1、7 MIL-P-81958 I6 W 9999906 0205307 9 W Type I II III rv V MIL-PA1958 (AS) 16 January 1974 Tire Working Pressure Range (Pew 80-129 130-199 200-284 285-399 400-579 MILITARY SPECIFICATION PRESSURE RELIEF DEVICES, OVERPRESSURIZATION PREVENTION, WHEEL/TIRE, AIRCRAFT This specification has been approved b
2、y the Naval Air Systems Command, Department of the Navy. 1. SCOPE 1.1 Scope - This specification covers the requirements for an overprersuurization relief device to replace standard Inflation valves for air- craft pneumatic tribeless wheel/tires. 1.2 Classification 2.1 Government documents normally
3、furnished - The following douuments of the issue in effect on date of invftatfon for bids or request for proposal, form a part of the specification to the extent specified herein. SPE CTFICATIONS Federal QQ-P-416 Plating, Cadmium (Ele c trodepos f tea) PPP-B-566 Boxes, Folding, Paperboard PPP-B-636
4、Box, fiberboard pTiG-1 , THIS DOCUMENT CONTAINS I PAGES. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. MIL-P-81758 Lb 77777Ob 0205308 b .3 SPECIFICATIONS Mili- MIL-P-116 MIL-S-8 879 Preservation, Methods of Screw Threads, Controlled Radius Root w
5、ith Increased Minor Diameter, General Specification for STANDARDS MiIitarp MIL-STD-129 Markfng for Shipment and Storage MIL-STD-143 Specifications and Standards, Order of Precedence for the Selection of MIL-STD-810 Environmental Test Methods MIL-STD-8 8 9 Dissimilar MetalB Mi333649 Bosse8, Fluid Con
6、nection-Internal Straight Thread (Copies of specifications, standards, drawtngs, and publications required by suppliera In connection with specific procurement functions should be obtained from the procuring activity or as directed by the contractfng officer. ) 3, REQUIREMENTS 3.1 Qualification - Th
7、e pressure relief devices furnished under this specification shall be products which are qualified for listing on the appli- cable qualified products list, at the time set for opening of the bids (See 4.3.1 and 6.3). 3.1.1 Retention of qualification - To maintain status on a Qualified Products List,
8、 oertlfication shall be submitted at two year intervals to indicate continued compliance with the requirements of this specifiaation (See 4.3.2 and 6.3). 3.2 Selection of speciffcations and standards - Specifications and standards for necessary commodities and services not specified herein shall be
9、selected in accordance with MIL-STD-143. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-81958 (AS) 3.3 Materials - Materials shail conform to the applicable specffi- cations. Materials for which there are no applicable specifications, or whi
10、ch are not specifically described herein, shall be of the best quality, of the lightest practical weight and suitable for the purposes intended. Materials used shall be compatible with titanium, magnesium, aluminum, steel, and plastic wheel ma- teriais. 3.3.1 Dissimilar metals - Unless suitably prot
11、eoted against electro- lytic corrosion, disaimilar metals, as defined in MIL-STD-889 shall not be used in intimate contact with each other. 3.3.2 Phtfntr - Ail ateel except corrosion resisting steel shall be cadmiam plated in accordance with Type II, Class 2 plating of QQ-P-416. 3. 3.3 Age - Elastom
12、er components, except silicone, shall not be more than 12 months old from the cure date of manufacture to the date of deliv- ery to Government procuring activity. 3.3.4 Fungus-proof materials - Materials which are not nutrients for fungi shall be used to the greatest extent practicable. External mat
13、erials which are nutriente for fungi shall be treated with a fungicidal agent approved by the procuring activity (see 4. 6.14). 3.4 Design and construction 3.4.1 General - The devices shall be designed to function 80 86 to preclude the possibility of pressurizing an aircraft tubelesis wheel/tire bey
14、ond the specified pressure limits for the applicable tire type when using an inflation source to 5000 psig. The devices shall not permit the pressure contained in the wheevtire to exceed the rated relief pressure (see 3.4.3) at operattng tem- peratures and shall reseat automatically after relief (Se
15、e 3.4.4). They shall be designed so as to prevent the instaliation of a device with an incorrect pressure relief setting. The devices shall maintain tire pressure under aervice uge conditions. 3.4.2 Threads - The pressure relief devices shall be designed to mount on wheel bosses conforming to MS3364
16、9 and have threads in accordance with ML-S-8879 in the sizes and thread designations listed below; 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-AL758 Ib 7777906 0205310 q m MIGP- 81958 (AS) i Thread Designation I Type I I II III rv V s. 4.
