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Building the Schuler 1:3 ASH 26
Rick Briggs
RDS Install in the ASH 26 Molded Wing
I am going to show you how to install the RDS System in a Molded wing with the ailerons pre mounted with a skin hinge. If you haven't seen this before please look at my other article on installing RDS on a ASW 24.

"News Flash! 3/20/01" you now can get heavy duty hardened 1/8" shafts and machined pockets from I.R.F. Machine Works Inc. in Oregon

In these shots I have made a mockup of how the mechanics of the system work. Here you can see the "BOX" that mounts in the aileron, and how it works with the 1/18" stainless steel drive shaft rod.

The important trick is to lineup the bend in the rod so it works smoothly with the hinge line. If its not, it will bind, and you won't have good travel up an down. At this point I would suggest you do a similar mockup so you won't mess up that beautiful scale ship you just bought, and explain to the wife why you had to have it and she couldn't have the new dinning room set she has wanted for the last 5 years.

Below, I am making the box with two pieces of smooth faced Formica, cut to 3/4" x 2 1/2" long. The slot is 1" wide, I have roughed up the sides on either side of the slot to assure good bonding. Then I have epoxyed two pieces of plywood to one side of the box, use a slow cure epoxy, not 5 minuet. Next using the two pieces of 1/18" as a guide sand the plywood so its just below the rods, this is to allow for a good fit to the rod without it being to tight or loose when you epoxy the other side of the box. Now wax the rods, we don't want them to stay in the box. Next epoxy the other side of the box, be careful not to get epoxy inside the slot, place a small weight on the top and let cure. You will need four boxes so I would make 6, that way you can pick the best fits.

 

 
This is currently the best systems to operate ailerons and flaps with the scale look we all want. The interesting thing also, is it doubles the output torque of the servo. So you get two rewards by using RDS for you models. No control horns sticking below your wings, and more power to move the surfaces.

This is the flap servo, it's a Multiplex power mc/v2 the servo mounts are from Hobby Lobby, part nr. RA 190 they come in pairs for $2.75. The servo mounts to a piece of 1/4" plywood. Here you can see the coupling of the RDS. I am using piece of 1/8 " brass tubing for alignment porpoises. You have to drill out the coupler with a 1/8'" drill for the shaft.

Before I epoxy the servo mount to the wing I lay in some 3.5 oz uni carbon to reinforce the wing skin. The carbon is epoxyed with west systems slow cure, don't use a fast setting epoxy it will warp the wing surface. Cut the carbon so it goes past the access hole, 1" each side.
Using masking tape, I lay out a 45 degree angle for the drive shaft and mark the rear spar for the exit hole location. The angle is pointing to the tip of the wing, make sure you lay out each wing with the shafts pointing to the tip, right and left panels.
Next mark the rear spar for the exit hole of the drive shaft, here the rear spar is the upper black carbon surface and drill a 1/4" hole in the center of the rear spar, at the same angle as the rod.
Now your ready to epoxy the servo and the aluminum sleeve for the drive shaft. This photo does not show the uni carbon on the wing skin, but lets assume it's there. The aluminum sleeve just fits the 1/8" s/s drive shaft, with no slop, K & S now has 1/8" s/s rod, and aluminum tubing at your local hobby shops. Don't use piano wire, it won't bend tight enough.

The aluminum sleeve needs to be just even with the edge of the access hole, leave it long on the rear spar side, we will cut it off later.
This is the aileron servo, it's a Hitec HS-225 mg with the same mounting system as the flap servo. It also is laid out a the same 45 degrees.

Mask the rear spar area so you don't get epoxy on the hinge and aileron. Mix up some west systems slow cure epoxy with some west filler added so as to make a paste, I use west # 404 high-density adhesive filler for all my epoxy bonding. Mark the location of the servo so it will lift out, keeping it as close to the leading edge of the wing as possible. I this shot, to the upper left corner of the hatch opening.

Now you can bond the servo mount to the wing. Also you can bond the aluminum sleeve to the rear spar. The 1/4" hole is over sized so you can get a good amount of epoxy paste around the tube and the spar. Remember to keep the tube just to the edge of the opening.
Here, cut the aluminum tubing off leaving 3/8" from the rear spar. This shot shows the drive shaft exiting the sleeve at a 90 degree angle to the aileron, it protrudes 3/4" from the hinge line of the aileron not the rear spar.

You now can make the drive shaft. Slide the brass tubing out that we used for alignment porpoises. With the nylon coupling of the servo, slide the s/s shaft in the sleeve so it hits the top of the servo shaft. Now mark the shaft at the end of the sleeve. That is the point to bend the shaft so it's 90 degrees to the aileron. You do need a sharp bend so I recommend using a vise.

Next slide the shaft back in the sleeve and mark a point on the shaft 3/4" form the hinge line, then make a cut there. Radius the end of the shaft so there are no burs. Also, very important!, with a dremell or fine girder, flatten each side of the drive shaft where the allen set screws will come in contact. This will prevent the shaft from twisting in the coupler. I flatten them the length of the coupler, that way you can position the shaft to operate smoothly with the hinge line.
Now the tricky stuff. How do we get the box in the aileron????

If you have messed with the mockup you will find that the drive shaft end only moves towards the tip of the wing!!! when you rotate the drive shaft. SO with that in mind, as in the photo, the inside left edge of the box is where you want the drive shaft to be when the box is epoxied to the inside of the aileron. Read that line again.

I can't show you the box in the aileron because, the aileron will not open enough to see it once it's assembled. So to bond the box where you want it, you have to cut the AILERON SPAR so the box will move side to side.

As in the photo, I used a dremell to cut away the aileron spar. I over cut the right side of the spar 1/2" longer than the box. By doing this you can slide the box in the aileron and at the same time with the servo remove from the wing, rotate the end of the shaft into the box, by bending the aileron towards the top of the wing enough to slip the shaft into the box. I know this sounds like doing YOGA with your wing but trust me it works.

Once you have done a dry run, you can remove the box, take a deep breath and get ready to do it for real. Now if the shaft is to long do some fine tuning on the length, you want as much of the shaft in the box as possible with smooth movement. Now before you epoxy the box in you need to fit it to the aileron. Refer to the mockup, the box is roughly 1/4" from the hinge line. Keep tuning till it feels smooth to move the aileron up and down. The other trick to smooth movement is done by sliding the shaft in and out till you get the movement you want. What your doing is finding the correct position of the bend in the shaft to the hinge line of the aileron.

When you have got the fit and movement the way you want it, and your ready to bond the box in the aileron, take some masking tape and protect the bottom open end of the box, use just enough to protect the open slot from getting epoxy in it, this would not be a good thing!!! Also mask off the wing and aileron so you don't get it all over the wing. Hang in there were almost done. Mix up some more slow cure epoxy and filler, butter the inside of the aileron where the box will be and proceed to install the box.

In the left photo you can see the aileron servo mounted on the uni carbon. Also the coupling is mounted and the drive shaft in locked in with the allen set screws. Notice the end of the aluminum tube and the 1/8 " culet . The culet is there to prevent the coupling from sliding off the servo shaft.
Here the flap servo, servo mount and shaft are visible. In addition I made an additional spoiler hatch to be able to get to the spoiler servo.

I hope this article has given you the information you need to install the "RDS" system. It might look a little difficult to install at first, but it's worth the trouble. This was my first attempt a installing this in an all molded wing. No pain No gain, right? When your fellow modelers see that there is no control horns below the wings of you all molded 1:3 scale beauty, they will be mighty impressed.

If you need one to one help please feel free to give me a ring at home, 562-865-2464 evenings after 6:00 pm.

Good luck, Rick