1、MIL-R-272BC 62 m 7797706 0076735 4 m . / MIL- R- 2 7 2 8C 5 December 1977 SUPERSEDING MIL-R- 272 8B 8 November 1961 (See 6.4) MILITARY SPECIFICATION REFLECTOR, LIGHT; PARABOLIC, SEARCHLIGHT This specification is approved for use by all Departments and agencies of the Department of Defense. 1. SCOPE
2、1.1 Scope. This specification covers parabolic reflectors for searchlights. 1.2 Classification. Reflectors shall be of the following sizes as specified (see 6.2.1). (These sizes are ratings based on serviceable reflector area, and are not overall dimensions. ) 12 inches 24 inches 2. APPLICABLE WCUME
3、NTS 2.1 Issues of documents. The following documents, of the issue in effect on date of invitation for bids or request for proposal, form a part of the specification to the extent specif ied herein : SPECIFICATIONS ST FEDERAL PPP-B-576 - BOX, Wood, Cleated, Veneer, Paper Overlaid. PPP-B-585 - Boxes,
4、 Wood, Wirebound. PPP-B-591 - Boxes, Shipping, Fiberboard, Wood-Cleated. PPP-B-601 - Boxes, Wood, Cleated-Plywood. PPP-B-621 - Boxes, Wood, Nailed and Lock-Corner. PPP-B-636 - Boxes, Shipping, Fiberboard. PPP-B-640 - Boxes, Fiberboard, Corrugated, Triple Wall. MIL-P-116 - Preservation-Packaging, Met
5、hods of. MIL-S-901 - Shock Tests; H.I. (High Impact); Shipboard Machinery, Equipment and Systems, Requirements for. MIL-L-10547 - Liners, Case, and Sheet, Overwrap; Water-Vaporproof MILITARY or Waterproof , Flexible. NDAFDS MILITARY MIL-STD-105 - Sampling Procedures and Tables for Inspection by Attr
6、ibutes. MIL-STD-129 - Marking for Shipment and Storage. (Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procurement functions should be obtained from the procuring. activity or as directed by the contracting officer.) the extent sp
7、ecified herein. Unless otherwise indicated, the issue in effect on date of invitation for bids or request for proposal shall apply. 2.2 Other publications. The following documents form a part of this specification to Beneficial comments (recommendations, additions, deletions) and any pertinent data
8、which may be of use in improving this document should be addressed to: Commander, Naval Ship Engineering Center, SEC 6124, Department of the Navy, Washington, DC 20362 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by
9、 letter. I FSC 6210 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-272C 62 W 9999906 0096736 b MIL-R-2728C UNIFORM CLASSIFICATION COMMITTEE Uniform Freight Classification Ratings , Rules and Regulations. (Application for copies should be addre
10、ssed to the Uniform Classification Committee Agent, G. F. Earl, Tariff Publication Officer, Room 1106, 222 South Riverside Plaza, -Chicago, Illinois 60606. ) UNITED STATES POSTAL SERVICE Postal Regulations. LEnfant Plaza West S .W. , Washington, DC 20260 .) avaiable for reference from libraries. The
11、y are also distributed among technical groups and using Federal agencies.) (Application for copies should be addressed to the United States Postal Service, 475 (Technical society and technical association specifications and standards are generally 3. REQUIREMENTS 3.1 Sample for first article inspect
12、ion. Prior to beginning production, a sample shall be examined and tested as specified in 4.3 (see 6.3). 3.2 Material. Material shall be at the option of the contractor, but shall be so selected as to meet all corrosion-resisting (see 4.6.8) and performance requirements set forth herein. Reclaimed m
13、aterials shall be used to the maximum extent possible. 3.3 Design. Reflector shall be of uniform thickness, an. of such thickness as may be Irregularities in thickness due to roughness of necessary to produce a rigid construction. the back or convex surface are not considered detrimental. The concav
14、e surface, when finished. shall be a mathematically true paraboloid, designed for a point focus with central focal axis perpendicular to the plane of the paraboloid reflective surface. 3.3.1 The reflector shall withstand high-impact shock as specified in MIL-S-901 (see 3.4 Dimensions. Dimensions sha
15、ll conform to table I and figure 1. 4.6.11). TABLE I. Weight and dimensions.2 I Dimensions 1 Weight I Angle Nominal size i/ J- 2/ H- 3/ Minimum Maximum KU B- I Pounds Degrees Inches Inches Inches Pounds I l I l I I l I 1 -/Tolerance minus 1/2 percent. ZTolerance plus or minus 2 percent. 3Tolerance p
16、lus 10 percent, minus 20 percent. ZTolerance plus or minus 5 degrees. SSec figure i. 3.5 Finish. The concave reflective surface shall be optically polished or so finished as to prod- optically efficient first surface reflector. surface shall be judged principally by the efficiency as a reflector (se
17、e 3.6). structure between the edges when examined with a 10-power magnifier will be permitted. reflecting surface may be the same metal as the blank structure, or may be a separate com- position. The finished reflective surface shall, however, in either case, be inseparable from the metal blank and
