Splicing servo wire via solder over pre-made extensions.
 

I just got through reading this thread [link=http://www.rcuniverse.com/forum/m_1505049/anchors_1505049/mpage_1/key_extending+servo+leads/anchor/tm.htm#1505049]Wire Question?[/link] and was wondering if I would have the same concerns by using regular wire designed for servos such as MPI 20 gage.

I just purchased a 10' roll of MPI 20 gage JR/Hitec wire to use in my first most expensive application the CA models 27% extra kit. The method I was going to use it in was to extend the servo leads form the tail mounted HS 5945's by splicing via solder thus extending the servo wires them self.

I was told that this would create less resistance thus giving me a better connection. The wire given is it any better suited then the Radio shack wire? Also my only other concern would be that by cutting the servo lead for the splice would this void the warranty of the servo?

Any help here would be greatly appreciated.

Thanks
Blackie

RE: Splicing servo wire via solder over pre-made extensions.
 

Makes it a ***** to replace servos.

RE: Splicing servo wire via solder over pre-made extensions.
 

Ran this through my head and can't figure out what you mean.

RE: Splicing servo wire via solder over pre-made extensions.
 

As long as the wire gage is the same, there will be no difference in performance. I prefer the wire that is made up of many small diameter strands rather than a few larger diameter wires as it is much more flexable and resistant to vibration problems. you are correct in thinking that soldered connection versus commercial extensions is much more reliable. To often, the extensions will slowly corrode at the connectors and, while working great initially, will eventually cause problems. This is most evident when there is a hidden connector that never gets exercised to wear away any minor corrosion at the contacts. Yes soldered connectors are much more reliable.

RE: Splicing servo wire via solder over pre-made extensions.
 

If your extension is soldered directly to the servo lead, you've got to cut/solder to replace a servo rather than just unplug it and pop in another. If you're proficient at soldering, no big deal. I guess it does mean you can't change servos at the field easily; but I do not carry spare servos to the field anyway.

RE: Splicing servo wire via solder over pre-made extensions.
 

Oh well that's what they make fishing string for. :)

RE: Splicing servo wire via solder over pre-made extensions.
 

I gave up using aileron extension a long time ago and do as you described. Just cut the servo lead and splice in a custom length of servo wire with six solder joints. Much preferable to my way of thinking than bunchs of extra plugs. For replacement it is not a major effort to just cut and splice agine.

In warrenty issues it has never been a problem with Hitec.

John

RE: Splicing servo wire via solder over pre-made extensions.
 

I have done both and I dont think it matters at all. I have often soldered in and extra pc from 4-20" especially for ailerons and it works well. I have also sent 2 servos back to hitec for warranty service and they covered them both with the extension leads soldered in place. As far as resistance etc, I am using 4 feet worth of extensions in my 33% extra. Airwild sells a very nice HD twisted extension that works quite well. I have a 3 foot airwild and a 1foot HD to get the elevator leads in my extra (servos are in the stab) and it gives me no problem whatsoever. More important IMO is good seperation from other lines, antennas, pull pulls other leads etc. If you use the extensions just tie a pc of string thru the extensions to keep them from coming apart and use gold plated connectors

RE: Splicing servo wire via solder over pre-made extensions.
 

My 2 cents worth

The critical point is where the solder stops! At that point you have a discontinuity - a little bit like the junction between the sand and the ocean.

On the one side you have something that can give, and on the other side you have something that gives easily (the stranded wire). The likely point of failure is at this point. depending on how far up the wire the solder wicks, it could be some distance from the joint.

For maximum reliability, what you want to do is reduce the discontinuity, my suggestion would be multiples layers of heatshring, start out with a long piece first, and then progressively shorter pieces on top of that - each one centred over the centre of the previous one. Practically, anything more than 2 layers is getting a little silly, but make sure that the shortest piece extends past the point at which the wire has gotten stiff (i.e. the point where the solder has wicked up the wire to).

Having said all this, the smaller the individual stands are, the less likely they are to break at the discontinuity (a small (in x section) piece of dowel bends more than a think piece before breaking), but what you really want to do is reduce the bending movement (vibration) at the discontinuity - hence the heatshrink.



Villy

ve6sq

RE: Splicing servo wire via solder over pre-made extensions.
 

My proof reading skills are showing their lack again

in my previous,

for

On the one side you have something that can give

read

On the one side you have something that can't give

RE: Splicing servo wire via solder over pre-made extensions.
 

I don't know if I would worry about giving/not giving on solder connections as the wire would probably just lay somewhere in the fuselage and vibrate a little.

I suppose the best connection would be to wrap both ends after tinning, and then solder while making sure you have a good, hot joint. If it has that satin look, don't trust the joint. Use a piece of good quality heatshrink tubing that will cover a generous portion of the the wire insulation on both ends. Don't get Radio Shack tubing. It is very cheap stuff that may turn brittle. Get the softer tubing that has a dull look to it. Good tubing costs more, but it always worth the extra buck or two. Shrink on both sides of the insulation so that each end of the wire holds the center solder connection firmly.

The thing that I don't trust in any connector are the cheap ends that are crimped and shoved into the plastic shell. That is where vibration will work these cheap connections loose, imho. A good solder connection is infinately better.

RE: Splicing servo wire via solder over pre-made extensions.
 

There was a post last year about the effects at the end of the solder joint. The person was an engineer for Nasa or Boeing. Do a good solder job and use heat shring tubing on each joint, and then over the whole wire. Do a search for soldering and it should turn up.

If you are goinf to this much work, I would suggest using dean's connectors where you plug in power, wings, and stabs.

Mark

RE: Splicing servo wire via solder over pre-made extensions.
 

NASA does not agree with you. They specify crimped connectors. It seems there is no way to inspect a soldered connection.
The problem with our connectors is the manufacturers no longer use gold plating. Too bad.