"Painting is finished. Who'll do anything better than that airplane
propeller. Tell me, can you do that?" Marcel Duchamp, speaking to
Brancusi and Leger at the 1912 Salon de la Locomotion Aerienne.
How to construct a Basic Wooden Airplane Propeller
Wood Selection
This process is not the choice of wood species but rather the
careful selection of individual boards of wood to be joined in a way
to achieve maximum strength as well as balance. Since wood is not
uniform in density, simple mass gluing of boards is likely to result
in uneven distributions of weight within the propeller. While many
propellers were made this way, the American Propeller Company
(Paragon) devised a method to balance half-blades individually, then
join these at the hub. In addition, wood grain (annual ring
orientation) was carefully matched to produce equal stiffness, or
resistance to torsional deflection, in each blade. Following the
matching of wood by weight and grain, the rough outline of the
individual piece, based on its position within the propeller was cut
out for gluing.
Gluing
A relatively straightforward process, pre-selected boards were
heated, warm glue applied to opposing surfaces, and multiple special
clamps applied at short intervals along the entire length of the
blade, beginning at the hub. Clamps were left in place for 24 hours
or more, then the rough form allowed to cure for several days before
milling.
Shaping
A surprising number of propellers went from the stage in the
photo below all the way to a finished product entirely using hand
tools, with cross sectional templates used to determine exact shape
along various distances from the center. Later, as production demand
increased, a variety of machines were created to accurately obtain the
final shape, some producing multiple propellers in one process. As
part of the shaping process, the center of the propeller was placed on
a knife edge balancing device, and small amounts of wood were removed
to obtain precise balance. At the completion of the final shaping,
after inspection of the product, the final drill holes were created in
the hub, and specification numbers stamped into the wood.
Fini****ng
The surface was smoothed with furniture scrapers or sanding
materials, then in some cases, the tips were covered with fabric and /
or metal sheathing before multiple coats of varnish were applied.
Many times the final balancing of the blades was actually
accomplished by the uneven application of varnish.
http://www.woodenpropeller.com/Basic_Propeller_Construction_-_Techniques.html
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