Wingtip Confusion

[PapuaPilot]

Also, I think the wingtips should be removable. Every condition inspection, I would pull them off on my KF4 to inspect. You can see a lot of the wing and it's condition through the wingtip end.

I agree. I pull my wingtips every inspection. I adds just a few minutes and allows you to see the inside. It gives me access to my landing lights, nav lights and magnetometer.

[Maverick]

I've also been trying to picture how that would work. As you say, gluing the tip attach strips to fabric doesn't sound like a good idea. However, I don't think having the fabric overlap the attach strips is a good idea either, as it would tend to form a wedge under the inside edge of the wing tip and the fabric would wear along that line.

I would be tempted to end the fabric with a clean cut at the outboard edge of the #10 cap strip. That would leave the underside of the cap strip clean for bonding and the fabric wouldn't foul the wingtip installation. If I do that, I see no reason not to install the strips before covering, and the fabric can hide the rivet line.

I looked at my pics and I wrapped the fabric around the side of the cap-strip of #10. I remember wondering about that but I recall that I sanded the epoxy varnish to roughen it up a little before applying the fabric and taking extra care to make a good glue bond of the fabric and then shrinking it so that it was good and flat against the underside of the cap-strip. I then bonded the aluminum with 3-M and rivets. I used nut plates for holding the wing tips on for reasons stated by Papua.

I don't know about cutting the fabric off. There's only 1" of surface on the cap-strip for bonding too. That idea crossed my mind but with the ironing of the fabric to shrink it, the idea of the strength of wrapping around the cap-strip was more appealing to me. With all the bonding and rivets holding the aluminum strips on, I don't feel concerned that the wing tips will go anywhere.

[taff]

This is how I done mine.
First dry fit the aluminum strip to the cap strip before fabric covering and drill the rivet holes, Countersink the cap strip for the rivet that will be installed later.
Apply the fabric and tuck it /glue it under the cap strip. Heat iron and shrink as normal.

Install the aluminum strips. No need for "bonding" you will be bonding to the fabric = no structural strength.
Rivet the strips in place with countersunk rivets. Use soft rivets or you may be damaging the rib cap strip.
When everything is secure fit the wing tip and drill pilot holes for where the Rivnut is going to be riveted. You need a tool for aligning the holes for the Rivnut.

Use countersink washers if you want to use countersink screws, or pan head screws.

Use a little beeswax on the threads of the screws. Makes easier removal from rivnut.

[Eric Page]

Yeah, I suppose wrapping the fabric makes sense to prevent it from lifting at the end of the wing, and given the number of rivets holding the attachment strip in place, the adhesive is probably superfluous anyway.

Thanks, everyone.