ISO 1151-1:1975
(Main)Title missing - Legacy paper document
Title missing - Legacy paper document
General Information
Relations
Standards Content (Sample)
INTERNATIONAL STANDARD @ 115111
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION .MEY.14 HAPOaHAI OPiAHM3AUMI no CTAHUAPTM3AUMM .ORGANISATION INTERNATIONALE DE NORMALISATIOh
Terms and symbols for flight dynamics -
Part I : Aircraft motion relative to the air
Termes et symboles de la mécanique du vol -
Partie I : Mouvement de Iavion par rapport à lair
Second edition - 1975-1 1-01
Reference No. amended 1976-08-1 5
-
w
-
MY UDC 629.7.015 : 003.62 Ref. No. IS0 1151/1-1975 (E)
PI
O)
c
-
Descriptors : aircraft, dynamic characteristics, flight characteristics, aerodynamics, vocabulary, symbols.
. F
MY
c
c
U
!3 Price based on 20 pages
'*I!@
---------------------- Page: 1 ----------------------
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 Member Bodies).’ The work of developing
International Standards is carried out through IS0 Technical Committees. Every
Member Body interested in a subject for which a Technical Committee has been set
up has the right to be represented on that Committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the Technical Committees are circulated
to the Member Bodies for approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 1151 was drawn up by Technical Committee
iSO/TC 20, Aircraft and space vehicles.
The first edition (IS0 1151-1972) had been approved in April 1971 by the Member
Bodies of the following countries :
Austria Greece South Africa, Rep. of
Israel Spain
Bel giu m
Czechoslov.akia Italy Thailand
Egypt, Arab Rep. of Japan Turkey
France Netherlands United Kingdom
New Zealand U.S.S. R.
Germany
No Member Body had expressed disapproval of the document.
In October 1974, draft Amendment 1 to International Standard IS0 1151-1972
was circulated to the Member Bodies. It has been approved by the Member Bodies
of the following countries :
Austria Germany Spain
Belgium India Turkey
Canada Mexico United Kingdom
Czec hosl ova k ia Poland U.S.S.R.
France Romania Yugoslavia
No Member Body expressed disapproval of the document.
Amendment 1 was then incorporated in the first edition of International Standard
IS0 1151 to form this second edition, which cancels and replaces the first
(1 151-1972).
O International Organization for Standardization, 1975 0
Printed in Switzerland
---------------------- Page: 2 ----------------------
International Standard IS0 11 51, Terms and symbols for flight dynamics - Part I :
Aircraft motion relative to the air, is the first in a series of International Standards
the purpose of which is to define the principal terms used in flight dynamics and to
specify symbols for these terms.
Other International Standards in this series, which will be further extended in the
future, are at present as follows :
IS0 11 52, Terms and symbols for flight dynamics - Part II : Motions of the
aircraft and the atmosphere relative to the Earth.
IS0 1153, Terms and symbols for flight dynamics - Part 111 : Derivatives of
forces, moments and their coefficients.
IS0 2764, Terms and symbols for flight dynamics - Part IV : Parameters used in
the study of aircraft stability and control.
IS0 2765, Terms and symbols for flight dynamics - Part V : Quantities used in
measurements.
In these International Standards, the term "aircraft" denotes an aerodyne having a
fore-and-aft plane of symmetry. This plane is determined by the geometrical
characteristics of the aircraft. When there are more than one fore-and-aft planes of
symmetry, the reference plane of symmetry is arbitrary and it is necessary to
indicate the choice made.
Angles of rotation, angular velocities and moments about any axis are positive
clockwise when viewed in the positive direction of the axis.
All the axis systems used are three-dimensional, orthogonal and right-handed, which
a clockwise (positive) rotation through n/2 about the x-axis brings the
implies that
y-axis into the position previously occupied by the z-axis.
Numbering of sections and clauses
Each of these International Standards represents a part of the whole study on terms
and symbols for flight dynamics.
