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It's not rocket science
ken555 - 23/7/15 at 09:09 PM

Nasa documents for electrical connection etc. Always worth a read. Page 80 is great for joining cables.

http://www.hq.nasa.gov/office/codeq/doctree/87394.pdf


bi22le - 23/7/15 at 09:38 PM

Page 46 mentions cable ties and spiral wrap.


coyoteboy - 23/7/15 at 10:03 PM

It's a part of my day job. ESA have similar docs. I keep copies of both on my desk for reference!


scootz - 23/7/15 at 10:06 PM

I guess these standards explain why NASA can land craft on comets gazillions of miles away, yet I can barely make an lighting connection last a winter!


ste - 23/7/15 at 10:26 PM

Very outdated stuff on there. I work on Eurofighters and most joints are crimped as they are more reliable.


coyoteboy - 24/7/15 at 01:08 AM

Not out of date, you may just have missed the fact that crimps are used but that there are significantly more constraining design drivers in space hardware. There is a general reluctance to use new kit if old kit/methods are proven to work flawlessly though I give you that. But that's generally because space builds are one-off, mentally high value and there's no one rushing you to find a faster, cheaper way of producing something that has to work flawlessly in the vacuum of space, swinging between -200 and +200 many times a day and can never be inspected, replaced, bypassed etc. NASA/ESA test things like this as they come available in projects and update as soon as a better solution or method is available and qualified.

The vibration requirements for MIL/plane hardware is pretty harsh, duration-wise, our vibration is limited to a few minutes, after that loadings are largely thermal induced or self generated.

What crimps are used on the Eurofighter and in what sort of locations?

Check out the ESA crimping standards for more fun reading.

[Edited on 24/7/15 by coyoteboy]


lsdweb - 24/7/15 at 07:18 AM

Very interesting - thanks for posting the link!

I wouldn't get past page 25 unfortunately (colour vision test!)

Wyn


Irony - 24/7/15 at 07:48 AM

This is a great thread. It should be stickied at the top of the electrical section. It is great to have some sort of a official document regarding this much argued over topic. Thanks guys.

P.S I'm a crimper by the way.


ste - 27/7/15 at 12:00 AM

quote:
Originally posted by coyoteboy


What crimps are used on the Eurofighter and in what sort of locations?


[Edited on 24/7/15 by coyoteboy]


Technical drawings I can't post as they are covered under the official secrets act.

Some off the internet here

http://www.peigenesis.com/en/amphenol-connectors/amphenol-sjt-series-mil-dtl-38999-type-1-5.html#contact-crimping

I fully understand why the methods are used for space, it takes a lot to qualify parts and techniques for aerospace


coyoteboy - 29/7/15 at 08:00 PM

Yep, good old amphenols - fairly commonly used but massively over-sized for the bulk of our work! (we do mainly subsystems, not harnessing) Customers generally specify D-sub connectors, often Positronic, but usually crimp terms - we just provide the black boxes and/or harnesses to suit. I'd still say 50% of the larger connectors we use are solder-bucket types, and wicking is controlled, plus additional strain relief in the form of heat shrink or separate support struts used. Plus it's normal for us to tie down at ~50mm intervals on large harnesses.


coyoteboy - 29/7/15 at 08:00 PM

[Edited on 29/7/15 by coyoteboy]


DaveFJ - 31/7/15 at 11:57 AM

Interesting that they specify that ty-wraps should always have the 'ribbed' side touching the wires.

When I was working on military helicopters we had to use 'special' ty-wraps with an external ratchet so that the ribs did not fret the wires......