[Andrew]

Just a question, why do canopies of modern aircraft have frames/lines on the top? Is that to indicate where the centre of the top of the canopy is?

[Fly Navy 75]

Which aircraft are you referring to?

[smartd]

These are frangible lines, (breakable) to aid in pilot ejections so canopy will break in a pre-determined way.

[Aircrafty]

And when they hit the ground they draw another chalk line around them

[swoop]

To hang the curtains on when your friends come to visit.

[Shamrock]

As far I'm aware there is explosive fitted along the seam which detonates at the same time the ejector seat is used. The Buccaneer was the first aircraft fitted if I recall correctly. If I'm wrong the pundits will correct me I'm sure! The other suggestions were excellent in goulish way. We need more black humour on the forum.

[Andrew]

Even the tomcat has a thin line in the middle.
Thanks for your info guys. Always wondered why. Thought it was incase the pilot lost orientation while looking for the enemy

[David Hingtgen]

Are you talking about the models or the real things? Because the F-14 doesn't have a "frame" on top of the canopy-----there is a very thin metallic strip along most of the length of the top (split into two sections), but it's for static electricity discharge. But every F-14/15/16/18/22 model usually has a thin visible line along the center because the canopy is molded from two halves due to the bubble cross-section, even when the real ones are perfectly smooth and featureless on top.

[Andrew]

Originally Posted by David Hingtgen

Are you talking about the models or the real things? Because the F-14 doesn't have a "frame" on top of the canopy-----there is a very thin metallic strip along most of the length of the top (split into two sections), but it's for static electricity discharge. But every F-14/15/16/18/22 model usually has a thin visible line along the center because the canopy is molded from two halves due to the bubble cross-section, even when the real ones are perfectly smooth and featureless on top.

Talking about the real thing. Yeah that thin line and also on planes like the Bae Hawk and I think the Harrier as well. It doesn't run the full length othe canopies though.

[David Hingtgen]

Well the Harrier and Tornado's lines are due to det-cord. But the F-14 is as I said.