Droop wing tip replacement/modification- KF III

[Jwayneball@aol.com]

The bottom of one of my tips is splitting. I could re glue or I could trim and refinish so the tips are square with the wing, or maybe find, or build new tips. Anyone have an opinion? I am not particularly fond of the drooped look and question it's functionality?

[Mnflyer]

Hi like you I'm not overly fond of the droop tips either, so I cut some of mine off, its been 5 /6 yrs so can't remember how much but I think it was 3 or 4 inch at the aft tip just used a straight edge and drew a pencil line on the tip and cut it offused JB weld make sure they were sealed and glued and its been good, I noticed no difference in stability or control nothing. Good luck with your decision.
If I were to do it again I think I'd cut even more off.

[Jwayneball@aol.com]

Thanks, Mnflyer. I probably will do the same. Wonder how Bondo would work as a filler?

[Paul Z]

Bondo will not bond the edge together. If it is a thick layer, bondo will crack, and probable delaminate under the vibration. It is design only as a thin coat filler.

I would recommend using some blue Styrofoam, bonded in the wing tip, shape with a sure form tool to desired shape (very easy to shape), use a couple of layers of 6 or 10 oz fiberglass over the shaped styrofoam, fill weave with Bondo, sand smooth, & paint.

[kitfoxSwede]

I would never use Bonbo on an airplane, Bondo is heavy and it does not stick well to epoxy. In fact when building a Varie-Eze, Long-Eze or similar Bondo is used when holding parts temporarly as it is easy to remove from the epoxy/glassfiber structure.

A tip is to get a copy of Rutans old booklet "Moldless Composite Sandwich
Aircraft Construction", it will tell you everything you need for a job like this. When using foam, glassfibre and epoxy, that is. There are a lot of information on this subject floating around these days but that booklet is still a good read on the subject of moldless composite construction.

[Paul Z]

Only a Very Light Coat of Bondo, but they make a specific Light Weight Filler to replace Bondo! I agree BONDO is heavy!

If you use the blue foam as a mold. Once the fiberglass has cured, you can remove the Wing Tip, you can chip out the blue foam with a screw driver.

[Mnflyer]

Hi Jwayneball@aol.com, I have to back up just a bit, just went down to my hangar and looked at my wing tips, I did not cut them off I did draw a pencil line on both tips but never cut them off, I did how ever round the trailing edge off (I use to get very disguised when I hit my head on the low hanging squared aft tip and I did seal them using JB weld. Looking again cutting off 2 to 3" would be easy enough and the top and bottom come together that far up so sealing / bonding them would not be a biggy.
As for using bondo I've used it for years with good success, example my wing tips did not match up to the wing leading edge there is a good 1/4" gap between the lE and the tip I filled it in with bondo 6 / 7 yrs and 500 hrs ago just looked tonight the bondo is perfect just like it was when put in.
There is a bondo with fiberglass in it and when it hardens its almost like steel and I've used it on fiberglass parts for tractor etc never had a problem it bonds and it holds.

[Jwayneball@aol.com]

Great response from you fellas out there who are more experienced in this than I am. Some very good ideas and a big boost toward resolving the issue. Thank you all for the information and advice.
Wayne