1、BRITISH STANDARD BS G152:1956 (Replacing, in part, BS G110) Specification for A.C. Electrically-operated artificial horizons for aircraftBSG152:1956 This BritishStandard, having been approved by the Aircraft Industry Standards Committeeand endorsed by theChairman of the EngineeringDivisional Council
2、,was published under theauthorityof the General Councilofthe Institution on 30August1956 BSI02-2000 The following BSI references relate to the work on this standard: Committee reference ACE/30 Draft for comment CT(ACE)8282 ISBN 0 580 34528 9 Foreword BS G110:1949, “Artificial horizons for aircraft,”
3、 specified requirements for the general and detailed construction, and for the accuracy of both air-driven and electrically-driven instruments. This standard has been prepared to provide an up-to-date and separate specification for A.C. electrically-driven artificial horizons in the light of experie
4、nce gained in the application of the relevant requirements of BS G110, which it supersedes. Information has been added relating to the incidence of testing, and recommendations included in respect of tests to verify the serviceability of the instruments. A British Standard does not purport to includ
5、e all the necessary provisions of a contract. Users 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, pagesi
6、andii, pages1 to6, an inside back cover and a back cover. This standard 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. Date CommentsBSG152:1956 BSI 0
7、2-2000 i Contents Page Foreword Inside front cover 1 Scope 1 2 Definition 1 Section 1. General requirements 3 Case size 1 4 Fixing holes 1 5 General construction 1 Section 2. Particular requirements 6 Construction 1 7 Electrical characteristics 1 8 Mechanical characteristics 1 9 Marking 2 Section 3.
8、 Tests 10 General 2 A. Type tests 11 Rotor over-speed test 2 12 Starting tests 3 13 Electrical tests 3 14 Mechanical tests 3 15 Vibration, acceleration and climatic tests 5 16 Temperature rise 5 17 Compass interference 5 18 Temperature tests 5 19 Radio interference 5 20 Power consumption 5 21 Endura
9、nce test 6 B. Routine production tests Appendix A Serviceability tests Inside back cover Table 1 Direction and acceptable amount of deviation in the quadrature axis during erection 4ii blankBSG152:1956 BSI 02-2000 1 1 Scope This BritishStandard specifies the general design requirements and test proc
10、edure for a.c. electrically-operated artificial horizons for aircraft. 2 Definition For the purposes of this BritishStandard the following definition shall apply: artificial horizon an instrument used on aircraft to indicate on a single dial the attitude of the aircraft in pitch and roll, by referen
11、ce to a gyroscope coupled mechanically to an indicating system comprising a miniature aeroplane and an horizon line Section 1. General requirements 3 Case size The instrument case shall not be more than4) in. in diameter, and not more than7in. in overall depth. 4 Fixing holes For4) in. diameter case
12、s, attachment shall be effected by four fixing holes equally spaced on a4# in. pitch circle diameter, with integral2B.A. stiff-nuts: otherwise the fixing holes should be in accordance with those specified for aircraft instrument cases in BS G100, “General requirements for electrical equipment and in
13、dicating instruments for aircraft”. 5 General construction The instrument shall be sound and suitable for its purpose and its design and construction shall comply with the relevant requirements of BSG100. Section 2. Particular requirements 6 Construction The instrument shall consist of an electrical
14、ly-driven gyroscope spinning about an axis substantially vertical in both pitch and roll. The gyroscope shall be coupled mechanically to an indicating system comprising a miniature aeroplane and an horizon line, and the relative position of the miniature aeroplane to the horizon line shall be qualit
15、atively the same as that of the real aircraft to the natural horizon. An indication of attitude shall be given for any combination of pitch and roll within the range 75 roll 60 pitch. 7 Electrical characteristics a) Supply. The instrument shall be designed to operate satisfactorily on a three-phase
16、supply of103.5126.5 volts,380420cycles, and in addition the gyroscope shall be capable of erection to the vertical when the symmetrical supply voltage does not exceed90volts at395405cycles. The maximum consumption shall be30VA and the power factor shall be0.8nominal. b) Phase sequence. The phase seq
17、uence shall be such that the terminal voltages measured from an artificial star point shall reach their maxima in the order A, B, C (red, white and blue respectively), giving the clockwise rotation of the gyroscope when viewed from above. c) Earthing. The supply to the instrument shall have the B (w
