MIkH-fkOIA
7 SEPTBMBEB 1981
SUPERSEDING
MIL H-8601
8 NOVEMBER 196Z
MILITARY SPECIFICATION
HELICOPTER FLYING AND GROUND HANDLING QUALITIES;
GENERAL REQUIREMENTS FOR
This apeca”jfcafion k been approved by iAe Department 0$ Defense and ia man-
-
for uee by the Department of the Army, the Nary, and the Air Form
1. SCOPE
1.1 This specification covers the design re-
quirements for flying and ground handling qual-
ities of U.S. military helicopter.
2. APPLICABLE DOCUMENTS
There are no applicable documents.
3. REQUIREMENTS
3.1 General.
3.1.1
With the exception of 3.6, section 3
contains the requirements for the flying qual-
ities, und for certain relevant ground-handling
characteristics, of all helicopters procured by
the Department of the Army, the Departmen L
of the Navy, and the Dep&mtnmnL of the Air
Force, that are required to operwto under visual
,n
flight conditions.
Paragraph 3.6 applies to
helicopters required to operate under instru-
ment flight conditions. The required charac-
teristics are those which are considered, on the
basis of present knowledge, as tending to insure
satisfactory handling qualities and are subject
to modification as indicated by new informa-
tion. Every effort shall be made by designers
to provide additional desirable characteristics
which have been omitted m
specific
requirements.
3.1.2 Unless otherwise specified, the require-
ments of section 3 shall apply at all normal
service loadings over the operating rotor speed
range and all operational altitudea and tem-
peratures. For the purposes of section 3,
normal service loadings shall include all com-
binations of gross weight and center of gruvity
locations that could ordinarily be encount.ared
in normal service operations.
$.2
Longitudind clmracteridics.
3.2.1
It shall be possible to obtain steady,
smooth flight over a speed range from at least
30 knots rearward to maximum forward speed
as limited either by power available or by
roughness due to blade aerodynamic limita-
tions, but not by control power. This speed
range shall be construed to include hovering
and any other steady state flight condition,
including steady climbs and s~ady descents.
Throughout the specified speed range a suffi-
cient mmgin of control power, and at least
adequate control to produce 10 percent of the
maximum attaimlb]e pitching moment in hov-
ering shrdl be avnilablc at each end to control
the effects of longitudinal disturbances. This
requirement shall apply I]ot only to powered
flight, but also to mrtorotative flight at forward
speeds between zero nnd tho muimum forward
speed for nutorotation. Within the Iimita of
speed specified in 3.2.1 and during the transi-
tions between hovering and the specified ex-
trehes, the controls and the helicopter itself
shall be free from objectionable shake, vibra-
tion, or roughness, as specified in 3.7.1.
3.2.2 The helicopter shall be reasonably
steady while hovering in still air (winds up to
3 knots), requiring a minimum movement of
the cyclic controls to keep the machine over a
given spot on the ground, for all terrriin clear-
ances up to the rlisnppearunce of ground effect.
In tiny case, it shall he. possible to riccornplish
this with lww thtin ~. 1.O-inch movement of the
cyclic controls.
3.2.3 For all conditions and spewls specified
in 3.2.1, it shall be possible in steady -stat.e
flight to trim steady, longitudinal control forces
to zero.
At these trim comiitions, t~le wti
shun exhibit positive self-centering c~M@.
istics. Stick “jump” when trim is uctuated is
undesirable.
E
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