- Chicken gun
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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 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, 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.
Uses
The chicken gun was first used in the mid 1950s at de Havilland Aircraft, Hatfield, UK. It was fired with a correct count down from a 'pill box' 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.
Another early use of a chicken gun was by the Royal Aeronautical (Aircraft) Establishment (RAE) in Farnborough, UK in 1961.[1]
The United States Air Force commissioned the AEDC Ballistic Range S-3 to test airplane canopies. The gun was later used to test other aircraft parts such as the leading edges of wings.
Pop culture
There is a longstanding urban legend about the gun being loaned to some other agency, who fired frozen chickens instead of thawed chickens.[2]
On MythBusters, a chicken gun was used in various experiments. The experiments conducted used both frozen and thawed chickens to test the cockpit window of a private aircraft.
The 1970s test of the British High Speed Train windscreens used the Farnborough chicken gun and expertise, not NASA based expertise, busting the Mythbusters myth relating to NASA telling the British "defrost the chickens first".
The CBC comedy series Royal Canadian Air Farce used to regularly use a chicken cannon to shoot rubber chickens and other projectiles at pictures of newsmakers.
See also
- Chicken powered nuclear bomb
- Spud gun
References
- ^ "It's a Bird, It's a Plane... It's a Bird Striking a Plane". National Research Council of Canada. 2007-01. http://www.nrc-cnrc.gc.ca/eng/news/nrc/2007/01/07/bird-plane.html. Retrieved 2009-09-14.
- ^ "Chicken Cannon". Snopes. http://www.snopes.com/science/cannon.htm. Retrieved 2008-06-16.
External references
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