1、-I -MIL-P8686 (ASG) 4 NOVEMBER 1955 Superseding MIL-P-7846( Aer) 30 December 199 MILITARY SPECIFICATION PowHz UNITS; AIRCRAFT AUXILIARY, GAS- .“UBBINE-TYPE, GENERAL SPECIFICATION FOR This Specification has been appr0ved.b the Department of the Air Force and by the Na%y Bureau of Aeronautics. 1. SCOP
2、E 1.1 Scope.- This specification covers the general requirements for gas-trbine- type aircraExLiary power units. 1.2 Classification.- Auxiliary power units shall be of the following types and model, as specified in the model specification (see 6.2) : Type I - Primarily used as a power takeoff unit (
3、source of Type II - Primarily used as a soume of compressed air bled Type III - Primarily used as a source of compressed air bled Type IV - Used as a combination power and compressed air source. Model - The model designation will be established by the mechanical power). from the compressor. from the
4、 compressor and mixed with combustion products. procuring activity. 2. APPLICABLE DOCUMENTS 2.1 The following specifications, standards, drawings, and publications, of the issue in effect on date f invitation for proposals, form a part of this specification to the extent specified herein: SPECIFICAT
5、IONS Federal QQ-“151 Metals; General Specification for Inspection of QQ-P416 Plating, Cadmium (Electrodeposited) Militaly MIL-A-8625 Anodic Coatings, for Aluminum and Aluminum Alloys MIL-C-8554 Cable; Ignition, High-Tension, Aircraft Cbality MIL-C-9282 Container, Shipping, Metal, Reusable 5 CurFt.-5
6、0 MIL-D-5028 Drawings and Data Lists: Preparation of Manufac- MIL-c- Thread Compound; Anti-Seize, Graphite-Petrolatum Cu. Ft. Volume turers (for Production Aircraft, Guided Missiles, Engines, Accessories, aqd Other Auxiliary Equipment) Provided by IHSNot for ResaleNo reproduction or networking permi
7、tted without license from IHS-,-,-? MIL-P-8686( ASG) MIL-E-5557 MIL-E-5607 MIL-F-S161 MIL-F-557.2 MIL-F-5624 r_ MIL-F-7024 MIL-H-3136 MIL-1-6181 MIL-1-6865 MGI-6866 MIL-1-6868 MIL-“3171 MIL-0-6081 MIL-P-6889 MIL-S-7742 . KU-X-64l JAN-A-699 STANDARDS Military MIL-STD-129 m28741 Enamel; Heat-Resisting
8、, Glyceryl-Phthalate, Black Engine, Gas Turbine, Preparation for Storage and Fuel, Referee, Aircraft Turbine and Jet Engine Fuel, Aircraft Reciprocating Engine Grades 80, 91/96, 100/130, 115/lJ Process for Corrosion Protec- Oil, Lubricating, Jet Engine Primer; Zinc-Chromate, for Aircraft Use Screw T
9、hreads, Standard, Aeronautical X-Ray Laboratories, Procedure for the CertFfica- Anti-Seize Compound, White Lead Base, General tion of tion of (for Inspection of Aircraft Components) Purpose (for Threaded Fittings) Marking for Shipment and Storage Hose Assembly, Detachable End Fitting,: Medium Pressu
10、re DRAWINGS Air ForceNavy Aeronautical Standard Drawings . 10060 Tubing End - Hose Connection, Standard Dimensions 10398 . Metals - Definition of Dssimilar 20006 Drive - Type XVI Engine Accessory for . PUBLICATIONS Air Force-Navy Aeronautical Bulletins No. 182 Material Changes and Substitutions; Air
11、craft Engine Parts (Production Contracts) Aircraft Engines and Propellers, Use of Propellers, and Aeronautical Equipment h Production and Service No. 410 Age-Controls Fuel System Synthetic, Rubber Part No. 343 Spedifcations and Stanaards Applicable to NO. 391 Changes; Engineering, to Aircraft Engine
12、s, (Copies of specifications, standards, drawings, and publications, required3by con- tractors in bonnection with specific procurement functions should be obtained -from the procuring activity or as directed by the contracting officer.) *2 . Provided by IHSNot for ResaleNo reproduction or networking
13、 permitted without license from IHS-,-,-2.2 Other publications- The following documents form a part of this specification. Unless otherwise indicated, the issue in effect on date of invitation for bids, shall apply. National Advisory Committee for Aeronautics NACA TN 3182 Manual of the ICA0 Standard
14、 Atmosphere Calculations by the NACA (Applioation for copies of the NACA publication should be addressed to the National Advisory Committee for Aeronautics, .1512 H St., N.W., Washington 25, D. O.) American Society of Mechanical Engineers ASM PTC 19.5; 4-1949 Pwer Test Codes (Application for copies
15、of the ASME publication should be addressed to the American Society of Mechanical Engineers, 29 West 39th St., New York 18, N. Y .) Society of Automotive Engineers (Aeronautical Material Specifications) AMs2640 Magnetic Particle Inspection AMs2645 Fluorescent Penetrant Inspection (Application for co
16、pies of AMs specifications should be addressed to the American Society of Automotive Engineers, 29 West 39th St., New York 18, N. Y.) 3. RWUIREMENTS 3.1 Materials.- 3.1.1 Critical materials.- The use of critical materials, as listed in the model specification, shall be held to a minimum. The estimat
