A device which does for the aircraft what change speed gears do for the automobile is the invention of Spencer Heath. It comprises a system of special blades and a mechanism for varying the pitch of the blades from zero to 360 degrees, while in flight or otherwise.
The "Universal" Adjustable and Reversible Propeller Built by Paragon Engineers, Inc., Baltimore, Md
1922-11-01
Miscellaneous
No indication
English
The paragon adjustable and reversible propeller
Engineering Index Backfile | 1923
Adjustable reversible pitch propeller
Engineering Index Backfile | 1930
Adjustable reversible pitch propeller
Engineering Index Backfile | 1930
Engineering Index Backfile | 1930