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Post by oj on Mar 12, 2010 22:38:45 GMT 12
I thought some might be interested in the RNZAF A4K Project Kahu avionics upgrade from a manufacturing angle. All of the electrical wiring looms and several of the electrical system panels & boxes were manufactured at PAC, tested, kitted and dispatched to Woodbourne where Safe Air did the installation to the airframes.
OJ
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Post by oj on Mar 12, 2010 22:49:39 GMT 12
The first photo is of the former CT4 assembly line occupied by a population of electrical wiring loom assembly boards.  Another view of the loom board area with "toast-rack" of stowed loom-boards on the right. There were 160 separate wiring looms for each aircrfat (some quite small).  A closer view of loom assembly:  ....and a typical reasonably-sized loom-build:  More to come (if anyone is interested). OJ |
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Post by corsair67 on Mar 12, 2010 23:38:42 GMT 12
What - have you got rocks in your head: of course we're interested!  Amazing photos there; and interesting from the point of view of a non-technical type like me, as they convey just what is involved in a project like Kahu. More please. |
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Post by skyhawkdon on Mar 13, 2010 7:30:24 GMT 12
HI OJ, these are very interesting to me as I was Avionics and am collecting photos for a book on the history of the RNZAF Skyhawk. I have sent you a PM... look forward to seeing more!
PAC and Fisher & Paykel's involvement in the Kahu update isn't well known, but the wiring and other components they produced were critical to the success of Kahu. The new wiring made a huge difference to the reliability and maintainability of the aircraft.
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Post by lumpy on Mar 13, 2010 8:30:38 GMT 12
I remember seeing the prototype " kahu " , with the looms fitted . I was initally astounded that all the wires werent colour coded ,but then realised that each wire had its own number , that was printed on it , all the way down its entire length . I guess that works better since there were more wires than there are colours .
Cool photos
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Post by Bruce on Mar 13, 2010 9:42:04 GMT 12
Standard aircraft Mil-spec wire generally comes in white only. It is quite different to what you find in a car in that the insulation material is "EFE" which is a variant of teflon. EFE insulation can be a lot thinner than the commonly seen PVC insulation, which means the wiring bundles can be a lot smaller diameter. It is really hard on wire strippers etc though as it is very hard, and also very slippery, but it has excellent flame resistant properties. Its a common mistake to see aircraft wiring in movies (perhaps being sabotaged) with lots of pretty colours!.
That said, the Adventuers wiring is colour coded (according to wire gauge) as not being bound to "aircraft" spec products, I found some identical, but commercial spec, EFE wiring in colours! (for a significantly cheaper price too!)
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Post by Dave Homewood on Mar 13, 2010 10:41:30 GMT 12
Very interesting stuff Owen, thanks for posting these shots. Don, what was Fisher & Paykel's involvement in the upgrades? Beer fridge in the cocjpit perhaps?  |
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Post by baz62 on Mar 13, 2010 11:06:52 GMT 12
Thats fascinating, I wondered how wiring looms were put together. Must be tricky actually fitting it all into the airframe though. More please Owen!! ;D
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Post by phil on Mar 13, 2010 12:38:19 GMT 12
Makes those PMBR wiring looms I made look like child's play.
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Post by oj on Mar 13, 2010 21:35:11 GMT 12
OK Guys, a few more. By the way F&P were an initial bidder for Project Kahu Wiring loom manufacture but did not receive or do any Project Kahu wiring work. However, a subsidiary of F&P, Screencraft, in Auckland, did manufacture the mil-spec printed-circuit boards for the "Panels & Boxes" part of the wiring kits, as a subcontractor to PAC. Here are some "Boxes" Junction Box ( Can't remember which one right now but we will find out ....  Relay control box (function to be advised)  Another relay box ....  And yet another relay panel .....  Here's one of those Screencraft-manufactured PCB's in a box. The PCB's were all hand populated and hand soldered at PAC to high-reliability mil-spec standards.  And here's a rotatable relay panel assembly jig to help you solder all those hundreds of connections onto the little relay terminals.  What? You're too confused already? OK lets take a break and put some more up later .... |
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Post by kiwiscanfly on Mar 13, 2010 23:30:10 GMT 12
it's a shame that so much good work and skill went into this project and the squadren was retired only 2 years later what a waste of money  |
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Post by corsair67 on Mar 13, 2010 23:55:14 GMT 12
Okay OJ, I'm not afraid to show my stupidity. Once the wiring looms were assembled, how were they then sent down to Woodbourne? Were they rolled up into a bundle of some sort? By the way, great photos of the relay and junction boxes too. Pretty tight fit to get everything into them too, and I can imagine after working on those all day, you'd just about go home with double vision. Don will love all these images! |
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Post by skyhawkdon on Mar 14, 2010 8:33:14 GMT 12
The first photo is the Audio Junction Box - the small grey "knobs" are fuse covers. Interesting on the later photos of the relay panels that none of the relays are yet potted (where each wire is soldered to a relay terminal the whole area was filled up with an RTV sealant to stop anything shorting out the exposed terminals). I'm sure they were all potted by the time they went into the aircraft.