17、8 Relief pressure - The devices shall be designed to relieve at the wheel/tire pressures specified below for the types indicated at operating tem- peratures of from -65F to 350aF. 1 Relief Presmre (psig) l I *15% I II I II N V 200 310 460 640 930 3.4.4 Reseating pressure - Type I devices ehall resea
18、t at 50 psig minimum following relief, Types, II, III, IV, and V shall reseat at 100 psig minimum. 3.4.5 Weight - Unless otherwise specified, the devices shall not exceed. 30 pounds each in weight (See 6.2). %4.6 Length - The devices shall not exceed 1.75 inches in overall length, including inflatio
19、n stem. 3.4.7 Environmental conditions - The device shall meet the perfor- mance requirements of this specification under the following environmental con- ditions when subjected to the tests specified herein, - 3.4.7.1 Temperatures - Design operating and nonoperating tempera- tures range from -65F t
20、o 350F and storage temperatures from -65F to 180F. 3.4.7.2 Ambient pressures - Ambient pressures to be encountered during operation range from 2.13 inches Hg to 31 nches Hg. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- . . MIL-P-81758 Lb m 9797
21、706 020531iL b m MIL-P-8195 8 (AS 3.4.7.3 Humidity - The device shall not be adversely affected by and shall hotion properly while being exposed to 95 percent rehtive humidity, including uonditions wherein condensation takes place in the form of water, fro a. Qualification inspection (See 4.3) b. Qu
22、ality conformance inspection (See 4.4) 4.3 Qualification inspection - Qualification inspection shall consist of all the examinations and tests of this specification conducted in the order listed under 4 6 and Table I. TABLE I Qualification and Quality Conformance Requirements, Tests, and Testing Seq
23、uence Examination inspec tion of Product Examination of Prep- erationfor Delivery Operation Pressure Cycling Impuleie Cy cling Relief Cycling Requirement 3.4 sect, 5 3.4.1 - 3.4 s. 4 Test Procedure 4.6.1 4.6.2 4. 6.3 4. 6.4. 1 4. 6.4.2 6 aualification X X X - X X 2ualitv Conformance Individual X X -
24、 Sampling X X X - X X Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. MIL-P-81958 Lb 7999906 0205333 T MIL-P-81958 (AS) TABLE I (Cont. ) Qualification and Qualtty Conformance Requirements, Tests, and Testing Sequescs Examination Pressure endurance
25、Burst Pm Em0 Simulated in-flight braking Extreme temperature High temperature LOW temperature Acceleration Shock Vibration Sand and duet Mud and slush Salt Spray Fungus Icing Government flight aervice High humidity Reqnf rement 3.4.1 3.5.1 3.4.1 - 3.4. 3 3.4.3 3.5.2 3.5. 3 3.5.4 3.4. 7.4 3.4.7.4 3.4
26、. 7.5 3. 3.4 3.4. 7.3 3.4.7.3 3.4.1 Test Prooedun 4.6.4.3 4.6.5 4.6.6 - 4. 6.7.1 4. 6. 7. 2 4.6.8 4. 6.9 4.6.10 4. 6.11 4.6.12 4.6.13 4.6.14 4.6.15 4.6.16 4. 6.17 Qualificatioij X X X - X X X X X X X X X X X X Quality Conformance Indivi duaI Sampling X - 4.3.1 Sampling for gualification-inspection -
27、 Qualification samples ehall consist of the following: a. 20 samples of each of the types to be qualified b. One cutaway sample of each of the types to be qualified Samples minimally shall be identified by the type, nominal relief pressure, sample number and manufacturers identification number and f
28、orwarded to the activity res- ponsible for testing as designated in the letter of authorization (see 6.3). 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ML-P- 81958(AS) 4.3.2 Retention of aualification - To comply with the requirements epeaified
29、in 3.1. I, the manufacturer shall forward a quaiificatfon certiffcatfon to the Commander, Naval Air Systems Command (AIR-530321C), Department of the Navy, Washington, D. C. 20361. This certification, sfgned by a respon- sfble official of management shall attest that the manufacturer has the capabilf
30、ty to produee pressure relief devices under conditions equal to those existfng at the time of the original approved listing, 4.4 Qualfty conformance inspection - The quality conformance in- spectfon shall consist of the individual inspeotion and the samplfng inspection. 4.4.1 Individual inspection -
31、 Each device shall be subjected to the foliowing inspection and test. Any device containing a defect or failing to pas the inspection or test shall be rejected. a. inspection of product (4. 6. i) b. Operation (4.6.3) 4.4.2 Sampling inspection - 4.4.2.1 - A lot shall consfst of 500 devices of each ty
32、pe, or any fraction thereof, manufactured under the same conditions and of the same ma- terial and submitted for acceptance at the same tfme. 4.4.2.2 Sampling: - Twenty-ffve devices shall be selected at random from each lot specified in 4.4.2.1. A sample unit for all tests, except for exam- ination
33、for preparation for delivery, shall be one device. A sample unit for pre- paration for delivery (4. 6.2) shall be one fully packaged shipping container with devices preserved, packaged and packed as specified herefn, except that the con- tainer shall not be sealed prior to examination. Failure of an
