ISO INTERNATIONAL STANDARD 1151-4 Secondedition 1994-11-01 Flight dynamics - Concepts, quantities and symbols - Part 4: Concepts, quantities and symbols used in the study of aircraft stability and control Mecanique du vol-Concepts, grandeurs et symboles- Partie 4: Concepts, grandeurs et symboles utilises pour I'etude de la stabilite et du pilotagedesavions OSI Reference number ISO 1151-4:1994(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 1151-4:1994(E) Foreword IsO (the International Organization for Standardization) js a worldwide federation of national standards bodies (IsO member bodies). The work of preparing inter- national Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which a technical committee has been established 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. IsO collaborates closely with the International Electrotechnical Commission (lEC)onallmattersofelectrotechnicalstandardization DraftInternational Standards adopted by thetechnical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 1151-4 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Sub-Committee SC 3, Concepts, quantities andsymbolsforflightdynamics. IsO 1151 consists of the following parts, under the generai title Flight dynamics - Concepts, quantities and symbols : Part 1:Aircraftmotionrelativetotheair 一 Part2:MotionsoftheaircraftandtheatmosphererelativetotheEarth Part 3: Derivatives of forces, moments and their coefficients Part 4: Concepts, quantities and symbols used in the study of aircraft stability and control Part 5: Quantities used in measurements Part 6: Aircraft geometry Part 7: Flight points and flight envelopes Par 8: Concepts and quantities used in the study of the dynamic behaviour oftheaircraft Part 9: Models of atmospheric motions along the trajectory of the aircraft @ISO1994 including photocopying and microfilm, without permission in writing gfromthe publisher International Organization for Standardization Case postale 56 . CH-1211 Geneve 20 : Switzerland Printed in Switzerland ii No reproduction or networking permited without license from IHS Not for Resale ISO 1151-4:1994(E) @ISO Iso 1151 is intended to introduce the main concepts, to include the more importantterms used intheoretical and experimentalstudies and,as far as possible, to give corresponding symbols. In all the parts comprising ISO 1151, the term "aircraft" denotes a vehicle intended for atmosphere or space flight. Usually, it has an essentially port and starboard characteristics of the aircraft. In that plane, two orthogonal directions are defined: that plane,foliows. When there is a single plane of symmetry, it is the reference plane of the aircraft. necessary to choose a reference plane. In the former case, the reference plane is one of the planes of symmetry. In the latter case, the reference plane is arbitrary. In all cases, it is necessary to specify the choice made. Angles of rotation, angular velocities and moments about any axis are positive clockwise when viewed in the positive direction of that axis. All the axis systems used are three-dimensional, orthogonal and right-handed, which implies that a positive rotation through π/2 around the x-axis brings the y-axis into the position previously occupied by the z-axis. The centre of gravity coincides with the centre of mass if the field of gravity is centre of mass in the definitions of ISO 1151; in which case, this should be indicated. Numbering of sections and clauses With the aim of easing the indication of references from a section or a clause, a decimal numbering system has been adopted such that the first figure is the numb