05-22-2015, 12:18 PM
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Born Late Rocketeer
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Join Date: Jul 2013
Location: Syracuse, NY
Posts: 568
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Yes, ejection pressures vary a lot. But you can in principle look at averages and extremes over many motors.
The article “Ejection Pressure Measurements” by Janice and Harold Larson in the Jan/Feb 2007 Sport Rocketry includes the following Editor’s note:
Quote:
The post by “doctor_dynasoar” quotes Ed Brown at Estes regarding the ejection charge sizes for Estes motors: 13 mm motors, 0.4 grain; 18mm motors, 0.6 grain; 24mm motors, 1.0 grain.
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HOWEVER, my understanding is that the units here are wrong: should be GRAMS not GRAINS.
In any case, 24mm ejection charges are nominally almost twice as large as 18mm ones.
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