Initial Commit - Copy from Altus Metrum AltOS

ao-utils/Makefile.am

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+dist_bin_SCRIPTS = ao-ejection
+
+man_MANS = ao-ejection.1

ao-utils/ao-ejection

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+#!/usr/bin/env nickle
+
+void main () {
+	real R = 22.16 * 12;	/* in lbf / lbm (gas constant for ffff powder */
+	real T = 3307; /* combustion temperature for BP */
+	real d_mm; /* diameter(mm) */
+	real l_mm; /* length(mm) */
+	real f_N;   /* force(N) */
+	real f_lb;
+	real A_mm²; /* area of bulkhead (mm²) */
+	real A_in²;
+	real V_mm³; /* free volume (mm³) */
+	real V_in³;
+	real M_lb;  /* mass of BP in lb */
+	real M_g;
+	real P_Nmm²;	/* pressure (N/mm²) */
+	real P_lbin²; /* pressure (psi) */
+
+	if (dim(argv) != 4) {
+		File::fprintf(stderr,
+			      "usage: %s diameter(mm) length(mm) force(N)\n",
+			      argv[0]);
+		exit(1);
+	}
+
+	d_mm = string_to_real(argv[1]);
+	l_mm = string_to_real(argv[2]);
+	f_N = string_to_real(argv[3]);
+	f_lb = f_N * 0.22480894;
+
+	A_mm² = pi * (d_mm/2) ** 2;
+	V_mm³ = A_mm² * l_mm;
+
+	A_in² = A_mm² / (25.4**2);
+	V_in³ = V_mm³ / (25.4**3);
+
+	P_Nmm² = f_N / A_mm²;
+
+	P_lbin² = P_Nmm² * 0.22480894 * (25.4 ** 2);
+
+	M_lb = (P_lbin² * V_in³) / (R * T);
+	M_g = M_lb * 453.59237;
+
+	printf ("Input parameters:\n");
+	printf ("    Diameter: %.1g (mm) %.3g (in)\n",
+		d_mm, d_mm / 25.4);
+	printf ("    Length: %.1g (mm) %.3g (in)\n",
+		l_mm, l_mm / 25.4);
+	printf ("    Force: %.1g (N) %.3g (lb)\n",
+		f_N, f_lb);
+
+	printf ("Chamber values:\n");
+	printf ("    Area: %.0f (mm²) %.3g (in²)\n",
+		A_mm², A_in²);
+	printf ("    Volume: %.0f (mm³) %.3g (in³)\n",
+		V_mm³, V_in³);
+	printf ("    Pressure: %.2g (lb/in²) %.5g (N/mm²)\n",
+		P_lbin², P_Nmm²);
+
+	printf ("Results:\n");
+	printf ("    FFFF powder: %.3g (g)\n", M_g);
+}
+
+main();

ao-utils/ao-ejection.1

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+.\"
+.\" Copyright © 2009 Keith Packard <keithp@keithp.com>
+.\"
+.\" This program is free software; you can redistribute it and/or modify
+.\" it under the terms of the GNU General Public License as published by
+.\" the Free Software Foundation; either version 2 of the License, or
+.\" (at your option) any later version.
+.\"
+.\" This program is distributed in the hope that it will be useful, but
+.\" WITHOUT ANY WARRANTY; without even the implied warranty of
+.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+.\" General Public License for more details.
+.\"
+.\" You should have received a copy of the GNU General Public License along
+.\" with this program; if not, write to the Free Software Foundation, Inc.,
+.\" 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+.\"
+.\"
+.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