1、AMSC N/A FSC 6680 INCH-POUND MIL-PRF-25439C 24 September 2013 SUPERSEDING MIL-PRF-25439B 1 July 1997 PERFORMANCE SPECIFICATION TRANSMITTER RATE OF FLOW, IN-FLIGHT REFUELING, 0-10,000 PPM, TYPE MB-3 Comments, suggestions, or questions on this document should be addressed to Oklahoma City Air Logistic
2、s Center/ENSDAA, 3001 Staff Drive, Suite 1AB81A, Tinker AFB, OK 73145 or emailed to af71tinker.af.mil. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.dla.mil. Provided by IHSNot for ResaleNo repr
3、oduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 2 This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers one type of in-flight refueling rate of flow and fuel transmitter, designa
4、ted Type MB-3. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While e
5、very effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements of the documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications and stand
6、ards and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-DTL-5624 - Turbi
7、ne Fuel, Aviation, Grades JP-4 and JP-5 MIL-PRF-38120 - Indicator, Rate of Flow and Transfer EFU-20/A DEPARTMENT OF DEFENSE STANDARDS MIL-STD-461 - Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment (Copies of these documents are available online
8、 at http:/quicksearch.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) 2.3 Non-Government publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues o
9、f these documents are those cited in the solicitation or contract. ASTM INTERNATIONAL ASTM-B117 - Salt Spray (Fog) Testing Apparatus, Operating ASTM-D910 - Gasolines, Aviation Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 3 (ASTM doc
10、uments may be obtained online at http:/www.astm.org/ or from American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.) SAE INTERNATIONAL SAE-ARP8615 - Fuel System Components: General Specification for SAE-AS31061 - Connector, Plug, Electric, Straight, Sold
11、er Contacts AN Type SAE-AS31081 - Connectors, Plug, Electric, Solder Contact, 90 Degree, AN Type (SAE documents may be obtained online at http:/www.sae.org/ or from SAE International Headquarters, 400 Commonwealth Drive, Warrendale, PA 15096-0001 USA.) 2.4 Order of precedence. Unless otherwise noted
12、 herein or in the contract, in the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIR
13、EMENTS 3.1 First article. When specified (see 6.2), a sample shall be subjected to first article inspection in accordance with 4.1 and 4.3. 3.2 Function. The transmitter shall be designed to provide an electrical output signal for a fuel flow range of 0 to 10,000 pounds per minute (ppm). The signal
14、shall be suitable for remote indication and for use in operating an EFU-20/A indicator conforming to MIL-PRF-38120. 3.3 Design and Construction. 3.3.1 Output signal. The electrical signal shall be single phase, 400 Hertz, AC voltage. The magnitude of the voltage shall be 1 V per 1,00 ppm fuel flow.
15、The electrical output signal shall have a carrier frequency identical to the input power frequency. The output voltage signal shall be at a leading phase angle of 15 with respect to the input voltage. 3.3.2 Excess flow. The transmitter shall not be damaged by fuel flow rates in excess of the rated v
16、alue provided the pressure rating of the transmitter is not exceeded. 3.3.3 Fuel variations. The transmitter shall be designed to operate satisfactorily when using fuel having any of the variations in standard characteristics specified in MIL-DTL-5624 and ASTM-D910. 3.3.4 Operating pressure. The tra
17、nsmitter shall be designed for a normal operating pressure of 120 psi, a proof pressure of 240 psi, and a burst pressure of 480 psi. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 4 3.3.5 Electrical power. The electrical power for the
18、 output signal circuit shall be 115 V AC, 400 Hertz. There shall be no voltage phase angle difference between this power and the power to the rest of the system. The wave form of the supply voltage may be nonsinusoidal with a crest factor of 1.414 10% and with harmonics having respective amplitudes
19、that are less than 5% of the fundamental. 3.3.6 External wiring. The in-flight refueling system interconnecting wiring diagram shall conform to Figure 1. 3.3.7 Density correction. The transmitter shall measure the fuel flow rate on a gravimetric basis without a separate and distinct density correcti
20、ng means. 3.3.8 Fuel line connections. The transmitter shall be designed for mounting by means of the fuel line connections or by straps. The fuel line connections shall be as specified by the procuring activity and shall be furnished with a suitable plugs or caps to prevent contamination by foreign
21、 material during storage and shipment. The fuel system tubing adjacent to the transmitter shall be in accordance with requirements of the procuring activity. 3.3.9 Damping. The transmitter shall be suitably damped. 3.3.10 Dimensions. The dimensions of the transmitter shall conform to Figure 2. 3.3.1
22、1 Flow direction. The direction of fuel flow through the transmitter shall be permanently and legibly marked on each side by an arrow as shown on Figure 2. 3.3.12 Weight. The weight of the transmitter shall not exceed 18.0 pounds. Provided by IHSNot for ResaleNo reproduction or networking permitted
23、without license from IHS-,-,-MIL-PRF-25439C 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 6 Notes: 1. Dimensions are in inches. FIGURE 2. Transmitter. Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
24、ense from IHS-,-,-MIL-PRF-25439C 7 3.4 Performance. The transmitter shall be capable of meeting the requirements specified herein when subjected to the following conditions: a. Temperature - Temperatures within the range of -54 to +71C. b. Humidity - Relative humidity up to 100%. c. Salt spray - Exp
25、osure to salt sea atmosphere for a 50 hour period. d. Vibration - Vibration incident to service use. e. Fungus - Fungus growth as encountered in tropical climates. f. Explosion proof - Operation in an explosive vapor within or surrounding the equipment. g. Altitude - Pressures ranging from 30 inches
26、 Hg down to 3.4 inches Hg (approximately an altitude of 50,000 feet). h. Shock - Shock forces as anticipated. i. Dielectric strength - A potential of 550 V AC, 60 Hertz for a period of 10 seconds when applied as specified in 4.5. j. Leakage - A hydraulic proof pressure of 240 psi applied and maintai
27、ned for 5 minutes. k. Cycling operation - The system shall be capable of operating for 500 hours of actual or simulated flow through the transmitter without failure when tested in accordance with 4.5.26. 3.4.1 Radio noise interference. The transmitter shall meet requirements of MIL-STD-461, Emission
28、 and Susceptibility Requirements CE102 and RE102, except that the frequency range shall be 0.15 to 150 MHz. 3.4.2 Contaminated fuel operation. The transmitter shall operate satisfactorily with fuels contaminated to the extent specified in 4.5.28. 3.5 Materials. Nonmagnetic and nonferrous materials s
29、hall be used for all parts of the transmitter, except where such materials are essential. Metals shall be corrosion resistant or suitably treated to resist corrosion. Unless suitably protected against electrolytic corrosion, dissimilar metals shall not be used in intimate contact with one another. 3
30、.5.1 Protective treatment. When materials are used in the transmitter that will deteriorate when exposed to climatic and environmental conditions likely to occur during service usage, they shall be protected against such deterioration in a manner that will in no way prevent compliance with the requi
31、rements of this specification. The use of any protective coating that Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 8 will crack, chip, or scale with age or the extremes of climatic and environmental conditions shall be avoided. 3.5.