18、hite) phase earthed, but no bonding shall be provided in the instrument. d) Erection supply. Pins D and E shall give access to the erection supply for test purposes. e) Cable bonding. A six-core screened cable3ft long, terminating in a suitable six-pin plug shall be provided from the instrument. The
19、 cable shall be screened overall and suitable detachable bonding provided between the screening of the cable and the instrument chassis. f) Cable connections. The six-core screened cable shall enter the instrument body radially on the side of the rear end of the instrument. The entry shall be capabl
20、e of being turned through180 in steps of45 . The colour coding is to be as follows: 8 Mechanical characteristics a) Freedom. The gimbal shall be designed to give complete freedom in roll and a nominal 80 freedom in pitch. A resilient stop shall be fitted to the gimbal system to prevent damage to the
21、 instrument when the limits of freedom are exceeded. b) Gravity control. The gyroscope movement shall be sufficiently pendulous to satisfy the requirements of Clause12 b). The maximum pendulosity acceptable where the design requires a compensating side tilt shall be such that the tilt, calculated in
22、 accordance with c does not exceed2 and shall be within! of the calculated values. Socket pins: A B C D E F Cable core colours: Red White Blue Green Yellow BlackBSG152:1956 2 BSI 02-2000 c) Turn error compensation. Where the gyroscope axis is tilted slightly to compensate for errors experienced in f
23、light, the amount of tilt to be applied, either forward or starboard, or in both directions, is to be obtained from the following: NOTEForward tilt shall not exceed2 . The values selected for r and V shall be declared. d) Gyroscope erection. Each instrument shall incorporate electrical means to erec
24、t the gyroscope automatically and to maintain it erect. e) Ventilation. Where the instrument is not hermetically sealed, suitably screened and filtered ventilation holes shall be provided so that the requirements in respect of environmental pressure, temperature and humidity changes and self-heating
25、 conditions are satisfied. f) Lubrication. The rotor and gimbal bearings shall be designed to give satisfactory performance throughout the operating life of the instrument without relubrication. g) Robustness. The instrument shall be so designed that shock loads giving an acceleration of50g in any d
26、irection do not impair the performance. h) Moment of momentum. The angular moment of momentum shall be as high as possible consistent with size. j) Balance. The rotor shall be dynamically balanced about its axis of spin. k) Torque motors. The design of torque motors shall be such that no serious ove
27、rheating takes place if the erection rate is increased to30 per minute for15seconds. 9 Marking In addition to the marking required by BS G100, instruments shall be marked with the rate of turn and true air speed selected for determining the tilt and turn error compensation. Section 3. Tests 10 Gener
28、al a) Tests shall be made to prove compliance with all the requirements of this BritishStandard. It is not intended or recommended that complete tests shall be made on every instrument supplied. Two kinds of test, therefore, are specified as follows: The tests in Clauses11, 12, 13 b),14 a),14 b),14
29、d), and18 shall be made at the relevant stage of construction before the instrument is cased. b) Minimum tests recommended to verify the serviceability of instruments manufactured in compliance with this BritishStandard are indicated in Appendix A. c) Unless otherwise specified the instrument shall
30、be tested: i) at room temperature(1520 C); ii) in the normal position (the normal position is that in which both the plane of the mounting face of the fixing flange is vertical and the centre line passing through the top fixing screw holes is horizontal and within10minutes of arc); iii) stationary,
31、on a three-phase test supply of113117 volts395405c/s, and after the gyroscope has been running for at least half an hour. A. Type tests 11 Rotor over-speed test 1) (This test has particular significance for sintered rotors but is applicable to all designs). With a power supply of115volts500cycles ap
32、plied to the instrument the rotor shall be allowed to reach maximum speed for a duration of5minutes and then to coast to rest, after which the test shall be repeated with a supply of115volts at475cycles. Finally, with the normal test supply applied to the instrument the rotor shall be run for a dura
33、tion of ten minutes. where R =erection rate in roll (Average5 /min) r =rate of turn. where M =pendulous moment due to bottom heaviness. V =true air speed. J =I angular moment of momentum. A. Type tests (Clauses11 to21), which shall be made on representative samples of each particular design. B. Prod
34、uction routine tests (Clause22), which shall be made on every instrument manufactured in accordance with this BritishStandard. 1) In view of the possibly dangerous consequences of failure of the rotor, suitable precautions should be taken during the performance of this test.BSG152:1956 BSI 02-2000 3
