X-Git-Url: https://git.gag.com/?p=web%2Fgag.com;a=blobdiff_plain;f=rockets%2Fresearch%2Ftest5.mdwn;h=22979dfd99d6416fd8165c8402f107f5c7025983;hp=ca27d89bdbbbf68c109a0d20e137ee3e6c5c57a7;hb=557f233a4474d20b87760499970ce618588d680b;hpb=2f24dee781b78df3c6a71b374c182cfa2fc2f87d

diff --git a/rockets/research/test5.mdwn b/rockets/research/test5.mdwn
index ca27d89..22979df 100755
--- a/rockets/research/test5.mdwn
+++ b/rockets/research/test5.mdwn
@@ -2,12 +2,12 @@
 
 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
+1.875" length, 250 gram batch using formula of
 
-* 65% KNO3
-* 35% Sorbitol
-* 1% red iron oxide
-* 3 drops Polystep-B1 
+* 65% KNO3, 162.5g
+* 35% Sorbitol, 87.5g
+* 1% red iron oxide, 2.5g, added after melt
+* 3 drops Polystep-B1, added before pour
 
 ## Process ##
 
@@ -24,24 +24,8 @@ cap installed and grain tapped down.
 * 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.
+## Simulation ##
 
-The original simulator data:
 <pre>
 Propellant             : propellants/knsb.xml
 Nozzle diameter        : 0.739 cm (0.291") (19/64")
@@ -74,3 +58,47 @@ Average Thrust : 169.555 N
 
 Motor          : H170
 </pre>
+
+![simulation data](test5-sim.png)
+
+## 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](http://www.quickburst.net/slim_gem_igniter.htm)
+igniter from [Quickburst](http://www.quickburst.net/).  Great 
+flight!  The motor seemed to come up to pressure quickly, and burned 
+brilliantly.
+
+The airframe weighed 1200 grams ready to launch, and 982 grams post-flight,
+of which 1g or so was BP in the ejection charge, and a few grams were in 
+the Aerotech delay grain.
+
+Post-flight measurement of the phenolic nozzle showed approximately an 
+0.330" throat, which clearly indicates some erosion from the 0.291" starting
+point.
+
+![flight acceleration data](test5-altosui.png)
+
+## Observations ##
+
+Pour went really smoothly.  Easier than previous batches, perhaps due to
+a bit more surfactant, perhaps just getting better, perhaps due to putting
+the mandrels in post-pour.  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.
+
+We were totally stoked that the burn time matched simulation (once we factor
+in a tenth of a second or two before the motor came up to pressure!).  We
+were also pleased that the max pressure was "right on time" at about 0.4
+seconds after coming up to pressure.  The regressive curve seems a bit
+exagerated in the flight accel data, which seems completely explainable by
+the nozzle throat erosion causing pressure to faill during that period.
+
+The airframe saw an average of 12 G acceleration on the way to Mach 0.6 and
+2838 feet above the laucnh site which is at 8800 feet MSL.  Perfect 
+recovery!  Pretty cool for our first real flight test!