This test will use two grains cast using the X2-18 propellant formula. The formula is: KNO3 63.45%/ Sugar 31.24%/ Mg 2.93%/ Extract 2.38%. Test motor will be the T-2.
Grain Length:2 @ 5.25"
Grain Diameter: 1.52"
Grain Weight: 230.5 grams each [(461 grams) 1.0143 lb.] Propellant only: 453 grams (.9967 lb)
Core Diameter: .5"
Throat Diameter: .42"
Inhibitor: 2 wraps 20 lb. copy paper
Burning area: Core and Ends
Starting Kn: 164
Ending Kn: 289
Grain Density (as cast): .0615 lb/cubic inch
Inhibitor Weight: 4 grams each, 8 grams total
Burn Time: 1.25 Seconds
Total Impulse: 132.478 lb seconds
Isp: 132.9
Maximum Thrust: 306.67 Pounds
Here is the thrust/time curve for the test.
As you can see from the graph, the burn was very nice, and very flat at peak thrust. I think the propylene glycol will be a nice additive to aid casting grains. It doesn't seem to have a large affect on Isp or burn time.