One for the air heads

archangel

archangel

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Help me settle this issue......

The lines on a cockpit glass is for when the pilot needs to eject.....yes or no? My mate reckons they are for lining up targets.....doh! Google has mixed reports but I know I am right..... :D
 
no personal experience but when a pilot ejects doesn't the whole canopy come off in one piece first (unless its like the F111 where there is a whole module ejected canopy and all) so its hard to see the lines being to do with that.
 
This might well be one of those reveal my idiocy moments but I thought they were to do with keeping the screen clear, like a heater :thinking:
 
big soft moose said:
no personal experience but when a pilot ejects doesn't the whole canopy come off in one piece first (unless its like the F111 where there is a whole module ejected canopy and all) so its hard to see the lines being to do with that.
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Apparently the pyrotechnics shoot through the lines and weakens the glass so that when the chair (which is taller than the pilots head) punctures the glass and shatters the glass along the lines
 
big soft moose said:
no personal experience but when a pilot ejects doesn't the whole canopy come off in one piece first (unless its like the F111 where there is a whole module ejected canopy and all) so its hard to see the lines being to do with that.
Click to expand...

That's one for the "I don't know" camp then :-)
 
simon ess said:
This might well be one of those reveal my idiocy moments but I thought they were to do with keeping the screen clear, like a heater :thinking:
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That would have been my guess too TBH.
 
archangel said:
Help me settle this issue......

The lines on a cockpit glass is for when the pilot needs to eject.....yes or no? My mate reckons they are for lining up targets.....doh! Google has mixed reports but I know I am right..... :D
Click to expand...

The HUD is projected onto the glass, not printed, etched or embedded in it. So your mate is incorrect.

But have you a specific aircraft in mind? - I've had a quick look online and the F16 and BAe Hawk both have explosive cord embedded in the canopy for ejecting.
 
big soft moose said:
no personal experience but when a pilot ejects doesn't the whole canopy come off in one piece first (unless its like the F111 where there is a whole module ejected canopy and all) so its hard to see the lines being to do with that.
Click to expand...

you havent been a pilot before? :p
 
Alastair said:
The HUD is projected onto the glass, not printed, etched or embedded in it. So your mate is incorrect.

But have you a specific aircraft in mind? - I've had a quick look online and the F16 and BAe Hawk both have explosive cord embedded in the canopy for ejecting.
Click to expand...


No aircraft in mind......just I was saying about ejecting
 
archangel said:
Apparently the pyrotechnics shoot through the lines and weakens the glass so that when the chair (which is taller than the pilots head) punctures the glass and shatters the glass along the lines
Click to expand...

doesn't sound likely - the pilot would get cut to f*** being ejected through the canopy - I'm fairly sure that if you watch slo mo videos of ejection you see the canopy blow off in one piece before the ejector seat fires
 
big soft moose said:
doesn't sound likely - the pilot would get cut to f*** being ejected through the canopy - I'm fairly sure that if you watch slo mo videos of ejection you see the canopy blow off in one piece before the ejector seat fires
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You could be right......off to YouTube I go.....:D
 
I was about to do the same.

Let us know what you find out.

I know for certain it's nothing to do with target acquisition. (I used to build HUDs in a previous life :))

I still reckon it's just a screen heater.
 
Ahhh . . . the useful bits of information that you pick up browsing on TP.

In response to the same question from someone in one of the photosharing threads :
Who needs Google when you have TP? :D

Cheesy said:
The black lines are actually miniature detonation cord - essentially plastic explosive. It's part of the Ejection Seat System.

Cheesy
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SarahLee said:
Ahhh . . . the useful bits of information that you pick up browsing on TP.

In response to the same question from someone in one of the photosharing threads :
Who needs Google when you have TP? :D
Click to expand...


Whoop! I was right :cool:
 
big soft moose said:
doesn't sound likely - the pilot would get cut to f*** being ejected through the canopy - I'm fairly sure that if you watch slo mo videos of ejection you see the canopy blow off in one piece before the ejector seat fires
Click to expand...

The pilot wearing a full helmet covering his face, and countless layers under his flight suit? He's fine :) If memory serves me correctly, the lines are indeed explosive but usually found mostly on those aircraft that are dual seaters.
 
Google is your friend, the squiggly line is a minature detonation cord.

