Wing Tip 9A. mounted,have a 5" dish indent

[ron sterba]

I just mounted my Left tip on my 9A by Clecoes. Two ribs are installed in the aft wing tip but I noticed a LOW spot in the Fiberglass aft tip. Imagine the position of the two ribs, draw a line from the aft tip rib (2" from wing tip trailing edge) to the end of the other rib that is near the outboard wing tip. It appears to dip 3/32" in the center of this dish area as some guys call it. What did you do? Could you put foam ribs under the dish area and glass them in? Can you heat the fiberglass and try reforming? What did I do wrong?

Thanks Ron in Oregon 9A

[rockwoodrv9]

Ron,
I just got my wing kit and was looking at the wingtips yesterday. They are pretty flimsy - they look like they would flex and flutter in the wind. I have been thinking about how to make them more stable and considered expanding foam. Im still not sure what I will do, but the plan forming in my head is to build the wing, fit the tip with clecos, then check the fit. If needed, I will build a form or some sort and fill the tips with foam so they will not flex. If there is a better way, Im all ears. I will have to keep this in my head to try and come up with an easier way. I will be interested in how you plan to fix the issue. Maybe the new gray tips are different than the white ones?

[Kyle Boatright]

Originally Posted by ron sterba

I just mounted my Left tip on my 9A by Clecoes. Two ribs are installed in the aft wing tip but I noticed a LOW spot in the Fiberglass aft tip. Imagine the position of the two ribs, draw a line from the aft tip rib (2" from wing tip trailing edge) to the end of the other rib that is near the outboard wing tip. It appears to dip 3/32" in the center of this dish area as some guys call it. What did you do? Could you put foam ribs under the dish area and glass them in? Can you heat the fiberglass and try reforming? What did I do wrong?

Thanks Ron in Oregon 9A

The tips are often wavy. Internal ribs will show through the fiberglass. Your best bet might be a microballoon mix to fill the divot.

[RV9A Bill]

Some builders use styrofoam shaped to fit to stabilize the tip. Styrofoam
Blocks help prevent oil canning.
Bill

[ron sterba]

Thanks Rockwood. Sorry been off line for a week. I used a fillet of epoxy and filler in a 5" dish shape but wasn't happy with the bond to the tip skin and ended up chipping it off in favor of a LITE weight filler from a auto paint specialities shop. Flexible and has a superior bond to the tip. Plus this week I had a friend, Steve, come over and we set up the incidence on the 9A wings.Check recheck recheck check and recheck and check and recheck before I drilled. I used a digital level and perfect was the game.Well not Boeing perfect but as close as .00 on the level. Pretty happy. Ron in Oregon

[ron sterba]

Thanks Kyle, Abandoned the rib idea on your suggestion. Trying another idea from a builder to heat the skin on the other un-installed tip. Seems laying on the shelf for the 3 years was enough to put that dish shape dip near the aft edge. I heated the skin with a heat gun and put small bags of sand in zip lock bags and placed them inside the tip to expand the dip in the skin. Very pleased with the outcome. Took a few days and four or five LITE heatings to do the trick. My suggestion to new builders is to get the two ribs in temporary placement in the aft part of the tip and place styrofoam between the skins to bring the surface to a pretty straight line as BILL has suggested. Good idea Bill. Again if your storing the tips my suggestion would be not do store them on their sides but with the open side down maybe with a piece of styrofoam cut to the wing skin shape and inserted to the bottom of the tip while stored on the shelf. My two cents. Thanks guys. Ron in Oregon