The USAF "chicken gun" is located at the Arnold Engineering Development Center on Arnold Air Force Base in Tellahoma, Tennessee. It is one of several special guns developed at the AEDC VonKarman Facilities to study high velocity impact phenomenon.
Arnold's a great place to do research and I spent 13 weeks there in 1979 using G-range to study hyperverlocity impact phenomon. I also did a few tests on S-1 which is in the same building as the "chicken gun" which is is formally known as S-3 The Bird Impact Facility. It can launch a 4 pound chicken or similar projectile at speed to Mach 1.4 to test aircraft component impact strength. The chickens are purchase from a local farmer, asphixiated, stored frozen and thawed to 70 F before the test.
You don't want to fire a frozen bird because it comes out of the gun about 10% faster than the thawed bird, and with 21% higher kinetic energy than anticipated, will go through the test object. And yes, it happened once. Only once.
I've download an interesting article about the chicken gun and abstracted the "meat" from an USAF press release from
https://www.arnold.af.mil/aedc/newsreleases/1998/98-149.htm
In an industry where technology is vital to providing accurate aerodynamic data, the means used by AEDCs Bird Impact Facility are quite surprising to visitors, said Randall Watt, an AEDC project manager in the facility . "They expect a more sophisticated test technique, but its really common sense, a very simple thing," he said. "If you are trying to simulate a bird hitting the windshield of an aircraft, the easiest and best way to do it is to catch a bird, accelerate it to the desired speed and have an aircraft windshield in its path."
Four-pound chicken carcasses are launched at a target at speeds to simulate a direct bird-strike encounter at in-flight conditions. This method of operation led to the facilitys nicknames, the "Chicken Gun" or the "Rooster Booster."
According to Watt, the Vietnam War prompted the need for the development and operation of the Chicken Gun. During the height of the war, the F-111 aircraft was equipped with terrain-following radar that allowed the aircraft to fly along a few hundred feet off the ground resulting in collisions with many birds. Thousands of aircraft and bird collisions occurred annually, some resulting in extensive damage to the aircraft and serious injuries to its crew. The worst scenario ended in a fatality.
An office at Wright-Patterson AFB was charged to do something about the bird-impact hazard.
"Familiar with AEDCs range gun experience, they asked AEDC what it would take to develop some sort of bird-strike test," Watt said.
Using some scrap hardware, including an old 8-inch Naval gun, and a little design and fabrication, AEDC engineers assembled a simple air gun. The first shot was on Sept. 14, 1972, and calibration shots continued until Nov. 29 when the F-111 crew escape module was tested.
Since its debut, the Chicken Gun has tested various components like wings, tail sections, windshields and canopies of a majority of aircraft flying in the Defense Departments inventory.
The official Air Force bird strike qualifying testing center, AEDCs Chicken Gun has bird-strike certified components of aircraft including the A-7, A-10, B-1, F-4, F-15, F-16, A-18, T-37, t-38, T-46 and T-6A.
But, the Chicken Gun doesnt always launch chicken carcasses. Other projectiles have been used to simulate in-flight bird-strikes, including spheres, gelatin birds, wet rags, DuxSeal, quails, a sirloin tip roast and rolled rib with chicken bones.
Although the American society for Testing and Materials Standard for bird-impact testing allows the use of imitation birds, the Air Force requires use of a real bird carcass.
As for the choice being the chicken, "The chickens are provided by a local chicken farmer, and they are accessible," Warren Shells, Sverdrup Technologies project manager, said.
Both Shells and Watt said the best thing to use to simulate a bird strike is a bird because it keeps the event as close to reality as possible.
For those of you with inquiring minds, check out the facilities at
https://www.arnold.af.mil/aedc/factsheets/aedc/AEDC.pdf
Bob Krech