Ailerons

1/20/05 - 3

I'm not following the plan on the ailerons. The plan has the aileron built up with balsa leading and trailing edges, 1/16" ply ribs, with some small pieces to build up the hinge points. I thought it would be easier to make the ribs from 1/16"balsa, cut them in half and glue them to 1/16" sheet. I'm not so sure it was after drawing lines on both sides of the balsa sheets for every rib and then gluing all the little half ribs on. But after I cut up the leading edge to get the hinge ribs in I was glad to have the support of the sheeting. The 3/8 x 3/4 balsa leading edge was sliced in half and glued onto the sheeting.

Since I'm not following the plan I got started on the ailerons by tracing the outline on 1/16" balsa sheet then I set my angle gauge to the rib angle and marked both sides for the ribs and hinge points. I copied the aileron ribs from the plan, attached them to the balsa with a shot of spray adhesive and cut them out. When I cut out the smallest one, the tip rib, it looked pretty small so I took it to the wing and placed it next to the wing tip rib and it was about a 1/16" too thin. The foam wing is a little bit thicker than the plan. I decided the best thing to do is to make new ribs using the aileron I cut from the sheeted foam.

I sliced up one of the foam ailerons at each rib and marked the outline on paper for the rib templates. I drew a line one each from the hinge center to the tip and drew a leading edge line 90 degrees from the center line. I put the new templates on a stack of two 1/16" sheets and cut them out and in half, Now I had ribs the right size. Well at this point they are oversized so I can final sand to fit. In the end they may not be exact scale but close enough. I also made the plywood tip, root and center ribs. I didn't cut them in half

I cut the 3/8 x 3/4 leading edge length wise with a taper, notched the corner where the hinge pin goes and glued them to the sheeting. The hinge pin rides on top of the sheeting. I notched all the top ribs for hinge pin clearance and glued them on, turned it over and glued on the rib bottoms. That was tedious work.

I did some rough shaping of the leading edge then marked and cut out the slots for the hinges and after sliding the hinge pin in for alignment, I glued on the tip, root and center ribs.

 

1/25/05 - 6

Today was spent finishing up the ailerons and fitting the ailerons to the wings. I put small ply rib lets at the hinge points that are not at ribs and glued in balsa to fill in and strengthen around the all hinge slots. The rotary drive socket went in too (see below for info on RDS). That done I sanded the ailerons down and shaped the leading edge so I can fit them to the wing and the ailerons are pretty much done. The right aileron weighs 23 g and the left is 28 g.

I started on fitting them to the wing by removing the hinge points that I put in before sheeting. My original plan was to use a long wire to drill the hinge holes while the aileron is in place but I thought it would be better to take them out, measure and drill. By cutting glue, melting foam, yanking and twisting I was able to get the hinge points out. I measured carefully, drilled holes, put them back in with a twist and tried to put the hinge pin in. The hinge pin just would not go through the third hinge point. The holes were off a bit so I made a new set of hinge points, re-measured, re-drilled and they were off a bit too. It's at this point I decided to just drill them while the aileron is in place!.

1/26/05 - 2

I made another set of hinge points but did not drill them. I put them in, taped and pinned the aileron in alignment with the wing and was ready to drill. I made a very long drill bit from the .047" hinge pin by filing the end and went in through the wing tip. Since the first two hinge points were OK I held the aileron in correct alignment and tried to drill through the third point but I couldn't so I pulled it out, drilled it through at the drill press, put it back in and did the next two that way. I now had one aileron mounted and it looks good!. That wasn't so bad the third time. If i would have stuck to my first hunch I could have saved some time but anyway, as always, the second one will go much faster. One benefit of the way the hinge points are is that they are removable but get completely locked in when assembled. I'm tempted to leave them removable but it's not worth the risk.

1/27/05 - 2 - The next couple pictures are a little blurry. I find it's hard to get a good shot with my camera.

The left aileron went much better than the right. I already had the hinge points made so it was just a little work to fit them in and then to drill the holes. I re-worked the drill bit tip (cut it off with wire cutters) and was able to drill right through all the hinge points in one shot. One problem though, the last hinge point hole was too close to the edge so I made a new one and re-drilled.

Now to get them moving. I originally was going to use the conventional "servo arm sticking out of wing, control rod slinging back to the control horn" but found something that intrigued me. A Rotary Drive System. I got mine at www.irfmachineworks.com/rds/ which sells heavy duty RDS. Also www.ncws.com/rcrock/rds.htm shows pretty much what I have done except my drive shaft goes straight out. The RDS uses a slightly bent 1/32"rod (Rotary Drive Shaft) to create the movement. The more bend, the more movement. I made a test device and it actually works very well and has lots of torque. I will use a 30 degree bend since I only need 20 degrees of movement.

The hole was already in the wing for the aileron servo and it just happens to be in the right place! so I just needed to mount it in. I made servo mounting plates and aluminum brackets, screwed the servos down, put the RDS on the servo and put them in to the wing and made some adjustments to the servo plates for a good fit. At this point I wanted to see it work so I put everything together, hooked up the servo to a receiver to check it out and it worked pretty good.

This picture shows the servo mounted and the rotary drive shaft in the neutral position.

 

2/2/05 - 2

Before gluing in the servo plates I wanted to glue down the hinge points. I glued them in with 20 min. epoxy to give me time to get everything together and aligned before the glue sets. With those in I glued in some 1/16" balsa on the trailing edge for strength and sanded it flush to the bottom.

I put glue on the servo plates and put everything together again but this time with the rotary drive shaft in place with the aileron for alignment. After it set for a couple hours I just had to hook up the power again and try it out. It works beautifully! It looks great because nothing shows. Before I started I thought it would be a bit hard to set up but I am now a convert. I love it. It was fairly easy to set up actually.

So that does it for now on the Ailerons. Hooray ! I'm about two weeks from fiber-glassing. My short term goal is to fiber-glass by the end of February, That will mark the one year anniversary of the building phase. I can't say it will be the end of the building phase though because I plan on glassing before doing the flaps. The reason for that is that right now it still has the foam in the flap area and that is keeping the sheeting straight so I want to glass it that way.

Next up: fitting the wings to the fuselage and generally just getting ready to glass.

 

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Updated July 14, 2009