1、I I MIL-1-38371 66 m 9999906 0138346 7 m F-QS . MIL -1-3 83 91 (U SAF) 5 PY 196.5 MILITARY SP E C IFIC AT ION INDICATOR, ELECTRICAL TACHOMETER, ERU-lB/A 0-350 RPM (ROTOR) , 0-7000 RPM (ENGINE) 1. SCOPE 1.1 This specification defines a her- metically sealed, dual pointer,0-700Q rpm and 0-350 rpm, hel
2、icopter tachom- eter indicator which is 3 inches in diam- eter and olamp mounted. (See 6.1 for suitable appiications.) 2. APPLICABLE DOCUMENTS 2. The following documents, of the issue in effect on date of invitation for bids, or request for proposal, form a part of this specification to the extent s
3、pecified herein: SPECIFIC AT IONS Federal DD-G-451 PPP-B-566 PPP-B-636 PPP -B-665 PPP -B-676 Military MIL-P-116 MIL-S-7742 MIL-P-7936 MIL-G-9398 Glass, Flat andcorru- gated, for Glazing, Mir- rors, and Other Uses Boxes, Folding, Paper- board Box, Fiberboard BoxeB, Paperboard, Metal Stay.ed Including
4、 Stay Material Boxes, Set-up, Paper- board Preservation, Methods of Screw Threads, Stand- ard, Optimum, Selected Series: General Speci- fication for Parts and Equipment, Aeronautical, Prepara- tion for Delivery Generator, Tachom- eter, High Tempera- ture, Two-Pole, Air- craft, Type MB-6 MIL -L -2 5
5、142 MIL-M-26512 MIL-G-26611 MIL -R-266 6 7 MIL-D-70327 STANDARDS Luminescent Material, Fluorescent Maintainability Pro- gram Requirements for Aerospace Systems and Equipment Generator, Tachom- eter, GEU-7/A, Mina- ture Reliability and Longev- ity Requirements, Elec- tronic Equipment, Gen- eral Speci
6、fication for Drawings, Engineering and Associated Equip- ment l Federal FED-STD-595 Military MIL -STD -12 9 MIL-STD-130 MIL-STD-143 MIL-STD-810 MIL-STD-838 MS3106 MS3108 MS33558 Colors Marking for Shipment and Storage Identification Marking of U. S. Military Prop- erty Specific at ions and Standards
7、, Order of Precedence for the Se- lection of Environmental Test Methods for Aerospace and Ground Equipment Lubrication of Miiitary Equipment Connector, Plug, Elec- tric, Straight Connector, Plug, Elec- tric, Angle 90“ Numerals and Letters, Aircraft, Instrument Dial, Standard Form of 7 FSC 6620 - - /
8、THIS DOCUMENT CONTAINS 2-2 PAGES. Id F Licensed by Information Handling ServicesMIL-1-3837L hh e 4749906 0238347 7 = MIL-1-38391 (USAF) MS33585 Pointers, Did, Stand- ard, Design of Aircraft Instrument MS33 58 6 Metals, Definition of Dissimilar . MS33639 Cases, Instrument, Clamp-Mounted, Air- craft M
9、S33678 Connector, Receptacle, Electric Integral Mounting (Copies of specifications, standards , publications, and drawings required by contractors in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 3. REQUIREME
10、NTS 3.1 Preproduction. This specification proms for preproduction testing. 3.2 Selection of specifications and - stands. Specmns and stand- ards for necessary commodities and services not specified herein shall be selected according to MIL-STD-143. 3.2.1 Requirements conflict, In the event ofa confl
11、ict, the requirements of this specification shall govern. 3.3 Materials 3i3.1 Nonmagnetic materials. Non- magnetic materials shall be used for all parts of the indicator except where magnetic materials are essential. 3.3.2 Metals. Metals shall be of the corrosion-resistant type or shall be suitably
12、protected to resist corrosion during normal service life, unless pro- tected by hermetic seal. 3.3.3 Dissimilar metals. Dissimilar metals are defined by MS33586 and shall not be used in intimate contact with each other unless suitably pro- tected against electrolytic corrosion by means of protective
13、 coating or her- metic sealing. 3-3.4 Fungus-proof - materials. Ma- terials which are not nutrients for fungi shall be used to the greatest extent practicable. In cases where materials that are nutrients for fungi must be used, such materials shall be treated with a fungicidal agent or be protected
