1、. . . . . . flIL-C-bO268 3b W 77777Ob O385330 3 9 . . . . . . . . MILITARY SPECIFICATION . -. . .-. . I , ._ .- - , . . ,.-. . . . .- . . . . 4 .l. ( . . “-.* . . - - . .- . . . _l-llll-.-I -. _ * _._.i I /- -y M Gen- eral Tests for. MIL-H-5606 - H y d r a u 1 i c Fluid, Petroleum B a s e, Aircraft
2、and Ordn- ance. S J- s t e m s , W he e 1, Aircraft, Design of. MIGB-8584 - Brake MIGA4625 - Anodic-Coatings, for Aluminum and Alu- minum Alloys. MIL-A-8629 - Airplane 8tr e% g t h and Rigidity. MIL-H-8775 - Hydraulic S y s t e m Components, Air- craft, General Spec- ification for. STANDARDS MILITAR
3、Y KL-STD-105 - Sampling Procedures and Tables for In- spection by Attri- butes. MIL-STD-129 - Marking f o r Ship- ment and Storage. (Copies of specifications, standards, drawings, and publications required by contractors in connection with spwific procurement funcons should be ob- tained from the pr
4、ocuring activity or as directed by the contracting officer.) 3. REQUIREMENTS 3.1 Preproduction sample. Prior to begin- ning quantity production, preproduction samples shall be subjected to preproduction testing. The preproduction sample shall be ir , ZI p e. Provided by IHSNot for ResaleNo reproduct
5、ion or networking permitted without license from IHS-,-,-MIL-C-6026B lb 7797706 018531l 3 MILG6026B produced by the same method and of the same material that will be used for quantity production of the item. 3.2 General. The requirements of specifi- cation MIGH-8775 apply as a requirements of this s
6、pecification with the exceptions and additions specified herein. When the two specifications conflict, this specifidion shall govern. 3.3 Design and construction. Design of control units for manually operated hydrau- lic brake systems shall consist of a mechanic- ally actuated hydraulic power genera
7、tor. The incorporation into the unit of a re- servoir to maintain a reserve supply of fluid shall be optional. This unit shall be operable by the pilots brake pedal, and it shall conform to the applicable requirements of Specification MIL-B-8584. 3.3.1 Operation tempwatures. The control units shall
8、be designed and constructed for operation at temperatures of from -54O to 71OC. (45O to 160OF.). 3.3.2 Operating pressure. Normal oper- ating pressure shall be that pressure re- quired to lock the wheels of the airplane, assuming a coefficient of friction of 0.31 be- tween the tires and the ground.
9、Maximum operating pressure shall be that pressure required to lock the wheels of the airplane, assuming a static coefficient o friction of 0.55 between the tires and the ground. 3.3.3 Pumping. Control units shall be de- signed to permit “pumping up” of the hydrau- lic pressure in a brake system wher
10、e the control unit travel to operate the brake may become greater than the travel normally re- quired, such as in the case of% failed pack- ing in the unit, or a leak in the brake sys- tem. It shall also serve to facilitate bleeding of air from the brake system and maintain- ing an airfree system. T
11、he pumping valve shall remain sealed at all times during the operating stroke of the unit, but shall be designed to open immediately at any time when the brake line hydraulic pressure may become appreciably less than the reservoir . pressure. Pressure drop through the valve during pumping shall be s
12、ufficiently low to assure complianee with the pumping test Specified in 4.8.3. 3.3.3.1 Return mechanhm. A means shall be provided within the unit to return the pressure generator to its relaxed position upon release of the actuating force. The return rate shall be sufficiently rapid to provide a pre
13、ssure drop in the unit enough greater than that in the brake system to assure a buildup to the required pressure within the required number of pumping strokes when tested as specified in 4.8.3. 3.3.4 Bleeding. Provisions shall be made in the design of the control unit in order that the pumping valve
14、 is mechanically unseated and remains open when the unit is in the relaxed position with no mechanical force applied. 3.3.5 Structurai strength. The structural stren.gth of the control units shall be such that no part of the unit or its mounting shall give evidence of failure under the maxi- mum imp
15、osed mechanical operating loads, or wrench torque loads required for making connections. Operating load strengths shall be as specified in Specification MIGA-8629. 3.4 Performance. The control nit shall satisfy the performance requirements speci- fied in Section 4 when subjected to the fol- lowing t
16、ests: (a) Immersion (4.8.2). (b) Pumping (4.8.3). (c) Elevated temperature cycling (4.8.4) . (d) Cold temperature cycling (4.8.6). (e) Life (4.8.6). (f) Proof pressure and leakage (4.8.7). (9) Efficiency (4.8.7.3). (h) Burst pressure (4.8.8). 3.5 Marking. All ports for tube connections shall be clea
