---
name: "ao-ejection"
section: "1"
platform: "linux"
package: "altos"
version: "1.9.21-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/ao-ejection"
---

# ao-ejection(1)

Compute rocket ejection charges

## 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.

## AUTHOR

Keith Packard