1、BRITISH STANDARD BS 2G 111: 1955 Specification for Rate of climb indicators for aircraftBS2G 111:1955 This BritishStandard, having been approved by the Aircraft Industry Standards Committeeand endorsed by theChairman of the EngineeringDivisional Council,was published under theauthority of the Genera
2、l Council of the Institution on 29April1955 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 0 580 35999 9 Foreword This revised standard has been prepared to provide an up-to-date specification for aircraft r
3、ate of climb indicators in the light of experience gained in the application of the relevant requirements of the first edition of BSG 111, published in1949, which it supersedes. Information has been added relating to the incidence of testing, and recommendations included in respect of tests to verif
4、y 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 their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.
5、Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4 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
6、issued since publication Amd. No. Date CommentsBS2G 111:1955 BSI 12-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Definition 1 Section 1. General requirements 3 Preferred size 1 4 Preferred units of measurement 1 5 General construction 1 Section 2. Particular requirements 6 Constructi
7、on 1 Section 3. Tests 7 General 1 8 Ranging test 2 9 Lag test 2 10 Position test 2 11 Insulation test 2 12 Temperature test 2 13 Overload test 2 14 Pressure test for leakage 2 15 Vibration test 2 16 Acceleration test 2 17 Climatic tests 3 18 Untitled 3 Appendix A Serviceability tests 4ii blankBS2G 1
8、11:1955 BSI 12-1999 1 1 Scope This BritishStandard specifies the general design requirements and test procedure for rate of climb indicators for aircraft. It applies to mechanical instruments of the “choke-capacity” type in which a capacity is connected to the source of static pressure on the aircra
9、ft 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 gauge or flowmeter mechanism. 2 Definition For the purposes of this BritishStandard the following definition
10、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 pressure Section 1. General requirements 3 Preferred size The preferred size is that of aircraft instrument ca
11、seType1, 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 measurement shall be thousands of feet per minute. 5 General construction The instrument shall be sound and suitable f
12、or its purpose and its design and construction shall comply with the relevant requirements of BSG 100. Section 2. Particular requirements 6 Construction a) The instrument shall have a self-contained capacity. b) The instrument shall preferably be designed to give readings independent of altitude mea
13、sured on the I.C.A.O. 1)scale up to30000 feet, but shall in any event comply with the performance requirements specified in this BritishStandard. c) The instrument shall be capable of withstanding overload to40000ft/min descent and20000ft/min ascent without derangement. d) Means for adjusting the ze
14、ro 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 the setting cannot casually or unintentionally be altered. The dial of the instrument shall remain fixed. e) The preferred
15、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. The climb scale shall be clockwise from the zero roundthe upper half of the dial, and descent counter-clockwise from the ze
16、ro round the lower half. The climb and descent scales shall fall short of180 each, with a gap between the maxima. f) Since the range of scale graduation will normally be considerably less than the rates of climb or descent to which the instrument may be subjected, the movement shall be fitted with s
17、tops. 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 that the pointer moves off scale in the appropriate direction past the full scale graduation, but does not move through180 ,
18、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 come, and whether a dive or climb is being registered. The limit stops shall be such that operation of the zero adjusting me
19、ans 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 requirements of this BritishStandard. It is not intended or recommended that complete tests shall be made on every instrument supplied
20、. Two kinds of test, therefore, are specified as follows: A. Type tests. (Clauses8 to17), which shall be made in that order on the same instrument, on representative samples of each particular design. B. Production routine tests. (Clause18), which shall be made on every instrument manufactured in ac
21、cordance with this BritishStandard. 1) International Civil Aviation Organization.BS2G 111:1955 2 BSI 12-1999 b) During the tests specified in Clauses8 a),9, 10, 12 and15 the pressure to which the instrument is subjected while being calibrated shall lie between those equivalent to heights of2000ft an
22、d10000ft, measured on the I.C.A.O.scale. c) Minimum tests recommended to verify the serviceability of instruments manufactured in compliance with this BritishStandard are indicated in Appendix A. A. Type tests 8 Ranging test a) The accuracy of the instrument over the whole range at all heights betwe
23、en2000 and10000ft shall be within10percent of the nominal scale reading at the point tested, or 50ft/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 between20
24、000 and30000ft on the I.C.A.O.scale shall be within15percent of the nominal scale reading at the point tested, or within 75ft/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 to2000ft/min is suddenly
25、 applied to or removed from the instrument, it shall reach an indication of not less than 1000ft/min within2“ seconds. 10 Position test The errors shall not exceed12percent of the nominal scale reading at the point tested, or75ft/min, whichever is the greater, when the instrument is tilted90 in any
26、direction from the position specified in Clause8 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) to20 C and to+50 C within15to20minutes in each direction, and shall be maintained at each temperature
27、 for15minutes. At any time during these tests the zero error shall not exceed 200ft/min. 12 Temperature test The instrument shall be tested at20 C and+50 C when the calibration errors shall not exceed12percent of the nominal scale reading at the point tested, or75ft/min whichever, is the greater. 13
28、 Overload test The instrument shall be subjected to overloads of20000ft/min ascent and40000ft/min descent. The pointer shall take up positions as specified in Clause6 f) and immediately afterwards the instrument shall still comply with the accuracy requirements of the ranging test specified in Claus
29、e8 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 of15lb/sq.in.above that of the interior without failure or leakage. The test shall be performed by placing the instrument in a suitable t
30、est 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 to15lb/sq.in.above atmospheric pressure when there shall be no change in the pointer reading, nor shall there be an
31、y leak from the static connection. b) On instruments not intended for pressure cabin use the test shall be applied at4lb/sq.in. 15 Vibration test The instrument shall show no errors outside the tolerance for the ranging test specified in Clause8 a)when subjected to the resonance and fatigue tests sp
32、ecified 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 ofacceleration test specified in BS G 100 appropriate to the pe
33、rformance grading declared by the manufacturer.BS2G 111:1955 BSI 12-1999 3 17 Climatic tests The instrument shall be subjected to the climatic tests specified in BS G 100 appropriate to the performance grading declared by the manufacturer. During these tests the instrument shall respond qualitativel
34、y and shall subsequently comply with the requirements of the ranging and leakage tests specified in Clauses8 a)and14. For the purpose of these tests the static connection of the instrument shall be connected to a20ft length of! in.bore static tubing. The tubing shall be coiled with the open end expo
35、sed within, but not lying upon the floor of, the test chamber. B. Routine production tests As defined in Clause7 a) B 18 Each instrument shall comply with the requirements of the tests specified in the following clauses of this BritishStandard: Clause 8 a) Ranging test 9. Lag test 13. Overload test
36、14. Pressure test for leakage.BS2G 111:1955 4 BSI 12-1999 Appendix A Serviceability tests The minimum tests recommended to verify the serviceability of instruments manufactured in compliance with this BritishStandard are as follows: a) Ranging test Clause8 a) b) Pressure test for leakage (Clause14)b
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