14、by hermetic sealing. 3.3.5 Corrosive fumes. The materi- als as installed in the indicator andunder the service conditions specified in 3.5 shall not liberate deleterious fumes. 3.3.6 Protective treatment. When ma- terials are used in the construction of the indicator that are subject to cor- rosion
15、in salt air or other atmospheric conditions Likely to occur during service usage, they shall be protected against such corrosion in a manner that will in no way prevent compliance with the performance requirements of this speci- fication. The use of any protective coat- ing that will crack, chip, or
16、 scale with age or extremes of atmospheric con- ditions shall be avoided. 3.4 - Design and construction 3.4.1 The indicator shaii be designed for operation from the varying-frequency alternating-current output of tachometer generators conforming to MIL-G-9398 or MIL-G-26611. The frequency of the gen
17、erator output shall be proportional to the speed at which the generator is rotating. The design shall be such that with increasing and decreasing speeds the pointers shall move smooth- ly at a uniform rate consistent with the speed change. It shall be possible 2 Licensed by Information Handling Serv
18、ices i MIL-1-38391 bb 99993Ob OL383Li8 O /- J -. MIL-1-38391 (USAF) to operate both movements from one generator without affecting the oper- ation of either movement, 3.4.1.1 The indicator shall be so cony structed that no parts will work loose in service. The indicator shall be built to withstand t
19、he strains, jars, vibra- tions, and other conditions incident to shipping, storage, installation, and service, The indicator shall be so con- structed that adjustments and repairs can be easily made by the personnel of overhaul bases with tools and equip- ment normally available commercially. 3.4.1.
20、2 Adjustment. Provisions for adjustmex ofindicator shall not be based solely on changing the strength of the magnets. 3.4.2 Reliability. The indicator shall have a mean-time-between-f ailure (MTBF) of 750 hours, me reliability level shall be demonstrated to a 90 percent confidence factor. 3.4-3 Main
21、tainabiliw. Maintainability shall be in accordance with MIEM- 26512 and the following: a. Minimization of the complexity of maintenance tasks (for example: cali- bration, adjustments, inspections, et cetera) by maximum use of simple design which includes optimum inter- changeability and use of stand
22、ardized equipment or commercial items b. Rapid and positive identification of the replaceable defective part, assembly, or component c. Optimum accessibility in ail systems, equipments, and components requiring mantenance, inspections, re- moval, or replacement d. Sufficiently low mean time to ac- c
23、omplish corrective maintenance to as- sure the required operational avail- ability of the equipment e. parts and assemblies, Minimum number and type of spare 3.5 Performance. The indic ator s shall conform to the following require- ments when subjected to the applicable tests of section 4. a. Scale
24、error. Scale error operation at room temperature, -54C, -35%, O%, and +71% temperatures in accord- ance with tables I, II, III, and IV. b, Friction error, Friction error not to exceed 40 rprn on the engine scale and 2 rprn on the rotor scale at tachom- eter generator drive speeds between 1000 and 46
25、00 rpm c. Position error. Position error not to exceed 25 rpm on the engine scale and 2 rpm on the rotor scale when indicator is positioned 45 degrees each way from the normal: operating position with a tachometer generator drive speed of 4000 rpm, The normal operating position is with the longitudi
