Aileron Design

[Will.A]

Hello All,

New Member/first time poster here. There were a couple places that this thread could go and if one is more appropriate feel free to move it.

I'm currently rebuilding/redesigning a Kitfox model 1 from the ground up. I'm not doing it because it is in any way practical. I'm doing it because I like thinking of ways things can be improved and it's a small enough plane that even though I'm spending way too much money it's not as much as it would be if the plane were a lot bigger.

I'm not going to go into a lot of detail on the project, just some basics. The original Kitfox model 1 has an 850 lb gross weight and a 100 mph VNE. It is built very light. I'm designing new wings, beefing up the structure to handle a 1000 lb gross weight, more robust landing gear, more horsepower, and a lot of aerodynamic cleanup. My goal is more of a cruiser that will fly nearer the top the the LSA speed limit than a extreme STOL machine. Given the light weight, low wing loading and heavy duty landing gear, it should still be able to do some off airport work though nothing extremely short/rough.

So why am I posting this on SuperCub.org when there are Kitfox specific forums? As the thread title hints, I'm ditching the junkers style flaperons in favor of the more traditional flaps and ailerons. I think I can get better cruise speed and more drag to slow down with traditional flaps for landing.

I would like some of your opinions on the best aileron designs that you've flown. As you might expect I have seen Mike Pateys Scappy videos and know that he is a Cub Crafters fan and incorporated the latest Carbon Cub ailerons in Scrappy. I also follow Steve Henry who is doing a video series on his Latest Highlander build. He has detailed his aileron design which is a triangular section that dips the sharp leading edge below the bottom of the wing on the upward deflecting aileron and significantly reduces the control forces. So those are 2 designs that I'm considering at the moment. It also should be noted that the ailerons will actually be flaperons and deflect downwards at about 1/3 the amount of the dedicated flaps.

[mvivion]

Take a look at a late model (post 2005) Husky ailerons.

MTV

[stewartb]

Look at PA-12 ailerons. Better than -18 ailerons. Or look at any of the recent SQ variants, which use -12 style ailerons and internal controls plus they’re shorter width and deeper chord. That provides more available space for flaps.

[skywagon8a]

It also should be noted that the ailerons will actually be flaperons and deflect downwards at about 1/3 the amount of the dedicated flaps.

Take into consideration in most designs which droop ailerons, the amount of droop is usually taken away from the up travel. Up travel is important during slow speed flight because it is used to dump lift for roll control. When the up travel is reduced, the roll control effectiveness particularly in a cross wind is also greatly reduced. With that in mind, Droop ailerons are good. Just recognize their limitations.

[KJC]

Stewart-
I wish I could convince both the builders and manufacturers how much better the -12/14 ailerons are. For most of the -18 owners on here who have never flown a -12, be aware that they are sooooo much better n the roll department. Much more responsive. Night and day difference. I’ve mentioned to Jay Javron about building a wide body -18 with long flaps and -12 ailerons. He seemed pretty open to the idea.

[BC12D-4-85]

Do a simple search for "frise aileron" and select "images" then hold on for all the info available. Helio Courier and Cessna Caravan added top wing spoilers activated by up ailerons to support roll.

Gary

[cubdriver2]

Look at PA-12 ailerons. Better than -18 ailerons. Or look at any of the recent SQ variants, which use -12 style ailerons and internal controls plus they’re shorter width and deeper chord. That provides more available space for flaps.

Piper first used the style aileron in 1939 on the J4

Glenn

[TurboBeaver]

When the X Cub was being designed, first thing they had to ditch was the J-3 style of ailerons. So they looked at the 12 style and copyed it to get the response they needed.
Piper was aware how to improve the old cable ,a couple of pulleys, and a horn on the front of the aileron system designed in the 30's . BUT they introduced it on spiffed up
models, that because of their "extra cost" and their choice of the Wrong underpowered engine (0235) it was doomed right out of the gate.
Had the 0320 been an option in 1948 the 12/14's would have made a very different mark in the history books! Jay will hit a big homerun when he offers his wings with PA 12
ailerons.

[skywagon8a]

It's not just the ailerons on the -12, it is also their differential control. More up travel than down. The Cubs have equal up and down travel.

[frequent_flyer]

CubCrafters "G series" ailerons on the FX-3 are +/- 18 deg. Several years between flying the PA-18 and the FX-3 so can't comment on how different they feel or perform. Same ailerons and flap used on the XCub but I didn't check XCub deflections.

http://cubcrafters.com/c/tag/ailerons/

[courierguy]

It's not just the ailerons on the -12, it is also their differential control. More up travel than down. The Cubs have equal up and down travel.

Same on my RANS S-7S, differential control, I am surprised to hear the SC's don't have it. I do know that the SC pilots who fly it seem to like the way the 7 flies.

[Will.A]

I appreciate the responses thus far. Windy(a member of this forum is in my EAA chapter)has a -12. I'm going to see if I can get a look at the ailerons, and get some measurements.

Do any of you know if there are drawings available? I know the name Univair and that they sell parts, if they sell drawings as well that would be good to know.

Just for your info my new wing will be 13.5 ft long (plus the screw on tip which will add about 1 ft of span) with a 47.5" chord. The ailerons will be 7.5 ft long and the flaps will be 6 ft long. I'm more interested in good roll control than extreme STOL performance.

