanks again, Cliff

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Posted (edited)

Cliff,

     With your 206, you might be familiar with the Robertson STOL and other STOL kits that droop the ailerons.  You lose some roll control with them, but it was meant for STOL when needed and the conditions were right - Of course, once we got off we went back to regular ailerons.

     If you can find info on the Wittman Tailwind, or possible other designs Steve Wittman made, you might look at them for ideas.  One person told me he used PVC pipe for bushings.

I will proudly be posting photos if I ever get my Foxy Flapper done - only started on it in 1997 in Alaska - but that's a long story with many stopsigns and detours.  I built it once and wrecked it before it ever flew - fell off of trailer in the Yukon Territory.  I needed new flaperons anyway, so splitting them was an easy choice.

EDMO

P.S.  With these powerful flaps, I had to design an automatic trim tab on the elevator to compensate for nose-down forces.

BTW:  This tube-in-a-tube aileron/flap control is nothing new - Flaperons aren't new either - the Germans did both about 80 years ago.

Edited by Ed In Missouri

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Posted

Ed,

Yea and the Wright Brothers used wing warping but you don't see that on any new designs. I  had just been day dreaming about how to improve the stol performance of the avid and came up with this idea. I watch the  stol planes with the huge flaps, Sherpa, supercubs, Highlander, and alike. They all have seperate flaps and ailerons. What got me to thinking about the yaw was, I had a Taylorcraft 15a a couple of years ago and when I got it, it was out of rig. We attempted to make it fly straighter by tweeking first the ailerons then the flaps. During the changes we actually induced some  yaw with a flap adjustment. I never did get the thing to fly perfectly hands off before selling it. It just made me realize that ailerons  at the root of the wing don't seem to make much sense. I know that Avids and Kitfox have been flying for years, I just don't like the set up. I was just trying to see if any one actually flew one with the split  set up to see if it is worth all the extra work.

Thanks, Cliff

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Posted

Ed,

 sorry I didn't give you my location . I live in south central Pennsylvania. Near Gettysburg. I fly out of Lazy B Airport in Dover PA.

 

Thanks, Cliff

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Posted

Zenair uses a similar Folker style flap/aileron system that you are proposing.  Some insight might come from their people and published designs…  ??

 

I have my Kitfox rigged for 26º of flap deflection and at that setting I still have very responsive aileron action.  I think this is the difference between the Avid/early Kitfox airfoil with the flat bottom flapperon versus the Kitfox IV and newer Riblett airfoil with the symmetrical flapperon design. 

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Posted (edited)

I have the builders manual somewhere for the early model Zen 701/801 - it just uses straight flaperons -

don't know about their low wing.

Seems like lots of pilots get along just fine with the flaperons - I had to make new ones anyway, and remember my days in the Cessnas.

EDMo

Edited by Ed In Missouri

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Posted

Maybe I'm wrong, but I could swear that my buddy's 701 had split control surfaces on the same axle, like you are proposing.

 

I am feverish and sick with a massive viral lung infection right now though….   :tumbleweed:

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Posted

hoping you get better soon - we just had a Mizry blizzard here - a foot of blowing snow - enough cold to make an Alaska guy think it was summer!

Could be that Zen made some mods to the ailerons, or someone else did.

EDMO

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Posted

I have a buddy that built a 601 xlb and it used the top skin of the aileron for the hinge.  That seemed a little different to me. He has had no problems in over 200hrs.   I guess I am just trying to reinvent the wheel when it comes to the flaperons, probably not worth the time and effort.

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Posted

Here's one of the beauty's of an Avid/Kitfox, once you learn how to fly it, if the crosswind is too powerful to hold the airplane on the runway, say anything above 15, just turn and land going across the runway. With that much headwind, you drag her up to the edge of the runway and set her down and roll a short distance. And then take a bow when you get out of the airplane and act like it was all you but know it was the airplane! And we'll keep this all between us😜â—ï¸ Bryce

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Posted

Bryce,

 Have done that several times in a weight shift Terratorn back in the early eighties. I don't think I would get away with it at my airport in an avid, our runway is maybe 50ft wide with lots of obsticals. Hopefully I will get the A model finished and flying by spring and get some more time in it and I will feel more comfortable. I need to cover the left wing, paint the wings, and install,  to have the A model ready to fly. I have a few  hundred hrs in taildraggers ( cessna 180, luscombe, taylorcraft, champ, kolb etc.) but my buddies avid is a hand full, or should I say feet full, in a cross wind. I just need more time in it. I don't consider myself a tailwheel expert by any means I am just a late rudder pedal input away from a ground loop like any one else.

Cliff

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Posted

The designers took away most ground loops in the 1930s when they moved the main gear behind the CG and put the steerable wheel on the nose, and ailerons and flaps replaced wing warping.

EDMO

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Posted

Hey Cliff,

The Avid is a lot more squirley compared to those planes. The worst thing a pilot can do is think they can handle an Avid cause they have flown other taildraggers. It'll bite they're a$$ real quick. Unless it was a Pitts. They're worse than Avids. Lots of practice cures it though. Start off in grass then move to pavement. Otherwise, if you start on pavement you'll probably end up in the grass😂â—ï¸ Good luck, Bryce

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