Jagged Lines on Flight Canopies
Name: Walt L.
What are the 'jagged' lines that can be seen in the
canopies of fighter plane cockpits?
The "jagged" lines are part of the canopy structure where there is a
seam between the "glass" and also where the canopy meets the aircraft.
This is most notable on aircraft with stealth technology and more
specifically on the Nighthawk also known as the stealth fighter. These jagged
lines are part of the design to reduce radar reflection back to the
Not knowing for sure what lines you are referring to, I offer two
possibilities. First are lines of reference allowing the pilot to have a
calibrated reference of his flight attitude compared to the horizon while
keeping his eyes outside of the cockpit. But more likely, if the lines are
jagged you are seeing a line of explosive that is used to shatter the canopy
prior to the pilot ejecting in an emergency. The canopy does not reliably
leave the plane during an ejection. (Did you see Goose in Top gun?) And
going through the canopy during an ejection would be painful.
Those small lines that you see might be craze marks. Crazing is essentially
a network of shallow cracks. Almost all clear polymers will craze when
exposed to stress or chemical attack by cleaning solutions or solvents. The
cracks are very small, and bridged by thin fibrils.
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Update: June 2012