35、 12 Starting tests a) With a supply of not more than90volts395405 cycles applied to the instrument, the rotor shall start to turn, in a clockwise direction when viewed from above, and continue to run at a speed of not less than75per cent of the nominal synchronous speed. b) With the nominal test sup
36、ply applied to the instrument the rotor shall run up from rest to at least50per cent of the nominal synchronous speed in not more than1“ minutes and shall fulfil the requirements of Clause14 c) within that time. 13 Electrical tests a) Normal current. When steady conditions have been reached the curr
37、ent in each phase shall be measured and shall not exceed0.2amp. on any phase. b) High voltage test. The instrument shall be subjected to a high voltage test at the conclusion of a functioning test e.g.Clause14 f). The supply shall be1000volts r.m.s.) at50c/s applied for a total of1minute between the
38、 terminals A, B and C grouped together at the plug and the chassis of the instrument. c) Routine insulation test. A routine insulation resistance test shall be carried out on all instruments within1minute after completing a functioning test e.g.Clause14 f). The test shall be carried out with a500vol
39、t d.c. supply applied between the3pins A, B and C grouped together on the plug and the chassis of the instrument. The insulation resistance shall be not less than20megohms. 14 Mechanical tests a) Gimbal freedom. The gimbal freedom shall be checked over the whole freedom range, which shall not be les
40、s than78 in pitch (both dive and climb) and complete freedom in roll, with the gyroscope running. b) Horizon bar clearances. With the gyroscope stationary the horizon bar shall be offset, in pitch75 each way separately and in these positions the outer gimbal shall be rotated through a complete revol
41、ution to check clearances between bars and chassis. c) Settling. The datum positions of the horizon bar and roll indicator shall be within1 (indicated) of their zero positions when the instrument is in the normal position seeClause10 c)ii) and with the gyroscope running. The zero position is that at
42、 which the associated fixed and moving indicators are in alignment. d) Bottom heaviness (if embodied). The following tests shall be made to determine that the pendulous moment due to bottom heaviness complies with the agreed figures: i) An appropriate weight or weights shall be applied to the gimbal
43、s of the gyroscope to counterbalance the designed pendulous moment. The test shall be successively performed with the instrument dial down and in its normal position, i.e.with the longitudinal axis of the case horizontal, the gyroscope axis being swung to the horizontal in both cases (in the latter
44、position the gyroscope axis will lie transversely). With the rotor stationary, the gyroscope axis shall be moved to various angles from the horizontal and the instrument gently tapped to ensure that the gyroscope axis remains stationary, indicating that the bottom heaviness has been removed. ii) Wit
45、h the counterbalance weight specified ini) removed and with the gyroscope rotor stationary, the gimbals shall be tilted in both the longitudinal and transverse axes25 from the vertical and when released without initial velocity the gyroscope shall settle to within20 of the vertical in both pitch and
46、 roll. e) Gyroscope axis inclination (if embodied). i) Instruments with inclination in both pitch and roll. The inclination of the gyroscope axis in both pitch and roll shall be determined by the following method and the top end of the gyroscope spindle shall be inclined to within! of the calculated
47、 values forward: A. The instrument shall be mounted on a table capable of rapid rotation about an axis truly vertical to within0.1 . With the gyroscope running, five minutes shall be allowed for stable conditions to be reached and then the position of the roll indicator shall be noted. B. The erecti
48、on control only shall be switched off and the instrument rotated quickly through180 about the vertical axis. The horizon bar shall move to indicate a “dive” condition. The angular displacement of the roll indicator from position A shall be counter-clockwise and twice the angular amount of the requir
49、ed roll tilt. C. With the instrument returned to position A the erection shall again be applied, the instrument allowed to re-erect and the position of the roll indicator noted.BSG152:1956 4 BSI 02-2000 ii) Instruments with inclination in pitch. The inclination of the gyroscope axis in pitch shall be determined by the following method and the top end of the gyroscope spindle shall be inclined to within! of the calculated values: iii) Instruments with inclination in roll. The inclination of the gyroscope axis in roll shall be determine