17、rly and permanently marked to indicate the proper connections to be made. , , . I . -. . . . - . 1 . 1 -1 -. . . . ! . 1 A . .-. ! . _.- .- . 7.: . . . -. . . . . . . .- . ._ . . . . . . . ”._ . . . . . . . . . . Provided by IHSNot for ResaleNo reproduction or networking permitted without license fr
18、om IHS-,-,-. MIL-C-60268 26 7779906 OL53L2 5 .: . . . . . . . . . . I . . . . . . 1 , . . 1 I . Y .I . . -. , . . 1 . I ._ 4 . - . - _._._.” . . -. . - . . r . -: - . . I - -.- . -., .-._ .- -.- . - .- . . .-.-.-. I.-.- -., -_ . . . _. - . _._ _._-_ . ., . , . . I . . . . - . .- - . i . 1 4. QUALITY
19、 ASSURANCE PROVISIONS 4.1 Unless otherwise specified herein? the supplier is responsible for the performance of all inspection requirements prior to sub- mission for Government inspection and ac- ceptance. Except as otherwise specified? the supplier may utilize his own facilities or any commercial l
20、aboratory acceptable to the Gov- ernment. Inspection records of the examina- tions and tests shall be kept camplete and available to the Government as specified in the contract or order. 4.2 The quality assurance provisions of Specification MIGH-8775 shall apply as quality assurance provisions of th
21、e specifica- tion with the exceptions and additions spec- ified herein. When the two specifications con- flict, this specification shall govern. 4.3 Classification of tests. The inspection and testing of control units shall be classified as follows: (a) Preproduction tests (4.4). (b) Acceptance test
22、s (4.5). 4.4 Preproduction tests. 4.4.1 One sample test unit of a new design shall be made with critical fits within 10 percent of the minimum allowed clearances specified by the detail drawing tolerances and with maximum squeeze piston and rod packings. This unit shall be used for the elevated temp
23、erature cycling test and the cold temperature cycling test, as specified in 4.8.4 and 4.8.5, respectively. 4.4.2 The second sample unit shall be made with critical fits within 10 percent of the maximum allowed clearances specified by the detail drawing tolerances. It shall also have maximum squeeze
24、piston and rod packings. It shall be subjected to the Life test (4.8.6) 3nd all other tests required by this specifi- cation? as described under 4.8. 4.4.3 Tests. The preproduction tests of brake control units shall consist of all he RIIL-C-6026B tests of this specification as described under 4.8. .
25、 4.5 Acceptance tests. The acceptance tests shall consist of individual tests and sampling tests. 4.5.1 Individual tests. Each control unit submitted for acceptance under contract shall be subjected to the following tests, as de- scribed under “Test methods” : (a) Examination of product (4.8.1). (b)
26、 Pumping (4.8.3)-. (c) Proof pressure and leakage (4.8.7) . 4.5.2 Sampling tests. Sample control units shall be selected from each inspection lot in accordance with Standard MIL-STD-105 at inspection level II using an acceptable quali- ty level (AQL) of 1.0 percent defective for the following tests
27、described under 4.8: - Immersion (4.8.2) . Elevated temperature cycling Cold temperature cycling (4.8.5) . Life test (4.8.6). Efficiency (4.8.7.3) . Burst pressure (4.8.8). Packing, packaging, and marking (4.8.4). (4.9). 4.5.3 Rejecton and retest. . 4.5.3.1 Preprmhcton test failure. The failure of a
28、ny preproduction test unit sub- jected to the tests as the first unit of a new design shall be cause for rejection of the design represented. The acceptance of the remaining control units on a contract or purchase order shall be dependent upon ap- proval of the test results on the preproduc- tion sa
29、mple required by 4.4.3 of this speci- fication. 3 I- I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-bO2bB MIL-CaO26B 4.5.3.2 Acceptance test failure. Rejected lots may be resubmitted in accordance with paragraph titled “Resubmitted lots” of
30、Standard MILSTD-105. A resubmitted lot shall be inspected using tightened inspection. Before . resubmitting, full particulars con- cerning the previous rejections and the action taken to correct the defects found in the original units shall be furnished to the inspector. The units rejected after ret
31、est shall not be resubmitted without the specific approval f the procuring activity. . 4.5.3.3 Inspectwa lot. For purpose of in- spection sampling, an inspection lot shall be all control units manufactured under the same conditions and offered for inspection at one time. 4.6 Report of tests. A test
32、report, in dupli- cate, showing the quantitative results for all the tests required by this specification, shall be submitted to the procuring activity. 4.7 Test conditions. 4.7.1 Test fluid. Hydraulic fluid used for all tests shall conform to the requirements of Specification MIL-H-5606. 4.7.2 Temp
33、erature. Unless otherwise spec- ified, tests shall be conducted with the oil at a temperature of 21 to 43OC. (70 to 110OF.). The actual temperature shall be reported. 4.7.3 Pressure. Operating pressures for all tests shall be those required by the parti- cular brake installation for which the contro
