Propeller, Two-Blade, Ground Adjustable Pitch, Metal


Display Status:

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Collection Item Summary:

Thomas Dicks, an English émigré, founded the Dicks-Luttrell Propeller Company in 1918 with a Westinghouse co-worker. Reorganization by Pittsburgh entrepreneurs resulted in creation of the Standard Steel Propeller Company, which was eager to receive an Army contract for an early experimental controllable and reversible-pitch propeller. Collaboration with the Army's Engineering Division began in 1919. Mechanical hub design was attributed to Dicks, who received the assistance of the Army's Frank Caldwell, a leading propeller designer of the early 20th century.

This highly significant artifact; a predecessor to the modern variable-pitch propeller, was the first design to employ counterweights. Built for the Liberty engine and DeHavilland DH-4 aircraft, the Dicks-Caldwell design appeared satisfactory from the standpoint of mechanical engineering after considerable development, but its excessive weight made it prohibitive. Standard Steel abandoned the design of a variable-pitch mechanism in 1923 and continued its specialization in the construction of metal blades in direct cooperation with the Army.

Collection Item Long Description:


Circa 1920

Inventory Number


Physical Description

  • Type: Two-Blade, Ground Adjustable Pitch, Metal
  • Diameter: 320 cm (126 in.)
  • Chord: Unknown
  • Engine Application: Liberty L-12, 300 kw (400 hp)

Credit Line

Gift of United States War Department, Air Corps Material Division


  • Frank Walker Caldwell, United States of America, 1889 - 1974
  • Thomas Andrew Dicks, United States of America, 1859 - 1944

Country of Origin

United States of America


Steel, Aluminum alloy, Paper, Preservative Coating


  • 3-D (Propeller): 320 × 30.5 × 35.6cm, 70.3kg (10 ft. 6 in. × 1 ft. × 1 ft. 2 in., 155lb.)
  • Storage (Aluminum Pallet): 351.8 × 121.9 × 129.5cm, 364.2kg (11 ft. 6 1/2 in. × 4 ft. × 4 ft. 3 in., 803lb.)

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


PROPULSION-Propellers & Impellers

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