Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 10–10 Revision 4, March 1, 2002
Figure 9
The leading edges of the wing, tail and control surfaces are the most common plywood bending
exercise in the Falco. There are several methods that may be used. One of these is to pre-bend
the plywood over a mandrel as shown in Figure 9. This is a method employed by a Falco builder
to pre-bend his wing skins. A large broom stick was used as the mandrel, and it was clamped
between two boards. One of the boards was cut to receive the broom stick. In most cases, the
weight of the plywood is sufficient to bend the plywood, but weights may be added as well.
Figure 10
After the skin is bent for the leading edge radius, the skin is glued in place as shown in Figure 10.
Next the skin is scarfed. Unlike most scarfs, this is not a straight cut. Instead, you must sand a
smooth, radiused scarf on the plywood. This is not as difficult as it may seem, since the layers of
wood and glue lines reveal any irregularities. Next the skin for the other side is glued in place.
After the glue is dry, they plywood is feathered to a smooth radius.
Most Falco builders do not pre-bend their skins off the airplane. Instead, they prefer to bend the
plywood over the leading edge strip using nails or clamps to hold the plywood in place. One
method developed by a Falco builder is to use large rubber bands to bend the leading edge skin.
This method is shown in Figure 11. The skin is cut so that it is a couple of inches longer than
needed at the leading edge. To this extra plywood, you glue a scrap piece of wood, say 20x20
pine. Before gluing the pine in place, drive a nail into it every 4 inches or so. Another piece of
20x20 pine-with-nails is used as well, and it is clamped to the rib. Cut an automobile inner tube
into long strips about 1” wide. If you cut the inner tube with a spiral cut, the rubber band will be