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Pyrotechnic fastener

Pyrotechnic fastener

Pyrotechnic fastener

(OP)
How to design a pyrotechnic bolt for aerospace application ?

RE: Pyrotechnic fastener

You buy them from the few companies in the world that design and mfg these. This is very highly specialized work.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Pyrotechnic fastener

are these the same as 'explosive bolts'? ones that can be detonated for release?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: Pyrotechnic fastener

(OP)
yes, they are also called explosive bolt, frangible bolt etc.

RE: Pyrotechnic fastener

Thanks...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

RE: Pyrotechnic fastener

Wow... just realized...

I've never dealt with pyro-connections: Only mechanical/pyro jettison/ejection systems... weapons/pylons or crew-seats/canopies. OH yeah... and jet-engine 'cartridge initiated starters'.

Where the researchers ever able to positively determine the cause of Gus Grissom's Mercury capsule 'hatch jettison'? I imagine the capsule as a mess on recovery... haven't heard any findings/conclusions. Maybe I haven't looked hard-enough.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Pyrotechnic fastener

Not even an engine fire extinguisher squib, Wil?

RE: Pyrotechnic fastener

SW... Thanks for reminding me...

Yesssss my 4-engine jet has [4] Kidde squib initiated Halon fire extinguisher bottles:[2-each] are co-located in the #2 and #3 strut fairings [inboard engines of each wing of the jet]. They can dispense one-or-both Halon-bottle-shots [bottle contents] to either engine on their side [#2, #1] [#3, #4], depending on which routing squib is initiated at each bottle. I mostly worked the Kidde bottle mountings, tubing and fire-warning loops. One-time I was thrust into working with Kidde service center for halon bottle refills for older-generation/configuration FMS jets [halon is an expensive and scarce controlled substance].

NOTE1. I think the squib-initiators are time-change items. Unsure, but I think each bottle-initiator [2 each/bottle] have a pyro-charge to thrust a penetrator thru the bottle-wall which dispenses the Halon-charge down the selected tube-to-engine. This set-up allows replacement of the 'squib-penetrators, tubing, etc' without disturbing the FE bottle... However a discharged FE bottle is throw-away.

Cute NOTE2. What is interesting is that Kidde employees always 'softly teach' you how to pronounce the company name... sounds more like 'Kid-Day'... as opposed to 'Kiddie'.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Pyrotechnic fastener

WKTaylor - Gus Grissom's Mercury capsule is on display at the Kansas Cosmosphere https://cosmo.org/ I've seen it many times. Gus had removed a red-anodized aluminum protective cover from the jettison button and it was recovered in the bottom of the capsule. The hatch remains in the Atlantic. Most likely he bumped it in the process of securing the capsule post-splashdown.

The best evidence comes from what happened afterwards. NASA rewrote and expanded their Mercury post-flight checklists as most of the emphasis had been on launch and flight portions of the mission. Grissom remained one of their top astronauts and died as the Command Pilot in the Apollo 1 test fire which was to have been the first flight of Apollo.

RE: Pyrotechnic fastener

I thought so Wil.

Meherrahul,
Design and integration of explosive bolts is not for the faint of heart, or for amateurs. The conditions where they get used are pretty extreme (fire extinguishers, rocket separations, parachute/canopy/seat/cable jettisons, etc.) and are almost exclusively "must work" situations where failure of the ex-bolt is catastrophic and/or the situation is already catastrophic and the explosive is the last-chance to escape.

It's a deep rabbit hole of research just to start figuring it out (I've tried). Compound that with your searches possibly raising red-flags with anyone who monitors the libraries/databases with this information. Note that many of these items are ITAR controlled and even need to be treated as hazardous items when being shipped locally.

Many experts in the field that you can contact. Pacific Scientific comes easily to mind.

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