1、MIL-R-38953C LO 9799906 0305520 0 w I f- -. MIER-38953C (um) 2.5 p.ig 1973 MIL-R-38953 1 SUPERSEDING 3 June i968 MILITARY SPECIFICATION RACK, BOMB EJECTOR, AIRCRAIT MU-UB/A AND RACK, BOMB EJECTOR, MRCm h%U-ZC/A *l. SCOPE 1.1 Scope. This specification covers the requirements for one “ype of equ-p- me
2、nt designated as Rack, Bomb Ejector, Aircraft MAU-12B/A and Rack, Bomb Ejector, Aircraft K4U-l2C/AY hereafter referred to as the rack for carrying and either freefall release or ejection of stores weighing up to 5000 pounds. 2. APPLICABLE DLXMWC“T *Sol The following documents of the issue in effect
3、on the date of invitation for bids, form a part of this specification to the extent specified herein: SPECIMCATIONS PPP-B-601 PPP-B-636 PPP-(2-843 Military MIL-P-U.6 MIL-D-10oO MIL-T-7743 MIM-9858 MIEC-45662 STANDARDS Military MIL-STD -E 9 MIESTD-130 MIL-STD-143 MIL-STD-202 Boxes, Wood, Cleated-Plyw
4、ood Boxes, Shipping, Fiberboard Cushioning Material, Cellulosic Preservation, Methods of Drawings, Engineering and Associated Lists Testing, Store Suspension Equipment, General Specification For Quality Control System Requirements Calibration System Requirements M%rking for Shipment and Storage Iden
5、tification Wkng of U.S. Military Property Specifications and Standards, Order of Precedence For The Selection Of Test Methods for Electronic and Electrical Component Parts FSC 10% A Licensed by Information Handling ServicesProvided by IHSNot for ResaleNo reproduction or networking permitted without
6、license from IHS-,-,-7 MIL-R-3753C LO 7777706 0305521 2 W I MIL-R-38953C (UM) MIL-STD-785 Requirements for Reliability Program (For Systems and Equipment) MIESTD-810 Environmental Test Methods for Aerospace and Ground Equipment LSTD-XL Cushioning, Anchoring, 9racing Blocking, and WaterpEoofing; With
7、 Appropriate Te WU-KC/A (Copies of specifications, standards, drawings, and publications required by suppliers in connection with specific procurement functions should be obtained fran the procuring activity or as directed by the contracting officer.) Rack Assembly, Bomb Ejector, Aircraft MU-U!B/A 3
8、. ES *3.1 Qualification. The racks furnished under tis specification shall be products that have been tested and passed the qualification tests specified herein, and have been listed or approved for listing on the applicable quali- fied products list at the time set for opening of bids. *3,2 Compone
9、nts *3.2.1 Selection of materials. Specifications and standards of aU. materials and parts, and Government certification and approval of processes and equip- ment which are not specifically designated herein and which are necessary for the execution of this specification, shall be selected in accord
10、ance with MIESTD-143 *3,2.2 The MAU-UB/A and MU-l2C/A Racks shall comprise an integral assembly consisting of: a. having i4 inch or 30 inch lug spacing and diameters from 10.70 inches to 33 inches. Cartridge actuated release mechanism which will accomnodate stores b. Solenoid actuated in-flight lock
11、ing mechanism to prevent inadvertent Controlled store ejection system with two ejection pistons which auto- release of special stores. matically return to their retracted positions at the completion of their ejection strokes. C. 2 1 J i 1 t 1 I Provided by IHSNot for ResaleNo reproduction or network
12、ing permitted without license from IHS-,-,- _. - . MIL-R-38753C 10 7999906 0305522 LI MIL-R-38953C (USAF) *3.3 Design and construction. The racks shall be constructed in conformme to hwings 64Jl3210 (HiU-S!B/A) or 69513060 (s shall be prepared as required, cartridge-actuated mechanism which shall al
13、low either freefall drop of stores or forced ejection of stores of all types weighing up to and including the 5000 pound class stores, having either 14 inch or 30 inch lug spacing and having a minimum diameter of 10.70 inches and a maximum diameter of 33 inches. Parts nuictionaily and dimensionally
14、interchangeable *3.4 Performance. The rack shall be capable of reeashg stores by means of a 3.4.1 Forced ejection. When forced ejection of the store is desired, the velocity of store, reaction forces and the flight attitude of the store sbaU be controlled by orifices which are placed in the gas syst
15、em and which meter the flnw of gases to the ejection pistons. 3.4.2 lhcked shut and eppthetic firing. The rack shall. be capable of with- standing the stresses incurred :en fired with the inflight safety lock engaged without inadvertently dleasing the store or damage to any structural part of the ra
16、ck. Both cartridges shall fire when only one of the firing Switches (S-1, S-3) is closed. 3.4.3 in-flight lock. With the in-flight lock in the locked position, no eledricai energy shall be transmitted to the cartridge electrical terminals when a 28 volt potential is applied to the cartridge firing c
17、ircuits. 3.4.4 Provisions for conventiona weapons *3.4.4.1 Arming controlso (Conventional weapons). The nose, center, and tail solenoid operated arming controls shall operate from an 18 to 30 vdc power supply and shall each draw a maximum of 0.15 amperes continuously when ener- gized at 24 vdc. Each
18、 control shall be capable of receiving and holding all standard arming wire loops. capable of providing for an unarmed release or ejection, or armed release or ejection, of stores weighing from 100 pounds through the SOO0 pound class. 3.4.4.2 Fuzing provision. When electrical fuzing of conventional
19、weapons is required, the interconnecting Group KMU-237/B shall be incorporated in the rack in conformance to drawing 64J13010. 3.4.5 Ufe. The rack shall function satisfactorily for 250 firings. 3.4.6 ReUability. The corrtractor shall initiate and maintain a reliability program in accordance with NIL
20、-STD-785. mdification by the procuring activity. Each control shall be selectively This program shall be subject to 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-38753C LO 7779906 0305523 b i1 I MIER-38953C (Um) 3.4,6.1 Reliability levels.
