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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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- Introduction
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- [151] This chapter
briefly summarizes the progress in design of propeller-driven
aircraft since the end of World War I by showing how a number of
important design and performance parameters varied over the years
1920 to 1980. The following parameters are discussed:
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- (1) Maximum speed, Vmax
- (2) Stalling speed, Vs
- (3) Wing loading, W/S
- (4) Maximum lift coefficient,
CL,max
- (5) Power loading, W/P
- (6) Zero-lift drag coefficient,
CD,O
- (7) Skin friction parameter,
CF
- (8) Maximum lift-drag ratio, (L/D)
max
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- The values of each of these parameters,
obtained from tables I, II, and III (appendix A) and reference 90, are plotted against the appropriate year in
figures 7.2 to 7.9. All of the parameters could not be obtained
for some of the aircraft; in particular, the zero-lift drag
coefficient and the maximum lift-drag ratio could not be
determined for a number of the aircraft because of insufficient
performance data from which to make the desired calculations. The
symbols identifying each aircraft are given in figure 7.1 and have
been used throughout the subsequent figures. At the left side of
each figure (figs. 7.2 to 7.9), bars have been drawn to indicate
the spread of each parameter during World War I as obtained from
the data in table
I. The year for which the
characteristics of a given aircraft are plotted is in some degree
arbitrary. For example, most of the World War II aircraft
characteristics are plotted for the year 1942. In other cases,
aircraft that were used for a number of years are shown at a year
corresponding to the first year of production, or....
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- [152] Figure 7. 1 - Symbols used in figures 7.2 to 7.9.
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- .... after the aircraft had achieved a
fully developed status. The points for the different aircraft show
a large spread in the different figures; hence, lines representing
an upper and lower bound are shown on each figure. (The shape of
these bound lines may be varied according to the manner in which
the data are interpreted. The lines shown are only suggested
fairings of the data points presented.) One of these bounds
corresponds to aircraft developed with the highest technology
available at a particular time, and the other is for aircraft of a
relatively low and slow-changing level of technology. Neither of
these bounds represents boundaries of maximum and minimum values
but, rather, corresponds to higher and lower levels of technology
for operational aircraft of a particular time period. No data for
racing or special performance aircraft are given in the
figures.
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