Archive for January, 2016

FAR January 2016

I had planned to launch a 4″ rocket on a 3″ motor with 34″ of propellant, however the clouds were hovering around 18,000′ (well below the expected altitude) so I opted to static fire the motor hooked up to my data acquisition system. Motor burned well but longer than expected due to the phenolic nozzle throat eroding another .080″ during the burn. Max Pc was 730 psi and assuming Cf= 1.4 the total impulse was roughly 7,500 N-s. A graphite insert should keep the Pc up and boost the total impulse closer to 8,000N-s.

Static Burn

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