So sand and chicken thrown into the engine to see how it react is that what meant?.
Yes. Not just react, but if the blades will survive.
These items are not merely tossed into the engine as the engine runs. To simulate collision in flight, the particular item must be literally launched at high speed into the engine. Sometimes at the engine's nosecone, sometimes at the engine pod, and sometimes at the blades.
Combined collision speed is the sum of the speed of both objects. The aircraft would be traveling at 500 mph and the duck at 40 mph. The combined collision speed would be 540 mph.
In the case of the chicken to simulate bird strikes, the jet engine would be stationary and the (dead) chicken is launched via compress air and into speed of up to 600 mph towards the running jet engine. The launch device is often called the 'rooster booster' and other assorted humorous names.
There are urban legends that have people used frozen chickens and they were stupid in doing so. However, there is a grain of truth in using frozen chickens. Birds, especially large avians like ducks and geese, are fairly rigid bodies when they are alive and in flight. A thawed chicken shot out of the pneumatic gun would be flip-flopping in flight and may not hit the running jet engine as planned. A fully frozen chicken would be unrealistic but a semi frozen, or partially thawed, chicken turned out to be just right. The tests for jet engine bird strikes are a bit different today but the essentials are still the same -- we need chickens.
Throughout the yrs motorcycling, four times I was hit by sparrows while running at freeway speed. Three times on my helmet and once on the chest. Three times my head was knocked back and the one hit on the chest left me with a bruise despite wearing a jacket that is racing leather heavy. Bird strikes are dangerous.
