I was looking at the Raptor and noticed the white looking tubes underneath the canopy. Do the tubes have a purpose? If so what is the purpose/function of the tubes? Are there any other aircraft with this kind function? Thanks.

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  • $\begingroup$ Speculating: this could be part of the canopy locking assembly, likely in addition to the six grey points you can see along the middle rim of the canopy. $\endgroup$
    – Jules
    Commented Nov 2, 2022 at 3:28
  • 5
    $\begingroup$ Chemtrail storage containers $\endgroup$
    – Richard
    Commented Nov 2, 2022 at 20:26
  • 1
    $\begingroup$ @Richard clearly its plastic downpipe from rainwater spouting, being used as air ducting so the incoming breeze is redirected at the windscreen to keep it defrosted.... $\endgroup$
    – Criggie
    Commented Nov 3, 2022 at 8:52
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    $\begingroup$ "Do the tubes have a purpose?" While I'm not an airplane designer, I'd bet everything on a (modern fighter) plane has a purpose - otherwise it would be removed to reduce weight. $\endgroup$
    – zovits
    Commented Nov 3, 2022 at 12:08

1 Answer 1


Those are Cartridge Actuation Devices (CADs) - pyrotechnic charges used during canopy separation for canopy jettison or ejection. Note the nozzles at the outboard ends and the ignition wires inboard.

You can see a ground test of a similar unit installed on an F-16 below.

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    $\begingroup$ What is that person doing there? Looks like they are holding something, a microphone or other sensor perhaps. Surely, given there are two rockets firing and in a few moments a canopy falling from the sky, they could have set up a tripod or something. $\endgroup$
    – user
    Commented Nov 2, 2022 at 12:05
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    $\begingroup$ It might be the guy who pulled the cable triggering the pyrotechnic cartridges (?) $\endgroup$
    – sophit
    Commented Nov 2, 2022 at 12:31
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    $\begingroup$ Looks like they're following the instructions on the side of most fighters, 1. Push button to open door 2. Pull ring/handle out X feet to jettison canopy. I feel like I'd want to tie on a longer rope and stand farther back if it's not an emergency, but maybe there's some reason they can't. $\endgroup$
    – CameronSS
    Commented Nov 2, 2022 at 14:05
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    $\begingroup$ @CarloFelicione from other photos in this sequence, and a video of what looks like the same test, it's a person yanking the cord. A lot more nonchalant about the canopy flying overhead than I'd be. $\endgroup$
    – CameronSS
    Commented Nov 2, 2022 at 16:16
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    $\begingroup$ @CameronSS cool guys don't look at explosions $\endgroup$
    – Plutoro
    Commented Nov 2, 2022 at 20:25

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