(b) Design dive speed, VD. For VD, the following apply :
(1)
VD/MD may not be less than 1.25 VC/MC : and
(2)
With VCmin, the required minimum design cruising speed, VD (in knots)may not be less than–
(i)
1.40 VCmin (for normaland commuter category airplanes);
(ii)
1.50 VCmin (for utilitycategory airplanes); and
(iii) 1.55 VCmin (for acrobatic categoryairplanes).
(3)
For values of W morethan20,the multiplyingfactorsinparagraph(b)(2)
S
of this section may be decreased linearly with W to a value of 1.35 where
S
W
=100.
S
(4) Compliance withparagraphs(b)(1) and(2) of this section need notbe shown if VD/MD is selected so that the minimum speed marginbetween VC/MC and VD/MD is the greater of the following :
(i) The speed increase resulting when, from the initial condition of stabili-zed .ight at VC/MC, the airplane is assumed to be upset, .own for 20 seconds along a .ight path 7.5'below the initial path, and then pulled up with aloadfactorof1.5(0.5g.accelerationincrement).Atleast75 percent maximum continuouspowerfor reciprocating engines, and maxi-mum cruisingpowerfor turbines, or,ifless, thepower requiredfor VC/MC for both kinds of engines, must be assumed until the pullup is initiated, at which point power reduction and pilot-controlled drag devices may be used;[and either:]
′
Elodie Roux. Septembre 2003
Subpart C : Structure
(ii) Mach0.05fornormal,utility, and acrobaticcategory airplanes(atalti-tudes where MD is established); or
(iii) [Mach0.07for commuter categoryairplanes(at altitudes where MD is established) unless a rational analysis, including the e.ects of automatic systems,is used todetermine alower margin.If a rational analysisis used, the minimum speed margin must be enough to provide for atmospheric variations(such ashorizontalgusts), and thepenetration ofjet streams or coldfronts),instrument errors, airframeproduction variations, and must not be less than Mach 0.05.]
(c) Design maneuvering speed VA. For VA, the following applies :
√
(1)
VA may not be less than VS nz where–
(i)
VS is a computed stalling speed with .aps retracted at the design weight, normallybased on the maximum airplane normalforce coe.cients, CNA ; and
(ii)
nz is the limit maneuvering load factor used in design.
(2)
The value of VA need not exceed the value of VC used in design.
(d) Design speed for maximum gust intensity, VB. For VB, the following apply :
(1) [VB may not be less than the speed determined by the intersection of the line representing the maximum positive lift, CNMAX, and the line representing
√
the rough air gust velocity on the gust V-n diagram, or VS1 ng, whichever is less, where :]
(i)
ng thepositive airplanegustloadfactordue togust, at speed VC (in accor-dance withSec.23.341),and at theparticular weight under consideration; and
(ii)
VS1 isthestalling speed with the .apsretracted attheparticularweight under consideration.
(2)
VB need not be greater than VC. Amdt. 23-48, E.. 03/11/96
(a)
The positive limit maneuvering load factor nzcl may not be less than–
(1)
[2.1+ for normaland commuter category airplanes, where W =design
W+10000 maximum takeo. weight, except that nzcl need not be more than 3.8;]
(2)
4.4 for utility category airplanes; or
(3)
6.0 for acrobatic category airplanes.
(b)
The negative limit maneuvering load factor may not be less than–
(1)
0.4 times the positive load factor for the normal, utility, and commuter cate-gories; or
(2)
0.5 times the positive load factor for the acrobatic category.
(c)
Maneuvering load factors lower than those speci.ed in this section may be used if the airplane has design features that make it impossible to exceed these values in .ight.
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 1(144)
