曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
is comparable in size to the wing. In that case, the same approach as that used for
the wing can be used to estimate its contribution. With these assumptions,
Clp = (Clp)W + (CLp)V
(4.555)
For aircraft with high-aspect ratio rectangular wings, an approximate estimation
of the wing contribution at low subsonic speeds can be done using the strip theory
as follows.
Consider a rectangular wing in a uniform rolling motion with a roll rate p about
the Ox axis as shown in Fig. 4.27a. Because of this rolling motion, the local angle
of attack of wing sections on the down-going (right) wing increases and that on the
up-going (left) wing decreases. Assuming that the steady~state angle of attack is
below the stall angle, we observe that the lift developed by the right wing increases
EQUATIONS OF MOTION AND ESTIMATION OF STABILITY DERIVATIVES 407
CVP
a
clfP
a
Clt P
a
Taper Ratio = 0.5
r~
L:
4
2
E
┏━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ ~ ┃
┃ '. .: .....j: A-6 ┃
┃"'- "< ┃
┃ .. ┃
┃,. . . . .-. . . . . . .. ┃
┃ . :/7j;_'_::.L'."' . ┃
┃ :--, .\ . \ ': ┃
┗━━━━━━━━━━━━━━━━━━━━━━━━┛
234
Mach Numtx r
qIP
a
Cw
a
qr!
a
A = 300
A = 45o
A : 60o
Taper Ratio = 1.0
Mach Number
Fig.4 26 The parameter (C,pla)w for supersonic speeds]
and that of the left wing decreases. This difference in lift gives rise to a restoring
or a negative rolling moment and is the aerodynamic mechanism that generates
the damping-in-roll because of the wing. Using strip theory, we can approximately
estimate the magnitude of this restoring moment and the damping-in-roll derivative
(Ctp)W as follows.
The increase in the local angle of attack of an elemental wing strip RT of width
dy at a spanwise distance y is given by
tan cxp = Zry
(4.556)
where Uo is the flight velocity. Assuming that the roll rate p is small, we obtain
so that
N py
ap - Uo
ai(y) = a + a'p = cy + 7jY
(4.557)
(4.558)
pctt_
k
408 PERFORMANCE, STABILITY, DYNAMICS, AND CONTROL
dL
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
PERFORMANCE, STABILITY, DYNAMICS, AND CONTROL2(150)
