Empennage fairing drilling??

amaris · #1 03-19-2020, 02:36 PM

Thanks to the incredibly detailed Van's instructions "see drawing 44 for the empennage fairing installation details", I'm wondering how I match drill the fairing attachment since I have the dark gray gel coat and can't just see through it.

Any tips, techniques?

Anyone else doing a fiberglass underside fairing? I'm fresh out of the Sportair Workshop and think I can do it!

PhatRV · #2 03-19-2020, 03:03 PM

I think you can just drill a pilot hole, cleco and drill/cleco the next hole using the empenage skin prepunched holes as guide.

amaris · #3 03-19-2020, 03:06 PM

Well yes, but I can?t get in there to back drill. Seems I need the VS in place to keep things in alignment. No?

JonJay · #4 03-19-2020, 03:37 PM

Strap duplicator. One the few places it works well for the task.

RussellT · #5 03-19-2020, 03:42 PM

I used a laser on a camera tripod, set it up square to the screw hole then put the fairing in place and drill the cross with a small bit. Use a needle file to enlarge the hole if you are a smidgen off. Bit fiddly in that you need to move the laser for each hole but no big deal in the scheme of things.
Russell

bjdecker · #6 03-19-2020, 04:04 PM

On the vertical and horizontal stab, draw two lines starting at the screw hole and extending out 1.75" to 2.5", angle should be between 30° and 45°. Now lay the empennage fairing in place, tape it down, etc. Now re-draw the two lines on the fairing, the intersection will be the location of the hole in the VS and HS.

Cheers!

B

amaris · #7 03-19-2020, 06:02 PM

Thanks for the suggestions. I was surprised at how easy the hole duplicator worked. I thought for sure it would cause misalignment from being lifted, but each hole worked and then I was done!

andrewtac · #8 10-04-2020, 08:45 PM

I saw this thread months ago when I was doing mine; figured I'd follow up for others. I bought some strap duplicators intending to do it that way. The guy helping me said those work but a better method is to just draw a line from the center of the holes, make some tick marks on the line (at know intervals, I think I used 1.5",2",2.5" on my ruler. Then put the fairing on, put the ruler on the line with the scribe marks at the proper locations and mark the hole. I did this, the holes were centered; worked well and is very simple.