Project Update - Ribs and Spars
I am beginning to think about wing assembly, and I have placed
a set of my scratch built ribs onto a set of spars. But first,
a quick update on my turtle deck and stringers.
The three stringers are now in place. Pulling 3 string lines,
and fabricating the bulkheads (stations) to the strings worked well.
The stringers shown here are currently clamped to little saddles welded
onto the bulkheads in the above photo. The stringers will later
be pulled riveted to the saddles.
The photo above is a saddle used to cradle the stringer in place
on the bulkheads. The saddle is made from a piece of steel tube.
The saddle gets welded to the bulkhead, and then the stringer gets
riveted to the saddle. I needed to add a little spacer to the bottom
of two of the saddles to ensure the stringers were nice and straight.
All other attachment points for the most part were perfect.
We are using aluminum tubing for the three stringers on the turtle deck.
It's light in weight, has a radius for the fabric to wrap nicely around,
and could be bought locally at our local steel supplier (no shipping charges).
We used 6061-T6 Aluminum Tubing, 1/2" diameter, and 0.049" wall thickness.
The bulkheads are 18" apart on center, and it appears that the tubing will
be stiff enough, pending control when a person shrinks the fabric, not to
distort it.
The photo above shows the saddle welded to the bulkhead,
and the stringer cradled onto the saddle, followed by a couple
of pull rivets later.
Rust Prevention
We use a light oil (air tool oil because it was handy) to prevent rust,
as rust tends to develop first on the welds, and later on the tubes.
We lightly wire brush any areas where rust is forming,
then coat the clusters and lightly coat the tubes as needed.
The entire fuselage will be cleaned prior to paint.
Ribs and Spars
It's pretty cold here in Wisconsin these days and my shop is not heated,
where I am working on my wings, so I can only make small progress
on my wing assembly. I can do enough in my cold shop to at figure out
what I have to either fabricate or purchase to continue.
Here's a photo of my ribs set on my spars. My friend Charlie
who is also building his own scratch build SuperCub with me,
picked up these 24 gallon wing tanks. He found enough for
two sets of wings. We'll need to pressure test them. We
bought the spars from Javron located in Brainard, Minnesota.
I built a one piece rib for quick and easy assembly.
I plan to fabricate the compression members (drag struts),
however I can not fabricate the drag and anti-drag diagonal wires
due to the threads needing to be rolled (not cut). I'm on the look out for two
sets of wires, new or good used sets.
My next step on the fuselage is to fabricate the upper doors (windows),
as the fuselages are located in a warm shop. More to come as these develop.
Thank you for viewing, and Happy New Year on this January 1, 2018.
John