The relay panel with the big red fuses on it was located in the engine bay and the fuses were the main generator power fuses (one for each phase). I think they were 50A fuses.
You can get an idea of the hand skills required for this work. Very intricate and a lot of attention to detail needed. PAC did a great job and the workmanship speaks for itself in these photos.
Thanks for sharing these Owen, it is bringing back a lot of memories!
The idea behind these relay panels is if a fault develops in a relay or component it is easy to unplug the panel, take it out of the aircraft, do the repair in a workshop with lots of light and access and then refit it. Prior to Kahu many of the relay panels were hard wired into the aircraft so you couldn't remove them - any repairs had to be done in situ which was not easy in most cases! A lot of thought went into these things as part of the Kahu design.
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Post by Dave Homewood on Mar 14, 2010 8:38:31 GMT 12
it's a shame that so much good work and skill went into this project and the squadren was retired only 2 years later what a waste of money Eh? Correct me if I'm wrong here but OJ's photos depict the period of 1986-1989. The first Kahu Sjyhawk re-entered service in 1989 and the rest followed. They flew for another 11 years, and were pretty much due to come to the end of their useful lives when the F-16's were to replace them. It was not a waste of money, they had a good run out of reconditioning and upgrading old aircraft. |
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Post by kiwiscanfly on Mar 14, 2010 13:27:02 GMT 12
sorry mate but there were major delays in the project and the last modified A-4K was only rolled out in 1998............ yes the manufacturing began in the mid !980's but was finished much llater as i belive i will look into this again  |
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Post by caromeg on Mar 14, 2010 14:14:36 GMT 12
This is very interesting, just proves to me that there is the industrial potential to maufacture UAVs in this country
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Post by phil on Mar 14, 2010 14:38:52 GMT 12
sorry mate but there were major delays in the project and the last modified A-4K was only rolled out in 1998............ yes the manufacturing began in the mid !980's but was finished much llater as i belive i will look into this again I'd suggest you do. I was on 75SQN in 1997, and they were all Kahu then, and they weren't new either. I would expect Don can even tell you when each tail number was accepted into service post mod. |
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Post by Dave Homewood on Mar 14, 2010 16:37:15 GMT 12
I'm almost sure they were all Kahu modded when I was at Ohakea in 1993!
Mind you, I tried to stay well away from hte nasty loud, pointy green planes as best I could.
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Post by oj on Mar 14, 2010 19:10:54 GMT 12
Hawkeye, we did manufacture large UAV's in NZ, at PAC.
In about 1993-94 PAC manufactured a 50% airframe content of a series of 14 new Jindiviks for the RAF. The other 50% of the airframe was made by ASTA in Melbourne.
But, of significance to the PAC Electrical Dept., was the awarding of all the wiring work and panels and boxes to PAC. Again, this was a complete modernisation and upgrade of the Jinvdivik, so yes, some of the ex-Project Kahu personnel did the Jindivik electrics, using existing equipment and tools, so there was pretty well instant ramp-up into production mode.
Sadly, a few months afer the aircraft were delivered to the UK, the MOD declared them obsolete and I think only one or two actually flew.
Most went straight to UK aviation museums as brand new aircraft!
Good old U.K. MOD. Massive fail. SNAFU par excellence.
You can read heaps about the Jindivik on line on several web sites and the UK parliamentary papers and debates ..... Also see videos etc. Just Google.
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Post by oj on Mar 14, 2010 19:47:44 GMT 12
Corsair, The looms were of course tested first while still on the loom board before being packed for dispatched. This testing was extremely important. Every wire had to be "rung through" from end to end to check continuity and insulation resistance tests done.
The "ringing-through" process is very simple and has its origins in early telephony. A simple buzzer and battery in a box is used with just two test prods which are inserted into the appropriate sockets of the multi-pin connectors at each end of the circuit. One person reads out the connector wiring socket numbers for each end and the probes inserted for the buzzer to work.
It takes a while (think of a loom with up to 400 wires, which we had) but our little buzzer box was $29,990 cheaper than the machine (called a DITMICO Tester or something like that) that the Yanks usually use to test aircraft production wiring looms.
.... then the looms had all the connectors fitted with dust caps and after final inspection clearance were tagged and folder carefully into plastic bags and cardboard boxes for dispatch to Safe Air.
....and Don, yes there were some potted plugs and relays, and conformal coating of PCB's but these photos were used to market our capabilities to other potential clients, and potted relays and plugs look ugly and you can't see the shiny solder!
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