26、nal axis of the indicator horizontal and the dial in an upright position (word “engine” at the bottom). d. Fogging and thermal shock. Sub- ject the indicator to 85.1 5% following which the indicator shall be immersed in an ice water bath. e, Vibration error, The error due to vibration shall not exce
27、ed 60 rpm on the engine scale and 3 rpm on the rotor scale, when the indicator is oper- ating while vibrating in a plane inclined 45 to the horizontal in a circle having a 0.009 to 0,011 inch diameter at a 3 Licensed by Information Handling Services- MIL-I-3373 bb 99777Ob 0338349 2 = GENERATOR DRIVE
28、 SHAFT SPEED MIL-1-38391 (USAF) CORRECT SCALE ERROR INDICATED TOLERANCE2 SPEED ROOM TEMP, TABLE I - ENGINE SCALE O 500 1000 2000 2500 3000 3300 3600 3900 4000 4100 4200 4400 4600 R PM O 770 1540 3080 3850 4620 50 82 5544 6006 6160 6314 6468 6777 7085 4 50 70 70 70 70 70 50 50 20 20 10 20 40 60 SCALE
29、 ERROR TOLERANCE *.AT SPEC1 FIED TEMPERATURE -54oc 100 100 100 120 120 120 120 120 120 120 120 150 i50 150 - 35oc 90 90 90 90 90 90 90 90 90 90 80 90 100 100 oo c 80 80 80 80 80 80 80 80 80 80 70 80 80 80 f 7I0C 70 70 70 80 80 80 70 70 60 60 50 60 70 90 I Licensed by Information Handling Services- u
30、 - I Y MIL-1-38371 66 W 7777906 0138350 9 MIL-1-38391 (USAF) TABLE II - ENGINE SCALE 5 Licensed by Information Handling ServicesMIL-1-38371 66 7777706 0138353 O I GENERATOR IRIVE SHAFT MIL-1-38391 (USAF) . TABLE III - ROTOR SCALE CORRECT SCALE ERROR SCALE ERROR TOLERANCE & AT INDICATED TOLERANCE SPE
31、CIFIED TEMPER ATURE -35oc 5 5 5 5 5 5 5 5 5 5 5 5 5 5 SPEED SPEED I ROOM TEMP. I ooc O 500 1000 2000 2500 3000 3300 3600 3900 4000 4100 4200 MOO 4600 RPM O 37.6 75.3 150.6 188.2 225.9 248.5 271.1 293.7 301.2 308.7 316.2 331.3 346.3 5 5 5 5 5 5 5 5 4 4 4 4 4 4 + 71C 5 5 5 5 5 5 5 5 3 3 3 3 4 4 - 6 Li
32、censed by Information Handling ServicesMIL-1-38391 (USAF) TABLE IV - ROTOR SCALE 7 Licensed by Information Handling ServicesMIL-1-38391 (USAF) slowly varying frequency of from 5 to 50 cps, f. Vibration failure. The indicator when mounted in the normal operating position shall withstand operation whe
33、n vibrated for a %()-hour period in a plane inclined 45“ to the horizontal in a circle having a 0.018 to 0.020 inch diameter at a frequency varied from 5 to 50 cps. g. Temperature and altitude. Subject to temperature ranging from -62 to +85“ C without failure and altitudes to 52,000 feet, (Helium te
34、st) h. Indicator starting. Starting and synchronous operation at an indicated speed of 200 rpm (engine scale) and 8 rpm (rotor scale) or greater with the following maximum voltages applied: (1) Room temperature - 0.63 volts at 180 cycles per minute. (2) -54. C temperature - 0.72 volts at 180 cycles
35、per minute. i. Magnetic effect. Subject the indi- cator, operating and nonoperating, rotated in increments of 45 degrees from normal, and positioned 5-1/2 inches from the center of afree- magnet compass having a field intensity of 0.17 to 0,19 oersted, .without de- flecting the compass more than 3 d
36、egrees. j, Indicator current. The current drawn by each of the %phase windings shall not exceed 0.3 amp when con- nected to 21V 4,200 cpm supply. k, Overspeed and reverse operation. Subjected to a generator shaft speed of 5,000 rpm for 5 minutes and then operated in the reverse direction at a genera
37、tor-shaft speed of 2,500 rpm for 1 rhinute without exceeding a change in reading of 40 rpm on the engine scale and 2 rpm on the rotor scale. 1. Endurance. Subjected to 1000 hours of operation at an indication of 4000 *500 rpm without failure or damage. m, Salt spray, Subjected to salt spray for a pe
