# Batch 2017-batch-04 # 4 grains of 29mm intended to be a reloads for the second-longest GMA 29mm snap-ring case, *and* 6 grains of 54mm intended to be 2 3-grain reloads, all in one sorbitol melt. 29mm grain length 45mm with 1mm spacing per grain, so we'll make the casting tubes 46mm long. Delrin coring rods of 5/16" diameter. 54mm grain length 76mm with 2mm spacing per grain, so we'll make the casting tubes 78mm long. Delrin coring rods of 1/2" diameter. Formula for a batch size of 1kg: * 65% KNO3, 650g, taken from the big bucket * 35% Sorbitol, 350g * 1% RIO, 10.0g * PolyStep B1, 15 drops With left-overs from batch-01, this was enough for all but two of the 29mm grains. We added enough materials for another 100g and were able to finish up with a bit left over. Presto Multicooker operated at 275F indicated. These grains were cast on 1 June 2017. Simulation says:

29mm 4-grain Sorbitol #14
Rating:99% G-180Max Pressure:6.47 MPa (939 psi)
Total Impulse:159 NsSpecific Impulse:133 s
Max Thrust:228 NVolume Loading:69%
Average Thrust:180 NFuel Mass:122 g
null

## Results ## Average 29mm casting tube mass 1.25g. 29mm grains * Grain 1, 29.3g gross, 28.05g net * Grain 2, 29.1g gross, 27.85g net * Grain 3, 28.9g gross, 27.65g net * Grain 4, 28.5g gross, 27.25g net Total of 110.8g propellant, vs 122g simulated. With a 7.40" liner, 14/64" nozzle throat, buna-n o-rings, simulation says this reload will be a 99% G-180, 159 Ns, with about an 0.8 sec burn. 54mm grains * Grain 5, 184.6g gross, ?g net * Grain 6, 183.3g gross, ?g net * Grain 7, 186.2g gross, ?g net * Grain 8, 182.6g gross, ?g net (canted - casting tube tilted at pour time) * Grain 9, 184.0g gross, ?g net * Grain 10, 180.5g gross, ?g net