1、BRITISH STANDARD OBSOLESCENT MARCH 1987 BS 185-9:1970 Glossary of Aeronautical and astronautical terms Section 9: Propellers UDC 001.4:629.7.035.5BS185-9:1970 This British Standard, having been approved by the AerospaceIndustry StandardsCommittee, waspublished under the authorityofthe Executive Boar
2、dof the Institution on 21July1970 BSI 12-1999 The following BSI references relateto the work on this standard: Committee reference ACE/1 Draft for comment 67/28249 ISBN 580 06451 4 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards a
3、re responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to3 and a back cover. This standard has been updated (see co
4、pyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBS185-9:1970 BSI 12-1999 i Contents Page Section 9. Propellers 1ii blankBS185-9:1970 BSI 12-1999 1 (Notes on the
5、arrangement and scope of the glossary are contained in the Foreword to Section 1.) Section 9. Propellers No. Term Definition 9101 airscrew An assembly of aerofoils, radially disposed, and designed to rotate in air with or without the application of power. The blade angle of each aerofoil usually var
6、ies along its length. balances 9102 aerodynamic balance A propeller is in aerodynamic balance when the aerodynamic action on the blades results in no periodic forces or couples on the mounting. 9103 dynamic balance A propeller is in dynamic balance when the inertial forces due to its rotation result
7、 in no periodic forces or couples on the mounting. 9104 static balance A propeller is in static balance if, when concentrically mounted on a spindle supported by knife-edges, it will remain at rest in any position at any blade angle. 9105 blade activity factor A non-dimensional function of the blade
8、 planform, used to express the capacity of a blade for absorbing power and defined by the formula: where R = blade tip radius. c = blade chord length at the radiusr. 9106 blade angle The angle, normally acute, between the pressure face of an element of a propeller and the plane of rotation. When the
9、 pressure face is curved, the blade angle is measured with reference to the chord. 9107 blade sweep The angular deviation of the locus of centroids of blade sections from the radial line tangential thereto at the propeller axis, projected on to the plane of rotation. 9108 leading sweep A blade sweep
10、 towards the leading edge. 9109 trailing sweep A blade sweep towards the trailing edge. 9110 blade tilt The angular deviation of the locus of centroids of blade sections from the plane of rotation (backward tilt, forward tilt). 9111 boss The central portion of an integral propeller. (Cf.9118.) 9112
11、diameter The diameter of the circle described by the tips of the blades. 9113 disc area The area of the circle described by the tips of the blades. efficiencies 9114 free air efficiency The ratio of the free air thrust horsepower to the torque horsepower. 9115 propulsive efficiency The ratio of the
12、propulsive thrust horsepower to the torque horsepower. 9116 shaft efficiency The ratio of the shaft thrust horsepower to the torque horsepower. 9117 geometric pitch PITCH The distance which an element of a propeller would advance in one revolution when moving along a helix to which the line defining
13、 the blade angle of that element is tangential. NOTEThe geometric pitch of an element of a fixed-pitch propeller at the standard radius is usually referred to as the “pitch” of the particular propeller, and is marked on it. 9118 hub 1. In an integral propeller. The detachable part on which the compl
14、ete propeller is mounted on the propeller shaft. 2. In a propeller with detachable blades. The central portion to which the blade roots are attached. (Cf.9111.)BS185-9:1970 2 BSI 12-1999 No. Term Definition 9119 nose cap A boss or hub fairing fitted co-axially and rotating with the propeller. It doe
15、s not extend aft of the front of the blade roots. (Cf.9148.) 9120 out-of-alignment Having the blade sweep of one blade different from that of the other(s). 9121 out-of-pitch Having the blade angle of one blade different from that of any other at the same radius. 9122 out-of-track Having the blade ti
16、lt of one blade different from that of the other(s). 9123 pitch setting BLADE ANGLE SETTING The blade angle of adjustable or variable pitch propellers, measured at the standard radius. 9124 braking pitch A pitch setting selected to give reverse thrust, either by windmilling at small positive pitch o
17、r by power operation at negative pitch. 9125 feathering pitch A pitch setting selected to give minimum speed of rotation and approximately minimum drag when the engine is stopped. 9126 reverse pitch A negative pitch setting. power losses 9127 induced power loss The power expended in overcoming the d
18、rag of the blade elements contributing to thrust. 9128 profile-drag power loss The power expended in overcoming the profile drag of the blade elements of a propeller. 9129 pressure face The face of a propeller blade formed by the lower boundaries of the blade elements considered as aerofoil sections
19、. 9130 propeller A power-driven airscrew designed to produce thrust by its rotation in air. 9131 adjustable-pitch propeller A propeller, the blades of which can be adjusted to a desired pitch setting when not rotating. 9132 club propeller A heavy, short-bladed, dummy propeller used to load an engine
20、 during testing on a test stand. 9133 coaxial propellers Two propellers mounted on concentric shafts having independent drives and normally rotating in opposite directions. 9134 constant-speed propeller A propeller, the pitch setting of which varies automatically to maintain a preselected constant r
21、otational speed. 9135 contra-rotating propellers COUNTER-ROTATING PROPELLERS Two propellers mounted on concentric shafts having a common drive and rotating in opposite directions. 9136 controllable-pitch propeller A propeller, the blades of which can be changed to certain predetermined pitch setting
22、s when rotating. 9137 fixed-pitch propeller A propeller having no provision for changing the pitch setting. 9138 integral propeller A propeller in which the blades and the boss form an integral whole. 9139 left-handed propeller A propeller rotating counter-clockwise as viewed from behind the aircraf
23、t. 9140 pusher propeller A propeller designed normally to produce compression in the propeller shaft. 9141 right-handed propeller A propeller rotating clockwise as viewed from behind the aircraft. 9142 tractor propeller A propeller designed normally to produce tension in the propeller shaft. 9143 va
24、riable-pitch propeller A propeller with provision for changing the pitch setting when rotating. 9144 slinger ring A device at the hub of a propeller from which de-icing or anti-icing fluid is thrown out along the blades by centrifugal force.BS185-9:1970 BSI 12-1999 3 No. Term Definition 9145 slipstr
25、eam The stream of air discharged aft by a rotating propeller. 9146 solidity The ratio of the total blade area to the disc area. 9147 solidity at standard radius The ratio of the sum of the chord lengths of the blades at the standard radius to the circumference of a circle of that radius. 9148 spinne
26、r A streamlined fairing, fitted coaxially and rotating with the propeller, enclosing the hub or less. (Cf.9119.) 9149 standard radius An arbitrary radius used for specifying the characteristics of a propeller. 9150 suction face The face of a propeller blade formed by the upper boundaries of the blad
27、e elements, considered as aerofoil sections. thrust 9151 free air thrust The axial aerodynamic force exerted by the blades in a uniform field undisturbed by nacelle or other structure. 9152 propulsive thrust The shaft thrust loss the increase in aircraft drag caused by the presence of the slipstream
28、. 9153 shaft thrust GROSS THRUST APPARENT THRUST The axial aerodynamic force exerted by the blades in the flow field in which they are situated. 9154 static thrust The thrust developed by a rotating propeller with no translational motion. 9155 torque The moment of the air forces on a propeller about
29、 its axis of rotation. 9156 windmill An airscrew designed to produce power by axial translation relative to the air. 9157 windmilling A propeller is “windmilling” when it is delivering power to the propeller shaft.BS 185-9:1970 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution
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