Wing tip stiffeners

[szicree]

I'm hoping to get some input regarding stiffening the top of my wingtips. I've heard folks say that they sag over time, but what is the approved method for reinforcing them? Any advice would be great and pics would be even better. Thanks.

[f1rocket]

I used some proseal to glue in some blue building foam from my local Lowe's Home Improvement Center.

[Mike S]

Randy, I noticed you have a tip antenna in there, a couple of questions if you dont mind.

Comm or VOR?

How well does it work?? Any problems, such as loss of signal when in certain positions-------signal blanked by fuse---------etc.?

I suspect others will be interested in your info.

Thanks, Mike S.

[Highflight]

The lightest and strongest way to reinforce an open fiberglass area is to lay in foam "beads" across the presumed weakest span, and then put a layer of fiberglass over them.

Imagine a round strip of foam cut in half lengthwise so that it forms a "D" shape profile. About 1/2" to 3/4" wide foam is plenty.
Put the flat side down on the inside surface of the wingtip, and then lay up the fiberglass cloth and resin over it so that the foam is covered and the layup extends about 3/4" of either side of the foam. It isn't necessary to glue the foam in place unless you just want to for grins.

The strength does not come from the foam itself, but rather, from the "D" shape of the fiberglass layup as a result of putting it over the foam.
Once cured, the foam has no value because it's only purpose was to determine the shape of the layup.
Also note that you don't have to use a very thick layup over the foam because the strength, again, comes from the shape of the resulting layup that forms a kind of reinforcing "beam". Two layers of 6 oz. roving is probably more than enough to stabilize the open area.

Highflight

[f1rocket]

Originally Posted by Mike S

Randy, I noticed you have a tip antenna in there, a couple of questions if you dont mind.

Comm or VOR?

How well does it work?? Any problems, such as loss of signal when in certain positions-------signal blanked by fuse---------etc.?

I suspect others will be interested in your info.

Thanks, Mike S.

It is my VOR antenna since its orientation is horizontal. My COM antenna is a bent whip on the belly. This is an Archer antenna.

The reception is very good. I have not noticed any problems with it although I have used the VOR sparingly. Gotta love GPS.

[Mike S]

Thanks for the info.

Mike

[RV_7A]

Steve,

I used a blue foam also, however I have mine oriented fore and aft on a slight diagonal.

http://www.jeffsrv-7a.com/WINGS/05-10-15.htm

-Jeff