document EasyMotor test flight at Hudson Ranch

[web/gag.com] / rockets / research / 2020-test-4.mdwn

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+# Test 2020-4 #
+
+3 grain 54mm Purple Pig motor with a Terry Lee dipped igniter in 3-inch test
+mule flown on 17 October 2020 at the first-ever Tripoli Southern Colorado 
+launch at Hudson Ranch.  In fact, this was the first-ever research flight
+flown at this location!
+
+Used 3-grain 54mm Kosdon case, Loki-style nozzle with an 0.390" throat, 
+forward closure had a 1600psi pressure sensor and EasyMotor protototype 
+mounted with an A23 alkaline battery, and shooter wire as a "twist and tape"
+power switch.
+
+The motor used three loose grains with 0.625" cores, thin o-rings as spacers, 
+and a greased phenolic liner. 
+
+[Burnsim](2020-test-4-burnsim.pdf) called this a 31% J-355, 838 Ns with 
+about 2.36 sec burn time, and max pressure on a relatively flat burn of 
+559.3s psi.
+
+## Results ##
+
+Perfect flight, no damage, easy recovery.
+
+This was the first flight during which we successfully captured in-flight
+chamber pressure data with an EasyMotor prototype board.  A quick look at
+the data shows about 540 psi maximum, which is pretty close to the Burnsim
+prediction!  Some software work remains to convert the data capture into 
+actual motor performance data.  The EasyMotor data is logged in file
+2020-10-17-serial-7085-flight-0007.eeprom
+
+The airframe's launch mass was about 4420 grams.  The TeleMega on board 
+reported 9.54 G max and 6.29 G average acceleration to a max speed of 
+Mach 0.5 and a GPS apogee of 4669 feet.  The TeleMega data is logged in file
+2020-10-17-serial-6667-flight-0003.eeprom
+