Turtle deck skin with side skin overlap

[Carlos Trigo]

Guys

In XENOS plans (and I suppose Sonex and Waiex plans would be the same), the overlap between the turtle deck skin and the fuselage side skin is made with the turtle deck skin inside the lower fuselage side skin.




Logic would tell me to put the turtle deck skin covering (by the outside) the fuselage side skin, at least to avoid rain and washing water to penetrate the tail fuselage.

Do you see any reason why the upper (turtle deck) skin should be installed under the lower (side) skin?

Thanks
Carlos

XENOS - B

[GordonTurner]

Hi Carlos

You are indeed reading the plans correctly. My assumption is that the curvature of the turtledeck forces it to stay tight with the side skin. I think I remember reading about somebody who did it the other way. I think he also built the plane with solid rivets, which might help if you want to research for the post.

Gordon

[sonex1374]

There have been many Sonex planes built with the turtle deck skin on top of the lower fuse skin. The challenge in doing it this way is to make sure the skin lays down flat between the rivets. The tension on the skin from the curvature of the turtledeck can try to lift the skin and cause small puckers along the rivet line. If you polish the skin the puckers will reflect the light differently and can really stand out. If you paint then the overlap in the skin will be sealed up by the paint and water won't penetrate the joint anyway. In any case, little if any water will tend to enter this joint no matter what you do (unless you are exposed to the elements constantly), and if you spray a little primer on that part that overlaps you can guard against any corrosion concerns.

Jeff

[Carlos Trigo]

[q . In any case, little if any water will tend to enter this joint no matter what you do (unless you are exposed to the elements constantly), and if you spray a little primer on that part that overlaps you can guard against any corrosion concerns.

Jeff[/quote]

Jeff

In case I decide to make the overlap as it is in the plans (waiting for more answers to make my mind ...), what about a fine bead of silicone rubber between both skins to prevent any water to penetrate?

Carlos

[Rynoth]

In case I decide to make the overlap as it is in the plans (waiting for more answers to make my mind ...), what about a fine bead of silicone rubber between both skins to prevent any water to penetrate?

Carlos

Are you also sealing all of your pulled rivets? I imagine they are as/more prone to water intrusion than the turtledeck joint. I haven't tested water intrusion at that joint but it is a very tight/straight seam the way the plans have you do it.

[NWade]

In case I decide to make the overlap as it is in the plans (waiting for more answers to make my mind ...), what about a fine bead of silicone rubber between both skins to prevent any water to penetrate?

Carlos

I would not recommend that. You don’t want anything that’s compressible between the metal as it will allow the rivets / joint to loosen up over time. Simply primer the metal before riveting together.

Also: Silicone will stop any paint from sticking to the area so you probably wouldn’t even want to use silicone on the outside of the joint after fastening it together.
A paintable body filler like SuperFil or a paintable latex type sealant (like DAP Alex Plus which is recommended in an EAA Hints for Homebuilders video for the base of antennae) would be a better choice - but again they would be applied from the outside after assembly is complete.

—Noel