My RV-7

Rudder Bottom Fairing

The fiberglass fairing at the bottom of the rudder was a bit of a pain. First, it is too tall as shipped. Second, even once I trimmed it to Van's scribe line, it interfered with the tailwheel spring. Finally, I want to put my tail light on it, so I had to come up with a way to run wires through it, yet retain the ability to remove the rudder...if nothing else, it'll have to come off for The Big Move to the airport. Someday.

I looked at a bunch of builder's web sites, I asked on VAF, and I looked at every RV I saw parked somewhere. Still, I couldn't get a good answer on how the wires are routed, how we avoid chafing as the rudder swings, and how you eventually remove the rudder. This is how I did it.

Oblibatory disclaimer: Don't copy my method. It would be bad. You'll die. Picture every molecule in your body exploding at the speed of light, and the end of all life as you know it. Total molecular inversion. And you'll waste 10 hours.

I started small...first I installed the adapter that the taillight screws into.

"How will you get the Clecos out of there" you ask? "Won't the get glued in place?" you wonder. "No!" claims I...I coated them with car wax. Nothing sticks to that.

Then out came the trusty UniBit to drill through the (rather beefy) fiberglass. This is where the wires for the taillight will need to poke through.

The corrugated black snake conduit...gotta love that stuff. This isn't there to protect the wire so much as to route it. Once the fairing is riveted onto the rudder, I won't have access to the inside. The conduit will let me (I hope) feed the wire through from one end of the fairing to the other.

This is what I thought it should look like attached to the bottom of the rudder. Sadly, the first fit checked showed that it was waay too deep. The tailwheel spring would go right through it.

But at least the top fairing went in well enough. It's pop riveted on for life.

We're starting to get the kernel of an idea. But the cable routing will have to wait until we resolve the fairing-to-tailwheel interference.

That required that I grind a hole in the bottom of this $60 part. I measured with a micrometer, marked it with a Sharpie, and cut it with a Dremel and a cut-off wheel.

That's about right...the tailwheel spring goes into that white steel tube at the bottom of the fuselage. Now that I know I removed enough of the fiberglass...

...it's time for a gluefest! Oh, how I hate gluejobs! This is why I'm building a metal airplane. But out comes the #$*@*! epoxy.

But while I wait for my glue-phobia to subside, here's a better photo of the bottom of this airplane. That grey piece across the bottom is the rudder bellcrank...the rudder cables go all the way from the pedals to that. If you look closely, you'll see the little rubber grommet that the taillight wires feed through. It's the black doughnut to the right of the green spar.

Another view of the rudder bellcrank. The front holes are for the rudder cables, and the rear holes for the tailwheel cables. Here you can see the taillight wires threaded through the grommet, protected by clear heatshrink tubing. Why clear? That's what I had on hand. Oh, sorry...want a more scientific reason? There are no magnetic monopoles. Hermitian operators have real eigenvalues.

Still not sure what the connector is going to be, but this one just fits. I ended up just using pins/sockets from a D-sub, with no shell...the Checkoway approach.

But back to my glue nightmare. I have to plug and fair the hole I made in the bottom of the fairing, so a trip to Home Despot netted a 4 x 8 foot hunk of pink insulation foam. Of that, six square inches made a plug that I stuffed in there.

Glassed it in on the inside.

Sanding is not my favorite activity, but that pink stuff sand easily.

Then I laid up a couple of plies of fiberglass on the outside. Sand, glue, sand, glue...lost of microballoons.

Having fixed Van's error, now I get to the useful part...routing the wires safely. This little foam bulkhead will a) provide a hole for the wires to go through, b) keep birds from building a nest in my rudder. That hole, by the way, is strategically placed. It's right on the hinge line, so that the wires twist but don't bend.

My die grinder quickly made a furrow for the black conduit to nest in.

A few more cycles of glue/sand/prime, and it's ready to install. Microballoons, flox, glue, etc. Thank goodness this isn't a Long-Eze.

The end is in sight!

Feeding the wires through is easier than I thought.

And as I hoped, deflecting the rudder doesn't bend the wires, it only twists them.

And to top it all off, I have adequate clearance between the bottom of my new rudder fairing and the tailwheel spring.

I started small...first I installed the adapter that the taillight screws into.	"How will you get the Clecos out of there" you ask? "Won't the get glued in place?" you wonder. "No!" claims I...I coated them with car wax. Nothing sticks to that.	Then out came the trusty UniBit to drill through the (rather beefy) fiberglass. This is where the wires for the taillight will need to poke through.
The corrugated black snake conduit...gotta love that stuff. This isn't there to protect the wire so much as to route it. Once the fairing is riveted onto the rudder, I won't have access to the inside. The conduit will let me (I hope) feed the wire through from one end of the fairing to the other.	This is what I thought it should look like attached to the bottom of the rudder. Sadly, the first fit checked showed that it was waay too deep. The tailwheel spring would go right through it.	But at least the top fairing went in well enough. It's pop riveted on for life.
We're starting to get the kernel of an idea. But the cable routing will have to wait until we resolve the fairing-to-tailwheel interference.	That required that I grind a hole in the bottom of this $60 part. I measured with a micrometer, marked it with a Sharpie, and cut it with a Dremel and a cut-off wheel.	That's about right...the tailwheel spring goes into that white steel tube at the bottom of the fuselage. Now that I know I removed enough of the fiberglass...
...it's time for a gluefest! Oh, how I hate gluejobs! This is why I'm building a metal airplane. But out comes the #$@! epoxy.	But while I wait for my glue-phobia to subside, here's a better photo of the bottom of this airplane. That grey piece across the bottom is the rudder bellcrank...the rudder cables go all the way from the pedals to that. If you look closely, you'll see the little rubber grommet that the taillight wires feed through. It's the black doughnut to the right of the green spar.	Another view of the rudder bellcrank. The front holes are for the rudder cables, and the rear holes for the tailwheel cables. Here you can see the taillight wires threaded through the grommet, protected by clear heatshrink tubing. Why clear? That's what I had on hand. Oh, sorry...want a more scientific reason? There are no magnetic monopoles. Hermitian operators have real eigenvalues.
Still not sure what the connector is going to be, but this one just fits. I ended up just using pins/sockets from a D-sub, with no shell...the Checkoway approach.	But back to my glue nightmare. I have to plug and fair the hole I made in the bottom of the fairing, so a trip to Home Despot netted a 4 x 8 foot hunk of pink insulation foam. Of that, six square inches made a plug that I stuffed in there.	Glassed it in on the inside.
Sanding is not my favorite activity, but that pink stuff sand easily.	Then I laid up a couple of plies of fiberglass on the outside. Sand, glue, sand, glue...lost of microballoons.	Having fixed Van's error, now I get to the useful part...routing the wires safely. This little foam bulkhead will a) provide a hole for the wires to go through, b) keep birds from building a nest in my rudder. That hole, by the way, is strategically placed. It's right on the hinge line, so that the wires twist but don't bend.
My die grinder quickly made a furrow for the black conduit to nest in.	A few more cycles of glue/sand/prime, and it's ready to install. Microballoons, flox, glue, etc. Thank goodness this isn't a Long-Eze.	The end is in sight!
Feeding the wires through is easier than I thought.
And as I hoped, deflecting the rudder doesn't bend the wires, it only twists them.
And to top it all off, I have adequate clearance between the bottom of my new rudder fairing and the tailwheel spring.