(a) Design cruising speed, V
(1) Where W/S′=wing loading at the design maximum takeoff weight, Vc(in knots) may not be less than—
(i) 33 √(W/S) (for normal, utility, and commuter category airplanes);
(ii) 36 √(W/S) (for acrobatic category airplanes).
(2) For values of W/S more than 20, the multiplying factors may be decreased linearly with W/S to a value of 28.6 where W/S =100.
(4) At altitudes where an M
(b) Design dive speed V
(2) With V
(i) 1.40 V
(ii) 1.50 V
(iii) 1.55 V
(3) For values of W/S more than 20, the multiplying factors in paragraph (b)(2) of this section may be decreased linearly with W/S to a value of 1.35 where W/S =100.
(4) Compliance with paragraphs (b)(1) and (2) of this section need not be shown if V
(i) The speed increase resulting when, from the initial condition of stabilized flight at V
(ii) Mach 0.05 for normal, utility, and acrobatic category airplanes (at altitudes where MDis established); or
(iii) Mach 0.07 for commuter category airplanes (at altitudes where MDis established) unless a rational analysis, including the effects of automatic systems, is used to determine a lower margin. If a rational analysis is used, the minimum speed margin must be enough to provide for atmospheric variations (such as horizontal gusts), and the penetration of jet streams or cold fronts), instrument errors, airframe production variations, and must not be less than Mach 0.05.
(c) Design maneuvering speed V
(ii) n is the limit maneuvering load factor used in design
(2) The value of V
(d) Design speed for maximum gust intensity, V
(1) VBmay 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) ngthe positive airplane gust load factor due to gust, at speed V
(ii) VS1is the stalling speed with the flaps retracted at the particular weight under consideration.
(2) VBneed not be greater than VC.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23–7, 34 FR 13088, Aug. 13, 1969; Amdt. 23–16, 40 FR 2577, Jan. 14, 1975; Amdt. 23–34, 52 FR 1829, Jan. 15, 1987; Amdt. 23–24, 52 FR 34745, Sept. 14, 1987; Amdt. 23–48, 61 FR 5143, Feb. 9, 1996]