Starting on the wing

May 5 , 2006

Assembling the wing panels

Each wing half comes in two panels, one inboard and one outboard. The first step to joing the two panels of each wing half is to sand the ends of the panels with a long sanding block. This will prepare the surface for gluing and provide better adhesion.

Next you can use 45 minute Epoxy to glue the panels together while securing them with low-tack tape on top and bottom. Keep an eye on them while the glue cures to be sure they stay in perfect alignment until the glue is set up.

Once that epoxy has set up, you can go ahead and remove the tape. Now use a sanding block again to sand the glue seam and knock of any excess glue residue. Repeat the process for the other wing and allow it to set up sufficiently

The rest of the wing will need sanded as well before sheeting, so you can go ahead and do that step now if you like.

Installing the flap spar

You will find two hard balsa sticks in your kit that are marked as "Flap Spars" for the wings. I applied a long piece of low-tack tape down the leading edge of the slot in the wing for the flap spar. Then, applying epoxy on the spar and/or in the slot, insert the spar down in as far as it will go. I didn't put epoxy on the back/trailing side of the spar as the foam it would have glued to will soon be completely cut out anyway.

As you put the spar in, any excess epoxy will ooze out and onto the tape and the flap foam. When you pull the tape off, it removes the excess epoxy. As for the flap foam, you're going to cut/burn it out soon anyway so that will take care of that excess epoxy.

When all is dry, you can proceed to sand the area with a long sanding block to get any epoxy missed, and get the spar down flush to the wing surface if needed. Later we will go back in and add hinge blocks behind the spar to provide stronger flap hinging with the Robart hinge points.

Installing wing servos

The first thing I did for the wing servo installation was to enlarge and square up the servo bays. I marked them up for a perfect 3 inch square and cut them out to my marks.

Next I assembled eight servo rails for the four servos to be installed. I made these by laminating 1/4" aircraft ply onto thick balsa blocks. This would give me a hard surface to run my servo plate screws into but keep the weight to a minimum with lots of strength.

I epoxied the servo rails into position making sure that the top surface was 1/16" lower than the surface of the foam wing... you'll see why in a minute. I also added a some balsa blocks and aircraft ply on a shelf just behind the aileron lead channels. These blocks would give the servo plates something to rest on and screw into.

I cut my servo plates from 1/8" aircraft ply, which would be relatively light but very strong. The strength will be needed as the servos themselves get mounted to these hatch plates. Now I cut out a long slot in each plate for the servo arm to extend through and lay out the positioning of the servos on the backside of the plates.

The picture below shows how the 1/8" servo hatch plate recesses 1/16" down into the bays on the servo rails. This makes it so the top surface of the servo hatch is flush with the top surface of the 1/16" balsa sheeting that will later be added on both sides of each wing.

I epoxied 2 hardwood blocks onto the backside of each servo hatch plate and mounted my servos directly to these blocks. Hitec HS-645MG servos were used for both ailerons and flaps. All that's left to do now is to run 4 screws down through the corners of the hatch plates into the ply structure beneath. The finished assembly is extremely strong and stable. Later I'll work out the aileron extension leads that will run down the pre-cut channels in the wing. But for now, it's time to move on to the landing gear!

"choosing landing gear"