Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 10–7 Revision 4, March 1, 2002
The same guidelines would apply to staples. We have already suggested in the chapter on tools
the two recommended staplers. Nails are difficult to handle and slow to install.
Staples and nails are used to hold the wood in place during gluing and to provide the necessary
clamping pressure. Many texts suggest that the best procedure is to leave the nails in the airplane.
We have found that Falco builders are reluctant to do this. For one thing, they worry about the
weight! Many go so far as to keep all of their old staples in a can. They can add up to a big pile.
For your information, the wing rib staples add up to nine ounces.
Because of the use of internal antennas, it is best to have as little metal in the wings as possible.
So if you ever needed an excuse to take out the staples or nails, there is your excuse! We think
most builders are just offended by the looks of the things.
If you remove the staples or nails, you have to be careful not to bruise the wood. This risk of
crushing the wood is the principal reason that the standard practice was to leave the things in the
airplane. You may be more careful than factory labor, but be careful. Many builders use diagonal
side cutting pliers to pull out staples. Others have fashioned custom homemade tools to remove
the staples.
When you install the skins, it is a standard practice to use nailing strips. These are thin strips of
wood through which you nail or staple. These become badly chewed up from repeated stapling
and removing the staples, and they protect the wood from bruising. They also help to distribute
the load from the staples or nails.
With wood production aircraft, it was the practice to use cotton tape under nails and staples. This
permitted the quick removal of the things. You should avoid, wherever possible, the use of
permanently installed nails on the exterior of the airplane.
When you remove staples and nails, it leaves a small hole. You should be careful to make sure
that the hole is filled with filler or sealer before you apply varnish. You cannot always depend on
varnish to fill such holes.
You may use either steel or brass nails. The steel nails are either plated, galvanized or cement-
coated to prevent rust, but they seem to rust with age anyway. Most builders prefer brass nails, but
it’s not really an important consideration.
In The Sportplane Builder , Tony Bingelis suggests the following nails and spacings. For 1/16”
plywood use 1/4” 20-gauge nails spaced 1/2” apart. For 3/32” plywood use 3/8” 20-gauge nails
spaced 3/4” apart. For 1/8” plywood use 1/2” 20-gauge nails spaced 3/4” apart. For 1/4” plywood
use 1” 18-gauge nails spaced 1” apart.
Staples are much easier to install if you have a pneumatic staple gun (see Chapter 4 “Tools”). You
will have to experiment to determine the best spacing for the staples. This will change depending
on the glue that you use. Resorcinol requires quite a bit of clamping pressure, while epoxy
requires very light clamping pressure.
Bending Spruce and Birch Plywood
There are a number of places in the Falco where you will have to bend spruce and birch plywood.
If the bend has a large radius in relation to the thickness of the wood, the wood can be easily bent,
clamped and glued in place. If the bend has a tight bend radius, then you must soak and pre-bend