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Quest for Performance: The Evolution of Modern Aircraft


Part I: THE AGE OF PROPELLERS


Chapter 4: Design Revolution 1926-39


Record Flights


[78] Another important factor in the formula for accelerated development and production of new aircraft were the many record-breaking flights of the time. They were extremely popular with the general public and played an important role in popularizing aviation and its potential as a serious means of transportation. The nonstop solo flight of Charles A. Lindbergh from New York to Paris in May 1927 had the most profound and lasting influence of any of the record-breaking flights. His magnificent flight thrilled and captured the imagination of people all over the world and stimulated an interest and enthusiasm for [79] aviation that had an incalculable effect on future aeronautical developments. As a result of his flight, a multitude of small companies dedicated to the manufacture of aircraft appeared throughout the United States. Most of these companies flourished for a few years and then quietly passed into bankruptcy as the country entered the Great Depression of the 1930's. Airline operations were given a tremendous boost by the enthusiasm engendered by the Lindbergh flight.

The Ryan monoplane employed by Lindbergh on his historic flight, illustrated in figure 4.1, was of the strut-braced, high-wing type equipped with a fixed landing gear. The fuselage consisted of a welded steel-tube frame, and the wings were of wooden frame construction. The entire aircraft was covered with cloth fabric. The pilot had no forward vision since the space immediately ahead of him was occupied by a large 360-gallon fuel tank. The wheels incorporated no brakes, and the tall skid was of the fixed type. The aircraft utilized the relatively new Wright Whirlwind engine. This engine had nine cylinders radially disposed about the crankcase and crankshaft. In contrast to the rotary engine described earlier, however, the cylinders and crankcase of the radial engine were fixed, and the crankshaft rotated with the propeller attached. The engine developed 220 horsepower and, for its day, was considered to be light and highly reliable. The air-cooled feature....




Figure 4.1 - Ryan NYP Spirit of St. Louis; 1927. [Ryan Aeronautical Library via David A. Anderton]
[80] ...resulted in the deletion of the radiator and associated plumbing that was always a source of maintenance and reliability problems on liquid-cooled engines. The maximum gross weight of the aircraft was 5135 pounds, and the zero-fuel weight was 2150 pounds. Thus, the fuel in the aircraft represented more than half of the gross weight and gave the Spirit of St. Louis airplane a zero-wind range of about 4200 statute miles. The cruising speed of the aircraft was about 95 miles per hour, and the maximum speed, 120 miles per hour. The zero-lift drag coefficient C_D,₀, given in table II (appendix A), was 0.0379. This coefficient represents a considerable reduction over the value of 0.0496 given for the DeHavilland DH-4 but still indicates that the fixed landing gear and multiple wing struts were serious drag-producing elements. The maximum lift-drag ratio of the aircraft was 10.1, which compares favorably with the value of 7.7 given for the DeHavilland 4. The higher effective aspect ratio of the monoplane, compared with the biplane, is in large measure responsible for the increased lift-drag ratio of the Spirit of St. Louis compared with the DH-4 and other typical contemporary biplane configurations. A complete description of the Spirit of St. Louis giving design and performance data is contained in the appendix of reference 86.

Record-breaking flights continued for many years to play an important role in the development of aviation, particularly as a means of focusing public attention on the possibilities of the aircraft as a safe and reliable means for travel. Long-distance flights, flights around the world, flights of exploration, and, of course, all sorts of air races formed part of the aeronautical scene in the late twenties and thirties. For example, Richard E. Byrd was in command of the first flight over the South Pole in 1929, and Wiley Post circled the globe alone in 7 1/2 days in 1933. The world's absolute speed record was increased to 440 miles per hour in 1934 by an Italian seaplane. The aircraft was equipped with pontoons similar to those shown on the Supermarine S-4 in figure 3.6 and employed wire-braced monoplane wings and a 24-cylinder engine driving two counter-rotating propellers. The absolute speed record was raised to 467 miles per hour in 1938 by the Messerschmitt 209V1 racer. The list of record flights could go on endlessly but will not be continued here. The following paragraphs deal with some of the advanced aircraft that were developed from 1926 to 1939. This era may be characterized as one in which concepts of aircraft design underwent radical change and rapid advances were made in performance.