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
(.
:!
fF
.i
i
i
h
"
.
::
',:
e
".
~:
i;
'; -
l;,
i
-'
,i
i:
.:
.:
::.
r
:,
c:
:,
:.
.~-.
c,
/
{<
.:
.;'
r
:.t
d;
./,
84 PERFORMANCE, STABILITY, DYNAMICS, AND CONTROL
Pmir,
v,
v
Fig.2.9 Power-required curves for propeller aircraft
value at some velocity, which will be denoted by Vmp and can be obtained as
follows.
ForPR, n,
or
dPR 3
d~ = ~p V2SCDO _ (:=k~WS)
- 0 (2.73)
4k W2
Vm4p = 3p2S2~DO
Vmp .-
(2-74)
1
= ~ VR (2.75)
The lift coefficient in level flight when the power required in level flight is
nunimum is as follows.
2W
CL.mp - .
= p S~2p
= ,~-
= V5Cz
(2.76)
AIRCRAFT PERFORMANCE
Similarly, we can show that
T
Emp = 0.8 6 Em (2.77)
Then, we get
8 kW2
PR.min = 3 p S /.-p
W Vmp
- (2.78)
= O 866Em
Thus, we observe that both thrust- and power-required curves assume their mini-
mum values at some velocities. In view of this, we have two intersection points
between power-available and power-required curves as shown in Fig. 2.10a for the
propeller airplane and between thrust-available and thrust-requircd curves for ajet
airplane as shown in Fig. 2.10b. These two intersection points give us two solutions
Pmin
D mln
Vmin Vm Vma^
a) Propeller aircraft
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 CONTROL1(50)
