12 – Rudder Lower Fairing

I decided to get on and face the composite work next, leaving the engine happy in it’s plastic bag for a bit longer.


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It becomes quickly obvious that although the basic shape of the composite components are pretty good, they require a fair bit of fettling to achieve a good fit.

I used a Dremel Cutting Disk to trim the material, marking the outline with masking tape, cutting undersize.

I found the tape easier to see under all the dust as the cut progresses.


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I found an ordinary file worked well to fine tune the cuts.


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This fairing is attached with screws, enabling access to the tail light wiring.

So an accurate cut has to be made to ensure a clean butt up against the rudder skin.

Of course these cuts govern whether the fairing is sitting inline with the rudder profile, so it took a few adjustments and eyeballing to be sure.


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The moulding on my fairing caused an unsightly lift of the front tabs, even after I had bent the flanges of the R-902-1 Spar as instructed.

I fixed this later by deflecting the tabs inwards and applying resin to set in the new shape.


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Once sure everything is set correctly, holes are marked and match drilled into the rudder lower attachment flanges.


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I used a nutplate/screw/nut to provide a jig for the nut plate holes …


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… using a cleco after drilling the first holes.


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The nutplate rivet holes are dimpled … needing a Close-Quarter Dimple Set for the aft ones.

One aft nutplate is offset from its mate the other side … it’s down to you how much, and it’s worth thinking ahead to position them so the riveting later on goes easier!


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Access for the aft nutplates is tight.


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The holes in the composite are machine countersunk to fit the AN507C632 screws.

I plan to use Tinnerman Washers here to provide a larger bearing surface.

I did the countersinking by hand, using a bit of scrap aluminium as a jig to prevent the cutter tip wandering.


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Simple jig.


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I had purchased a Tail Light Mounting kit from Cleaveland ages ago, so used this for the light mount since it already had the holes tapped for the screws.


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I used a micro balloon mix to blend the mount into the profile.


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I added a micro balloon mix at the aft edge to allow the profile to be sanded down to match the thin rudder trailing edge.


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The forward lower edge of the fairing is trimmed to provide clearance for the tailwheel spring.


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This is done with a template in the manual, but I checked mine by temporarily attaching the fin/rudder to the fuselage.


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A fibreglass patch is made by laying up a couple of layers of glass cloth on a piece of scrap aluminium. I just used some cloth I had left over from the canopy layup.

I used a candle to wax the aluminium prior to the layup, and it worked as a release agent very well.

After first attaching with resin …


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… another layer of cloth is added on the inside, together with a flox mix at the join.


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Sanding down to the profile produced a very strong and pleasing result.


It’s worth spending a bit of time getting the aft edge of the fairing to match the rudder trailing edge profile, because as supplied the fairing is too wide at this point.

The Tinnerman washers work well.

That’s the first fairing done!

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1 Comment on "12 – Rudder Lower Fairing"

  1. Great detail in this section. I am about to start the fairing attaching today. After reading through your blog I feel much better about the process. Nice work.

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