RE: ZIROLI P-61 BLACK WIDOW BUILD
AT-6:
thanks.
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Center fuse (cont)
Stringers
After removing the gear and finishing epoxy'ing in F-2, it was time to do some 'stringers'.
Initially, I was just going to start, blindly, putting in stringers into the former notches but I decided that I'd better number them first (good thing because the first one would have been incorrect!).
I started numbering at the bottom notch on each former as -6 and worked up to 0 along the side (just under the bottom wing support).
I then started positive numbers from 1 to 6 (on some formers but only +3 in other formers).
The stringers are only about an inch longer than the fuse so, virtually, no waste.
I started on the left side at 0 and worked down to -3 and then from +1 to +3.
I used a piece of scrap stringer to check each notch: usually they needed 2-4 strokes of sanding to get the stringer to fit in the notch.
I then dry fitted the full length stringer along the entire length of the fuse (usually) and put a tick mark on the stringer where the stringer contacted each former. I could then remove the stringer, put carpenters glue on each tick mark and re-insert the stringer.
Most of the time the snug fit kept the stringer in each notch.
After getting the left side done, I figured that I'd better get the right side done, tonight, to prevent any possible warping of the fuse.
pic 1/2:
Formers all numbered by each notch.
pic 3:
Only about an inch of waste per stringer.
pic 4/5:
-3 to 0 and +1 stringers have been added.
pic 6:
This short piece of stringer was bowing in the middle on some ply, with no place to use a pin, so I put carpenters glue along the length except about a half inch in the middle where I put some CA after putting the stringer in place; the CA holding the stringer in place until the carpenters glue dried.
pic 7:
This completes, for tonight, what I'll be stringing on the left side from -3 to +4.
EITHER A COOL IDEA OR NOT WORTH IT!
pic 8:
While 'stringing', I was remembering how long the fuse is from the wing to the nose gear and was thinking that a double wall along the stringers would really make that area strong (like shear webbing). Along the inside of the stringers, between each former, I was thinking of sheeting that area so the fuse would have a double wall, with stringers in the middle, between the wing and nose gear!!
pic 9:
This BVM metal sander works nice in sanding the former notches to the proper size.
pic 10:
Before I forget and cover them up, I epoxied the nose gear blind nuts.
pic 11:
Tick marks on the stringer at each former so I know where to apply the carpenters glue.