Month: February 2015
While some glue was drying i decided to work on fabrication some metal parts. After making the first aileron cable bracket for the flap controls I noticed that it need modified. I believe the aluminum angle used originally did not have a radius on the inside where the part in my kit does. Using the plan measurements the cable cannot be attached straight. You can see how the nut is held at an angle.
Moving the cable hole out 1/8″ moves the nut off of the radius.
Rather minor modification, here you can see original design on the left and my modified design on the right.
The completed assembly looks great.
With both aileron cables attached to the control stick you can see them in action.
The triangle torque plate provides the aileron differential where the aileron moving up travels more than the aileron moving down. In the picture above you can see how the front cable moves side to side where to rear cable moves more up to down so it travels less.
The RS-17 that makes up the trailing edge needs a 45° angle cut on the back side. To use my router I stapled the top and bottom together so the router bearing had something to ride on.
Next I cut the ribs to accept the trailing edge. This was not real simple because they needed cut behind the notch in the plywood rib gusset.
After cutting the piece to length I put it in place so I could mark where I need to put glue. I also put wax paper on the aileron to prevent glue from dripping onto the aileron.
I lined up the ribs with the aileron rib then stapled the RS-17 in place.
Here you can see that the 45° angle is not quite enough to provide good clearance for the aileron to freely move.
A few passes with the hand plane resolve this issue.
After planing the angle of the bevel ends up being about 30° not 45°.
When I flipped the wing over to install the trailing edge on the bottom of the wing I used some clamps to keep the wing from rocking. First I clamped a few large clamps to the workbench and rested the rear spar on them.
To keep the wing from sliding off of the clamps I used some small clamps to hold the spar onto the large clamp.
This held the wing vary stable but did put the trailing edge a little high.
The RS-512 aileron nose skin is applied just like the wing nose skin except varnish is not needed everywhere, just the areas that are open like those shown below.
I started at one end and worked towards the other using rubber bands and staples to hold in place while glue dries.
Using a file I made a small hole on the center section where the bearing support on rib five is located. Once the glue is dry I will make this hole a little bigger to allow proper aileron travel.
The wing is nearly completed, time to cut off the aileron. To remove it I simply cut the RS-1 of the ribs until the only thing holding the aileron in place were the hinges.
With the aileron removed I cut the excess RS-1 so they follow the curve of the nose ribs.
Now the aileron is ready to have the plywood skin wrapped around the nose ribs. Before I do that a few areas need to be varnished similar to the wing nose rib area.
Now that all the varnish is dry its time to attach the RS-539 leading edge plywood.
I used rubber bands to hold the plywood skin tight against the ribs.
The skin was stapled to the nose stringer every inch or so. After ensuring the skin was tight against the ribs I stapled it to the spar top and bottom. Each piece was added one at a time.
The final result looks good.
The next step is to cut off the aileron.
After the leading edge stringer was contoured to match the nose ribs I pre-fit the plywood sheeting. While the plywood was installed I marked the centerline of the stringer on each end and from the inside I attempted to mark the stringer and rib locations.
Then the plywood was removed and lines connected and added so I know where the glue areas are so I can avoid putting varnish there. Two coats of varnish were applied to all non glue areas.
The spar, ribs and stringer were varnished except where glue will be applied.
At least two coats need applied, once dry it will be time to glue the plywood on the leading edge.