18、shall, in effect, be amalgamated or alloyed with the blank. The reflective surface, in addition to being corrosion-resisting to an extent equal to the metal blank, shall resist tarnish or oxidation from the contact with gases and fumes encountered in shipboard service, among which are flue gas and t
19、he gas generated by the arc of the light source of a searchlight where the arc is used. The quality of the polished 3.5.1 Reflectors having scratches that are so fine that they show a smooth edge and no The 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from I
20、HS-,-,-MIL-R-272C 62 U 7777706 0076737 MIL- R- 2 72 8C 3.6 Reflectance. The specular reflectance of the reflective surface shall be not less than 63 percent for light from an incandescent tungsten lamp at a color temperature of 2848 kelvin (K) , and there shall be no appreciable selective absorption
21、 of colors of the white light spectrum between 4,000 and 7,000 Angstroms (A). (Narrow dips, not exceeding 10 percent of the average between these limits shall be allowed.) 3.7 Temperature. The metal from which the reflector is formed shall be of such characteristic as to have a low linear coefficien
22、t of expansion, and shall show no distortion which will alter the efficiency of a reflected beam of light under service conditions more than five percent within a temperature range of OC to 15OOC. Normal optical characteristics shall be taken as those found at 23OC. Construction shall be such as to
23、withstand any forces induced internally through specified temperatures without damage or permanent distortion of the reflector. surface, with makgers name or registered trademark, serial number, rated focal length and nominal size. Marking shall occupy an area not greater than 1-inch by 2-inches, an
24、d shall extend inward from the edge not more than 1 inch. Marking shall indicate the bottom of the reflector as determined by the beam pattern test specified in 4.6.3. The optical and geo- metrical center of the reflective surface shall be indicated by a spot not greater than 0.0625-inch diameter in
25、dented permanently in the reflector surface. The back of the reflector shall be marked in large figures with the actual weight of the reflector. “H“ shall be the minimum measured thickness through the base of the depression, and the tolerance specified shall be on this measurement. The roughness sha
26、ll not exceed a tolerance of plus 50 percent of the thickness “H“. which would affect the serviceability or performance. 3.8 Markin . Each reflector shall be plainly marked at the edge on the reflective 3.9 Measurements. When the metal blank is rough on the convex surface, the dimension 3.10 Workman
27、ship. Parts shall be free from blemishes, deformations, and other defects 4. QUALITY ASSURANCE PROVISIONS 4.1 Res onsibilit for ins ection. Unless othewise specified in the contract, the contractor isPresponsibfe-for th: performance of all inspection requirements as specified herein. Except as other
28、wise specified in the contract, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the Government. The Government reserves the right to perform any of the inspections set forth in the specificatio
29、n where such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. 4.2 Classification e inspection. classified as follows: The inspection requiremen ts specified herein are (a) First article inspection (see 4.3). (b) Quality conformance inspection (see
30、4.4). 4.3 First article ins ection. First article inspection shall consist of the examination and tests specifiedn4.6 fhroush 4.6.11. Production shall not be started until the con- tractor has- furnished evidence that the sample has passed the first article tests. 4.3.1 Test report. The contractor s
31、hall prepare a first article test report dance with the data ordering document included in the contract or order (see 6.2.2) 4.4 Samplinq for guality conformance inspection. 4.4.1 Lot. For purposes of sampling, a lot shall consist of all reflectors o same size offered for delivery at one time. n acc
32、or- the 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-R-272BC 62 m 9997Ob 00b736 T W MIL-R-2 7 2 8C 4.4.2 Sam lin for group A examination and tests. A random sample of reflectors shall be selected in tccoldance with table II from each lot an
33、d subjected to each of the group A examination and tests specified in 4,S.l. TABLE II. Sampling for group A examination and tests AQL (approx.) = 1.5 percent defective. Number of reflectors in lot 2 to 8 9 to 15 16 to 25 26 to 40 41 to 65 66 to 110 111 to 180 181 to 300 301 to 500 501 and over Numbe
