Well you can also buy 27500 cheapo wire.. no change.. same “acceptable” quality.
A Raychem wire.. torch it with your heat gun as long as you like.. if you are lucky you might see som disscoloration…
(I dont work for raychem and I dont use their wires, expensive.. But I have no problems in admiring the quality.
There are sooooo many different cables. As long as Im satisfied and the wiring is good enough according to CS standards…
PA28, Cessnas, Mooneys and other’s.. think cheapo will do just fine.
There is a lot of “generic spec” wire out there, which gives one the opportunity to cut costs whole being happy they are using the right stuff.
This (data sheet) is what I think is the “proper” Raychem double wall airframe wire. Now look at the price. It’s not easy to compare because RS sells a wide range of similar wire (sometimes with “Type 55” typewritten data sheets which are from the 1980s) but the proper ETFE stuff seems to be 30-50% above the cheaper stuff.
Oddly enough, if you don’t want the double wall, you can get PTFE (which has to be the very top stuff) for very slightly more.
A while ago I was sourcing some RG400 coax – for a TCAS installation where the installer was less than keen to use such pricey coax. I found several cheap “RG400” variants, with lower specs. The proper one was £6.80/m plus VAT. That’s £680 for the full reel… The cheaper ones were about 1/2 that.
The usable life remains a good question… I wonder whether it is PTFE or ETFE that has the corrosion problem. The wire I have seen corroded was almost certainly ETFE. The age was impossible to tell – here is the label and maybe it has a date code. It was bought about 5 years ago
FLT0111 is here (data sheet) and the insulation is neither ETFE nor PTFE. Yet this is a double wall “airframe” type wire. ENG_CD_FLT011X_7_pdf
I’ve been scouring the net for 6 AWG (or 8 SWG) TERSIL cable but can’t seem to find anywhere that currently stock it. I only require about metre!
This is a very flexible wire suitable for tight bends with good resistance to heat and oil, like in an engine bay. Would anyone know if there is a modern day equivalent; say Raychem etc.
If you don’t need the abrasion resistance then silicone insulation with a large number of thin strands should do. Otherwise sheath the silicone wire in some protective sleeve.
Why do you need special flexibility? That’s unusual in GA.
The google hits suggest this was developed in the 1980s and nobody uses it anymore.
As Peter says TERCIL is obsolete what you need is some Rayfast 55.
LAS Aerospace sell this in small quantities.
Raychem 55 is however not very flexible which is why I asked the question, but without an answer one can’t say anything useful.
My guess is that this is for a starter motor, and has to run past the engine rubber mounts so some movement is involved, but Type 55 cable has been used for this for decades. You just have to make sure there is enough slack. After all, one runs loads of cables past the rubber mounts: fuel flow, CHT+EGT thermocouple cables, not to mention the various fuel and oil hoses.
I’m trying to replace a loom where two 6 AWG and one 14 AWG wires terminate into the size of a matchbox and the wires need to make a 180 deg turn to fit. I have sourced some 6 AWG but it’s difficult bend to shape and probably isn’t suitable for making the tight bend I need. Also the entrance to the terminal (matchbox) is approx 15-20mm, so the o/d needs not to be too large.
I was surprised that there appears to be no modern equivalent Raychem that fits the spec.
Thanks for all your suggestions!
If you warm up the wire, it should bend OK. On Type 55, most of the stiffness (relative to other types) is the insulation.
Otherwise, there is silicone insulated wire, but it may be harder to get it with “paperwork”.
There is a modern cable for moving machinery (robots etc) – example
Another way to make a tight bend is to bend the bare wire (solid or stranded as appropriate) and then heat-shrink it. You can get PTFE heatshrink so achieving the working temperature range is no problem. In fact one can make up short length of heavy cable quite effectively by starting with bare wire and putting heatshrink over the top. Then you can choose a conductor like this and get everything you want.
What is the best current practice for avionics wire, and what place do people recommend to buy it from?
I bought some reels of ETFE double wall from RS recently (I think Raychem), although I had to get a short length of screened cable for audio from elsewhere.
Going back to the older post, I think the difficulty in soldering this stuff (especially the bigger gauge stuff) is that it wicks heat away so effectively. Unlike PVC coated wire (where the thick PVC is quite a good thermal insulator), the thin ETFE allows the heat to escape very readily so unless you have a massive soldering iron, the wire just acts as a heatsink and you can never get it hot enough. I’ve only found the smaller stuff (e.g. 20 awg and smaller) to be solderable, without using a firestarter of a soldering iron. I had to solder a couple of D connectors for a glider radio installation, but that was all 20 awg and quite easy to do, and since it was just a pigtail between an airframe connector and the radio, I could do it on the bench rather than try to do it in the hangar (and wire up a test harness to bench test the radio and mic, so I knew everything was correct before fitting it).
I crimp everything that can be crimped. It’s a lot easier to do, especially when you have to do it in a hangar and makes reliable connections; I have very few soldered wires on the Auster. Avoid the cheap crap crimp tools. A good crimp tool is worth its weight in gold especially if you have to do anything in the field (my most recent misadventure with soldering was trying to solder the centre pin on an N connector on a boat, which had to be done outdoors. A job that would take 30 seconds on the bench at home was bascially impossible to do outside. Fortunately I discovered one of my coax crimp dies had the correct one for doing the centre pin of an N connector too).
