Hatz Biplane Association

Just got started on the C/S and have a couple questions about the plans. As I read them, it seems that the plywood placed on the tops of the c/s ribs is going to raise the profile 1/8" above the adjacent wing. Am I reading this correctly? What about supporting the fuel tank? On the c/s that I'm disassembling off of a wrecked airplane, the tank was supported by two straps. The plans are not specific but do mention three 3" pads glued to the back of the rear spar. Is that support pads for three straps?

Help me out here guys!

Sarpy Sam

I have a CB-1, not a Classic, center section. There are two plwwood pads glued to the bottom piece of plywood to support the tank. I also have two straps bolted to the front and rear spars, lined up with the pads, along with turnbuckles on the top to hold the tank in.
I'm not sure about the Classic plans.
As far as the 1/8" ply, I put a 1" wide strip of plywood on the top and bottom of each wing root going from the front spar all the way to the tip. This gave me a place to put the screws for the fairing strips. If you cover it correctly, use the tapes wisely and properly size the fairing you won't notice a thing.

Jeff Moore

Thanks for the info. I've also been shown that there's an adjacent strip of ply that goes on top of the first rib(butt rib) of the upper wings which masks the height difference. The three pads on the aft of the rear spar seem to be consistent with the larger fuel tank where the second inboard ribs have been removed and replaced with the second strut. I'll be using the smaller tank with the two inboard truss ribs which apparently only requires two straps.


Sarpy Sam