Single Servo, Stock electronics Aileron Mod

[jklong03]

Inspired by dwane's post on his single servo aileron mod, I decided to take the plunge and do one of my own. I didn't want to upgrade the RX, and just didn't like the way two servos hanging under the wing looked, so that is what prompted this approach.

First, here are the main components I purchased at my LHS:


I chose the standard servo that came with an extension cable to make it easy to remove the wing. (P-KZ1090). I used the clevis and pushrod from an F-27 Styker only because it was about the right length and alread had z-bends at one end, I knew I wasn't going to need the clevis' as I bout a nifty little Dubro aileron horn with ball links (Dubro Cat No. 189) that I was going to solder the ends of the pushrods to to complete my linkage. I bought the servo arm assortment only because is had a straight across horn which is what I was looking for (PKZ1132). Also in the picture is the carbon rod for reinforcing the wing and removing most of the dihedral, a smaller carbon tube that the 1/16" rods would fit in.

First I put the carbon rod on the bottom of the wing, making a pocket for it with a soldering iron and used white Gorilla glue to hold it in place (and as you can see, stacked a lot of weight on it as it setup) I placed the rod at just about the CG point, about 2-1/4" back from the leading edge. As you can also see, I had already marked out the standard 14" ailerons to cut later.



I wanted everything as "hidden" as possible. I cut about 8" lengths of the carbon tubing, then made 90 degree bends at each end, with the second one (the one near the center of the wing) at a 90 degree angle to the other. Careful when you make the bends, as they will be opposite of each other on each side of the wing (as I figured out after just duplicating the first setup and then realizing the one was up-side down, oops!). I hollowed out a pocket for the servo right up against the main spar since I wanted to keep as much weight as close to the CG as possible, and just Gorilla glued it in place. Cut out the ailerons (the point of no return!) and here is how the pieces look kind of to give you an idea of where I was heading.



I covered the carbon spar with black duct tape to hide the pocket.
I used the soldering iron to make pockets for the control tubes in the trailing edge of the wing and corresponding pockets for the part that was in the center of the wing. As you can see, I cut little triangle wedges first, then cut the channels in the center part, planing to use the cut out foam to cover the tube pocket later (which I did as you will see). You can also see where I drilled a hole for a short, 3/4" tube to receive the control rod in the aileron.



Next I Gorilla glued the control rod tube in place in the wing by slipping it through the point where the channel in trailing edge meet the pocket I cut in the center. Put some medium sized nylon hinges in the ailerons, aligned the holes for the control rod in the ailerons and marked the spot on the trailing edge where the hinges met up and Gorilla glued them in place. Almost there, I looked like a wing again! You can also see how I used the little triangle strips I cut earlier to cover the pockets for control rods.



Sorry, but this was the best shot I could get to show how I buttoned up the control linkage. I put the z-bend in the outer holes of the control arm, slipped the ball joint connectors over the control rods protruding up from the bottom of the wing, screwed the brass threaded tubes about half way into the ball sockets, lined everything up and cut the rods from the servo to length. Soldered the rods to the brass tubes, aligned everything up with the ball sockets about 3/8" above the bottom of the wing (had to worry about things hitting the existing rudder and elevator servos when the wing was mounted. You can also see why I bought the servo that included the extension cable, since I can remove the wing without having to try and get to the small connectors on the side mounted receiver in my fuselage!


Here is the completed wing, sitting next to the plane. And below are two shots of the whole thing ready for the always nerve racking test flight to come! I'll post an update once I've flown it!

[jklong03]

First flight went well, but was shortened by my elevator clevis coming loose in flight! My mistake, I adjusted the trim and simply forgot to slide the little rubber keeper back in place! No major damage that a little gorrilla glue couldn't fix thank goodness!

But what time I did get I realized that I much prefer aileron turns to rudder turns and the resulting loss of altitude. Much nicer to make a nice sweeping turn and not have to worry about the elevator through the whole thing! Working 7 days straight, so will be a while before I get to try again, but can't wait!

[jd]

That's a good looking mod, nice and clean.

[jklong03]

I love building, tweaking and modding almost as trying to learn to fly as you can tell. However, after a several weeks living with this very complex design, I have now "unm-moded" my wing almost completely and done away with all this complexity. First of all, it was too difficult to maintain symmetry between the two ailerons with this setup, secondly, my use of the fiber tubes in the leading edge of the ailerons interfered with placing my hinges on the inside edges.

So I did an almost complete 180. I ripped out the carbon main spar and remove the ailerons. I cut the carbon fiber spar and sandwiched it between two popsicle sticks to provide about 1/2 original dihedral (yes, I know it makes me learn bad habits flydiver, but I just want to keep it flying long enough to get comfortable with ailerons, then I'll buy another carbon fiber rod and flatten the wing again! the I clipped all the torsion rods flush and glued them down so they don't vibrate in flight and add noise. I then re-cut the aileron leading edges to the usual near 45 degree angle like everyone else and used tape hinges. Of course, my slight OCD forced me to clear tape the trailing edges of the cut-outs and the leading edge of the finished, beveled ailerons (I didn't want any squeaky foam rubbing against itself. I then tape hinged them like most folks did. Next I'm going the two servo, y-cable method and putting the servos and control horns at about 1/3rd in from the inside edge of the cut-out points. And to cover up the slight blemishes from all this rework, I cut thin strips of black tape to make the hinge lines look a little cleaner.



3 days till payday, then all the parts will come together and I'll keep you posted on how it flies.