Copied "Aircraft designed for low-level use sometimes have ejection seats which fire through the canopy, as waiting for the canopy to be ejected is too slow. Many aircraft types (e.g., the BAE Hawk and the Harrier line of aircraft) use Canopy Destruct systems, which have an explosive cord (MDC - Miniature Detonation Cord or FLSC - Flexible Linear Shaped Charge) embedded within the acrylic plastic of the canopy. The MDC is initiated when the eject handle is pulled, and shatters the canopy over the seat a few milliseconds before the seat is launched. This system was developed for the Hawker Siddeley Harrier family of VTOL aircraft as ejection may be necessary while the aircraft was in the hover, and jettisoning the canopy might result in the pilot and seat striking it. This system is also used in the T-6 Texan II."

http://en.wikipedia.org/wiki/Ejection_seat

David
 
Willid1 said:
Google is your friend, the squiggly line is a minature detonation cord.

Copied "Aircraft designed for low-level use sometimes have ejection seats which fire through the canopy, as waiting for the canopy to be ejected is too slow. Many aircraft types (e.g., the BAE Hawk and the Harrier line of aircraft) use Canopy Destruct systems, which have an explosive cord (MDC - Miniature Detonation Cord or FLSC - Flexible Linear Shaped Charge) embedded within the acrylic plastic of the canopy. The MDC is initiated when the eject handle is pulled, and shatters the canopy over the seat a few milliseconds before the seat is launched. This system was developed for the Hawker Siddeley Harrier family of VTOL aircraft as ejection may be necessary while the aircraft was in the hover, and jettisoning the canopy might result in the pilot and seat striking it. This system is also used in the T-6 Texan II."

http://en.wikipedia.org/wiki/Ejection_seat

David
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Yip, I think that in some aircraft there is also a rail projected up through the canopy (or where it was) to guide the seat up and prevent the pilot being struck by the fin.
 
The zip zag lines along the top of the canopy are called miniature detention cords. They shatter the canopy just before the seat fires you out.
Some aircraft canopies are designed to blow off, but its a fail safe to save cutting the aircrew to bits if it fails to fire.
 
archangel said:
Help me settle this issue......

The lines on a cockpit glass is for when the pilot needs to eject.....yes or no? My mate reckons they are for lining up targets.....doh! Google has mixed reports but I know I am right..... :D
Click to expand...
Yes.

There are lots of ways for the pilot to get out when ejecting (not all applicable to all planes or all ejection systems).

1. The entire cockpit glass assembly is blown off as one
2. The glass is shattered with explosives (the lines you see in it)
3. (last resort) the seat rails running up the back of the ejection seat have hardened points manufactured at the top to cause the glass to shatter as the top of the ejection seat hits the canopy if the other systems fail.

Those are the ones I remember. I'm not a fighter pilot, but I worked for Martin Baker Aircraft (google them) once upon a time and have some knowledge of their products.
 
My office furniture is a Martin Baker seat, the view from my office window is (occasionally) obscured by lines of miniature detonation cord that will fracture the canopy after the seat has risen about a centimetre.

If the MDC fails tgen there is a fair to middling chance that (while the seat head box will probably punch through the canopy) my neck wouldn't do to well trying to force my head through a centimetre of reinforced perspex at ~15g. Death would be messy!

Thankfully, when operated and serviced properly the seats are fantastically reliable. I wouldn't strap a Hawk to my back each day if I had any doubts about the ejection sequence.

Regards,

Cheesy
 
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Cheesy said:
My office furniture is a Martin Baker seat, the view from my office window is (occasionally) obscured by lines of miniature detonation cord that will fracture the canopy after the seat has risen about a centimetre.

If the MDC fails tgen there is a fair to middling chance that (while the seat head box will probably punch through the canopy) my neck wouldn't do to well trying to force my head through a centimetre of reinforced perspex at ~15g. Death would be messy!

Thankfully, when operated and serviced properly the seats are fantastically reliable. I wouldn't strap a Hawk to my back each day if I had any doubts about the ejection sequence.

Regards,

Cheesy
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can I go to work with you? Pleeeeease
 
Cheesy said:
My office furniture is a Martin Baker seat, the view from my office window is (occasionally) obscured by lines of miniature detonation cord that will fracture the canopy after the seat has risen about a centimetre.

If the MDC fails tgen there is a fair to middling chance that (while the seat head box will probably punch through the canopy) my neck wouldn't do to well trying to force my head through a centimetre of reinforced perspex at ~15g. Death would be messy!

Thankfully, when operated and serviced properly the seats are fantastically reliable. I wouldn't strap a Hawk to my back each day if I had any doubts about the ejection sequence.

Regards,

Cheesy
Click to expand...

The End

Well said, to anyone who doubts take it from one who defiantly does not. Cut by perspex defiantly better than neck broken by intact perspex.
 
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