spaschal on DSK3GDR082PROD with CFR

Federal Aviation Administration, DOT

Section 27.501

(i) For the forward wheels, 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
(ii) For the rear wheel, 0.8 times the
vertical reaction.
(2) The loads specified in paragraph
(f)(1) of this section must be applied - 
(i) At the ground contact point with
the wheel in the trailing position (for
non-full swiveling landing gear or for
full swiveling landing gear with a lock,
steering device, or shimmy damper to
keep the wheel in the trailing position); or
(ii) At the center of the axle (for full
swiveling landing gear without a lock,
steering device, or shimmy damper).
(g) Braked roll conditions in the level
landing attitude. In the attitudes specified in paragraphs (b) and (c) of this
section, and with the shock absorbers
in their static positions, the rotorcraft
must be designed for braked roll loads
as follows:
(1) The limit vertical load must be
based on a limit vertical load factor of
not less than - 
(i) 1.0, for the attitude specified in
paragraph (b) of this section; and
(ii) 1.33, for the attitude specified in
paragraph (c) of this section.
(2) For each wheel with brakes, a
drag load must be applied, at the
ground contact point, of not less than
the lesser of - 
(i) 0.8 times the vertical load; and
(ii) The maximum based on limiting
brake torque.
(h) Rear wheel turning loads in the
static ground attitude. In the static
ground attitude, and with the shock
absorbers and tires in their static positions, the rotorcraft must be designed
for rear wheel turning loads as follows:
(1) A vertical ground reaction equal
to the static load on the rear wheel
must be combined with an equal
sideload.
(2) The load specified in paragraph
(h)(1) of this section must be applied to
the rear landing gear - 
(i) Through the axle, if there is a
swivel (the rear wheel being assumed
to be swiveled 90 degrees to the longitudinal axis of the rotorcraft); or
(ii) At the ground contact point, if
there is a lock, steering device or shim-

my damper (the rear wheel being assumed to be in the trailing position).
(i) Taxiing condition. The rotorcraft
and its landing gear must be designed
for loads that would occur when the
rotorcraft is taxied over the roughest
ground that may reasonably be expected in normal operation.
Section 27.501 Ground loading conditions:
landing gear with skids.
(a) General. Rotorcraft with landing
gear with skids must be designed for
the loading conditions specified in this
section. In showing compliance with
this section, the following apply:
(1) The design maximum weight, center of gravity, and load factor must be
determined under SectionSection 27.471 through
27.475.
(2) Structural yielding of elastic
spring members under limit loads is acceptable.
(3) Design ultimate loads for elastic
spring members need not exceed those
obtained in a drop test of the gear
with - 
(i) A drop height of 1.5 times that
specified in Section 27.725; and
(ii) An assumed rotor lift of not more
than 1.5 times that used in the limit
drop tests prescribed in Section 27.725.
(4) Compliance with paragraphs (b)
through (e) of this section must be
shown with - 
(i) The gear in its most critically deflected position for the landing condition being considered; and
(ii) The ground reactions rationally
distributed along the bottom of the
skid tube.
(b) Vertical reactions in the level landing attitude. In the level attitude, and
with the rotorcraft contacting the
ground along the bottom of both skids,
the vertical reactions must be applied
as prescribed in paragraph (a) of this
section.
(c) Drag reactions in the level landing
attitude. In the level attitude, and with
the rotorcraft contacting the ground
along the bottom of both skids, the following apply:
(1) The vertical reactions must be
combined with horizontal drag reactions of 50 percent of the vertical reaction applied at the ground.

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