Page 159 - Aeronautical Engineer Data Book

Section 9

Aircraft performance

9.1 Aircraft roles and operational profile
Civil aircraft tend to be classified mainly by
range. The way in which a civil aircraft operates
is termed its operational profile. In the military
field a more commonly used term is mission
profile. Figure 9.1 shows a typical example and
Table 9.1 some commonly used terms.

9.1.1 Relevant formula
Relevant formulae used during the various
stages of the operational profile are:
Take-off ground roll
S = 1/(2gK ).ln[K + K .V 2 LOF )/K ].
A
G
T
A
T
This is derived from � V LOF [( a)dV ]
2
1
0 2
Total take-off distance
S TO = (S )(F )
G
p1
where F is a ‘take-off’ plane form coefficient
p1
between about 1.1 and 1.4.
V TRANS = (V LOF + V )/2 � 1.15V S
2
Rate of climb
For small angles, the rate of climb (RC) can be
determined from:
(F – D)V

� V d V �

RC = W 1 +
h
g d
where V/g. dV/dh is the correction term for
flight acceleration