Cockpit canopy shattering using exploding wire techniques

The emergency shattering of the plastic cockpit canopy of a modern jet aircraft by means of exploding wires represents a potentially very attractive alternative to the more obvious use of explosives. This paper presents the main results from a preliminary investigation of the possibilities of this, in which wires were embedded in sheets of elasto-plastic material and exploded by the discharge of a suitable capacitor. The underlying physics involved is the interaction between the metal plasma and the surrounding media is discussed. During the investigation, the significance of the wire material and its dimensions, the thickness of the plastic containment, and the waveform and amplitude of the current pulse were all considered, with a view to optimizing the shattering effect produced by the exploding wire. Significant conclusions are drawn, concerning both the best optimum characteristics of the exploding wire and its arrangement within the sheet. The most important finding however is that the single most important factor for an optimized system is the peak electrical power input to the exploding wire rather than the dissipated Joule energy.