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[web/gag.com] / rockets / research / test5.mdwn

diff --git a/rockets/research/test5.mdwn b/rockets/research/test5.mdwn
index 1c82653f01fe13213c13ba70bdd4a5c18faa0409..23f80a1ce2cf9c9f5b539fd5786ea198a1d65595 100755 (executable)
--- a/rockets/research/test5.mdwn
+++ b/rockets/research/test5.mdwn
@@ -69,6 +69,14 @@ 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.
 
 igniter from Quickburst.  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 ##
 ![flight acceleration data](test5-altosui.png)
 
 ## Observations ##


@@ -80,3 +88,11 @@ 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.
 
 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.
+
+Pretty cool for our first real flight test!