From: Bdale Garbee Date: Thu, 1 Jun 2017 06:14:43 +0000 (-0600) Subject: another batch X-Git-Url: https://git.gag.com/?p=web%2Fgag.com;a=commitdiff_plain;h=d905beaa8df6e988894de9a326687e567a7def48;hp=4958d33687bbd22dbcef81293db00ab749b12536 another batch --- diff --git a/rockets/research/2017-batch-03.mdwn b/rockets/research/2017-batch-03.mdwn index 200bd2e..096f6bf 100755 --- 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. diff --git a/rockets/research/2017-batch-04.mdwn b/rockets/research/2017-batch-04.mdwn new file mode 100755 index 0000000..a0e376f --- /dev/null +++ b/rockets/research/2017-batch-04.mdwn @@ -0,0 +1,40 @@ +# Batch 2017-batch-04 # + +4 grains of 29mm using sorbitol, intended to be a reloads for the +second-longest GMA 29mm snap-ring case. Grain length 45mm with 1mm spacing +per grain, so we'll make the casting tubes 46mm long. Delrin coring rods of +5/16" diameter. + +Formula for a batch size of 135g: + +* 65% KNO3, 87.75g, taken from the big bucket +* 35% Sorbitol, 47.25g +* 1% RIO, 1.35g +* PolyStep B1, 2 drops + +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 casting tube mass 1.25g. + +* Grain 1, ?g gross, ?g net +* Grain 2, ?g gross, ?g net +* Grain 3, ?g gross, ?g net +* Grain 4, ?g gross, ?g net + +Total of ?g 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. +