add write-up of my first APCP test stand burn

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+# Test 2019-1 #
+
+This was my first test burn of an APCP motor using grains I cast myself.
+
+2 grain 54mm Everclear motor with #24 nozzle, using one of Terry's igniters,
+on the test stand in Hartsel at the first Tripoli Colorado launch of the year.
+The grains used were from teh 7 January 2019 batch:
+
+* Grain 1, 2.990" long, 163.7g gross, 5.50g casting tube, 158.20g net propellant
+* Grain 2, 2.992" long, 163.8g gross, 5.51g casting tube, 158.29g net propellant
+
+Used abou 7.5" of ARR liner, the grains were definitely "loose" in the 
+case.  The buna-n o-rings were lightly lubed, but the liner was put in without
+any grease.
+
+Tested without simulation, using the "standard" EX nozzle for a 2-grain 54mm
+case according to the Loki Research data table.  Tapped forward closure for
+pressure sensor, buna-n o-rings.
+
+Simulation says  ...
+
+## Results ##
+
+Test stand data logged as sn 3634, flight 16.  Note that the sensor calibration
+was re-done after the weekend, at which time we observed that the load cell
+wasn't really linear unless another 10 lb or so were added to the arm vs what
+we were running with.  So all thrust values from this and all prior test
+sessions are suspect.  Chamber pressure numbers are with fairly high confidence
+but not great resolution due to reduced output on the 2500psi sensor used.
+
+No measurable erosion of nozzle throat.  The liner was pretty well cooked, but
+no signs of burn-through or case damage of any kind.  The o-rings on each end
+looked relatively undamaged, but were of course discarded after use.
+
+This motor burned very cleanly.  Almost no visible flame, just some yellow-ish
+flashes near the end of the exhaust plume.  The 2.8 second burn was slightly 
+progressive, starting around 117 N, peaking at 212 N.  Peak chamber pressure
+was around 740psi.
+
+These results make me think it would be "safe" to fly more grains  as long as
+I stick with the Loki recommended EX nozzle throat for each grain count.