Chicken gun

A chicken gun is a large-diameter, compressed-air cannon used to test the strength of aircraft windshields and the safety of jet engines. A common danger to aircraft is that they collide with birds in flight. Most parts of an aircraft are strong enough to resist such a bird strike. Jet engines may sustain serious damage, however, and cockpit windows are necessarily made of transparent, thin materials and are a vulnerable spot.

The chicken gun is designed to simulate high-speed bird impacts. It is named after its unusual ammunition: a whole, dead, standard-sized chicken, as would be used for cooking. This has been found to accurately simulate a large, live bird in flight. The test target is fixed in place on a test stand, and the cannon is used to fire the chicken into the engine, windshield, or other test structure.

The gun is driven from a compressed-air tank. In the 1970s, Goodyear Aerospace in Litchfield Park, Arizona, United States, used a gun with a ceramic diaphragm to seal the compressed air in the tank from the gun's barrel. To fire the gun, a solenoid-driven needle struck and ruptured the diaphragm, allowing the compressed air to drive the chicken (in its container—a cylindrical cardboard ice cream carton) down the barrel. At the muzzle, a metal ring stopped the carton, but allowed the chicken to pass through. Slow-motion cameras photographed the chicken impacting a fighter windshield in the test bed. These cameras were started in time with the breaking of the diaphragm.

The chicken gun was first used in the mid-1950s at de Havilland Aircraft, Hatfield, United Kingdom. It was fired with a correct countdown from a pillbox housed in the woods at de Havilland's. The chickens were killed shortly before firing and obtained from a local farm also at the edge of the woods. After firing, the jet engines were taken away and examined for damage. High-speed cameras recorded the complete action.

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