34、y device to pass any test specified in 4.4.2.3 and Table I, except preparation for delivery, shall be cause for rejecting the lot. 4-4.2.3 Sampling tets - Samples selected as specified in 4.4. 2.2 shall be subjected to the following teats in addition to the Individual inspections. a. Pressure cyclin
35、g (4. 6.4) which includes (i) Impulse cycling (4.6.4.1) (2) Relfef cycling (4. 6.4. 2) Examination of preparation for delivery (4.6.2) b. 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-819 58 ( AS) 4.5 Test conditions - 4.5.1 Temperature, pr
36、essure and humidity - Whenever the pregsure, temperature and humidity existing at the time of test are not specified definitely the teest shall be conduuted at an ambient barometric pressure of 28.5 92, -4.5 inches of mercury and an ambient temperature of 75 h18“F and a relative humidity of 50 f 30%
37、. When tester are conducted with conditions differing materially from the preceding vahea, proper allowance shall be made for the difference from the specified condition. 4.5.2 Test Set-up - Unless otherwise specffied for the particular test, the pressure relief device may be mounted either on a rim
38、 and tire assembly when suitable, or on a one half cubic foot maximum volume pressure bottle, The bottle shall be equipped to permit the introduction of pressure from either the inflation side or the tire side of the pressure relief device. 4.6.3 Test fluid - Unless otherwise specified in a particul
39、ar test, the test fluid may be either air or an inert gas. 4.5.4 Test and inspection records - Test and inspection Records shall be maintained by the contractor for review by the procuring activity, as required, unless specifically required by the contract to be furnished as a data item (see Section
40、 6). Test and inspection Records shall shall include complete identification of all test equipment and accessories. The data shall include the actual test sequence used, measured ambient conditfons recorded periodically during the test period, measured characteristics of the unit under test, the dat
41、e of test and signature of the test conductor. 4.6 Test methods 4.6.1 insmction of product - Each relief device shall be inspected to determine compliance with the requirements specified herein with respect to materials, size, design, construction, marking, workmanship and other require- menta not c
42、overed by tests. 4. 6.2 Examination of preparation for delivery - The packings shall be examined to ascertain that the preparation for delivery conforms to the require- ments of Section 5 of this specification and a.s required by the apecificatlons ref- erenced herein. 4.6.3 Operation - A relief dev
43、ice shall have a pressure introduced from the inflation end by a 5000 psig minimum source and maintained for a minimum of 30 seconds, followed by a pressure cut off. The device shall relieve within the re- lief range for the type being tested (See 3.4.3) and shall reseat, at or above the 9 Provided
44、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-81958 Lb W 9999906 020531b 5 I MIGP- 819 58 (AS minimum Iceseating presmre (See 3.4.4) with no leakage as determined by chem- ical means. Whemical means“ indicates uae of soap sblution or other bubble form
45、- ing liquid. 4.6.4 Pressure cycling 4.6.4.1 impulse cycling - A device shall be subjected to 25 impulse cycles with the pressure introduced through the tire side of the device, Each cycle, of 17 seconds maximum duration, shall consist of an increase from the minimum tire working pressure to 75 perc
46、ent of the rated relief pressure of the type device beng tested (see 3.4.3) in a maximum of 2 seconds, dwell for 3 secondlsl, decay in a maximum of 2 seconds to minimum tire working pregimre and dwell for 10 seconds. During the 10 second dwell period the inflation end of the device shall show no vis
47、ible evidenoe of leakage when tested by ahamical means. 4.6.4.2 Relief cycIing - A device shall be subjected to 6 relief cycleer with pressure introduced through the inflation end of the device. Each cycle shall consist of inflation, by a source of 5000 psig minimum, maintained for a minimum of 30 s
48、econds, followed by pressure cutoff, The device shall relieve within the relief range for the device being tested (See 3.4.3) and shall reseat, at or above the minimum reseating pressure (See 3.4.4) for each cycle with no leakage as determined by chemical means. Readings shall be taken of the relief
49、 pressure and the reseating pressure reached for each cycle. 4.6.4.3 PreBsure endurance - A device shall be subjected to a pressure, introduced from the tire side, of 80 percent of the rated relief pressure of the device being tested, for a period of 10 days. exceed five percent of the original inflation pressure, Leakage durng this test shall not 4.6.5 Burst pressure - A device shall be plugged on
