Rudder return springs

With the rudders installed, it was time to install the return springs. These springs bring the rudders to their neutral position when there are no wind loads to do the job.

The original plans gives us instructions on how to make the rudder return spring assembly (on page 20-6) using:

    -Aluminum tube 4.5" long, 1" OD x 0.035 wall
    -4" steel spring (0.35" OD x 0.050 wire dia
    -a hook formed out of 3/32" piano wire
    -1/4" birch plywood plug

The idea being to make a 1" dia disk out of plywood, attach a hook to it, and use it to plug the aluminum tube. This way the assembly can be floxed inside the winglet and the spring can have something to hook on to.

So I ordered all the parts, including 3/32" piano wire. Have you ever used 3/32" piano wire?! Not sure how one is supposed to bend this thing but it was impossible to bend a clean hook out of it!

Instead, I made the 1" plywood plug and used a large cotter pin. I fished it through the plug, added a washer (to protect the pin from eating into the plywood for years to come) and used a flat head screwdriver to split the pin legs apart. I then used a dremel to cut the legs shorter than the plug's diameter. Taaaaa-daaaa!

Notice how I also beveled the plug so it would have a nice fit on top of the aluminum tube.

I then used 5-min epoxy to bond the plug onto the aluminum tube...

Ok, so now to install it inside the winglet. The "high performance rudder plans" says to install the assembly at WL25. HOWEVER, the RST-2802 antenna manual (the Holy Grail manual that explains everything you ever wanted to know about canard airplane antennas) says "If there is a piece of metal more than an eighth of a wavelength long within a quarter wavelength of the plastic plane antenna design, the antenna performance will be degraded". They go on to say "with the classic dipole 'rabbit ears' design, metal close to the center of the antenna where the ears come together has practically zero effect. Metal out at the tips of the ears has a tremendous effect."

Hmmmmm... but the High Performance Rudder plans tell us to install a blob metal object at the tip of the antenna! Nooooooooo!!! Why!!!!?!?!!

If you recall from earlier posts, I purchased my antenna from Advanced Aircraft Electronics... their antenna is 43" long.. so there was no way I could move the rudder return spring assembly further down... as you can see from the pic below... my antenna pretty much spans the entire winglet (from top to bottom)...

So I decided to follow RST's suggestion and move the metal tube assembly closer to the middle of the antenna (where the rabbit ears come together). Since the middle of my antenna has a 1" cube (where the BNC connector is), I decided to get as close to the cube as possible. I took a square to the trailing edge of the winglet and marked where I wanted to the tube installed.

 I then uninstalled the rudder and drew a 1" dia circle at the same waterline where my marks were..
Since the rudder only deflects outboard, I biased the hole to the inboard wall of the winglet. This way the spring will be most effective.

Ok, time to drill! I took a large drill bit and made a pilot hole... making sure to be parallel with my mark lines...

 I then used a dremel to open up the hole to 1" dia...

Here I am test fitting the aluminum tube assembly...

 Perfect fit!

Time to flox it in! I started by painting the tube with plain epoxy...

I then painted the tube with wet flox...

 I also painted the hole inside the winglet with wet flox...

 And installed the tube in place..

 I pressed the tube in until it was only extruding about 1/16"...

 With the tube assemblies installed inside the winglet, it was time to install the hook on the rudder side. Again, rather than using piano wire, I used a cotter pin. Since it will be embedded inside the rudder in a pot of flox, I used the vice to crimp zig-zags for better grip...

 Now I had to drill the hole on the leading edge of the rudder where the hook was going to be installed. Again, biasing it towards the inboard wall..

After drilling the hole, I used a metal file to remove any micro from the glass and have a really nice prepped surface for the flox to bond to... 

Test fitting the hook...

 I then poured wet flox inside the hole and used a nail to work the flox all the way in...

With the hole filled with flox... I then installed the hook...

 I inserted the hook such that only the head was above the surface...

 After cure, I installed the springs inside the tube assembly, reinstalled the rudders... and then used needle nose pliers to extend the spring and hook it onto the rudder hook...

And there you have it... the rudders now return to their neutral position on their own!