From a14ba311ab903887ab759c867464c5cea1a0a608 Mon Sep 17 00:00:00 2001 From: Bdale Garbee Date: Sun, 28 Jun 2015 22:16:24 -0600 Subject: [PATCH] more text --- rockets/research/test5.mdwn | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/rockets/research/test5.mdwn b/rockets/research/test5.mdwn index 1c82653..23f80a1 100755 --- 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. +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 ## @@ -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. +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! -- 2.30.2