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24 – Wing Tips Part 4 – Finished!

Wing Tip Ribs


The manual is vague when describing how to position these wing tip ribs … it talks about a “snug” fit without any distortion.

After playing around with the fore/aft position, I selected a location that matched the wing tip TE profile to the aileron profile ie too far aft and the tip profile was thicker than the aileron and vice versa.


I found it easier to drill the holes in the fibreglass first, and then match drill the tip rib rather than drilling through both at the same time.

As I drilled I made sure the inner edge of the wing tip remained flush with tip rib, not relying on the tape.


I decided to do a bit of filling to improve the look of the tip rib interface with the wing tip … there are two holes and an unsightly gap at the aft end.


I used some scrap fibreglass layup, (from the fin fairing rear face), to cover up the holes on the inside. This gave a secure backing for the holes to be filled.


Once the holes are machine countersunk it’s a quick job to rivet the tip ribs in place.

From the number of arms in this picture you’ll spot that my rivet partner Tim reported for duty : )


Using the smallest amount of filler as possible I improved the look of the tip rib installation.

Archer Antenna


I decided to use the right wing tip to house the Archer Antenna for the ILS receiver in the GTN650.

Researching various sources in the US seemed to confirm that an adequate reception is achieved using this antenna, as long as it installed correctly.


Installing correctly means providing a sound earth to the airframe.

Attaching the inboard edge of the antenna using the wing tip attachment nutplates should get the job done.


The leading edge of the antenna is secured by two screws through the fibreglass, which also serve to secure P-Clips for the lighting wiring.

I didn’t really want to drill these holes, but eventually decided it was probably best because it would allow easier removal of lighting wiring for maintenance etc.

I temporarily taped the outboard arm of the antenna whilst laying up two fibreglass cloth strips to form a permanant attachment.


The resulting installation. The wiring for the wing tip lighting will be carefully routed through the P-Clips to avoid any conductor crossing the antenna leading edge, as per the Bob Archer instructions.

Trimming Trailing Edges


The aft edge of the wing tips need trimming to match the aileron trailing edges.

I marked the tips using a long steel ruler …


… and having marked the line with tape, used my Permagrit long sanding block to remove the material.


After trimming, one of the wing tips showed a gap.

This was because the loop of fibreglass tape inside had not been pushed fully aft during the layup.


Nothing that a bit more resin/flox couldn’t remedy.


I test fitted the wing tips several times during the sanding process … I couldn’t face accidentally taking off too much!


Anyway, it all turned out pretty well.

The wing tips proved quite a bit of work, and was caused mainly by my decision at Oshkosh 2019 to fit AeroLED VX’s : )


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