When you first offer up the tailplane tip fairings to the tailplane with the elevators attached, it seems as though they are far too wide and too thin!
But when forced into a profile to match the elevator thickness, it all fits much better : )
The foam I used for this job was DIVINYCELL FOAM PVC which I had purchased from Aircraft Spruce … I had planned to use it to fill the elevator mass balance inside surfaces, but I’ve changed my mind.
This foam proved perfect for this job, being very rigid but easy to cut. But wooden blocks or some other ingenious product etc would do just fine.
Initially you need to make a conservative guess on how much to trim off so you can attach the fairing and begin to make fine adjustments.
Vans stipulate at least a 1/8″ gap.
I find marking with tape makes the trimming process a bit easier, sanding up to the tape edge.
Once close to the finished size I temporarily attached the rear face fibreglass layup to check clearances …
… fine tuning accordingly.
I bonded on the rear faces with the packing material inside the fairings to ensure a correct profile … it needed a clamp with gentle pressure as well to keep the fairing in line withn the tailplane surfaces.
Then the rear faces are strengthened with flox around the edge and a layer of cloth, extending up the sides.
Sanded to profile after the resin had set.
The usual washers and countersinking.
Nicest job of the whole process … pop riveting : )
A 1/8″ gap.
These two fairings were probably the most challenging to fit and align correctly, but with perseverance it eventually gets done!