fighter jets, there seems to be a molded wire pattern above the pilot in the canopy, what is this for&is it?

Question

on most fighter jets there seems to be a mouled wire pattern on or in the clear canopy above the pilot. what is the purpose of this unique pattern?

Answer 1

I assume you mean the strange wire arrangement laid into some cockpit canopies, such as in the following picture . . .

http://www.operations.mod.uk/telic/images/air/gr7_cockpit.jpg

This is actually part of the emergency escape system. It's an electric wire which is charged when the pilot ejects from the aircraft. The theory being that the wire is charged with high voltage electricity which shatters the canopy just before the pilot ejects "through" the canopy.

I believe that in more modern aircraft, the explosive wire system has been replaced by a canopy that jettisons completely as the pilot ejects. There are pros and cons for both systems but that's probably another question.

In short, the answer is that it is a wire that is electrically charged to shatter to cockpit when the pilot ejects.

Edited to add . . .
Capt J . . . the wire doesn't "carve a hole" in the manner you describe - it does actually cause the canopy to shatter - I've seen it first hand!

Answer 2

Researchers were trying to design the best ejection seat possible. They realised that there are precious fractions of a second wasted while waiting for the canopy to leave the aircraft before the seat carrying the pilot does. Someone suggested they just bang the poor bugger through the canopy and be done with it. Everyone else is right, the cord shatters the canopy as the ejection process starts so the pilot doesnt waste any time leaving the aircraft. You'd want to hope that it all worked as planned wouldn't you?

Answer 3

Let's consider flying straight and level. If there were a small amount of liquid, it would feel the same as sitting in a bath. If a large amount, it would feel like floating in a swimming pool. I suppose you'd like to assume the cockpit is water tight, so they don't have to sit in a container and can reach the pedals. I f you want to feel positive g, get into a nice steady dive and pull the stick back. If you perform a nice smooth loop, the water will be forced towards the floor of the aeroplane, even when it's up side down, so all the way round the loop, the water will remain between the waist and feet of the pilot. I think the part of his body under water will feel the support of the water and feel less g than in a dry cockpit. The part of his body out of the water should feel the same as usual. Now for negative g. That's the one where you push the stick forward and keep on pushing - the manoeuvre in which delicate pilots deliver their tea, lunch and breakfast in that order. Outside loops are rough on aeroplanes, so let's assume the wings don't fall off. The water will be forced towards the canopy, so let's assume that doesn't break. The pilots head and shoulders will be in the water and his lower body will be dry. He'll probably be more worried about drowning than the g forces.

Answer 4

Pongopilot is spot on. When you set of det-cord it doesn't just crack the canopy it gets rid of the pieces, you need to give the whole thing enough of a bang so that it's well out of the way before the seat(s) fire the crew out through the space it was previously in.

Different aircraft have different techniques for making a hole when the pilot wants to leave before the normal schedule. Some jetison the canopy as a whole, some just blow it away, some even use an escape pod. This is just one of the several methods. In most cases the seat is leaving anyway, this just should save the pilot the unfortunate experience of making the hole himself.

Answer 5

The cord that you re referring to is an explosive cord that fractures the canopy. If the ejection system for the aircraft does not blow the entire canopy off then sometimes this is part of the ejection sequence used to break up the canopy just before the seat fires. Other times it is for emergency evacuation in the event of a fire while on the ground.

Answer 6

Obviously some people do not want to hear the RIGHT answer..St Louis nailed it...It is for emergency egress, in the even the canopy doesnt pop in the ejection sequence...this little thing "carves" a hole just big enough to fit the seat with a body out of....to all that thumb down the other correct answers...shame on you...hope this helps!

Jonathan S
ATP-LRJET,HS-125
CFI/AGI

Answer 7

It's there to trap, diffuse or reflect incoming radar signals from another enemy fighter rather than have the whole cockpit be a radar target through the clear canopy. Some fighters use a thin layer of copper or gold for the same effect.

Answer 8

wh knows. either reinformcent or communications or part of heads up targeting system?