HS Tip Fairing Fiberglass - Grrrr...

[ERushing]

Has this happened to anyone? After laying up the 2 interior layers of FG on the HS Tips and cleco'ing them to the HS, the layup bowed out so much that the elevator couldn't pass without rubbing. I had to push it in (toward the front of the HS) to let the elevator pass and ended up with this when the layup dried.

Any idea why this happened? I haven't seen this on any builder sites.

My plan to fix it is to lay up small pieces of cloth until the layup is ~1/8" from level with the edges and then shape the remainder with micro and sand smooth.

Any suggestions?

Thank you!

 

[Mike S]

Use some foam to make a close out for the tip, carve the profile you want in the foam, then glass over it.

 

[ERushing]

Hi Mike,

I had glassed over a foam insert for the first (outer) layer. The plans indicate that you should remove the insert before laying up the 2 inner layers. After laying up the 2 inner layers the first layer must have gotten wet enough that it became very pliable...

Or are you saying make a small foam insert to fill the sag and then glass over that??

 

[Mike S]

. After laying up the 2 inner layers the first layer must have gotten wet enough that it became very pliable...

Cured epoxy FG should not become pliable when the next layer is added. Did you let it cure fully before adding the second layer of FG?

Or are you saying make a small foam insert to fill the sag and then glass over that??

No, although that should work, personally I would just start over.

I have no idea why they want you to remove the foam after the first layup. A "sandwich" of glass-foam-glass is strong and light. Ask someone who flies a Rutan design or one of their spinoffs.

 

[9GT]

Cut that out and start over using Mike's procedure.

 

[bruceh]

I filled the ends with pieces cut out of aluminum sheet from the scrap pile. Epoxy that in with a fillet of flox, then fill the outside with micro.

Pictures here.