Aluminum Fuselage Formers

[Archer39J]

Another question, are people finishing the aluminum formers? I'm not seeing any easy moisture traps, and they mostly get covered in areas they're exposed, so I'm inclined to leave them bare.

[Mark Goldberg]

The aluminum for the formers is 5052H32 - also called the "marine" aluminum. So no primer is required. The door sill is 6061T6 (harder) which is also very corrosion resistant. Mark

[Archer39J]

Right on, appreciate it Mark!

[svyolo]

Donna asked about my unsatisfactory method.

The bottom formers were no problem. When I installed my side formers I did not try starting at the tail like Jim Parker. I was not aware of Mark G's method for bending the formers. Instead I started from the front and worked my way back.

The unmodified formers placed a significant amount of stress on one of the fuselage tubes when I fit into place. By fit, I mean I applied pressure to the stringer to force it into its "clip" and make a nice bend to form the fuselage contour. When I placed pressure on the former, the stringer (Which is really tough material...way stronger than needed...a mark of good quality) would spring into position, but not yield. It did not bend, and this put pressure on the fuselage tubing. I was not comfortable with this at one particular point. Stresses were just too high.

My fix was to remove some material from the former and bend the tubing by using a method I show in photos below. I got the former bent and fit into the clips nicely so I thought. But the shape that resulted from my method did not result in a nice rounded appearance. At every point where I 'shaped' (by drilling a stop hole, cutting into the inside edge of the former, and slightly bending the former at the place where I cut it.) the tubing it resulted in a bend, followed by a straight section of the former. So looking at it from the rear, I got a squarish look rather than a nice rounded shape that it should be. It just looked goofy, and I wasn't going to let it go.

So, I got some replacement stringers from Mark G. (Thanks to scratch Patrol builder Ed Welfred from my neck of the woods for transporting them) and will do them over.

TAKE AWAY for those quick build kit owners just starting: If have some doubt about a task, e-mail Mark G. instead of trying to figure it out on your own. Don't guess, and don't experiment at least until you have found out how Mark does it. I did not do that. I guessed.


You can see the squarish look in the stringer in this photo to the left of the top of the Cleco.
IMG_3256.jpg

jpeg Screen Shot 2018-04-20 at 2.52.47 PM.jpg

I am using spruce for my stringers and they fit the same as the pictures from Brooks. The upper side stringer takes a hard turn inboard at the tail end. No problem for the stringer, but how does the fabric lay? Will it go back naturally to the tailpost, separating from the stringer, or should it be stitched to the stringer and tubing in the tail to keep the fabric against them?

[alaskabearhawk]

FWIW: http://www.mykitlog.com/users/displa...=217910&row=92