2.8.4 Rudder Horn Installation

This entry is part 3 of 8 in the series 02 - Wing / Winglets

Now that the rudders are mounted, the control of the rudders is the next task. The rudders are activated by a “horn” (basically a bellcrank) that is attached to the bottom of the rudder. But there’s a slight problem. The book says “Place your rudder horn on the bottom of the rudder.” But there’s no part number. Which would indicate that this is not a supplied part. But there’s also no template that is typically used to make one. A phone call to other builders indicate that this is supposed to be included in the kit. I’m sure that I could get the two horns shipped out to me. But where’s the fun in that???

So the first thing I had to do is make a template.

This is the bottom of the left rudder. I’ve drawn a line to indicate how far the horn will extend.

Here’s the template held against the right rudder.

Since the rudders are a symmetrical, I only need one template. I’ll just need to flip it over to for the other rudder.

The rudder horn is mounted to the bottom of the rudder by means of a hardpoint embedded in the foam. But the hard point provided is a puny piece of 1/8″ aluminum about 1 inch x 2 inch square. I decided to upgrade to a 1/4″ hardpoint the covers the entire area under the rudder horn.

First I removed the foam where the rudder horn and hardpoint will go.

Then the web (fiberglass) is removed at the front of the rudder.

Here’s the hardpoint dryfitted.

And the rudder horn.

Then I filled the pocket with an epoxy/cabo mix, pushed the hardpoint in place and covered it with 3x BID.

After it cured, I trimmed away the excess and was left with this.

Then the rudder horns were sanded along the edges to remove any nicks from cutting and the fit was checked again.

Two holes were drilled for mounting

Then I put the horn in position, drilled into the hardpoints and tapped the holes.

After that I drilled a hole in the end and mounted the rudder cable attach pulley.

Here’s the finished product.

And this is a factory hardpoint.

Not very impressive, huh?

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