21、The following reliability levels shall be achieved and demonstrated by the contractor: a. inadvertent release. With proper adjustment of the wer center Unk- age, there shall be no inadvertent release during the design service life of the rack (250 firings under senrice conditions), b. Release perfor
22、mance requirements. With proper maintenance and re- pacement of parts, the achieved rate of failure SU be no failures in 250 releases under service conditions, excluding cartridge failure . C. Reliability failure. !Che bomb rack shall be constructed as specified herein and successfully complete the
23、tests of paragmph 4.6 of this specifi- cation with no failures as defined herein preventing satisfactory performance. Reliability of 98.0 per cent for a 2-hour estimted mission time with Mean !Time Between Failure (MTBF) .value of 100 hours is required. Compliance will be acceptabiy demonstrated at
24、90 per cent confidence level by 440 hours or mre of total qualification testing tirne with no uncorrected fiilUres. 3.5 Envir-ntal requirements. The rack shall be capable of proper operation during or after, as applicable, in the following environmental conditions: and -54OC (-659) to 176.70 (35m) f
25、or the MAU-UC/A mck. * a, Temperature from -*OC (-65%) to %OC (2CF) for the MU-12B/A Rack b. Monidity up to 95 per cent, relative. C. Salt spray incident to use, storage or transportation near or on a large body of salt water. d, Icing conditions incidentto service use. e, Sand and dust likely to be
26、 enountered under desert conditions. f. Vibration incident to flight, transportation and haning. e;. Shock incident to flight, transportation and handling, 3.6 shall be marked for identification in accordance with MIL-STD-130. Identification of product. The rack and all component parts thereof I *3.
27、7 Government furnished property. When specified in the contract, the Government will furnish the following to the contractor, upon his request, for use in testing the racks, Bomb Ejector, Aircraft NlU-l2B/A and MAU-ISC/A: Item Number Part Number Description of Item Quantity ARD 446-1 contract ARD 86
28、3-1 Contract CCU-1/B Contract * 1 mn-1 Cartridge, Bomb Ejection, As stated in the * 2 10-3400 Cartridge, Bomb Ejection, As stated in the * 3 67FJ-4000 Cartridge, Bomb Ejection, As stated in the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-39
29、53C LO 9797706 0305524 E 3.8 Workmnship. The rack shall be fbbricated and finished in a manner which will insure that the criteria of appearance, fit, smoothness of operation, and adherence to specifiedtolerances are observed. These criteria must apply to all accessories and to all extemal non-funct
30、ioning parts, such as nameplates, 8s well as to functional parts. ParbicuUr attention shall be given to neat- ness and thoroughness of mar-king of parts and assemblies, plating, painting, riveting, machine screw assemblage, and freedom of parts from burrs and sharp edges . 4, QUAIJ.TY ASSURANCE 4.1
31、Responsibility for inspection. unless otherwise specified in the contract or purchase order, the supplier is responsible for the performance of ali inspection requirements as specified herein. Except as otherwise specified, the supplier may utilize his own facilities or any conanescial laboratory ac
32、ceptable to the qualifying activity. The Government reserves the right to perform any of the inspections aet forth in the specification where such in- spections are deemd necessary to assure supplies and services conform to prescribed requirements. 4.2 C, performed by an independent laboratory accep
33、table to the activity responsible for the Qualified Products List (see paragraph 6.5). produced with manufacturing equipment and procedures normally used in production. Jt4.3.1 Testing. Qualification testing of preproduction rack(s) shall be Racks shall have been *4.3.2 Qualification test reports. Q
34、ualification data shall be prepared and -submitted for evaluation in accordance with the requirements of the procurjng *4.3.3 Qualification test requirements. Qualification tests shall consist of activity . ail tests specified herein under “4.6 Test methods“ as listed in Table I. 4.4 Acceptance test
