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1、BRITISH STANDARD BS 2G 111: 1955 Specification for Rate of climb indicators for aircraft Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2G 111:1955 This British Standard, having been approved by the Aircraft Industry Standards Committee
2、and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council of the Institution on 29 April 1955 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference ACE/30 Draft for comment CT(ACE)8819 ISBN
3、 0 580 35999 9 Foreword This revised standard has been prepared to provide an up-to-date specification for aircraft rate of climb indicators in the light of experience gained in the application of the relevant requirements of the first edition of BS G 111, published in 1949, which it supersedes. Inf
4、ormation 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 include all the necessary provisions of a contract. Users of British Standards are responsible for th
5、eir 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 to 4 and a back cover. This standard has been updated (see copyright date) and
6、 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: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2G 111:1955 BSI 12-19
7、99i Contents Page ForewordInside front cover 1Scope1 2Definition1 Section 1. General requirements 3Preferred size1 4Preferred units of measurement1 5General construction1 Section 2. Particular requirements 6Construction1 Section 3. Tests 7General1 8Ranging test2 9Lag test2 10Position test2 11Insulat
8、ion test2 12Temperature test2 13Overload test2 14Pressure test for leakage2 15Vibration test2 16Acceleration test2 17Climatic tests3 18Untitled3 Appendix A Serviceability tests4 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licens
9、ed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2G 111:1955 BSI 12-19991 1 Scope This British Standard specifies the general design requirements and test procedure for rate of climb indicators for aircraft. It applies to mechanical instruments
10、of the “choke-capacity” type in which a capacity is connected to the source of static pressure on the aircraft through a choke. The pressure drop across the choke or the air-flow through it gives a measure of the rate of climb or descent and is measured by means of a suitable differential pressure g
11、auge or flowmeter mechanism. 2 Definition For the purposes of this British Standard the following definition shall apply: rate of climb indicator an instrument used on aircraft to indicate the vertical speed or rate of climb or descent of the aircraft by measurement of the rate of change of static p
12、ressure Section 1. General requirements 3 Preferred size The preferred size is that of aircraft instrument case Type 1, as specified in BS G 100, “General requirements for electrical instruments and indicating instruments for aircraft”. 4 Preferred units of measurement The preferred units of measure
13、ment shall be thousands of feet per minute. 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 BS G 100. Section 2. Particular requirements 6 Construction a) The instrument shall have a self
14、-contained capacity. b) The instrument shall preferably be designed to give readings independent of altitude measured on the I.C.A.O.1) scale up to 30 000 feet, but shall in any event comply with the performance requirements specified in this British Standard. c) The instrument shall be capable of w
15、ithstanding overload to 40 000 ft/min descent and 20 000 ft/min ascent without derangement. d) Means for adjusting the zero reading of the instrument shall be provided; the zero adjustment shall be readily accessible from the front of the instrument when mounted on a panel, but shall be such that th
16、e setting cannot casually or unintentionally be altered. The dial of the instrument shall remain fixed. e) The preferred presentation is a horizontal centre zero on the left, with symmetrical scales of climb and descent which shall be at least twice as open on the lower readings as on the higher. Th
17、e climb scale shall be clockwise from the zero round the upper half of the dial, and descent counter-clockwise from the zero round the lower half. The climb and descent scales shall fall short of 180 each, with a gap between the maxima. f) Since the range of scale graduation will normally be conside
18、rably less than the rates of climb or descent to which the instrument may be subjected, the movement shall be fitted with stops. For the differential pressure gauge type of instrument the stops should preferably act directly on the capsule. The stops shall limit the pointer movement in such a way th
19、at the pointer moves off scale in the appropriate direction past the full scale graduation, but does not move through 180, coming to rest in the gap referred to in e) short of a point diametrically opposite the zero, so that it is apparent, even under overload, from which direction the pointer has c
20、ome, and whether a dive or climb is being registered. The limit stops shall be such that operation of the zero adjusting means required in d does not affect the position on the scale at which they operate. Section 3. Tests 7 General a) Tests shall be made to prove compliance with all the requirement
21、s of this British Standard. 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: A. Type tests. (Clauses 8 to 17), which shall be made in that order on the same instrument, on representative samples
