KNO3/Sorbitol (65/35)w Test Stand Results
KNSO 65/35
Burn Time = 1.78 sec
Propellant wt. = 115.2g = 0.254 lb
Nozzle throat = 0.02558 in2
Max. Thrust = 28 lbs
Max Chamber Pressure = 730 lbs
Ave. Thrust = 18.3 lbs = 81.4 N
Total Impulse = 145 N sec = 32.6 lb sec
Isp = 128
Motor Class = G81
KNSO w/ carriage bolt nozzle
and o-ring grain face seporator
Burn Time = 1.6 sec
Propellant Wt. = 115.0g = 0.253 lb
Nozzle Throat = 0.0230 in2
Max. Thrust = 33.5 lbs
Max. Chamber Pressure = 1165 psi
Ave Thrust = 19.7 lbs = 87.8 N
Total Impulse = 140.5 N sec = 31.5 lb sec
Isp = 125
Motor Class = G88
Note: Nozzle coef. Estimated at 1.25
Isp of 128 at 730 psi chamber pressure indicates excellent agreement with Richard Nakka's SRM spread sheet calculations for this size motor. Crude carriage bolt nozzle works well but needs to be crafted better. O-ring (# 025) grain face separator worked well. Some "plateau" thrust curve shape has appeared.
