Insulated control lines??

[Larry Renger]

What is the skinney on  insulating control lines to run an electrical control signal out to a scale model.  I want to fly a 1/2A, so the lines are pretty small.

[Mike Anderson]

You need to get in touch with Clancy Arnold - supplies the U-tronics system(s).  Also Brodak sells insulated lines and I just was given a set of "e-flite" (I think) insulated lines which I have yet to measure, so I don't know how much they will affect a 1/2A.

Also, John Vlna has been experimenting successfully with insulating his own lines using varnish and urethane coatings - see the Navy Carrier forum.

[Dick Byron]

I have one set ready to go. Insulated with connectors. They are on a brodak reel. $20.00 plus postage. .012 thick as required by rules.

[CircuitFlyer]

Larry,
 
I'm using Clancy's U-Tronics on my 1/2a electric birds.  Here's what I posted previously last Summer for low drag insulated lines:

"Here's the details of my control lines:  I still used my .008" braided steel control lines.  I stretched them out and loosely wound 36AWG (.005" dia) magnet wire around them (one turn every 6") then used a drop of BSI Super Gold foam safe odorless water thin CA glue every 6" or so to secure the wire to the control line.  Use foam safe glue, I read that regular CA will eat the insulation on the magnet wire.  At the ends I attached a small single pin and socket type of connector.  Any micro connector should do.  My total resistance - 31.7 ohms over 70' (35' x 2).  Voltage drop - .67 volts.  Current draw of my ESC - .021 amps.  Voltage out at the handle - 4.65 volts.  Voltage at the ESC under load - 3.98 volts.  (Yes, I have an oscilloscope).  The ESC probably is based on the old TTL voltage levels and should detect an input signal down to 2.5 volts.  36AWG wire used on 70' control lines should work OK.

I have to treat the lines a little more carefully as the insulation is very thin and easily scrapped off.  I have tested them by twisting them up a ridiculous amount and flexed the control surface up and down a zillion times - no wear detected and no short circuits.  In flight the additional drag was very low.  I'm guessing my insulated lines are about as draggy as .010" braided lines.  For larger airplanes and lines the added drag would be negligible."

I have put several more flights on the lines and they are still working great.  I found designing a housing for the electronics at the handle end a bit of a challenge.  What's your idea for a control handle?

Paul

[Mike Anderson]

Here is John Vlna's handle from an article he wrote for the Navy Carrier newsletter -

This is only a single channel unit - and is designed to allow control of an ESC, so the battery and Utronics are in the handle.  You can also put the battery/Utronics in the plane and just connect the control pot via the lines.

[Larry Renger]

 ???I am definitely planning on dual battery packs, two small ones, one in the handle to drive the controller, the other in the plane to drive either a throttle servo, or speed control for electric.  A 6v, 150 mAH pack in the handle, and a 4.8 v, 50 mAH in the plane should do the job.  Charge them up between flights!

Currently, (ooh, bad pun, sorry) I am thinking of a single braided line with a couple of wipes of urethane, and a solid uninsulated line, both wiped down with dri-lube.  Minimize the chance of breaking down the insulating layers!

The goal, of course, is high reliability, minimum control drag, and long life.

[Howard Rush]

Talk to Dean Pappas about his scheme.  It requires no insulation.

[Bill Mohrbacher]

Larry,  I had wondered about using only one insulated line.  I asked Clancy about this at Brodak's last summer.  He said it had been tried, but the difference in drag between the 2 lines caused some control problems; mechanical due to the insulated line tugging, not electronic!

Maybe this wouldn't be such a big problem on 1/2A?

[Mike Anderson]

That was probably from my conversations with Clancy - long ago I tried flying with only one insulated line and one normal braided line.  The insulated line had at least twice the diameter of the non-insulated one, therefore it had twice the drag.  It happened that it was the up line, and once the plane got up to speed I had my handle down between my knees and pointed straight down at the ground just to fly level.  I eventually realized that I also had throttle control - I had gutted an old RC system of its RF parts and was sending the control signals down the lines with the transmitter hanging from my belt - so I reduced throttle and landed.  Then I slapped myself in the forehead for not realizing what was going to happen before I tried it.

[CircuitFlyer]

The first handle I made was a little to bulky and heavy for the light weight 1/2A planes I have.  The latest one has a much better feel to it.  I use a 4SR44 battery (6v) in the handle.  It's about the same diameter and half the length of a standard AA battery.  The current is so low it should last a while.

Paul

[Clancy Arnold]

Larry
I talked to John Vlna about this problem.  I gave John a suggestion that he use standard lines but coat them with polyurethane paint.  John tried it this summer using two coats of paint and had no problems after a full season of flying.

The buildup in almost unmeasurable over the size of the steel. 

The reason behind my Universal U/Tronics Control handle design is that the electric motor/ESC gives off a lot of electric noise that interfears with my Single Channel U/Tronics unit using my standard hookup information.  This is part of the reason most fliers still use their three line hookup on Electric powered Navy Carrier models.

If you use either my Universal U/Tronics Handle design or any of my U/Tronics Multi Channel Control systems with two lines insulated They work fine with either Electric or Glow power.
Clancy