(1)
Sideloadscombined with one-half of the maximumground reactionsobtained inthelevellanding conditions ofSec.27.479(b)(1); and
(2)
Theloads obtained under subparagraph(1) of thisparagraph applied–
(i)
At the ground contact point; or
(ii)
For full-swiveling gear, at the center of the axle.
(b)
The rotorcraft must be designed to withstand, at ground contact–
(1)
When onlythe aftwheels contacttheground, sideloads of0.8timesthe vertical reaction acting inward on one side, and 0.6 times the vertical reaction acting outward on the other side, all combined with the vertical loads speci.ed in paragraph(a); and
(2)
When all wheels contact the ground simultaneously–
(i)
For the aft wheels, the side loads speci.ed in subparagraph (1) of this paragraph; and
(ii)
For the forward wheels, a side load of 0.8 times the vertical reaction combined with the verticalload speci.edinparagraph(a) of this section.
FAR 27.493 : Braked roll conditions
Under braked roll conditions with the shock absorbers in their static positions–
(a)
The limit vertical load must be based on a load factor of at least–
(1)
1.33, for the attitude speci.ed in Sec. 27.479(a)(1); and
(2)
1.0 for the attitude speci.ed in Sec. 27.479(a)(2); and
(b)
The structure must be designed to withstand, at the ground contact point of each wheel with brakes, a drag load at least the lesser of–
(1)
The vertical load multiplied by a coe.cient of friction of 0.8; and
(2)
The maximum value based on limiting brake torque.
FAR 27.497 : Ground loading conditions : landing gear with tail wheels
(a)
General. Rotorcraft with landing gear with two wheels forward, and one wheel aft, of the center of gravity must be designed for loading conditions as prescribed in this section.
(b)
Level landing attitude with only the forward wheels contacting the ground. In this attitude–
(1)
The vertical loads must be applied under Secs. 27.471 through 27.475;
(2)
The vertical load at each axle must be combined with a drag load at that axle of not less than 25 percent of that vertical load; and
(3)
Unbalanced pitching moments are assumed to be resisted by angular inertia forces.
(c)
Level landing attitude with all wheels contacting the ground simultaneously. In this attitude,the rotorcraftmustbedesignedforlanding loading conditions asprescri-bedinparagraph(b) of this section.
(d)
Maximum nose-up attitude with only the rear wheel contacting the ground. The atti-tude for this condition must be the maximum nose-up attitude expected in normal operation, including autorotative landings. In this attitude–
(1)
The appropriategroundloads speci.edinparagraphs(b)(1) and(2) ofthis section must be determined and applied, using a rational method to account for the momentarmbetween the rear wheelground reaction and the rotorcraft center of gravity; or
(2)
Theprobabilityoflanding withinitial contact on the rear wheel mustbe shown to be extremely remote.
(e)
Level landing attitude with only one forward wheel contacting the ground. In this attitude, the rotorcraft mustbedesignedforgroundloads as speci.edinparagraphs (b)(1)and(3) of this section.
(f)
Side loads in the level landing attitude.In the attitudes speci.edinparagraphs(b) and(c) ofthis section,thefollowing apply :
(1)
The side loads must be combined at each wheel with one-half of the maximum verticalgroundreactionsobtainedforthatwheel underparagraphs(b) and (c)of this section. In this condition, the side loads must be–
(i)
For theforwardwheels,0.8 times the vertical reaction(on one side) acting inward, and 0.6 times the vertical reaction (on the other side) acting outward; and
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 4(78)
