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Old Nov 05, 2007, 04:26 PM
I'm a pilot... 100 yrs to late
Thermalin's Avatar
USA, FL, Palm Harbor
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Question
Adding Servo Wire Length

I see servo wire for sale at the LHS and online sites but what is the best way and what is max lenght before running into interference issues. I realize each install is different and a number of factors come into play... but I'm planning on Bipe with ailerons rather short in the top wings only out at the tips.. I would like to have the servos out in the tips for a direct connection. I'm trying to stay away from using extensions with plugs at both ends as it seems like more points of failure.

Mike
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Old Nov 05, 2007, 05:53 PM
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United States, WA, Puyallup
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Go for it. Lots of modelers (me included) prefer soldered in extensions. Maximum length? Probably no rule a person can quote - do it and check. No idea what size servos you are using or how long the run, but some of the available servo wire is a bit wimpy - I prefer 22 AWG.

Bill
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Old Nov 05, 2007, 07:30 PM
You can call me FANBOY!
Goodlettsville, TN
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Use twisted wire and solder them and it shouldnt be an issue. If it is it will be due to ignition noise or something else.
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Old Nov 05, 2007, 10:59 PM
I'm a pilot... 100 yrs to late
Thermalin's Avatar
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Quote:
Originally Posted by chrisf testpilot
Use twisted wire and solder them and it shouldnt be an issue. If it is it will be due to ignition noise or something else.
So... would I clip the wire mid length between servo and plug.. insert my extra "run" in the middle? any special type solder... is some better for electrical work, etc...
This is for the proctor nieuport 17.. approx 53" span but woulid need to run the servos off a Y harness up to the upper wing. Was going with hitec HS-81's when the time comes.. plenty of power and small to preserve the scale appearance.

Test Pilot... the thicker the wire the better i presume? I assume dont go thicker than what is already there?

Twisted is better than straight?
thanks.. Mike
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Last edited by Thermalin; Nov 05, 2007 at 11:16 PM.
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Old Nov 06, 2007, 12:11 AM
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Use rosin core electrical solder - 60/40 (60% tin/40% lead); 63/37 is better. Radio Shack has both.

For that short of a span and those servos, 24 AWG is fine. You can always use larger wire (smaller AWG number), but ought not use smaller wire.

Twisting helps prevent common mode interference but most commonly available servo wire is flat ribbon and doesn't lend itself to easy twisting. For a 26" run, I'd use the flat ribbon cable.

Bill
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Old Nov 06, 2007, 10:05 AM
I'm a pilot... 100 yrs to late
Thermalin's Avatar
USA, FL, Palm Harbor
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Quote:
Originally Posted by ebill3
Use rosin core electrical solder - 60/40 (60% tin/40% lead); 63/37 is better. Radio Shack has both.

For that short of a span and those servos, 24 AWG is fine. You can always use larger wire (smaller AWG number), but ought not use smaller wire.

Twisting helps prevent common mode interference but most commonly available servo wire is flat ribbon and doesn't lend itself to easy twisting. For a 26" run, I'd use the flat ribbon cable.

Bill
Great... thanks.
Mike
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Old Nov 06, 2007, 12:02 PM
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I just had an extension come loose. Might have been because the plane fell 15' out of a tree nose down onto pavement, can't be sure. Soldering in the wire is a good idea, maybe I'll do it for this plane.
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Old Nov 06, 2007, 12:37 PM
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Yes, soldered in extensions are far superior to plug in extensions. Yes, use as large or larger wire than the original servo wireing. It is doubtful that twisting the wires will help in any way other than to make the run a little neater phyically. Twisting is only needed when in high AC field and common mode signals would get you in trouble, things that do not exist in your model. Your biggest problem will be any losses in the power leads if you have high current (digital) servos and even then it is doubtful that that will be a problem.
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Old Nov 06, 2007, 03:44 PM
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Quote:
Originally Posted by Thermalin
So... would I clip the wire mid length between servo and plug.. insert my extra "run" in the middle? any special type solder... is some better for electrical work, etc... This is for the proctor nieuport 17.. approx 53" span but woulid need to run the servos off a Y harness up to the upper wing. Was going with hitec HS-81's when the time comes.. plenty of power and small to preserve the scale appearance. Test Pilot... the thicker the wire the better i presume? I assume dont go thicker than what is already there?
Twisted is better than straight? thanks.. Mike
1. Available from your LHS 3 Colour Servo Lead Wire 50FT (15.24M) . Recommend attaching new lead direct to servo board and adding the original lead to the end of the extension. Only one join and original plug is retained.
2. The Nieuport 17 is to big and heavy for HS-81 servos. Whilst powerfull, they are designed for use in easy flying gliders and many EP models, the gears are to thin and will quickly strip if used for ailerons in that Nieuport 17. HS-81MG specifications = 1/2A or throtttle when used with GP models.
Refer to 101 - Servo FAQ & picking the right servo for the job As a minimum, suggest use of HS-85MG+ specifications. or HS-125MG specifications, preferably HS-225 specifications.
3. Extension leads were always twisted in the days of AM systems but not required for typical FM instalations except where digital servos are being used and which also use heavy duty leads. A flat lead may be twisted if using either AM RC system or Digital servos by clamping one end in a vise and grip other end in a drill chuck. For such short leads, should not be necessary, but a Ferrite Filter / RF Choke could be included close to RX. examples:
Ferrite filter (RF Choke)
Snap Shut Ferrite Chokes
Regards
Alan T.
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Old Nov 06, 2007, 08:52 PM
PGR
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United States, CA, Costa Mesa
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If I can find some the right length, I use plug-in extensions in a hybrid role:

I remove the pins and sockets from the plastic housings on the ends of the wires to be joined, slip some small heat-shrink tubing on the wires, plug them together, sweat some solder into the joints, and then insulate each joint with the heat shrink.

I don't think there's any real advantage to doing it this way versus just splicing the wires together except it's a lot faster and you end up with a nice joint.

Pete
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Old Dec 02, 2007, 03:59 PM
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Madetswil, Switzerland
Joined Jul 2006
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How to insulate soldered connections for wire extentions?

Hi there

Just a stupid question: after soldering the three wires of a servo extention, how do you insulate it?

Do you use three separate heat shrink tubes, one for each wire? When I tried this the plastic insulation of the servo wire wanted to melt before the tubes really shrinked

Are there maybe any better techniques for insulating the soldered parts?

Thanks for your hints - Wolfgang
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Old Dec 02, 2007, 04:07 PM
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United States, WA, Puyallup
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Yes, three separate shrink tubes. I use regular heat shrink and hot air and the insulation does not melt.

Bill
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