airgun, air rifle

The test design

The "receiver". Steel cylinder threaded for the barrel and with internal electrode. About 80 cubic centimeters (4.9 cubic inch) volume including the charging tube.

The trigger. 420V, 420µ capacitor. The discharge is between the internal electrode and the burst foil, initiating the foil failure and the release of the air. The disk disintegrates probably in less than a millisecond.

The air gun design

There are a number of ways to initiate the rupture and to  fire the projectile. Shown below is the conceptual design where the burst is initiated by an electrical spark. In this design the projectile is loaded into the breach  and the bolt closed. The bolt  internal volume is pressurized by opening a valve contend to the compressed air bottle. Shown is a needle valve that allows the operator to adjust the pressure to the desired level, but a pressure regulated  valve operated by the bolt closing action can be used instead.

Here is a more detailed drawing.

The bolt volume as shown is probably too small and other details need to be finalized following the tests.


vacuum Valve1

In the case of a rupture disc attached to the projectile the trigger can as well be mechanical; a needle like firing pin, spring loaded or electromagnetically propelled. Here is an example


In the case of the integral flange (and as well with the attached one) a lower pressure rating flange or disk can simply burst or break off when the desired pressure is reached. In this case the air release mechanism can be the same as used in other air guns: a hammer released upon a valve. The advantages, are however the same  - the fast discharge of the full volume behind the projectile. It might as well reduce air consumption for same energy. Here is an example (hammer mechanism not shown) and below a photo of the torn flange, at about 3500 psi, of the brass projectile.

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