Downloaded from https://www.everyspec.com MIL-STD-81OD’” 19 JUIY 1983 test a. Determine from the test plan the test item configuration and other parameters. b. Determine from the test plan”the operational requirements. c. Clean all traces of oil and grease from ~alloutside surfaces of the item which are not oilv in the normal Oneratinc’mode. Even thin films of ..- oil or grease will preve’ntice from adhering to the test item and change the test results. test d. To facilitate measurement of ice thickness, copper bars or tubes 2.5 cm in diameter and at least 60’cm in length shall be mounted in a horizontal poaiticn in places where they will receive the same general rainfall as th”etest item.
Other thickness measurement techniques may be used if they can be shown to accurately measure and indicate the ice thickness. NOTE: Structures with large height variations,.such as antenna “masts,should have teat bars placed at the different heights, since artificially produced freezing accretion rates tend to depend upon the distance between the test item and the spray ‘frame. Water used in’the epray system should be cooled to between 0° and 30c (3A. When chilled water cannot be obtained, unchilled water will produce acceptable results. The main factcr affected by the warmer water temperature is the ice buildup rate. 11-2’.2 Pretest s&anfLardambLs.@ chec@u.L.
All test items require a pretest standard ambient checkout to provide baseline data. Conduct the checkout as follows: Step 1. Insert the test item into the chamber and stabilize”the test item at standard ambient conditions per General Requirements, 4.U. ‘Step2. Conduct a ccmplete visual examination of the teet ‘item. Step 3. Prepare 4.5.2, and required test the teat item in accordance with General Requirements, item configuration (I-3.2a). Step 4. Ccnduct approved teat plan. an operational checkcut in accordance with the any i“ntegraldeicing equipment, such as defroster, wipers, etc., tc assure satiafaotory operation. Step 5. Operate Step 6.
Record the results fcr compliance with the requirements dccument(s). a> Step 7. If the test item ‘operatessatisfactorily, proceed to Procedure 1 (11-3). If not,resolve the prcblems and restart at step 1 above. Repeat steps 1 through 6 until the test item operates acceptably. II-3 URE I - Gla~. The following test procedure providea the basia for collecting the necessary information concerning the test item in a freezing. rain environment. 521.0,-7 METHOD 521.0 19 July 1983