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.\" Copyright © 2009 Keith Packard <keithp@keithp.com>
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.TH AO-EJECTION 1 "ao-ejection" ""
.SH NAME
ao-ejection \- Compute rocket ejection charges
.SH SYNOPSIS
.B "ao-ejection"
\fIdiameter(mm)\fP
\fIlength(mm)\fP
\fIforce(N)\fP
.SH DESCRIPTION
.I 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,
.I 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.
.SH EXAMPLE
.nf
	$ 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)
.fi
.P
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.
.SH AUTHOR
Keith Packard