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1、BRITISH STANDARD BS G 123:1949 Specification for Aircraft magnetic compass remote-reading (non-stabilized) NOTEThe Institution desires to call attention to the fact that this standard is intended to include the technical provisions necessary for the supply of the material herein referred to, but doe
2、s not purport to comprise all the necessary provisions of a contract. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 123:1949 This British Standard, having been approved by the Aircraft Industry Standards
3、 Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council of the Institution on 15 December 1949 BSI 02-2000 ISBN 0 580 34523 8 A British Standard does not purport to include all the necessary provisions of a contract. Use
4、rs of British Standards are 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, pages i and ii, pages 1 and 2 and a back cover. This sta
5、ndard has been updated (see copyright 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.DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Dec 0
6、9 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 123:1949 BSI 02-2000i Contents Page 1Definition1 2General construction1 3Detailed construction1 4Supply1 5Accuracy1 6Vibration2 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Un
7、controlled Copy, (c) BSI ii blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 123:1949 BSI 02-20001 Preferred size: British Standard aircraft instrument case, Type 1. Preferred units of graduation: Ang
8、ular degrees. 1 Definition For the purpose of this British Standard the term “remote-reading magnetic compass (non-stabilized)” denotes an instrument comprising a master magnetic compass or detector and one or more indicators remote from the detector which show the heading of the aircraft relative t
9、o the magnetic meridian, the system not employing a gyroscope either for stabilization or for smoothing of indication. 2 General construction The construction of the instrument shall be mechanically sound, suitable for its purpose, and in accordance with the requirements laid down in BS G 100, “Gene
10、ral requirements for indicating instruments and electrical apparatus”1) with respect to climatic proofing, temperature performance, and ability to withstand aircraft vibration. 3 Detailed construction a) The detailed construction of the units shall be in accordance with relevant requirements laid do
11、wn in BS G 100. b) The instrument shall consist of a magnetic compass, or detector (master unit), designed for mounting in the most suitable magnetic location in the aircraft. Means shall be provided for transmitting its indications to a suitable repeater or repeaters mounted in the instrument panel
12、, or at any station in the aircraft. c) The general construction of the master unit shall be of non-magnetic materials with the exception of the magnets or the direction-sensitive elements. d) Any fluid or electrolyte, if used, shall not re-act with any of the materials with which it is in contact.
13、Provision shall be made to accommodate volumetric changes of the liquid throughout the temperature range 70 C. to + 70 C. e) Suitable provision shall be made for isolating the magnetic element from excessive aircraft vibration. f) In the case of master units employing pendulously pivoted magnets, th
14、e pendulously of the system shall be such that the change of one oersted of vertical force at London results in a change of tilt not in excess of 3 degrees. The damping of the directional element and its magnetic characteristics shall be adjusted to promote maximum stability under all conditions of
15、flight. g) The instrument shall function satisfactorily when tilted through any angle up to and including 20 degrees. h) The repeater shall be accurate in accordance with an approved presentation, which may consist either of a vertical dial with a moving compass card or a vertical dial with a moving
16、 compass pointer. The repeater shall be provided with a course-setting device readily adjustable from the front of the instrument. The repeater dial shall be accurately divided in units of 2 degrees or 5 degrees according to the size of the dial. The treated dial markings shall satisfy the requireme
17、nts of BS G 100. i) Means shall be provided for correcting the deviations of the compass. 4 Supply The instrument shall operate either on a nominal supply of 24 volts D.C. or 400 cycles, 115 volts A.C. 5 Accuracy a) The following performance requirements shall be maintained with nominal power supply
18、 of 24 volts D.C., normal field strength at London, and throughout the following temperature range: b) Master unit. The directional error of the master unit on any heading shall not exceed the following values: 1: degrees with the master unit horizontal. 1 degrees with the master unit tilted 10 degr
19、ees. 2 degrees with the master unit tilted 15 degrees. 3 degrees with the master unit tilted 20 degrees. c) Repeater. The error of the repeater indication when checked against a calibrated master unit on any heading shall not exceed 1; degrees. 1) In course of preparation Magnetic detector unit, 70
20、C. to + 70 C. Other units, 20 C. to + 50 C. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 123:1949 2 BSI 02-2000 d) Combined transmission error. The maximum combined transmission error of any master unit
21、 and repeater of a given type, as indicated by the repeater pointer, shall not exceed 2; degrees irrespective of the direction from which the heading is approached. e) Sensitivity. The master unit shall respond to a minimum change of course of : degree when operating on normal supply voltage. The va
22、lue corresponds of the “dead sector” and shall be not greater then 2 degrees when the instrument is operating at any supply voltage within the specified range. f) Follow-up. The repeaters shall follow the master unit accurately at any rate of rotation up to 20 degrees per second and shall not become
23、 permanently de-synchronized at any speed of follow-up of which the system is capable. g) Friction error. The friction error shall not exceed 2 degrees, and shall be defined as the angular distance between the two settling positions after deflecting the magnetic system 10 degrees to each side of the
24、 meridian in turn. The instrument shall be kept free from vibration during the test. 6 Vibration The instrument shall show no errors outside the tolerance specified in Clause 5 when subjected to the varying frequency vibration tests relevant to its installation position in the aircraft (which may be
25、 the wing tip) laid down in BS G 100, and any pointer oscillation shall be within the limits permitted therein. The instrument shall also withstand the appropriate endurance vibration test laid down in the same standard without damage or derangement. Licensed Copy: London South Bank University, Lond
26、on South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS G 123:1949 BSI 389 Chiswick High Road London W4 4AL BSI British
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34、xtract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as
35、symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel: 020 8996 7070. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:22:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
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