34、r of reflectors in sample 6 8 10 13 17 22 28 35 45 55 Number of equipments nonconforming on any group A examination and tests Rejection number 1 1 1 2 2 L 3 4 4.4.3 Sampling for group B tests. A random sample of reflectors shall be selected in accordance with table III from each lot and subjected to
35、 each of the group B tests specified in 4.5.2. TABLE III. Sampling for group B tests. 1 Number of reflectors in lot 2 to 8 9 to 15 16 to 25 26 to 40 41 to 65 66 to 110 111 to 180 181 to 300 301 to 500 501 and over Number of equipments nonconforming on any group B tests Rejection Number of reflectors
36、 in sample 3 4 5 6 8 10 13 17 22 28 1 I 2 3 3 I 4.4.4 Sampling for group C tests. A sample number of reflectors shall be selected in accordance with table IV from the end of each months production and shall be subjected to the group C tests. TABLE IV. Sampling for group C testS. Number of reflectors
37、 Number of in 1 months reflectors for production group C tests 65 and under 66 to 300 301 to 800 1 2 3 4 Y. - , -_I_ P - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-R-2728C 62 = 999770b 0096739 1 MIL- R- 2 7 2 8C 4.5 Inspection. 4.5.1 Group A
38、 examination and tests. Each of the sample reflectors selected in accor- dance with table II shall be subjected to the examination and each of the tests specified below, and the results of the examination and each test compared with specification require- ments. Failure to conform to the specificati
39、on requirements for any group A examination and test shall be counted as a defect and the reflector shall be rejected. such nonconforming reflectors in any sample exceeds the acceptance number for that sample, the lot represented by the sample shall be rejected. If the number of Reference Group A ex
40、amination and tests - Screen pattern 4.6.1 Focal point 4.6.2 Beam pattern 4.6.3 Surface and dimensional examination 4.6.4 4.5.2 Group E tests. Each of the sample reflectors selected in accordance with table III shall be subjected to each of the tests specified below, and the results of each test com
41、pared with specification requirements. Failure to conform to the specification require- ments for any group B test shall be counted as a defect and the reflector shall be rejected. If the number of such nonconforming reflectors in any sample exceeds the acceptance number for that sample, the lot rep
42、resented by the sample shall be rejected. Group B tests Reference Color selection 4.6.5 Reflecting efficiency 4.6.6 4.5.3 Group C tests. Each of the sample reflectors selected in accordance with table IV shall be subjected to each of the tests specified below, and the results of each test compared w
43、ith specification requirements. In the event of any failure to conform to the specification requirements for any group C tests, the contractor shall correct the cause of failure on future production units and repair the deficiency in any reflectors not yet ship- ped. 4.6 Group C tests Reference Temp
44、erature changes 4.6.7 Staining 4.6.10 Shockproofness. 4.6.11 4.6.1 Screen pattern. The reflector shall be held at room temperature long enough to It shall be placed assure a senciblyunifonn temperature throughout the mass of the metal. in a jig with a diaphragm, the opening of which equals the nomin
45、al size shown in table I. The jig for the reflector shall be constructed so that the front edge of the reflector bears on eight shims equally spaced and the reflector shall be restrained by spring pressure buttons opposite the shims. The reflection of straight horizontal and vertical lines shall be
46、photographed. The line width shall be 3/8 inch, forming 2-1/4 inch squares or smaller on a flat surface of sufficient area to furnish a complete reflected pattern on the mirror. The distance between the vertex of the reflector and the screen shall be five times the focal length of the individual ref
47、lector. Under these conditions, no line shall depart along its entire length from a straight line, measured in a horizontal direction, by more than 3.2 percent for the 12-inch size and 4.3 percent for the 24-inch size of its horizontal distance from the center of the photograph. 4.6.2 Focal point. W
48、ith the reflector mounted as specified in 4.6.1 a light beam 1 inch in diameter, collimated to parallelism shall be projected on the reflector, parallel to the focal axis. The reflected beam from any and all parts of the reflective surface shall pass through the focal center of the reflector, conden
49、sed to a point at the focal center. (A composite photograph, with plate surface substantially parallel to the focal axis in any and all planes across the plane of the mirror surface shall show all of these points falling within a sphere not to exceed the diameter shown in table V.) This shall be the limits per- mitted for the spherical aberration of the reflector. The photographic plate shall be placed 5 Provided by IHSNot for ResaleNo reproduction or networking permitted
