Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 8–4 Revision 4, March 1, 2002
content, typically around 5 to 7%. If you use the plywood immediately, the plywood will be drier
than the spruce. In time, the plywood will pick up moisture and expand. For most parts, this is of
little consequence. If the plywood is used for skinning the wing however, the appearance of the
airplane will be seriously degraded. The expansion of the plywood will cause depressions between
the ribs. If you want a smooth finish on your Falco, you should order your plywood well in
advance and let it equalize.
Tests have shown that the smoothest wings will result if the moisture content of the plywood is
1.25% to 1.50% greater than the airframe. This way, the skin will tighten slightly to give a
smooth finish. To accomplish such precision, a wood moisture meter is essential.
The second thing to watch out for is that if you work in a heated shop in the winter, the wood in
your airplane will become very dry. Because of the contraction of the dry wood, one Falco builder
had corner blocks crack and pull away from the wing ribs. If you work in a heated shop in the
winter, get a humidifier and hygrometer to moniter the relative humidity.
As a further guide to the moisture content of wood, Figure 3 shows the recommended moisture
content averages for interior woodwork for use in various parts of the United States. This map
was developed for residential housing construction, but the patterns of moisture content may be of
assistance.
(Courtesy U.S. Forest Products Laboratory)
8% average moisture content
11% average moisture content
11% average
moisture content
6% average
moisture content
Figure 3
Glues
We recommend that Aerolite 306 glue be used to build the Falco. Aerolite is a gap-filling, water-
resistant adhesive that is very easy to use. It sets up quickly, allowing—and requiring—quick
assembly. Of all the glues available, this glue is the best choice for most builders. The original