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