22、of each particular design. B. Production routine tests. (Clause 18), which shall be made on every instrument manufactured in accordance with this British Standard. 1) International Civil Aviation Organization. Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontroll
23、ed Copy, (c) BSI BS 2G 111:1955 2 BSI 12-1999 b) During the tests specified in Clauses 8 a), 9, 10, 12 and 15 the pressure to which the instrument is subjected while being calibrated shall lie between those equivalent to heights of 2 000 ft and 10 000 ft, measured on the I.C.A.O. scale. c) Minimum t
24、ests recommended to verify the serviceability of instruments manufactured in compliance with this British Standard are indicated in Appendix A. A. Type tests 8 Ranging test a) The accuracy of the instrument over the whole range at all heights between 2 000 and 10 000 ft shall be within 10 per cent o
25、f the nominal scale reading at the point tested, or 50 ft/min, whichever is the greater, when the instrument is in the normal position with the dial upright and in a vertical plane. b) The accuracy of the instrument over the whole range of heights between 20 000 and 30 000 ft on the I.C.A.O. scale s
26、hall be within 15 per cent of the nominal scale reading at the point tested, or within 75 ft/min, whichever is the greater, when the instrument is in the position specified in a). 9 Lag test When a steady rate of change of pressure equivalent to 2 000 ft/min is suddenly applied to or removed from th
27、e instrument, it shall reach an indication of not less than 1 000 ft/min within 2“ seconds. 10 Position test The errors shall not exceed 12 per cent of the nominal scale reading at the point tested, or 75 ft/min, whichever is the greater, when the instrument is tilted 90 in any direction from the po
28、sition specified in Clause 8 a). 11 Insulation test The instrument shall be placed in a suitable chamber in which the ambient temperature is changed from room temperature (1520 C) to 20 C and to + 50 C within 15 to 20 minutes in each direction, and shall be maintained at each temperature for 15 minu
29、tes. At any time during these tests the zero error shall not exceed 200 ft/min. 12 Temperature test The instrument shall be tested at 20 C and + 50 C when the calibration errors shall not exceed 12 per cent of the nominal scale reading at the point tested, or 75 ft/min whichever, is the greater. 13
30、Overload test The instrument shall be subjected to overloads of 20 000 ft/min ascent and 40 000 ft/min descent. The pointer shall take up positions as specified in Clause 6 f) and immediately afterwards the instrument shall still comply with the accuracy requirements of the ranging test specified in
31、 Clause 8 a). 14 Pressure test for leakage a) If the design is intended for use in pressure cabin aircraft the instrument shall withstand an external pressure difference of 15 lb/sq. in. above that of the interior without failure or leakage. The test shall be performed by placing the instrument in a
32、 suitable test chamber to which air pressure can be applied. The static connection of the instrument shall be connected to the external atmosphere. The air pressure in the chamber shall be raised to 15 lb/sq. in. above atmospheric pressure when there shall be no change in the pointer reading, nor sh
33、all there be any leak from the static connection. b) On instruments not intended for pressure cabin use the test shall be applied at 4 lb/sq. in. 15 Vibration test The instrument shall show no errors outside the tolerance for the ranging test specified in Clause 8 a) when subjected to the resonance
34、and fatigue tests specified in BS G 100 appropriate to its installation position and its declared vibration grade, and any pointer oscillation shall be within the limits permitted therein. 16 Acceleration test The instrument shall be subjected to the grade of acceleration test specified in BS G 100
35、appropriate to the performance grading declared by the manufacturer. Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2G 111:1955 BSI 12-19993 17 Climatic tests The instrument shall be subjected to the climatic tests specified in BS G 100
36、appropriate to the performance grading declared by the manufacturer. During these tests the instrument shall respond qualitatively and shall subsequently comply with the requirements of the ranging and leakage tests specified in Clauses 8 a) and 14. For the purpose of these tests the static connecti
37、on of the instrument shall be connected to a 20 ft length of ! in. bore static tubing. The tubing shall be coiled with the open end exposed within, but not lying upon the floor of, the test chamber. B. Routine production tests As defined in Clause 7 a) B 18 Each instrument shall comply with the requ
38、irements of the tests specified in the following clauses of this British Standard: Clause 8 a)Ranging test 9.Lag test 13.Overload test 14.Pressure test for leakage. Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2G 111:1955 4 BSI 12-1999
39、 Appendix A Serviceability tests The minimum tests recommended to verify the serviceability of instruments manufactured in compliance with this British Standard are as follows: a) Ranging test Clause 8 a) b) Pressure test for leakage (Clause 14) Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28
40、 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 28 14:00:23 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 2G 111: 1955 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body respon
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