Lots of back-seat photos of fighter jets will show the canopy with some squiggly shape on the inner surface. It seems to start in the back, wander to the front of the canopy on one side, then return to the back again on the other side.
Is is some sort of reinforcement? Antenna?
My best guess is some sort of explosive cord to shread the canopy for ejection but having an explosive inches from my head would worry me if I were a pilot.
I think it is a small explosive charge.
I was at an RAF (Royal Air Force) base on an open day and I sat in a cockpit of a Harrier and asked the pilot the very same question.
The explosive charge is quite small and because of the black stuff is direted upwards and outwards away from the pilot.
Quite clever really.
Chris.
Good ole Howstuffworks…
Another note (actually saw a show on the subject of ejection seats [gotta love Discovery Wings] where this was addressed…) - the explosive cord is only integrated into the canopies of V/STOL aircraft or others that fly extremely slow.
It was introduced on the original BaE Harrier due to worries about ejection while hovering - other (conventional) ejection-seat equipped aircraft use explosive bolts to detatch the canopy and the slipstream yanks it out of the way as the plane moves forward. Low airspeed = weak slipstream and a canopy that hasn’t been blown out of the way could be very uncomfortable for the ejecting pilot.
The British seem to have integrated this safety feature into several non-V/STOL aircraft (anyone ever gotten a good look at a Tornado canopy? Is there explosive cord?), but the only American aircraft I’ve seen this on are the new F-35 Joint Strike Fighter and the AV-8B Harrier - McDonnel Douglass’ (now Boeing’s) updated version of the British Aerospace Harrier.
Here’s a pic of a Tornado canopy.
a la Top Gun… poor goose!
Detonation cord is also used on T-45 Goshawk trainers for the US Navy. I’m not sure about BAE Hawks sold to other countries though. It’s not easily discernable in the Tornado pic that Chalkpit posted, but there is a line of det. cord along the center line of the canopy in that picture. Another safety feature employed on Harrier (and I assume others as well) ejection seats is a pair of spikes on top of the seat pointed up. These are designed to shatter the canopy (which btw, isn’t glass) if the det. cord doesn’t work properly.
FWIW, the Grumman A-6 Intruder’s normal mode of emergency aircraft egress was through the canopy. As El Marko has pointed out ejection seats normally have some sort of canopy-breaking device mounted of the top of the seat and this was relied on to break the canopy open.
The reason for such a drastic exit mode was that the Intruder’s canopy sild horizontally (more or less) backwards on rails to open. It was thought that a failure in retract might leave the metal front canopy frame directly over the pilot and B/N as they attempted to eject. Thus, the idea was to guarantee the worst thing they would hit was Perspex or Lexan or Plex.
For wild ejection schemes think of the early F-104. It shot down out of the fusleage because the ejection seats available wouldn’t fit through the top of the fuselage!
Your comments on the A-6 reminded me of a story I read not long ago, with legit pictures as documentation, of a partial ejection incident in an A-6. The co-pilot’s seat charges went off, but it got stuck half-way up the rails, so the pilot had to execute a carrier landing with the co-pilots body sticking out the top of the canopy. They both survived.
The Discover Wings channel show I watched - where my stunning expertise on ejection systems was raised yet another notch - had an interview with the Navy B/N who partially ejected as well as flightdeck video of the aircraft landing with him stuck halfway out of the canopy…the wind blast tore his helmet and mask off and he was unconscious for a few minutes on landing, but has recovered fully and gave the show’s producers one hell of an interview…
BTW - it should be mentioned that neither the pilot or the B/N had initiated an ejection, the seat blew spontaneously as the result of an equipment malfunction…
Better view of the Tornado’s canopy - looks like the British like to make absoloutely sure the canopy isn’t gonna be a problem. The explosive cord is plainly visible.
Nice pic. At first glance it looks like there’s no pilot !
[slight hijack] Dosen’t the F-111 have a whole ejection pod for emergencies? I seem to recall building a model a long time ago like that…[/hijack]
Yup - the entire cockpit ejects and parachutes to the ground with the aircrew inside. I understand it floats, too. The Cavanaugh Flight Museum in Addison, TX (Dallas suburb) has one.
Some aircraft also have frangible glass canopies… an electric charge pre-shatters the glass, and they blow straight through it.
And IIRC the B-58 Hustler had unique ejection seats. Each seat had a small poddish shutter device that would close around the head and upper body of the crewman before ejection. Since the Hustler was designed to penetrate at Mach 1+ it would have a been a real bitch to get out into that supersonic airstream.
The B-47 had the Pilot and Co Pilot sitting tandem under a canopy. The Bombardier/Navigator station was below in the nose. The B/N seat ejected downwards, Pilot and CP upwards. I have a friend who used to fly B-47’s and told me that his B/N asked that if it was necessary to bail out during a take off or landing if my friend could bank it a little first.
One of the biggest gaffes in Top Gun, a nearly impossible situation. The canopy pulls an embedded cord to enable the seats to fire and this doesn’t happen until the jettesoned canopy is well away from the cockpit. If such a thing did happen the front seat would fire into the canopy a short fraction of a second later killing the pilot as well as the RIO.