17、ed weight of each critical ma- terial required in the construction of the gas-turbine-type auxiliary power unit shall be specified in the model specification, 3.1.2 Dissimilar metals.- The use of dissimilar metals in contact, as defined on Drawing AND10396, shall be avoided wherever practicable. 3.1
18、.3 Synthetic rubber parts.- 3.1.3.1 Mgking.- All synthetic rubber parts, such as diaphragms, excepting IfOtf rings and parts with no suitable surface, shall have printed, stamped with ink, or other- wise noted on the part, the year and month of the curing date of the part. 3.1.3.2 Serviceability.- A
19、ll synthetic rubber parts shall be readily replaceable with a minimum replacement of attaching parts. 3.1.3.3 Uniformity.- For components which include parts fabricated of synthetic material in contact with fuel, manufacturers shall control subsequent batches to provide for uniforrrdty. 3.1.3.4 Age
20、controls.- Age controls for synthetic rubber parts shall comply with the requirements of ANA Bulletin No. UO. 3.1.4 Materials, processes, and products.- Materials, processes, and products used in th manufacture of auxiliary power units shall be of high quality, suitable for the purpose, and shall co
21、nform to applicable specifications selected in accordance with ANA Bulletin No. 343, Where contractorts spec: %cations are used for materials and f 3 - 4 C Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-(AsG) processes which affect performance
22、 or durability of the finished product, such specifica- tions shall be subject to release by the procuring activity. The use of nongovernmental specifications shall not constitute waiver of Government inspection. 3.1.4.1 Standard parts.- Standard parts (MS, AN, or JAN) shall be used wherever .they a
23、re suitable for the purpose, and shall be identified on the drawing by their part numbers. In the event there is no suitable corresponding standard part in effect on date of invitation for bids, comercial parts may be used provided they conform to all requirements of this specification. 3.2 Design s
24、tandards.- MS and AND Design Standards shall be used wherever applicable. 3.3 Model specification.- A model specification conforming to Appendix III of this specification shall be-submitted by the contractor for approval. Unless otherwise specified by the procuring activity, a revision of the model
25、specification and drawings forming a part thereof,.shall be submitted to the procuring activity after approval of the unit. 3.4 Preproduction and acceptance. - 3*4.1 Preproduction.- The approval of any complete gas-turbine-type auxiliary power unit as a service type or model shall be predicated on t
26、he satisfactory completion of a Prepyoduction test in accordance with the requirements of Appendix I of this specification 3.4.2 Acceptance requirements.- An Acceptance test shall be conducted on each production unit and shall consist only ofthoserequirements specified in Appendix II of this specifi
27、cation. 3.5 Performance characteristics.- The performance characteristics shall be as specified in the model specification. These performance characteristics shall be deer-. mined, using Specification MIL-F-I- fuel and the type and grade of oil specified in the model specification. These performance
28、 characteristics shall be determined under the sole control of the automatic control system furnished on the unit. 3.5.1 The unit shall function satisfactorily throughout its operating range with fuel, conforming to Specification !-ftL-F-5624, and shall also function satisfactorily throughout its op
29、erating range with fuel conforming to Specification mL-F-5572. Ekter- na1 control adjustments shall be allowed to meet this requirement. In particular, the operating limits specified in the engine model specification shall not be exceeded hen fuel having any of the variations in characteristics perm
30、itted by Specification MIL-F-L is used. 3.5.2 Fuel contamination.- The unit shall function satisfactorily when using fuel contaminated to the extent of 80 grams of foreign matter per 1,000 gallons of fuel. Contaminant shall be considered to consist of not less than 68 percent Si02 and shall have a p
31、article-size analysis as follows: Particle size microns Percent of total o to 5 39 22 by weight 5 to 10 18 53 by weight 10 to 20 16 53 by weight 20 to 40 18 53 by weight Over 40 9 23 by weight Through a 200-mesh screen 100 by weight Demonstration of the foregoing requirement on the complete unit by
32、the contractor shall not be required unless so specified in the model specification. If a filter is required, it shall be a part of the unit, and the filter element shall be of sufficient capacity to permit a minimum of 30 hours continuous operation at normal ratzd output without being cleaned. 4 Pr
33、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-i NIL-P-8686 28 m 7777706 0187512 L W 3.5.3 Lubrication.- No change in lubricants shall be requlired for operation throughout the cmplete ground temperature range. 3.5.5 Estimates.-. The estimated perform
