Thread: Ejection charge
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Old 05-22-2015, 12:18 PM
Rich Holmes's Avatar
Rich Holmes Rich Holmes is offline
Born Late Rocketeer
Join Date: Jul 2013
Location: Syracuse, NY
Posts: 565

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:

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.

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.
Rich Holmes
Camillus, NY
Secretary / newsletter editor
Syracuse Rocket Club
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