This Hartzell propeller was manufactured by the U.S. Forest Service's Forest Products Laboratory (FPL), Madison, Wisconsin, for an experiment with wood adhesives. At the time of World War I, the FPL established a propeller laboratory to investigate problems caused by atmospheric humidity.

Allotments from the U.S. War Department financed research on the equipping and operation of an experimental propeller plant, for which the central problem was to produce a propeller with sufficient stability to resist warp, twisting, and unbalancing of the blades with changes in humidity. Such defects had caused countless propeller failures, and FPL established the special laboratory to investigate the problem.

Begun in March 1918, the propeller research involved the manufacture, storage, and finishing of experimental propellers from seven species of wood under closely controlled conditions. Experimental propellers were produced at a rate of 10 a week, a schedule that called for work on a three-shift per day basis.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Country of Origin United States of America Type PROPULSION-Propellers & Impellers Manufacturer Forest Products Laboratory
 Physical Description Type: Two-Blade, Fixed-Pitch, Wood Diameter: 254 cm (100 in.) Chord: 19.1 cm (7.5 in.) Engine Application: Hall-Scott A-5-A or A-7-A, Dimensions Rotor/Propeller: 254 x 19.1 x 19.1 x 10.2 x 0.8 x 6.8cm (100 x 7 1/2 x 7 1/2 x 4 x 5/16 x 2 11/16 in.)
3-D: 254 x 18.7 x 10.2cm (100 x 7 3/8 x 4 in.)
 Materials Wood
Copper Alloy
Varnish
Paint
 Inventory Number A19510012000 Credit Line Transferred from the Forest Service, U.S. Department of Agriculture Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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