Laying out rib stitching (top verses bottom of wing)

[LSaupe]

Getting ready to rib stitch and see that I just cant lay out the same distances on the top vice the bottom (as I had hoped), due to the significant differences in arc length. How do you guys typically hadle this? At first pass I am thinking about laying out the bottom and them thansferring the top holes by putting a pointer through the bottom holes with a device to keep the pointer normal to the bottom surface.

How is this typically accomplished?

[Av8r3400]

My method: from the butt rib face mark your top surface (important one) use a vertical level (wing flat) or horizontal level (wing vertical) and mark bottom surface. Then measure bottom surface marks from trailing edge and transfer to tip end of wing. Snap chalk lines. Done.

Learned this from a Poly Fiber seminar.

[TahoeTim]

good tip.

I am wondering if it matters whether the lacing goes vertically through the wing. Would an angled lacing hurt anything?

[neville]

see pages 33 and 34 of the Poly-Fiber manual " how to cover an aircraft".
In essence you make a cardboard pattern of the shape of the wing, lay out
the stitches on the bottom, and transfer them to the top perpendicular to the cord, and use the pattern to mark top and bottom on each end of wing, then snap chalk lines. Kitfox sells the manuals at a very competitive price.

[ken nougaret]

Like Neville said, make cardboard template of rib, mark your parellel vertical lines on it, transfer marks to each end of wing, snap chalk line.

[jiott]

My method: Essentially the same as Av8tr3400 but I transferred the marks from the butt rib to two (for top & bottom) 1" wide strips of flexible fiberglass trimmed from the wingtips, flush with the trailing edge. Then transferred the marks from these strips to each rib-eliminated the need to snap chalk lines. One caution-when you first lay out the spacing marks you must check that your stitching will miss all internal structure, cross bracing, etc. It takes some fudging and adjusting of the spacing, but it is possible to find a layout that works for all ribs.

[LSaupe]

Perfect. Many thanks guys.