Quest for Performance: The Evolution of Modern Aircraft
Chapter 7: Design Trends
Maximum Speed
[152] Trends in maximum speed of propeller-driven aircraft are shown as a function of time in figure 7.2. The maximum speeds of high-technology operational aircraft are seen to increase steadily from about 125 miles per hour in 1920 to nearly 450 miles per hour in the World War II years. The highest maximum speed shown is for the P-51D aircraft, which had a speed of 437 miles per hour at 25 000 feet. Late in the war, a Republic P-47J achieved a speed in level flight of 507 miles per hour at 34 000 feet. The upper bound through the years closely follows the advancement of fighter-type aircraft. The large increases in maximum....

chart illustrating trends in speed from 1920 to 1980
[153] Figure 7.2 - Trends in maximum speed of propeller-driven aircraft.
...speed that occurred between World War I and World War II resulted from increases in engine power and reductions in drag area through improved aerodynamic efficiency. For example, the 10 000-pound P-51 fighter of World War II had a drag area of only 3.8 square feet (this corresponds to a circular disc 2.20 feet in diameter) and was equipped with an engine of 1490 horsepower; by comparison, one of the highest performance fighters in use at the end of World War I, the 1807-pound SPAD XIII C.1 (chapter 2), had a drag area of 8.33 square feet (a circular disc 3.26 feet in diameter) and was powered with a 200-horsepower engine. The corresponding values of the ratio of power to drag area are 392.11 and 24.01, respectively. Also contributing significantly to the large increases in maximum speed were the development of the supercharger and controllable-pitch propeller, both of which permitted efficient high-power flight in the low-density, high-altitude environment. No increases in the maximum speed of operational propeller-driven aircraft have been achieved since the end of World War II because of the inherent limitations imposed by the effects of compressibility on the efficiency of conventional propellers.
The lower bound in figure 7.2 shows an increase in maximum speed from about 80 miles per hour to about 130 miles per hour. This bound indicates a continued desire for low-performance aircraft [154] throughout the years. The general aviation aircraft of today are seen to encompass a range of maximum speed from about 130 miles per hour to almost 350 miles per hour, which indicates the wide range of technical sophistication in contemporary propeller-driven aircraft.
Although not shown in the data presented in figure 7.2, the performance of representative, specially built, propeller-driven racing aircraft through the years may be of some interest and is indicated as follows:
  1. 1913, absolute speed record of 126.64 miles per hour established by French Deperdussin landplane
  2. 1920, absolute speed record of 194.49 miles per hour established by French Nieuport 29V landplane
  3. 1923, absolute speed record of 267.16 miles per hour established by American Curtiss R2C-1 landplane
  4. 1927, absolute speed record of 297.83 miles per hour established by Italian Marcchi M-52 seaplane
  5. 1931, absolute speed record of 406.94 miles per hour established by British Supermarine S-6B seaplane
  6. 1934, absolute speed record of 440.60 miles per hour established by Italian Marcchi-Castoldi MC-72 seaplane (This record for propeller-driven seaplanes still stands and is unlikely to be surpassed in the near future.)
  7. 1938, absolute speed record of 469.22 miles per hour established by German Messerschmitt 209VI landplane
  8. 1969, absolute speed record of 483.04 miles per hour established by highly modified American Grumman F8F landplane
The world speed records cited above are officially recognized by the Federation Aeronautique Internationale and were established under sea-level flight conditions.