more EX work

[web/gag.com] / rockets / research / test4.mdwn

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+# Test 3 #
+
+More KNER grains.  Since we had 8 plausible grains from test 3 and
+want to burn 5 at a time, we decided to cast another 4 so we'd have
+enough for two motors plus a couple single-grain open air burn tests.
+
+Formula is a simple mix of 65% KNO3 and 35% Erythritol.  Both used in
+granular form directly from stock.  A 275 gram batch for 4 2.25" 
+38mm grains.
+
+Used our new casting bases, now with the mandrel holes drilled all the
+way through.
+
+## Process ##
+
+Same as Test 3B.
+
+## Results ##
+
+* Test 4, Grain 1, 61.50g net
+* Test 4, Grain 2, 62.38g net
+* Test 4, Grain 3, 60.18g net
+* Test 4, Grain 4, excessive visible inclusions, set aside
+
+## Observations ##
+
+Not surprisingly, results were essentially identical to test 3B.
+
+Seems pretty clear that the post-casting process of having to cut off
+the "skin" at the top of the grain and impart a concave shape is 
+losing .. means we'll never get uniform grain masses.  REally need
+to figure out how to do this better.
+
+The last grain was "poured" by spooning in material that seemed 
+to be clumping a bit, and we probably didn't tap it down enough.