To permit easier reference to a section or a clause from one part to another, a
decimal numbering has been adopted which begins in each International Standard
with the number of the part it represents.
iii
---------------------- Page: 3 ----------------------
CONTENTS
Page
1.0 Introduction . 1
1.1 Axis systems . 2
1.2 Angles . 3
1.3 Velocities and angular velocities . 4
1.4 Aircraft inertia, geometric and dynamic characteristics . 6
1.5 Forces, moments, coefficients and load factors . 8
1.6 Thrust, resultant moment of propulsive forces (airframe) aerodynamic
force, (airframe) aerodynamic moment and their components . 10
1.7 Coefficients of the components of the (airframe) aerodynamic force and
of the (airframe) aerodvnamic moment . 13
1.8 Motivator deflections . 14
1.9 Hinge moments . 16
Figure 1 - Orientation of the aircraft velocity with respect to
the body axis system . 17
Figure 2 - Orientation of the body axis system relative to
the aircraft-carried normal earth axis system . 18
Figure 3 - Orientation of the air-path axis system relative to
the aircraft-carried normal earth axis system . 19
Annex - Symbols of the components of the (airframe) aerodynamic force
and the non-dimensional coefficients of these components in use,
or coming into use, in different countries . 20
iv
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD IS0 1151-1975 (E)
Terms and symbols for flight dynamics -
Part I : Aircraft motion relative to the air
1.0 INTRODUCTION
This International Standard deals with the motion of the aircraft in an atmosphere at rest or in uniform motion.
To fully account for the effects of aeroelasticity and of the Earth’s curvature would necessitate more detailed consideration
of certain aspects of the definitions given, although these have been framed in such a way that they can be more generally
interpreted. The definitions of the axes apply as they stand when the Earth’s surface is treated as a plane, that is, when the
Earth’s radius is taken as infinite, and, in the case of the body axes, when the aircraft is treated as rigid.
1
---------------------- Page: 5 ----------------------
IS0 1151-1975 (E)
1.1 AXIS SYSTEMS
-
Definition Symbol
Term
No.
A system with both origin 0, and axes fixed with
1 .I .I Earth-fixed axis system
respect to the Earth, chosen to suit the problem.
Normal earth-fixed axis system An earth-fixed axissystem (1.1.1) in which the
1 .I .2 xo, Yo, 20
but
zo-axis is vertically downward.
xg, Yg, zg
is an accepted
alternative.
A system in which each axis has the same
1 .I .3 Aircraft-carried earth
xo, YO, 20
direction as the corresponding earth-fixed axis,
axis system
with origin O, fixed in the aircraft, usually at the
centre of gravity.
1 .I .4 Aircraft-carried normal A system in which each axis has the same direction
xot Yo, 20
as the corresponding normal earth-fixed axis, with but
earth axis system
origin O, fixed in the aircraft, usually at the centre
xg, Yg, zg
is an accepted
of gravity.
alternative.
1 .I .5 Body axis system Axis system fixed in the aircraft with origin O,
usually the centre of gravity, containing the lon-
gitudinal axis, the transverse axis and the normal
axis according to the following definitions :
An axis in the plane of symmetry or, if the X
Longitudinal axis
origin lies outside this, in a parallel plane through
the origin, and in some suitable forward direction.
An axis normal to the plane of symmetry, and
Transverse axis Y
positive to starboard.
z
An axis in the plane of symmetry or, if the
Normal axis
origin lies outside this, in the parallel plane through
the origin, normal to the longitudinal axis, positive
in the ventral sense (when viewed from the origin O).
Axis system with aircraft fixed origin O, usually
1.1.6 Air-path axis system Xa, Ya, za
the centre of gravity, and containing the following
axes :
An axis in the direction of the aircraft velocity
xa-axis
(1.3.1 ).
(air-path axis)
An axis normal to the air-path axis and the za-axis
y,-axis
defined below. It is positive to starboard.
An axis in the plane of symmetry, or, if the origin
2,-axis
lies outside this, in the parallel plane through the
origin and normal to the air-path axis. In normal
flight conditions it is therefore ventral (when
viewed from the origin O).
2
---------------------- Page: 6 ----------------------
IS0 1151-1975 (E)
1.2 ANGLES
Orientation of the aircraft velocity with respect to the body axis system (see figure 1)
No. Term Definition
Symbol
1.2.1 Angle of sideslip The angle that the aircraft velocity (1.3.1) makes
P
with the plane of symmetry of the aircraft. It is
positive when the aircraft velocity component
along the transverse axis (1.1.5) is positive. It has
by convention the range
71 71
--
2' '2
1.2.2 Angle of attack The angle between the longitudinal axis (1.1.5) (Y
and the projection of the aircraft velocity (1.3.1)
on the plane of symmetry. It is positive when the
aircraft velocity component along the normal axis
(1.1.5) is positive. It has by convention the range
-n<(YQ71
Transition from the aircraft-carried normal earth axis system to the body axis system is effected by the rotations yi0.0
defined below, taken in that order (see figure 2).
