Just for the record, they do NOT fire frozen chickens at canopies. They use a big compressed air gun to fire *thawed* frozen chickens at something like 300+ MPH.
I think they did use frozen chickens once, not knowing any better and the canopy did not fare too well. Then the line directing defrosting the chickens was added to the procedure! Maybe this is an urban legend, but with my experience in the Navy and as a Government contractor, it's really believable
I thought that several layers of glass interleaved with layers of vinyl, then bonded together, served to make windscreens capable of withstanding the impact of a large bird when plane velocities reach up to 400 mph. Has this practice been superseded ?
Safety glass has been used for numerous applications like canopies. Safety glass uses glass layers separated by polyvinyl butyral. However, monolithic polymers like polycarbonate also are used for these applications.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
You are refering too transparent armor, which consists of polycarbinate laminates. Polycarbonate is a plastic material 30 times stronger than acrylic which is 17 times stronger than an equal thickness of single strength glass. Usually glass-clad polycarbonate products are a multi-ply composite laminate combining polycarbonate and glass using special polyurethane high adhesion bonding layers. The outer layer has a wear glass layer and inner layers are spall resistant. Made by companies like Simula, Inc or PPG.
