(b)
Thelandinggear may notfail,but mayyield,in atest showing its[reserve] energy absorption capacity, simulating a descent velocity of 1.2 times the limit descent velocity, assuming wing lift equal to the weight of the airplane.
Amdt. 23-49, E.. 03/11/96
FAR 23.725 : Limit drop tests.
(a) If compliance with Sec. 23.723(a) is shown by free drop tests, these tests must be made on the complete airplane, or on units consisting of wheel, tire, and shock absorber,intheirproperrelation,fromfreedropheights notlessthanthosedeter-mined by the following formula :
W 2
h(inches)=3.6
S
However, the free drop height may not be less than 9.2 inches and need not be more than 18.7 inches.
(b) If the e.ect of wing lift is provided for in free drop tests, the landing gear must be dropped with an e.ective weight equal to–
h+(1 .L)d
[We = W h+ d ]
where–
We :the e.ective weighttobe usedinthedrop test(lbs.); h :speci.ed free drop height(inches); d :de.ection underimpact of the tire(at the approvedin.a-
tionpressure)plus the vertical component of the axle travel relativetothedrop mass(inches);
W :W = WM for main gear units (lbs.), equal to the static weight on that unit with the airplane in the level attitude (with the nose wheel clear in the case of the nose wheel type airplanes);
:W = WT for tailgear units(lbs.), equalto the static weight on the tail unit with the airplanein the tail-down attitude;
:W = WN for nose wheel units(lbs.), equal to the vertical component of the static reaction that would exist at the nose wheel, assuming that the mass of the airplane acts at the center of gravity and exerts a force of 1.0g downward and 0.33g forward; and
L :the ratio of the assumed wing lift to the airplane weight, but not more than 0.667
′
Elodie Roux. Septembre 2003
Subpart D : Design and Construction
(c) Thelimitinertialoadfactor mustbedeterminedin a rationalor conservative manner, during the drop test, using a landing gear unit attitude, and applied drag loads, that represent the landing conditions.
(d) The value of d used in the computation of We inparagraph(b) of this section may not exceed the value actually obtained in the drop test.
(e) The limit inertia load factor must be determined from the drop test in paragraph (b)of this section according to the following formula :
We
n = nj + L
W
where–
nj :theloadfactordevelopedin thedrop test(thatis,the ac-
/dv 、
celeration in g’s recorded in the drop test) plus 1.0;
dt
and We, W, and L :are the same as in the drop test computation.
(f) The value of n determinedin accordance withparagraph(e) may notbe morethan the limit inertia load factor used in the landing conditions in Sec. 23.473.
Amdt. 23-48, E.. 03/11/96
FAR23.726 :[Groundloaddynamic tests.]
(a) [Ifcompliance with the ground load requirements of Secs. 23.479 through 23.483 is shown dynamically by drop test, one drop test must be conducted that meets Sec.
23.725 except that the drop height must be–
(1) 2.25 times the drop height prescribed in Sec. 23.725(a); or
(2) Su.cient to develop 1.5 times the limit load factor.
(b) The critical landing condition for each of the design conditions speci.ed in Secs.
23.479 through 23.483 must be used for proof of strength.]
Amdt. 23-7, E.. 09/14/69
FAR 23.727 : Reserve energy absorption drop tests.
(a) If compliance with the reserve energy absorption requirement in Sec. 23.723(b) is shown by free drop tests, the drop height may not be less than 1.44 times that speci.ed in Sec. 23.725.
(b) [Ifthe e.ect of wingliftisprovidedfor,the units mustbedropped with an e.ective
()
h
mass equal to We = W , when the symbols and other details are the same
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 2(31)