NOTE - Analogous angles can be defined with respect to any aircraft-carried earth axis system. The same symbols Y, O, @, with appropriate
suffixes as necessary, may then be used. On the other hand, the terms azimuth angle, inclination angle and bank angle refer only to the special
case where the 2,-axis is vertical.
Term Definition Symbol
Azimuth angle
The rotation (positive if clockwise) about the Y
zo (zg)-axis which brings the xo (Xe)-axis into
coincidence with the projection of the longitudinal
(1 .I .5) on the horizontal plane through the
axis
origin O.
~~
Inclination angle (elevation) The rotation in a vertical plane, following the
rotation Y (1.2.3) and which brings the displaced
xo (xg)-axis into coincidence with the longitu-
dinal axis (1.1.5). It is positive when thex-axis
lies above the horizontal plane through the origin O.
It has by convention the range
1.2.5 Bank angle The rotation (positive if clockwise) about the
longitudinal axis (1.1.5) which brings the dis-
placed y ( )-axis into its final position y from
9 y?
the position it reached after rotation through Y
(1.2.3).
3
---------------------- Page: 7 ----------------------
IS0 1151-1975 (E)
Transition from the aircraft-carried normal earth axis system to the air-path axis system is effected by the rotations xa,
ya and pa defined below, taken in that order (see figure 3).
~~
Definition Symbol
No. Term
____________~~~~~~ ~
Air-path azimuth angle The rotation (positive if clockwise) about the
1.2.6 Xa
(air-path track angle) z, (zg)-axis which brings the x, (xg)-axis into
coincidence with the projehion of the air-path
xa-axis (1.1.6) on the horizontal plane through
the origin O.
Air-path inclination angle The rotation in a vertical plane, following the
1.2.7 Ya
rotation xa (1.2.6) which brings the displaced
(air-path climb angle)
x, (xg)-axis into coincidence with the air-path
xa-axis (1.1.6). It is positive when the xa-axis
lies above the horizontal plane through the
origin O. It has by convention the range
I
Air-path bank angle The rotation (positive if clockwise) about the
1.2.8 Pa
air-path xa-axis (1.1.6) which brings the dis-
placed y, (yg)-axis into its final position ya
from the position it reached after rotation
through Xa (1.2.6).
1.3 VELOCITIES AND ANGULAR VELOCITIES
~~
Definition Symbol
No. Term
The velocity of the origin O of the body axis
1.3.1 Aircraft velocity
system (1.1.5) (usually the centre of gravity)
relative to the air unaffected by the aerodynamic
field of the aircraft. The corresponding scalar
quantity is the airspeed.
a
1.3.2 Speed of sound The velocity of propagation of a sound wave in
the ambient air unaffected by the aerodynamic
field of the aircraft.
M is recommended.
1.3.3 Mach number The ratio of the airspeed (1.3.1) to the speed of
However the sym-
sound (1.3.2). Equal to Vla
bols Ma and ??2
may be used if
otherwise there
would be a possi-
bility of confusion
I
4
---------------------- Page: 8 ----------------------
IS0 1161-1975 (E)
Term Definition Symbol
No.
-c
1.3.4 Aircraft velocity components The components of the velocity V, for any of the
axis systems used.
In the axis systems 1.1.1 to 1.1.4 :
component along the x,-axis
component along the yo-axis
component along the 2,-axis
In the body axis system (1.1.5) :
component along the longitudinal axis U
component along the transverse axis V
W
component along the normal axis
In certain comput-
ations the velocity
:omponents may be
written Vi where i
UOTE - In the air-path axis system (1.1.6) the
:omponent along the x,-axis is O, = V. i a dummy subscript
1.3.5 The angular velocity (corresponding scalar
Aircraft angular velocity
quantity) of the body axis system (1.1.5)
relative to the Earth.
-
The components of the angular velocity SZ, for
1.3.6 Angular velocity components
any of the axis systems.