35、s. Acceptance testing shall consist of the following: a. Udividual tests b. sampling tests 4.4.1 Individual tests. tests as listed in Table I, except as otherwise specified. Each rack shall be subjected to the individual 4.4.2 Sampling pian and tests. 5 Provided by IHSNot for ResaleNo reproduction o
36、r networking permitted without license from IHS-,-,-*4.4.2.1 Sampling pian. One sample shall be selected at random by the quality assurance representative from each 200 production racks. subjected to the sampling tests, the sample racks shall Wve passed the individual tests . Prior to being 4.4.2.2
37、SampUng tests. Sampling tests shaU. consist of the sampling tests shown in Tabh I. 4.4.3 Rejection and retest . When the sample rack fails to meet the specified test, no rack on hand or later produced shall be accepted until the extent and cause of frrilure are determined. The failure shall be corre
38、cted and the unit shall demonstrate compliance by satisfactorily passing the failed test before acceptance of on hand or Later produced units. 4.4.4 Defects in items already accepted. The investifption of a test failure could indicate that defects may exist in items already accepted. contractor shal
39、l fully advise the procuring activity of ail defects likely to be faund and methods of correcting them. if so, the 4.5 Test conditions. test under “4.6 Test methods.“ Test conditions shall be as specified in each specific QUAUFI- INDI- REion shall have a minimum ultimate tensile strength of 160,000
40、psi. A 2000 pound simu- lated store as shown in Figure 2 shall be installed on the 30-inch hooks of the rack, The set of sway braces at each end of the rack shall be torqued to 840 4 50 inch-pounds. torque shall be applied by turning each bolt of a set the same number of turns f i/8 turn. After the
41、studs are in contact with the store, the A recommended fixture is shown in Figure 1. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-38753C LO E 77Ob 0305527 3 4.6.3.1.1.2 Test procedure. The yield load test of the rack shall consist of the sim
42、ultaneous imposition of loads for each condition along or about, as applicable, the axes shown in Figure 2. For each conditicm the loads shall first be imposed in increments of 10 per cent of design load until 100 per cent of design load is reached, then in increments of 5 per cent of design load un
43、til U5 per cent of design load is reached. The loads shall be held at each per cent increment for three minutes before proceeding to the next per cent increment after 60 per cent of the design load is attainedo The rate of loading shall not exceed 5 per cent of the design loads per second. When a lo
44、ad of U5 per cent of design load has been reached and held for three minutes, the load shall be relieved to zero and the rack inspected. The sim* ated store shali be released and the position of the rack in the fixture shaU be reversed. permanent deformation shall be cause for rejection. shown in Ta
45、ble II. Test set up and procedures shall be repeated. Any Design loads shall be as WIE II DESIGN UIADS 30 INCH mom (MAU-EB/A CONDITION NUMBER px Lbs Pym pz Ibs %-Lbs MyIn-lbs Mz In-lbs - 1 887 2240 -u933 4473 -88867 302533 2 2000 1633 -12600 O -214000 23333 3 amcl 37933 -12600 O -256800 213600 4 193
46、 4687 -10800 4300 -a33 -301200 30 INCH IHM% (MAU-E!C/A CONDITION NUMBER PX Ibs py Lbrz % Ibs 5s In-lbs MyIn-lbs Mz In-Ibs 2 3050 10800 -20300 36m 384000 -lloooo Reference axes and positive directions of those axes are shown in Figure 2. 4.6.3.1.2 Fourteen Sich suspensione 4.6.3.1.2. Test set up. Tes
47、t set up shall be as specified for the 30 inch suspension except that the simuhted store shall be suspended on the i4 inch hooks of the rack as shown in Figure 3. 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-38753C LO 7777906 0305528 5 1 A
48、CCESS HOLE I r 20“ DIA. X 3/# WALL STEEL PIPE I SIMULATED STORE L HYDRAULIC CYLINDER TO SIMULAT VERTICAL 8 SIDE LOADS FIGURE I STATIC LOAD FIXTURE 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I MIL-R-38753C LO 777770b 0305527 7 Y 10 W a o Provid
49、ed by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-38953C LO = 9999906 0305530 3 MIL-R-38953C (W) The test procedure sball be as specified for the 4.6.3.1.2.2 Test procedure. thirty inch suspension. Design loads shall be as shown in Table III. The rejection criteria for the 30 inch suspension also applies to the 14 in