34、ance shall be as specified in the del specification. 3.5.7 Altitude-temperature .limits for starting and operating.- The unit starting and operating altitude and temperature limits shall be -defined in the model specification. 3.5.8 Attitude-conditions.- The unit shall function satisfactorily under
35、.any one of the following attitude conditions: (a) Normal horizontal level position. (b) O to 45 degrees positive displacement to either side with up to - 10 degrees positive and negatiwe displacement of the fore and aft ks . (c) O to L5 degrees negative displacement of the fore and .aft ! shall not
36、 be furnished with the Unit. 3.22 Air intake.- The air intake size and location(s) shall be shown on-the gas- turbine power-unit outline drawing which shall be a part of the model specification. 3.22.1 Air intake screen.- Unless otherwise specified in the model specification, . a screen shall be pro
37、vided at the air inlet to prevent the entrance of foreign objects of dimensions equal to, or greater than, a 0.125inch sphere. 3.22.2 Duct attachment.- Provisions for intake duct attachments shall be as shown on the unit outline drawing. The maximm permissible shear io$, axial load, and over huilg m
38、oment for the attachment provisions shall be as specified in the model Specification. 3.22.3 Inlet air pressure &OE.- The mu allowable inlet air pressure drop Mch will permit operation of the unit without adverse effects shall be specified in the model specification. . 3.23 Exhaust system.- 3.23.1 “
39、grbine exhaust.- Provisions for quick-disconnect-type attaohments shall be furnished for the turbine exhaust system to permit ready removal of the unit from its installation. These provisions shall be shown on the outline drawing. The maximurn allowable shear load, axial load, and overhung moment sh
40、all be specified in the model specification. 3.23.1.1 Turbine exhaust pressure drop.- The ma%imum allowable exhaust pressure drop which will pernit operation of the unit without adverse effects shall be specified in the model specification. . 3.23.2 Cooling air discharge.- Provisions for quick-disco
41、nnect-type attachments shall be furnished at the cooling air outlet port( S) if an air outlet port(s). is provided. These prov5sions shall be shown on the outline drawing. The allowable shear load, axial load, and overhung mment shall be specified in the nyxlel specification. 3.23.2.1 Cooling air di
42、scharge pressure- drop.- The maximum allowable cooY.ng air pressure drop which will permit operation of the unit without adverse effects shall be pecified in the model Specification. 3.24 -m.- The lubricating system shall adequately lubricate the auxiliary.power unit throughout its operating range.
43、3.24.1 Lubrication points.- All points in the unit requiring pressure lubrication shall be lubricated from the nit lubricating system. No lubricating from an external some shall be required. 3.24.2 Oil interruption.- The unit shall be capable of operathg continuously, with no detrimental effects dur
44、ing and after operation, when & only is supplied to the inlet of the oil. pump for a period of 10 seconds. 3.2b.3 Oil drainage.- Provisions sipU be made to prevent oil drainage into the turbine. “ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.2h.
45、4 Oil filter.- A. suitable AN-type oilfilter ele.aent shall be provided as a cmponent of the unit. The filter element shall be of sufficient capacity to operate satisfactorily between oil changes as specified in the mcdel specification. 3.24.5 Scavenging. system.- If a scavenging system i,s used, it
46、 shall adequately scavenge the basic gas trbine and compressor for extended periods of tim, under the operating conditions specified herein, including negative “g“ operation for a period of 10 seconds. The scavenge pump shall operate satisfactorily during the. low-temperature starts specified. 3.24.
47、6 Oil pressure.- 3.24.6.1 Oil pressure pump.- The oil pressure pump shall maintain not less than the specified oil pressure for all operating speeds ad all altitudes up to and including the absolute altitude specified in the model specification. 3.24.6.2 Oil pressure measurement.- Provisions shall b
48、e made for the measurement of oil pressure, The connection for this measurement shall be shown on th unit outline drawing. The oil pressure indicator shall not be furnished with the unit. 3.24.6.3 Pressure adjustment.- The lubricating system. shall be arranged to provide oil pressure without adjustm
49、ent throughout the operatin& range specified in the model specification. If oil ?ressure adjustment is required during nornial maintenance, it shall be readily adjustable without parts change. 3.24.6.4 Pump relief valve,- The oil-pump relief vzlve shall be so designed that it will be unnecessary to change adjustment of the valve when operating under any condition specified in the model specification. 3.24.6.5 Oil bypass The lubricating system
