Hatz Biplane Association

Good evening ladies and gents,

I have to share a simple and excellent solution to attaching the leading edge plywoon. This method also works for the upper wingwalk plywood.

First, I glue and clamp just the front edge of the plywood onto the leading edge wood and leave it overnight. Next day, I apply glue to all the ribs and false ribs. Then I pile on bags of concrete. Yep, you heard it. The concrete powder is dense and really heavy, and the bag conforms to the contours of the wings. It holds the plywood down so that it is contacting the full noserib edge. It was so simple and fast, I could hardly believe it. Last thing I did was add a few clamps to small sections of the plywood above the spar, usually in between the bags of concrete where the edge might have been sticking up a little. No staples or nails, few clamps and very fast.

Nick

Hmmm interesting idea. Thanks John.

Nick

I bought a couple of ratcheting tiedown sets (8 total) and prepared some 3/4 x 3/4 strips long enough to span the plywood leading edge material. Similar to the suggestion about starting at the leading edge then working back, I progressively tightened the straps, adjusting the position of the plywood and the pine strips until everything was where it was supposed to be before final tensioning. A tip learned in the process was that the whole process worked better with the ratchets placed over the pine strips. I think that I remember running the straps back to the rear spar, experiment.

John Kerr

Just a thought...I imagine I would not nail one whole strip at once, but do all the bottom nails, then all the next nails up and so forth. Does that make sense? I've found that if I bend it in place and clamp at the top, then the plywood is bowed out so that it doesn't contact in the middle, and the clamps keep it out, so I need to loosen the clamps to move the plywood into position. Hope that makes sense.

Nick

Thanks for the advice guys. I'll give the first one a go this weekend.

NIck

Nailing strips work great and they really speed up the process.
You get all the strips ready with the nails all started in them so all you have do is tap them in. No fumbling around with needle nosed pliers while the epoxy is going off.
The only tough part is making sure the parts are exactly in-line and tight before starting with the nailing strips. Straps, clamps and indexing nails are all helpful for that.
Don't forget to varnish the inside areas that aren't in contact with the ribs before you seal it all up.
Mark

Hi Nick,
I used 1/16" x 2" wide nailing strips tacked parrallel to the leading edge at the center of the nose ribs and false ribs along with the very leading edge molding. I used 1" x 1" strips that I clamped the leading edge skin down with at the spar and clamped it about every 6" or so. After the epoxy had cured I filled the tiny left over nail holes that were barely visible with Bond Aide. It worked perfect as long as I made very accurate measurements to locate the nose ribs and false ribs. I used 3/8 brass aircraft nails mainly because they are so small in diameter and left such a small hole after removal. Removal was accomplished by breaking away the thin plywood leaving the nail exposed to pull out with duck bill pliers. Hope this helps some and if I can help just send me a email and I can give you additional infor on how I did it.[attachment=0]Top wings complete resized.jpg[/attachment]

Howdy folks,

It's time for me to glue on my LE plywood. Now I've seen how most folks seem to nail it on to hold it in shape as the glue sets. I could do this, but I'm penny pinching on weight and would rather not use nails. Has anyone come up with a better nail-less solution? I tried just bending it over and clamping firmly at the spar, but it bows out in the middle, losing contact with the ribs. It's an interesting problem. Anyone?

Nick