Looms

This blog covers the manufacture of various looms.

Overview
Wire looms of wire are an outcome of building a sophisticated aircraft but how to create professional looms has been a vexed issue to amateurs like this builder. For a long time, cable ties provided a replacement for lacing but never look professional in the mind of this builder, with cable ties renown for their ability to tear flesh from there trimmed edges.


Labels
A Dymo Rhino 4200 was used to generate labels, and this was covered in an earlier blog. 

The builder is happy with that choice and also the numbering system developed, however doing it again, the yellow labels would be considered over the white because they can get dirty with handling.


Looming Materials
The choice of loom tube worked well in the cockpit, giving a  conduit appearance but increasingly PPS monofilament expandable tubing is being used to tie together groups of wires into tight, tidy looms. 

The 10 mm [3/8''] loom tube was used in the cockpit interior to bundle all the runs from each wing into a single loom.



"PPS or Polyphenylene Sulfide monofilament sleeving is ideal in high-temperature environments and offers lightweight mechanical protection to your cabling. The construction expands up to 3 times its diameter to allow both easy assembly and a snug fit. The open weave design also dissipates heat and doesn't trap moisture." Jaycar

The builder has found it to be flexible, light while providing a professional appearance that can be combined to create complicated looms.

The most useful size has proved to be 3 mm along with the 6 mm to combine individual ruins into one bundle. Shrink fit tube with adhesive is used to tie it to the wires at each end.

Note: Aircraft Spruce has this at the time of writing: EXPANDABLE ICO-FLEX XFP SLEEVING. 

This sleeving has to be cut using a sharp edge. A used 18 mm boxcutter blade provided the ideal tool, heat to a cherry red and cut tubing then pause for a few seconds to allow end-to fuse.

Doing it again, I would have used this material when running the wires down the starboard channel, a lot more wire could have been run this way over the loom tube used - live and learn.

Ignition loom 

Wing loom for fuselage area

Typical instrument loom and switched loom for EGT

Looms various

Wire
Coloured wire as required was used in all looms and has proved helpful when sorting out looms, with black used for earth. Use of coloured wire makes checking easier if only that there can only be so many of one colour to check.

This was not possible with the shielded wire, but as these are generally wired into plugs that variation was not viewed as a deal-breaker. Once the looms are covered with the PPS, they all look the same, creating a professional look when installed.

Heat Shrink Tubing
While not a looming material, it is required to construct the looms. The most useful sizes proved to be 6 mm with 4/8 mm proving useful. A length of 16 mm was also necessary to close the ends of larger looms with the best tube the dual-wall type. The single wall was useful where bear wair in a loom had to be covered as the thickness of the dual walls does create lumps in a loom.

Cable Ties
Cable ties were used with a particular preference for miniature 1.6 mm wide, there smaller profile proved to be most useful in assembling cables behind panels

Loom Branch
To create a branch, select the point for the wire set to exit and terminate the external sleeve using heat shrink tube about 20 mm long. Fit the required length of the outer sleeve up to the branch loom and cover that end using the heat shrink then on the branch if required. Finally, cover the between the two lengths of heat shrink about 5 mm short at both ends covering the branch also.

Note: To secure the sleeving or to tape ends of the wire for looming, Tamyia 12 mm masking tape was used, as its thinner than standard masking tape and creates fewer problems when fitting a sleeve.


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