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   1 # Batch 2017-batch-04 #
   2
   3 4 grains of 29mm using sorbitol, intended to be a reloads for the
   4 second-longest GMA 29mm snap-ring case.  Grain length 45mm with 1mm spacing
   5 per grain, so we'll make the casting tubes 46mm long.  Delrin coring rods of
   6 5/16" diameter.
   7
   8 Formula for a batch size of 135g:
   9
  10 * 65% KNO3, 87.75g, taken from the big bucket
  11 * 35% Sorbitol, 47.25g
  12 * 1% RIO, 1.35g
  13 * PolyStep B1, 2 drops
  14
  15 Presto Multicooker operated at 275F indicated.
  16
  17 These grains were cast on 1 June 2017.
  18
  19 Simulation says:
  20
  21 <p>
  22 <!--Begin motor 29mm 4-grain Sorbitol #14 HTML export from MotorSim-->
  23 <table class='motor' style='text-align: left; border: 1px solid black'><tr><th colspan='6' class='title'>29mm 4-grain Sorbitol #14</th></tr><tr class='summary'><th>Rating:</th><td>99% G-180</td><th>Max Pressure:</th><td>6.47 MPa (939 psi)</td></tr><tr class='summary'><th>Total Impulse:</th><td>159 Ns</td><th>Specific Impulse:</th><td>133 s</td></tr><tr class='summary'><th>Max Thrust:</th><td>228 N</td><th>Volume Loading:</th><td>69%</td></tr><tr class='summary'><th>Average Thrust:</th><td>180 N</td><th>Fuel Mass:</th><td>122 g</td></tr><tr><td colspan='4' class='thrust'><img src='http://chart.apis.google.com/chart?chxt=x,x,y,y,r,r&chs=400x200&cht=lxy&chco=3072F3&chds=0,0.89,0,227.96&chxr=0,0,0.89|2,0,227.96|4,0,51.25&chd=t:0,0,0,0,0,0,0,0,0,0,0.02,0.04,0.07,0.12,0.19,0.29,0.44,0.52,0.65,0.78,0.8,0.88,0.89|0,10.15,19.94,29.95,39.31,47.83,55.66,62.85,69.45,75.47,134.47,149.05,157.98,170.21,186.92,207.36,225.35,227.96,219.77,198.86,37.95,0.12,0.06&chxl=1:|s|3:|N|5:|lbf&chxp=1,50|3,50|5,50' width='400' height='200' alt='null' /></td></tr></table>
  24 <!--End motor 29mm 4-grain Sorbitol #14-->
  25 </p>
  26
  27 ## Results ##
  28
  29 Average casting tube mass 1.25g.
  30
  31 * Grain 1, ?g gross, ?g net
  32 * Grain 2, ?g gross, ?g net
  33 * Grain 3, ?g gross, ?g net
  34 * Grain 4, ?g gross, ?g net
  35
  36 Total of ?g propellant, vs 122g simulated.
  37
  38 With a 7.40" liner, 14/64" nozzle throat, buna-n o-rings, simulation says
  39 this reload will be a 99% G-180, 159 Ns, with about an 0.8 sec burn.
  40