AO-EJECTION(1) General Commands Manual AO-EJECTION(1)
NAME
ao-ejection - Compute rocket ejection charges
SYNOPSIS
ao-ejection diameter(mm) length(mm) force(N)
DESCRIPTION
ao-ejection computes the amount of black powder necessary to generate the desired force to
separate sections of a rocket airframe. It assumes a cylindrical airspace covered by a
circular cap. With that and the force to be exerted on the cap, ao-ejection can compute
the necessary pressure rise within the chamber, the volume of gas necessary and finally
the mass of BP to generate the gas.
EXAMPLE
$ ao-ejection 54 300 500
Input parameters:
Diameter: 54.0 (mm) 2.126 (in)
Length: 300.0 (mm) 11.811 (in)
Force: 500.0 (N) 112.404 (lb)
Chamber values:
Area: 2290 (mm²) 3.550 (in²)
Volume: 687066 (mm³) 41.927 (in³)
Pressure: 31.66 (lb/in²) 0.21832 (N/mm²)
Results:
FFFF powder: 0.685 (g)
This demonstrates that a 54mm airframe with a 300mm chamber requires .685g of FFFF BP to
generate 112lb of force on the end of the chamber. This is usually sufficient to sever two
2x56 nylon screws.
ao-ejection AO-EJECTION(1)