# Test 5 #

Trying again using KNSO with our new casting bases.  We also have a real
eye-dropper now for measuring the surfactant.  4 38mm grains of 
1.875" length, using formula of

* 65% KNO3
* 35% Sorbitol
* 1% red iron oxide
* 3 drops Polystep-B1 

## Process ##

The multi-cooker was preheated to about 250F with the lid on.  Temp was
increased during melting to 275F indicated.

Individual casting tubes with fill marks, coring rod inserted after pour,
cap installed and grain tapped down.

## Results ##

* Grain 1, 51.56g net
* Grain 2, 52.80g net
* Grain 3, 52.30g net
* Grain 4, 51.23g net

## Observations ##

Pour went really smoothly.  One grain looked "perfect" with the propellant
settled evenly and a couple mm of open gap at the top of the casting 
tube.  We think this one may have been slightly under-filled compared to
the others, all of which had some evidence of propellant sticking to the 
cap and leaving an uneven top surface.  This resulted in some quick trim
work with a knife, ergo final grain masses not matching all that well.

## Flight Test ##

These four grains were assembled in an AT 38/480 case with a random AT
delay grain from the pile of left-overs, and flown in Robert's Madcow
Little John at Tripoli Colorado Spring Fling 2015.  We used a Slim Gem
igniter from Quickburst.  Great flight!  The motor seemed to come up to
pressure quickly, and burned brilliantly.

The original simulator data:
<pre>
Propellant             : propellants/knsb.xml
Nozzle diameter        : 0.739 cm (0.291") (19/64")
Number of grains       : 4
L/D ratio              : 5.550
Port-to-throat ratio   : 2.952
Mass Flux              : 1.374 lbs/inch^2
Mach number            : 0.697
Propellant length      : 18.440 cm (7.260")
Web Thickness (max)    : 1.026 cm (0.404")
Burn rate              : 0.773 cm/s (0.304"/s) (a=7.852mm/s; n=-0.013)

Total propellant weight: 216.00 g (7.619 oz/0.476 lbs)
Average grain weight   : 54.00 g (1.905 oz)
Theoretical density    : 1.841 g/cm3 (0.067 lb/in3)
Actual density         : 1.582 g/cm3 (0.057 lb/in3)
Density ratio          : 85.953%
Specific impulse (Isp) : 106.342 s (estimated)
Initial Thrust         : 169.37 N (38.08 lbs)
Peak Thrust            : 182.21 N (40.96 lbs) at 34.00% (0.45 s)

Kn Ini : 309.48 (488.04 psi)
Kn Max : 330.39 (520.59 psi)
Kn Fin : 248.87 (393.56 psi)
Kn Avg : 309.70 (488.40 psi)

Total Impulse  : 225.104 Ns (40.69% H)
Burn Duration  : 1.328 s
Average Thrust : 169.555 N

Motor          : H170
</pre>