Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 10–15 Revision 4, March 1, 2002
Bolt Torques
With a metal airplane, all bolts are expected to be torqued to a specific value. This is not true of a
wood airplane. The bolts are expected to be tight but not so tight that the wood is crushed. You
will notice that the more important fittings have wide plates on the reverse side to distribute the
load into the wood. The larger the backing plate, the more the bolts may be tightened without
damaging the wood. Other fittings use channel-nuts or wide washers. If you overtighten the
bolts, you will notice that the large washers will start to cone. If this happens, you have gone too
far, and you are crushing the wood. By the same token, you do not want any of the bolts loose.
Drain and Vent Holes
When an airplane climbs to altitude, the air becomes thinner. Any air trapped within a closed
compartment will try to force its way out due to the lower outside air pressure. For this reason,
you should not build any such closed compartments in the airplane. Because of the nature of the
Falco design, this will require that holes be drilled in the tail ribs and at other places to allow air
to move about the airplane.
These holes should be positioned so that they will drain any water that may enter the airplane or
condense within it. The bottom of the wing, tail and fuselage should have drain holes drilled in
the lower skins to allow any water that may be in the airplane to escape.
The vent holes should be positioned so that it also makes it difficult for moisture to enter the
airplane. For example, the leading edge of the rudder is a closed compartment without any vent
holes drilled. At the upper leading edge, it is best to route any vent holes through the spar instead
of “daylighting” out at the upper hinge opening. The escape path for the air should lead to the
bottom of the rudder.
Drain holes are normally 1/4ӯ. For vent holes, all you need is a 1/8ӯ hole. With many of the
drawings, we drew all of the vent and drain holes as 1/8ӯ. Many builders blanch at the thought
of 1/4ӯ holes in the airplane, and you may use any size hole you like. The only important thing
is that the holes be open so that water will drain out. This is a maintenance item, and the larger
holes are less likely to become clogged with dirt.