38、riod of 24 hours in accordance with MIL-STD-810 without evidence of external corrosion or deterioration af- fecting subsequent operation. n. Insulation. Withstand the test voltages specified herein for a period of 5 seconds between connector pins A, B, and C and any metal part of the case or connect
39、or shell. o. Sealing. Case leakage not to ex- ceed 0.01 micron cubic foot per hour when the filling medium is nitrogen and helium, and 0.1 micron cubic foot per hour when the filling medium is 100 percent helium. 3.6 Part numbering of interchangeable - parts. - All parts having the same man- ufactur
40、ers part number shall be func- tionally and dimensionally interchange- = able. The item identification and part number requirements of MIL-D-70327 shall govern the manufacturers part numbers and changes thereto. 3.7 Case. The case shall be in accord- ance with MS33639 for the 3-inch size. The length
41、 of the case shall not be more than 5.00 inches excluding the connector. The case shall provide a hermetically sealed enclosure for the internal mech- anism of the indicator, The case shall be so designed that the internal mech- anism may be removed from the case, replaced, and the case resealed at
42、least Licensed by Information Handling Servicesthree times. This shall be accomplished without the use of special tools and fixtures unless they are approved by the procuring activity. The hermetic sealing shall be so accomplished that the seal will not be dependent upon materials which will be affe
43、cted by the action of any atmosphere to which the indicator may be subjected. The distance between the outer surface of the cover glass and the front edge of the case shall be the minimum practicable and shall not ex- ceed 1/32 inch. 3.7.1 Material. The hermetically sealed case shall be constructed
44、of a suitable material applicable to hermetic sealing, and the material shall be uni- form in texture with a smooth external surface. 3.7.2 Finish. The portion of the in- dicator case exposed to view from the front of the mounting panel shall be finished in durable dull black. The fin- ish applied t
45、o the remainder of the case shall be durable dull black. 3.7.3 Filling medium. The fillingmedi- um shall be at least 98 percent pure, free of dust particles, and contain not more than 0.006 milligram of water vapor per liter (dewpoint -65%) at the filling pressure. The fillingmedium shall be either
46、100 percent heiium or or a mix- ture of 88 percent to 92 percent nitrogen and the remainder helium as specified by the procuring activity (see 6.2). The absolute pressure of the filling medium in the case shall be approximately 1 at- mosphere. 3.8 Cover glass. The cover glass shall be in accordamth
47、DD-G-451, type II quality AA. The minimum thickness of the glass shall be 0.093 inch. Any fiaws allowed by DD-G-451 shall not interfere with the visibility of the dial. 3.8.1 Dial to cover glass distance. The distance between the inside surface of the cover glass and the indicator dial shall be the
48、minimum practicable and shall not exceed 0.22 inch. MIL-1-38391 (USAF) , 3.9 Dial. The dial shall consist of one flat s-ce. The dial material shall be suitable for the purpose and shall be subject to the approval of the procuring activity. The dial shall be securely fastened to the frame of the mech
49、anism in such a manner that it wili not loosen nor turn when the indicator is vibrated. If screws are used for attaching the dial, they shall be so located that they will not interfere with any dial marking or prevent proper location of dial mark- ing. 3.9.1 Markings. The dial markings shall conform to figure 1, figure 2, and table V and shall be durable enough to withstand environmental conditions spec- ified herein. Unless otherwise specified, the style and proportions of numerals and letters on the dial shall conform to MS33558. The graduation to whic