In the axis systems 1.7.1 to 1.1.4 :
component about the x,-axis
Po
component about the y,-axis
90
component about the 2,-axis
r0
1 n the body axis system ( 1.1.5) :
component about the longitudinal axis
Rate of roll P
component about the transverse axis
Rate of pitch 9
component about the normal axis r
Rate of yaw
In certain com-
putations the angu-
lar velocity com-
ponents may be
written SZi where i
i a dummy subscript
5
---------------------- Page: 9 ----------------------
IS0 7151-1975 (E)
No. Term Definition Symbol
1.3.7
Normalized angular The normalized form of the components of the
velocities angular velocity (1.3.5), formed as follows :
In the body axis system (1.1.5) :
- Pl
Normalized rate of roll
P*
V
- ql
Normalized rate of pitch q*
V
rl
-
r*
Normalized rate of yaw
V
where I is the reference length (1.4.6).
Analogous quanti-
ties using a cons-
Similar normalized quantities can be formed for
tant reference speed
the other axis systems.
in place of V (1.3.1)
may also be defined
These require diffe-
rent symbols.
DYNAMIC CHARACTERISTICS
No. Term Definition Symbol
1.4.1 Aircraft mass The current mass of the aircraft. rn
Moments of inertia
1.4.2 The moments of inertia of the aircraft with
respect to the body axes x, y, z ( 1.1.5).
Moment of inertia about the longitudinal axis is
(y2 + z2)drn
Moment of inertia about the transverse axis is
J (z2 +x2)drn
Moment of inertia about the normal axis is
I (x2 + y2)drn
4
(A, B, C
are acceptable
alternatives)
1.4.3 Products of inertia The products of inertia of the aircraft with respect
to the body axesx, y,z (1.1.5). These are :
I YZ drn
Jzx drn
Iw drn
are acceptable
alternatives)
1.4.4 Radius of gyration The square root of the ratio of the moment of
inertia to the aircraft mass (1.4.1) :
for the longitudinal axis (1.1.5)
dIx lrn
for the transverse axis (1.1.5)
rn
for the normal axis (1.1.5)
a
6
---------------------- Page: 10 ----------------------
IS0 1151 -1975 (E)
Symbol
No. Term Definition
S
1.4.5 Reference area An area used in forming various non-dimensional
quantities. For the complete aircraft the most
commonly used reference area is the gross wing area
(i.e. the area obtained by continuing the edges
within the fuselage and the nacelles).
NOTE - Hinge moment coefficients are not usually based
on this reference area.
A length used in forming nondimensional coef-
1.4.6 Reference length
ficients of the aerodynamic moments and various
normalized quantities. In a given document this
length has a specified constant value. In the absence
of a length having some aerodynamic significance
the choice should correspond to an easily estab-
lished geometric feature.
NOTE - Hinge moment coefficients are not usually
based on this reference length.
~~~ ~ ~
b
1.4.71 )
Wing span The distance between the two planes parallel to
the plane of symmetry, tangential to the wing
surface and lying wholly outside the aircraft.
1.4.8 Normalized mass Non-dimensional coefficient defined as follows :
m
i PeSl
where
m is the aircraft mass ( 1.4.1 1;
pe is a datum (air) density (3.3.2);
S is the reference area (1.4.5);
I is the reference length (1.4.6).
A quantity defined as follows :
1.4.9 Dynamic unit of time
m -- Pl
-
i Pe Ves Ve
where
m is the aircraft mass ( 1.4.1 );
pe is a datum (air) density (3.3.2);
ve is a datum speed (3.3.1);
S is the reference area (1.4.5);
1 is the reference length (1.4.6);
y is the normalized mass (1.4.8).
TA
A quantity defined as follows :
1.4.10 Aerodynamic unit of time
1
-
Ve
where
1 is the reference length (1.4.6);
V, is a datum speed (3.3.1).
It is intended that this item will be transferred to part VI of this series of standards relating to terms and symbols for flight dynamics. Part VI
1 )
(in preparation) will be entitled "Aircraft geometry" and will coiltain an improved definition of wing span.
7
---------------------- Page: 11 ----------------------
IS0 1151 -1975 (E)
1.5 FORCES, MOMENTS, COEFFICIENTS AND LOAD FACTORS
Definition Symbol
No.
4
The resultant vector (magnitude of the resultant R (RI
1.5.1 Resultant force
vector) of the system of forces acting on the air-
craft including the (airframe) aerodynamic forces and
the propulsion forces, but excluding the
gravitational, inertial and reaction forces due to
contact with the Earth's surface.
NOTE - In the special cases where only the (airframe)
aerodynamic forces or the propulsive forces are consi-
dered, a distinguishing symbol is necessary (see 1.6).
-O
The components of the resultant force vector, R.
1.5.2 lomponents of the resultant
Force
In the bo
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.