Plastic flaperon tips

[colospace]

Has anyone installed the factory optional plastic flaperon tips?
Looks like their outer profile matches the outer profile of the flaperon (i.e. it is not intended to slip inside of the flaperon skins). There is no "mounting lip" formed into the part.
Also (in a plan view), there is little taper toward the trailing edge and a relatively small radius at the aft end. I'm cogitating on how to make this gracefully blend into the flaperon trailing edge.
Just wondering how others may have handled this before I start messing with the parts.

[HighWing]

Gary,
I will tell you how I would do it. I would first scuff sand the entire outer surface of the tip and the surface for a half inch or so inside the flaperon to create a tooth for adhesive. Then using the Hysol cover the edges and squeeze the sides so it will fit into the flaperon. Clean it up a bit and let it cure there. I would then use Micro or Superfil to fair in all surfaces to get a continuity with the tip and the outer flaperon skin. I can't imagine where the tip is in relation to lots of very delicate parts - trailing edge for example - that it wouldn't last the life of the airplane in original condition.

[n85ae]

What Lowell suggests is the way I did mine.

[colospace]

My current thinking (to preserve the existing good outer profile match and fit at the leading edge) is to bond a 3/8" to 1/2" plug of balsa/basswood halfway into the end of the end of the flaperon and bond the tip onto this "lip".
Then do a little SuperFil and trimming at the trailing edge.

[n85ae]

Then you will have the opposite problem that the tip is then outside the flaperon skin. Better solution is to mark a reference line on the tip with
pencil and with a sanding block sand the tip where it inserts and remove
the sheetmetal's thickness of material. This will make it so the outer part
is flush where it meets the metal. Then do what Lowell says - Hysol it in
place.

Regards,
Jeff Hays

My current thinking (to preserve the existing good outer profile match and fit at the leading edge) is to bond a 3/8" to 1/2" plug of balsa/basswood halfway into the end of the end of the flaperon and bond the tip onto this "lip".
Then do a little SuperFil and trimming at the trailing edge.

[n85ae]

Ten years later - As I recall I cut the trailing edge of the tip open and bonded
in a piece of aircraft ply. Then sanded this to form a proper trailing edge

[HighWing]

I tend to be with Jeff on this. A bit of history: From the get go, the flaperon tip was made with a block of foam that was glued in place and sanded to shape,then covered with a layer of epoxy - in the day, the structural adhesive - and finish sanded to shape. One of the guys in Kitfox Aircraft had a long career in the heat formed plastics business and he brought his expertise in and some of the featured options are from his experience - wing tip, flaperon tip and a no longer available closeout at the Model IV door to wing interface. I have seen the formed plastic flaperon tip simply glued inside the skins and left as it. It was designed to fit inside. If a smoother finish is desired, the FeatherFil or other material could be used to finish all joints and surfaces for a one piece look - similar to what was done in the old days.

Keep in mind that the original foam and Structural adhesive was just foam and epoxy shaped to fit - no glass for strength. My original suggestion had pretty much that idea in mind. There were few if any issues with the strength of the foam tips over time. My first foam and glue tips lasted ten years and 900 hours and I suspect survived the crash.

[n85ae]

Oh, correction again! Lowell is right, I had the foam blocks, that were sanded
and then coated with structural adhesive mixed with micro balloons. I must be
getting old.

[jiott]

I used balsa blocks sanded to just slip inside and bond. Outer profilecan be sanded for a perfect fitup with very little need for SuperFill. Nearly as light as the foam or plastic, but I believe stronger.

Jim

[dginok]

I haven't done much with them yet, but I remember thinking there's no way those plastic tips are meant to go inside the flaperon skin. I trimmed just a hair off of the end of the tip and it slid right in.