I'll also look at the newer Husky wings.

Again thanks for the replies.

[mvivion]

I once owned a PA 12. And I’ve flown several Huskys, including “new wing” Huskys. Those Friese type, deed chord ailerons on the new wing Husky are far better than any aileron Piper made.

MTV

[aktango58]

Might take a look at the Helios, they had some fantastic roll control ideas. Narrow but deep, and a spoiler. Maule went to the short but deeper option out on the tip also.

Length is not always the best option for roll.

[Will.A]

I once owned a PA 12. And I’ve flown several Huskys, including “new wing” Huskys. Those Friese type, deed chord ailerons on the new wing Husky are far better than any aileron Piper made.

MTV

Any chance you've got some pics or could get some? I've done a Google search and could only find a couple images of the underage of the wing with the aileron deflected up, but couldn't really see any details.

Might take a look at the Helios, they had some fantastic roll control ideas. Narrow but deep, and a spoiler. Maule went to the short but deeper option out on the tip also.

Length is not always the best option for roll.

In worried that a deep chord narrow span aileron will twist the wing.

[BC12D-4-85]

Here's an earlier discussion about ailerons and good roll control: https://www.supercub.org/forum/showt...sion-solutions

Gary

[mvivion]

[QUOTE=Will.A;817014]Any chance you've got some pics or could get some? I've done a Google search and could only find a couple images of the underage of the wing with the aileron deflected up, but couldn't really see any details.



Here's an image of a new wing Husky aileron:



And, a pretty poor video, explaining (sorta) how it works....by the owner of the company.

https://www.facebook.com/watch/?v=626259114692328

MTV

[bcone1381]

It seems to me like the new generation Husky aileron and the new X-cub ("fat" profile shown in the link on Post #10) aileron surface skin is slightly proud of the wing profile. I wonder if their positive attributes might have something to do with getting its surface into fresh air that has more energy.

[BC12D-4-85]

From some reading I believe the fat aileron design was also developed for the aerobatic world. Rate of roll and control stuff like for the Extra aircraft and others. Also they made some with the aileron tips having a greater chord length. Gave better roll control from the aileron tip than fuselage ends. Might be due to that energy enhancement noted. Then there's the trend towards blunt aileron trailing edges.

Gary

[Skywalker]

When introduced in the seventies RC aerobatic models used fat ailerons to reduce deadband, or aerodynamic sloppiness around center.

[stewartb]

Sharp trailing edges can cause aileron flutter. Or so I’ve been told by guys who know of such things.

[Farmer Hank]

[CharlieN]

Sharp trailing edges can cause aileron flutter. Or so I’ve been told by guys who know of such things.

Different airfoils will react, well differently. Attributes such as pressure differences on upper / lower surface in the aft portion of the airfoil. Relationship of trailing edge velocity difference.
During the late '60s when the NLF series of airfoils designed by Dan Summers and utilized on many new designs such as the Grumman Tiger and related, Beech Skipper and the Tomahawk and others,
I utilized the airfoil on a plane I designed and built. Dan made it clear to me, use the airfoil as the coordinates call out, this resulted in the TE being 1/4 thick. This was odd to me but he specifically warned against a sharp TE. He was also adamant to have a full re-flexing TE, ailerons and flaps.
I must admit a wood/foam VW powered side/side that ran 175 full throttle, cruise as 150-155 and came over the fence at 35, That one was a win for me.
So that example, no sharp TE, many planes obviously have very thin TE, I would say these are mostly non laminar airfoils but I expect there are many exceptions.
The plane I am building has one of H. Ribblets airfoils. I wish I started earlier when I could have consulted him.

[Farmer Hank]

A little off subject, perhaps, but this photo shows my aileron/flap hangers. They transfer a little force from the false spar to the rear spar. This might be a consideration if you plan to increase deflection of the flaps and/or ailerons.

[Will.A]

I've read a few books on aircraft design, and the Carbon Cub and Huskie aileron that stick up above the surface of the wing are in keeping with what I've read. If I remember correctly making the aileron 10% thicker is about standard. The one thing the Carbon Cub does different than what I've read is the convex surface aft of the hinge line. The one book I can remember states that the surfaces aft of the hinge line should either be flat or concave otherwise you risk flutter. I wonder if the cub crafters design has to be built to exacting standards or else it might be a problem?

[Steve Pierce]

When the X Cub was being designed, first thing they had to ditch was the J-3 style of ailerons. So they looked at the 12 style and copyed it to get the response they needed.
Piper was aware how to improve the old cable ,a couple of pulleys, and a horn on the front of the aileron system designed in the 30's . BUT they introduced it on spiffed up
models, that because of their "extra cost" and their choice of the Wrong underpowered engine (0235) it was doomed right out of the gate.
Had the 0320 been an option in 1948 the 12/14's would have made a very different mark in the history books! Jay will hit a big homerun when he offers his wings with PA 12
ailerons.

The X Cub aileron is a symmetrical airfoil and nothing like a PA12. Had a long conversation with Jim Richmond at Oshkosh 2019 about the design. Interesting story and they are really nice. Same aileron on the EX/FX2 and 3s but they are cable operated vs the push rods in the X and NX Cubs.