more info about our second batch of igniters

diff --git a/rockets/research/2017-batch-05.mdwn b/rockets/research/2017-batch-05.mdwn
index c610803b541afda56723218ccef5cf15a4b3e054..c0e50699ece0cc318db4aee7ac21c95f352be52f 100755 (executable)
--- a/rockets/research/2017-batch-05.mdwn
+++ b/rockets/research/2017-batch-05.mdwn
@@ -49,5 +49,32 @@ Mg particle size.  It could be that we need to go back to using the finer Mg
 powder when making smaller igniters, and reserve the "chunky" stuff for large
 ones?
 
 powder when making smaller igniters, and reserve the "chunky" stuff for large
 ones?
 

+At NCR's Mile High Mayhem 2017, we used a 12V battery to test one of the
+larger igniters, and the bridge wire burned and burned a small amount of
+the pyrogen, but then it fizzled out without doing anything really 
+useful.  That made us skittish about trying them on the rail, and we used
+up the rest of our commercial igniters and bought a couple more that weekend 
+instead. 
+
+Once home, we tested the rest of the batch.  About 2/3 ignited and burned ok,
+but fairly slowly and not very evenly.  About 1/3 did what the one we tested
+at the launch did, burning slightly then fizzling out. 
+
+The burn time was at least 5 seconds on each igniter, with about 1" length
+of pyrogen.  That really seems too slow.  1-2 seconds would be better?
+

 ## Observations ##
 
 ## Observations ##
 

+We think the larger magnesium particles, which make nice "spitty" igniters
+when the igniter actually ignites, would probably help start big sugar motor
+grains, but we really can't call this batch successful.  Our theory is that
+the failed igniters hit a big chunk of magnesium that they didn't have enough
+energy to ignite before enough of the epoxy-based pyrogen was burning to 
+sustain combustion.
+
+Robert noted that large magnesium particles also seem to raise the risk of
+starting a grass fire around the launch pad if the motor does light and the
+rocket takes off before the igniter completely combusts.
+
+Next, we'll try going back to the powdered magnesium with bridge wires.
+