Cockpit Building — Articles / Posts — Flaps 2 Approach

ferrules. They enable easy connection of thin wires to terminal blocks

What are ferrules some of you may ask – no they are not the undesirable neighbours that play loud music and park old cars in front of your house; they are called “feral”…

A ferrule is a small electrical connector that comes in a variety of different sizes that is very handy when connecting electrical wires. The metal needle of the ferrule is hollow allowing you to fit the correctly sized wire for maximum connectivity and faithful conductivity.

Solid Connection

1mm red ferrules connected to a terminal block

Building a simulator involves the connection of a multitude of wires to interface cards, power supplies, terminal blocks and other electronic components. Having a method to easily secure wires that ensures reliability is a great asset.

Whilst you can solder wires to the above items, it is often necessary to remove a wire for testing purposes or to add an additional function to the connection. Twisting and clamping the wire beneath the screws or under a screw tab while functional is far from tidy, and eventually the wire will become damaged with loose wire strands.

Loose and damaged wires can translate to poor connectivity leading to frustration when something does not work correctly.

A ferrule can easily be attached to the end of a small wire (22 gauge) and crimped. The ferrule needle can then be cut to size to fit into an interface card or terminal block. Ferrules come in a variety of colour-coded sizes and can be used for differing wire gauges.

A special crimper tool is used to crimp' the ferrule in place securing the wire.

I’ll submit that ferrules are not suitable to use everywhere; however, for certain applications they are useful to have in your simulator-building toolkit.

When I first began to work on my simulator, I used whatever wire was available; usually this was automotive electrical wire. The wire was inexpensive and seemed to do the job; however, there were several shortcomings.

To carry the appropriate amperage the wire selected was quite large in thickness; therefore, quite inflexible. This inflexibility resulted in the wire coming loose at connections quite easily. The thickness also made routing numerous wires quite challenging and at one stage, my simulator looked like a rat’s nest of snaking coloured wires.

After a few connection issues, I began to rethink my approach.

I have since replaced the automotive wiring with a wire grade more suitable for the purpose. The wire I use is aviation wire which is available in various gauges (thicknesses) and colour options. The benefits in using this wire are it:

Withstands physical abuse during and after installation
Has a good high and low temperature properties
Is very flexible and small enough to be run in tight places
Can be obtained in varying gauges and colours
Has a high flex life
Has good out-gassing characteristics
Has a fair cold flow property (probably not that important as the simulator is not going to altitude)

The wire can easily be obtained in rolls from supply chain stores or from e-bay. Enter the following wire reference code into either e-bay or google: Part Number: 22759-16-22-9; 22 AWG WHITE TEFZEL WIRE.

Please note, this is the wire I use (and many other builders). There is a wide variety of wire available in the market that is suitable for building, so don't become overly concerned if you've already used a different type of wire. The main point to remember is that wire is rated to the application and voltages your intending to use. The wire mentioned is ideal for all wiring requirements of the simulator with the exception of very high voltage requirements. High voltage requires a wire of lower gauge (thicker wire) to ensure minimal voltage drop over distance.

The same type of wire as mentioned above can be purchased in differing gauges (thicknesses). I find 22 gauge is a good overall gauge to use. Remember that voltage (amps) is rarely being applied to the wire continuously (exception is from power supplies).

Easy Connect/Disconnect Connectors

Often there is a need to connect a piece of wire to another piece of wire or part and have the ability to be able to disconnect the wires easily and quickly. For example, often panels must be removed from the center pedestal; having the ability to disconnect wires easily allows complete removal of the item without destroying the attachment wires!

There are dozens of connectors available for joining or extending wires – some are better than others.

I use (where possible and when voltage/amp requirements dictate) JR servo wire security clips. These little clips allow three wires to enter to either side of the connection, are made from heavy duty plastic, and have a guaranteed clipping mechanism that will not unplug itself. Search the Internet for JR extension servo clips.

For applications requiring more than three wires, or higher voltage/amps, I use a high quality terminal block, Canon style plug or a D-Sub plug. The later two requiring each wire to be very carefully soldered into the appropriate wire reciprocal in the plug. I also use Mylar quick release plugs for some applications.

All other wires that require a permanent connection are usually soldered together with wire shrink wrap. Soldering always provides the best connection.