- Reinventing the Propeller: Aeronautical Specialty and the Triumph of the Modern Airplane by Jeremy R. Kinney
As Charles Lindbergh prepared for his historic, nonstop flight from New York to Paris in 1927, he faced a crucial, life-threatening decision. The pitch of his propellers had to be set for high power to lift his fuel-laden airplane above the wires at the end of Roosevelt Field, but they also should have been set for low power to cruise at maximum fuel efficiency once at altitude. His quandary was that he needed something like an automobile's first gear for takeoff and fourth gear for cruising, but he could not have both. An astute and experienced aviator, he got it just right. He cleared the wires by twenty feet on takeoff and made it to Paris with fifty-four gallons to spare. Still, his dilemma dramatized the importance of developing a propeller whose pitch could be shifted in flight.
Reinventing the Propeller tells the story of how that happened. Between the world wars, aeronautical engineers sought a light, safe, reliable variable-pitch propeller, one that could be adjusted, automatically or by pilot control, to suit conditions of speed, altitude, and precipitation. This study focuses on the United States, the leading innovator, comparing its experience with a more conservative Great Britain and a late contender in Germany.
The author situates this story in the "Aeronautical Revolution" of the 1920s and 1930s, when a cascade of innovations in airframes, engines, and auxiliary equipment transformed the airplane from a fragile instrument of military activity and civilian amusement into a powerful aerial weapon and a fast, long-distance transport vehicle for passengers and cargo. The DC-3 is the iconic symbol of this revolution, the first airplane to incorporate streamlined, all-metal, monocoque fuselage; multi-cellular, stressed-skin wings; radial, cowled, air-cooled engines burning high-octane fuel; retractable landing gear; and variable-pitch propellers. All these developments were the result of intense competition in aeronautical research throughout the interwar years.
The narrative is predictably dense. It involves multiple developers, customers, applications, institutions, and personalities. Both commercial companies and government laboratories conducted research, and some researchers moved back and forth between these places of work. Commercial and military airplanes had different specifications and different operational demands. Furthermore, some commercial airplanes served passengers, while others served more specialized functions, such as mail, photography, and meteorology. So too with the military. Transport planes and bombers were more like commercial airliners, but fighter and attack aircraft were in a high-performance category of their own. Different [End Page 987] countries embraced different standards of competition and risk. For all these reasons and more, the road to the variable-pitch propeller passed through multiple stages, such as adjustable-pitch propellers that could be set on the ground, high-speed propellers tailored for a specific flight profile, varying propeller weights and compositions, hydraulic variable pitch, automatic variable pitch, and electric variable pitch. Even after workable variable-pitch propellers began entering service in 1933, innovation continued. Constant-speed propellers and feathering mechanisms followed, the latter to allow a malfunctioning engine to be shut down without the propeller wind-milling in the airstream.
The author invokes the "Aeronautical Revolution" (p. 2) and a "shared culture of performance" (p. 3) within the propeller research community, and he speaks of the airplane as a "synergistic collection of technologies" (p. 9). But none of these quite seems to rise to the level of a thesis. Speaking in the "Introduction" about the propeller research community, he says, "this book is the story of those specialists, their beliefs, their successes and failures, and the propellers they created while standing at the intersection of the technical and cultural forces that shaped the airplane over the course of the twentieth century" (p. 3). Fewer trees and more forest might have helped. For example, more might have been done with patents, and path dependence might have illuminated some of the roads not taken. Still, the book is well-researched...