34、l unit will be used, as specified in 3.3.3. 4.8 Test methods. 4 4.8.1 Examination of product. Each con- tiwl unit shall be carefully examined to de termine conformance to this specification with respect to materials, workmanship, and conformance to the limiting dimensions in- dicated on the applicab
35、le manufacturers drawings as approved by the procuring act+ ivity. 4.8.2 Immemion of plastic parts. Control units containing plastic parts shall be sub- jected to and shall meet the test requirements of Specification MIL-P-5517. These tests shall be conducted prior to all other tests for first artic
36、les unless these tests are specifi- cally waived by the procuring activity on the grounds that the plastic material used has been previously approved in similar us- age. 4.8.3 Pumping. The reservoir inlet port of the control unit shall be connected to a supply reservoir -and the brake port to a simu
37、lated brake consisting of a cylinder hav- ing a spring-loaded piston. Line lengths, types, and sizes, together with reservoir head pressure used (or intended to be used) in the airplane installation, shall be simulated in the test. The simulated brake shall re- quire a minimum of 30 psi for initial
38、move- ment of the piston, after which pressure reaction shall increase linearly with displace- ment, reaching at least 200 psi after havinq been displaced by a volume equivalent to 200 -cl0 percent of the minimum full dis- placement of the control unit. At that point it shall bottom. The control uni
39、t shall fully displace the piston and reach normal op- erating pressure within five actuating strokes with hydraulic fluid and the control unit at (a) 71 ir3OC. (160O -c5OF.), and b) -29O -c3OC. (-20 k5OF.). Return of the unit to its relaxed position preparatory to the next pumping stroke, shall be
40、self- motivated. A schematic diagram of the test setup is shown in figure 1. - ,:I I . , . . . . . - . . . i - -7 . -. - . d* . . I. . P. . A 1 . . . . . 1 .- . . . I._. . . I.I . . I-. . -.-i: . . . - I ._. _ . . . Provided by IHSNot for ResaleNo reproduction or networking permitted without license
41、 from IHS-,-,-. MIL-C-6026B 1h m 777770b 0185314 7 m . _.I_._. . -. . . # . . .- - - -.- . -_ . _-. .-_ _._-_._. 5 .- . _. _._ . . ._ “ .-_ _-. -._._ - . “ . _._- _._I._._._. - . - _ . r _._.I_._-_ . . . . . . . . . .-. . . . - _ - ,_._ ON SIMULATING AIRPLANE INSTALLATION CONSISTING OF CONTROL UNIT
42、TEST CQhTROL UNIT PUSH-TYPE CONTROL UNIT SHOW? IN THIS SCHEMATIC DIAGRAM. PUU-TYPE COWTROL UNIT. REVERSE PORTING FOR FIGURE 1. Pumping test setup 4.8.3.1 A qualitative type of pumping test may be substituted in place of the foregoing test for individual tests only, in which the brake port shall be c
43、apped while the control unit is held in its fully actuated position. As the control unit is cycled, a rapid decrease in the length of successive pressure strokes of the piston shall be noted. Return of the piston, preparatory to the next pressure stroke, shall be self-motivated. This test shall be c
44、onducted at a room temperature of 9.9O to 43OC. (50 to 110OF.) and with hydraulic fluid at a temperature of 21 to 54OC. (TO0 to 130F.). w i 4.8.4 Elevated temperature cycling. Both the reservoir supply port and the brake port of the control unit shall be connected to a reservoir, with a shut-off val
45、ve in the brake port line. The shutoff valve shali be opened and the unit and lines filled with hydraulic fluid. The reservoir shall provide a static fluid pressure head to the unit of at least 2 feet. The unit shall be so mounted that all working ports, gaskets, and seals are in con- tact with the
46、fluid, The unit shall be held in the fully actuated position (but with zero operating pressure) and the temperature of the unit maintained at 70 -i-loC. (1580 I . . i Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- VIL-C-b26B MIEG6026B k2OF.) for 3
47、hours. Observation shall be made for any external leakage. The shutoff valve in the brake port line shall then be closed and the unit operated through at least 20 cycles at the elevated temperature. Where part of the test setup is outside the hot box, care should be taken in order that no cool fiuid
48、 comes in contact with the unit. One elevated temperature cycle shall consist of one cornrilete suction stroke followed by the npjlication of sufficient force maximum .operation pressure. to produce This force FBSERVOIR f BOX . - . -h . . . . . 16 M 7777906 0185315 O M shall be maintained for 5 minu
49、tes, and any indication Of pumping valve leakage as eVi- denced by visible rod movement after the force is applied shall be noted. Any bind- ing within the unit, failure of the unit to generate pressure, or any other malfunction- ing at any point in the cycle shall be noted. Not more than one or two drops of external leakage shall be allowed during the temper- at
