Whatever you fly these days, you'll be needing plenty of these!
Servo extension leads can be purchased from most retailers but in my experience, only in limited pre-set lengths. Now while these are perfectly fine for most people, if like me, you have to have things 'just so', then why not make your own?
Before I start, I'm well aware that in this hobby, if there are 10 ways to do something there will be 20 opinions. What follows then is what I do, a method that's served me well for the past 7 years or so.
2. The knowledge and confidence to do so
3. Practiced the technique
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Why make your own? Well not just to save money, in fact the initial first few will cost more than the ready-made alternatives essentially through having to buy the tools and materials required. For me it's a case of having the correct length for the run, and as we will see later, the correct plug/socket to make life easier at the patch.
This crimp tool comes with the Al's Hobbies starter kit.
Cable – Cable comes in two colour types JR & Futaba and in several sizes. Long servo runs with small cable can mean that you wont be able to draw enough current to drive the servo, or hold the servo against the forces in flight. For this reason you will need to at least match the extension lead cable with the same cable as used on the servo. As a rule of thumb I would say it is fine to use cable that's larger than fitted to the servo (I do); but it's not recommended you use smaller.
There's plenty of cable to choose from, try and match the thickness to that of the servo. If in doubt go large, not small.
Plugs and sockets – there are many suppliers for these but buy those that match your equipment, if in doubt use JR as they are more universal (see list at the end).
HOW WE DO IT
First, measure the length of extension you will need, if it's for wing mounted ailerons then cut 2 lengths the same. I tend to make one end, fit it to the servo and then make off the other end to suit, with a little bit of slack.
Once you have your length, unravel the wire or tear the strands apart so you have some (small) length to work with. This is where the twisted cable comes into its own in that you can unravel more than you need knowing that you can twist it together again.
Decide if the end you are wiring is a plug or socket and use the correct terminals.
The terminals have 2 different grips, strain relief for the insulation and electrical joint for the wire, it is important that you insert the wire such that each is in it propper position, as shown in Pic.4.
Pic.4 – It's important to have the wire in the correct position.
Care must be taken to insert the terminal into the crimp tool the right way round, (refer to the instructions that come with your crimpers). Once you have applied full pressure which usually means squeezing the crimp tool together as hard as you can, the terminal will be very tight in the tool, some gentle easing is required to release the terminal and once out, give it a good tug to check it is secure.
Better quality crimp tools have a ratchet that you have to squeeze beyond to release the crimp head, this ensures that enough pressure is applied to make the termination properly.
Once done it should look something like this (Pic 6).
Pic.6 – Crimped and ready to slide into the casing.
Fit your plastic plug casing to suit, taking care to insert the terminals, not only in the right positions (refer to an already wired servo lead here) but also the right way round so that the catch on the case engages with the terminal. Give a final tug to check security.
SPECIAL PLUGS AND SOCKETS
This is where being able to make your own leads really comes into its own. A lot of models these days use a servo in each wing, which means 2 sets of servo wire to go into the receiver, imagine having a servo for each aileron and flap, that's 4 sets of servo wires (12) wires!
Some of the products available from Ashloc.
What you do is remove the terminals from your servos (unfortunately they are not compatible with the Ashtek cases) and follow the instruction above.
Pic.9 – The E Blaster connector.
I've also rewired servos and just terminated with a plug, but care must be taken when dismantling a servo. Be aware also that you may void any warranty in doing so.
Long cable runs can, in some circumstances, pick up noise which can find its way into the receiver and cause glitching. A common method to eliminate this is to use ferrite rings at the receiver end. Wrapping the servo wires around ferrite cores a few times cancels out this noise. Its easy to fit ferrites before you fit the cases but don't forget to leave extra cable for the ferrite when cutting the lengths.
Well, that's it. I do hope this has helped show that with a little practice, you too can be making bespoke extension leads, saving money and making life easier.
www.robotbirds.co.uk (see Shopping Partners link on this site)
www.alshobbies.com (see their advert on this page)
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