32、2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous
33、 life cycle costs. 3.6 Identification plate. An identification plate shall be provided on transmitter. Information provided shall include the government designation for the transmitter, the manufacturers part number and the manufacturers Commercial and Government Entity (CAGE) Code. 3.7 Workmanship.
34、 The transmitter shall be constructed and finished in a thoroughly workmanlike manner so that no parts will work loose service. Particular attention shall be given to neatness and thoroughness of soldering, wiring, welding, riveting, brazing, plating, machine screw assemblies, impregnation of coils,
35、 and painting. All parts shall be free from burrs and sharp edges. Gears shall be of high quality and shall be properly aligned and meshed, and shall be operable without interference, tight spots, loose spots or other irregularities. 4. VERIFICATION 4.1 Classification of inspections. The inspection
36、requirements specified herein are classified as follows: a. First article inspection (see 4.3). b. Conformance inspection (see 4.4). 4.1.2 Inspection conditions. Unless otherwise specified, all inspections shall be performed in accordance with the test conditions specified in 4.2. 4.2 Test condition
37、s. 4.2.1 Atmosphere. Whenever the pressure and temperature existing at the time of the test are not otherwise specified, the test shall be made at atmospheric pressure (29.92 inches Hg) and at room temperature (approximately 25C). When tests are made with atmospheric pressure or room temperature dif
38、fering materially from the above values, proper allowance shall be made for the difference from specified condition. 4.2.2 Tapping. Unless otherwise specified, the transmitter shall be gently tapped or vibrated before a test reading is taken. 4.2.3 Test position. Unless otherwise specified, the tran
39、smitter shall be tested in the normal operating position. The transmitter will be in the normal operating position when Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 9 horizontal with the electrical connectors at 3 oclock position wh
40、en viewed from the inlet end of the transmitter. 4.2.4 Test power. The test power of the transmitter shall be as follows: a. The 3 phase power into the transmitter shall be 400 cycles. This frequency shall be held by the power supply to within +0.1%. The AC voltage fed into the power supply inverter
41、 shall be 28 0.5 VDC. b. The voltage input to the output signal network shall be 115 0.1%V AC with a frequency of 400 2 Hertz. c. The 400 Hertz supply voltage may be nonsinusoidal with a crest factor of 1.414 10% and with harmonics whose respective amplitudes are less than 5% of the fundamental. 4.2
42、.5 Test fuel. The fuel in testing or for calibration purposes shall conform to MIL-DTL-5624 (JP-4). The specific gravity of the fuel shall be 0.785 0.005 at room temperature. A commercial equivalent with a higher flash point may be used. 4.2.6 Master flowmeter. A master flowmeter to establish flow r
43、ate may be used. The calibration of this master shall be verified by the procuring activity. 4.2.7 Master voltmeter. The output signal from the transmitter shall be measured with a master voltmeter accurate to within 0.1%. The input impedance of the voltmeter shall be 100,000 5% resistive load or be
44、tter. 4.2.8 Phase angle meter. The phase angle meter shall be accurate to 0.1o. 4.3 First article. The first article inspection shall consist of all tests described under paragraph 4.5. 4.3.1 Inspection sample. The first article inspection sample shall consist of 3 transmitters which are identical i
45、n all respects to the transmitters that are produced as production items. 4.3.2 First article test report. Upon completion of the first article inspection and tests, a test report shall be prepared in accordance with a contractor format. The report shall include the results of the tests conducted as
46、 well as checklists used during testing. 4.4 Conformance inspection. Inspection of transmitters shall consist of individual tests and sampling tests. 4.4.1 Individual tests. Each transmitter shall be subjected to the following tests as described under 4.5. a. Physical examination Provided by IHSNot
47、for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-25439C 10 b. Dielectric strength c. Leak test d. Scale error and friction e. Phase angle tolerance 4.4.2 Sampling tests. Unless otherwise specified a minimum of 2 transmitters shall be selected at random from each
48、 100 items produced on the contract or order and subjected to all the tests as described under 4.5. 4.4.3 Rejection and Retest. When an item selected from a production run fails to meet the tests of this specification, no items still on hand or later produced shall be accepted until the extent and c
49、ause of the failure have been determined and corrected. The contractor shall provide a written explanation as to the cause of the failures and the actions taken to preclude recurrence. After correction, all tests shall be repeated. For production reasons individual tests may be continued pending the invest
