another batch

[web/gag.com] / rockets / research / 2017-batch-03.mdwn

diff --git a/rockets/research/2017-batch-03.mdwn b/rockets/research/2017-batch-03.mdwn
index 200bd2ec4c683e8dce71c8811ab9d5cf57507caf..096f6bfcb838d8eb7725603075b20d63ab00509f 100755 (executable)
--- a/rockets/research/2017-batch-03.mdwn
+++ b/rockets/research/2017-batch-03.mdwn
@@ -25,13 +25,27 @@ Simulation says:
 
 Average casting tube mass 1.13g.
 
-* Grain 1, ?g gross, ?g net
-* Grain 2, ?g gross, ?g net
-* Grain 3, ?g gross, ?g net
-* Grain 4, ?g gross, ?g net
-* Grain 5, ?g gross, ?g net
-* Grain 6, ?g gross, ?g net
-
-With a 10.00" liner, 14/64" nozzle throat, buna-n o-rings, simulation says
-this makes a 37% H-156, 208 Ns, with about a 1.2 sec burn.
+Coring rods extracted easily, new hickory tube caps came off without too
+much effort.  Slight cleanup at the top of each grain since propellant always
+seems to fillet around the coring rod.  Grain average fill levels looks pretty
+good, with on the order of 1mm space at the top as expected.
+
+* Grain 1, 26.57g gross, 25.44g net
+* Grain 2, 26.63g gross, 25.50g net
+* Grain 3, 26.65g gross, 25.52g net
+* Grain 4, 26.01g gross, 24.88g net (visible undefill)
+* Grain 5, 26.51g gross, 25.38g net
+* Grain 6, 26.75g gross, 25.62g net
+
+Total of 152.34g propellant, vs 159g simulated.
+
+Note that after casting grains and cutting a liner to 10.0", I realized I'd
+mis-measured the case, and we actually had 10.4" of liner/propellant length
+to play with!  Fix this for the next time we make grains...  For now, we'll
+fly these grains in a correct length liner and live with the fact that we 
+could have put another 0.4" of propellant in the case!  That'd be another
+13 Ns according to the simulator...
+
+With a 10.40" liner, 14/64" nozzle throat, buna-n o-rings, simulation says
+this reload will be a 37% H-155, 208 Ns, with about a 1.2 sec burn.