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Quest for Performance: The Evolution of Modern
Aircraft
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Part I: THE AGE OF PROPELLERS
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Chapter 7: Design Trends
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Maximum Speed
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- [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....
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[153] Figure 7.2 - Trends in maximum speed of propeller-driven aircraft.
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- ...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.
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- 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.
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- 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:
- 1913, absolute speed record of 126.64 miles per hour
established by French Deperdussin landplane
- 1920, absolute speed record of 194.49 miles per hour
established by French Nieuport 29V landplane
- 1923, absolute speed record of 267.16 miles per hour
established by American Curtiss R2C-1 landplane
- 1927, absolute speed record of 297.83 miles per hour
established by Italian Marcchi M-52 seaplane
- 1931, absolute speed record of 406.94 miles per hour
established by British Supermarine S-6B seaplane
- 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.)
- 1938, absolute speed record of 469.22 miles per hour
established by German Messerschmitt 209VI landplane
- 1969, absolute speed record of 483.04 miles per hour
established by highly modified American Grumman F8F landplane
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- The world speed records cited above are officially recognized
by the Federation Aeronautique Internationale and were established under sea-level
flight conditions.
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