SonexBuilders.net

I just set the aft fuselage tunnel on the horses and am ready to start the turtle deck. Reading down construction order it says to
locate, pilot drill and cleco left skin of F19-02 assembly to left longeron/side skin of tail cone box then repeat with the right skin maintaining a 1" overlap of side skins. Since there are no holes I assume you tuck the skin behind the side skins to use those holes as a reference for the turtle deck skin.
Next it says to locate, drill and cleco former #5 then 2,3 and 4. What I'm confused about is how I can install the formers with the turtle deck skin in place first. I expected to install them first and then lay the skin in place and drill them like a wing rib. I have both skins clecoed to the slice channel assembly which doesn't seem right either because I don't know how it could get attached to the lower verticals but that was the first thing on the construction order. What's not making sense here? Seems like I should have all those formers in place with the splice assembly attached before the skin goes on. Input appreciated as always. Pat Murry

No answer to your specific questions but ... If you're up for a little break it might be good to give this a listen before starting.

http://sonexflight.com/34/index.html

Good Luck,

Wes

Thanks for the reply. I've actually listened to all the podcasts. They are helpful for sure and Jeff and his crew do a great service to all of us. I remember them going into great length to describe how to avoid riveting in big dimples into the turtle deck skin but I don't think they talked about the procedure as far as assembly.
I decided to try clecoing the formers in place and seeing how that went and I realized that there's no holes in the turtle deck formers to attach it to the vertical channels in the fuselage. So apparently you have to locate those holes in the process of fitting them to the skin inside. If that's the case then it's a good thing I didn't rivet the bottom skin on yet because you'd about have to work from inside. I don't think laying inside the fuselage would be very enjoyable.

Turtle deck goes on before any formers go in. No bottom skin till the end of build.

Thanks for the help. It seems like those formers would be match hole like everything else and you could lay the skin over the assembly and tighten it down and drill the longerons last. Oh well, there's always the 51% rule.

Hi All,
I clecoed the turtledeck skins to the aft fuselage and presented the formers and looked for mismatches. I then removed the formers one by one and hammered them into shape on a sandbag until they nicely followed the contours of the turtledeck. A lot of work but the final result is a smooth turtledeck!

Rofomoto wrote:Turtle deck goes on before any formers go in. No bottom skin till the end of build.

Just like Billy says. Your formers should have a blue line on them, so you can have a helper see it through the hole before they drill. I also tweaked the flanges parallel-ish to the skin for a good fit. Last holes are to the verticals.

It seems like the top end of the formers could be predrilled to attach to skin splice assembly and then you could go one hole at a time and work your way down. I suppose you'd want to work from end to end on all the formers. It seems like it would help to have the formers clecoed to the splice assembly and lift the whole thing in place rather than trying to mark and drill them from underneath. I suppose it will make sense once I get going. Sounds like I'm going to need someone on the outside looking for the blue line and drilling and clecoing. I hope this doesn't constitute grounds for divorce. Thanks

I would not predrill. The shape of the skin will be very different on the bench than installed in the airplane.

I think Ryan trained his dog to help. Maybe ask him for advice.

The main reason (I think) for the order (skins first, formers last) is that it'd be WAY easier to jam/shape the formers into position under the skin, than to try to make the skin fit the formers. The skin is big, heavy, and stiff. The name "formers" is kind of a misnomer, as they don't really do much to "form" the actual shape of the turtledeck, rather they mostly act as support/ridgidity. There's no way around the fact that you will have to work over your head, inside the aft fuselage, which is always a bear.

Blue-line the formers as was said, drill the formers along the blue line from the top of the turtledeck pilot holes. This is the same method of drilling used for the wing ribs.