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Reversing Y-harness and different travel on elevators

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Old 11-27-2002, 05:08 AM
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Rcpilot
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Default Reversing Y-harness and different travel on elevators

I am using dual elevator servos on my H9 Cap 232 ARF. I am using an Expert Reversing Y-harness.

I am having troubles with the amount of control surface travel. One elevator moves up 1" and down 1 1/8". The other side is completely opposite. It goes up exactly 1 1/8" and down 1".

The control rods are the same length. The control horns are mounted identically. The servo horns are mounted identically.

Whats the deal here? It seams like the servos travel more in one direction. Thats why they are both moving more in opposite directions.

Only solution I can come up with is to use a standard Y-harness and mount servo horns so that they push from the same side of the servos. Or: I can mix the servos together on different channels. The problem with mixing is that only one servo (master) will respond to trim tab inputs from the transmitter. The slave servo will not respond to trim tab inputs from transmitter. Kinda hard to trim plane like this.

JR 652 radio with Hitec 625MG servos and a 6Volt 1650mah niMH pack.

Anyone have this problem before? How did you fix it?

Thanks
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Old 11-27-2002, 05:12 AM
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Default Reversing Y-harness and different travel on elevators

get an Equalizer or Matchbox
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Old 11-27-2002, 05:24 AM
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Default Reversing Y-harness and different travel on elevators

Can I run a JR matchbox with Hitec reciever and servos?

Where can I buy an equalizer? What is an equalizer?

Thanks very much for the input.
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Old 11-27-2002, 05:27 PM
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Default Reversing Y-harness and different travel on elevators

Originally posted by Rcpilet
Can I run a JR matchbox with Hitec reciever and servos?

Where can I buy an equalizer? What is an equalizer?

Thanks very much for the input.
I'm sure the Equalizer will work, and pretty sure the Matchbox will.
Get the scoop on the Equalizer at:
smart-fly.com
It will allow you to reverse one servo and set the neutrals and end points.
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Old 11-27-2002, 06:55 PM
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Default Reversing Y-harness and different travel on elevators

Another easy fix is to swap out the servos for two hitec digitals. You can easily reverse one using the programmer or hitec can do it for you for free. This makes setup a breeze. The servo's cost about $50 a piece. The matchbox would work but it would probably be cheaper to just sell you 625's and put the money towards some new digitals.
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Old 11-27-2002, 07:36 PM
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Default Reversing Y-harness and different travel on elevators

I had the same problem with a servo reverser, the travel would not remain constant. I learned how easy it was to simply reverse one servo (Hitec 625) and had no more problems.
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Old 11-28-2002, 12:12 AM
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Default Reversing Hitec 625MG?

Barry:

How do I reverse the Hitec 625MG? Is it a simple matter of resoldering the + and - wires on the board?

I'd really like to know how to do this. It would be the cheapest fix for me and it wouldn't cost $50.

The Equalizer ll is $45+shipping and a JR Matchbox is about $69 at the LHS.

I won't get the digital servos. Yes, they would cost about $50 apiece, but when you factor in the price of the Hitec gizmo to calibrate these servos, it's gonna be VERY expensive.

After looking around at Smart-fly.com: I've been leaning towards that idea. The Equalizer ll has + and - endpoint adlustments as well as neutral adjustments. I'm sure it would do the job, but I hate to spend the $50 if I can reverse the servo internally by myself.

The JR Matchbox would work, but I believe that it a bit overkill for my application. It's designed to run up to 4 servos and it costs $69. The Equalizer ll only costs $45 and it's specifically designed to run only 2 servos.

Thanks for the input.
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Old 11-28-2002, 06:03 AM
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Default Servo reversing

I got the servo reversed. A fellow club member is an electrical engineer. A quick phone call to him and I got things figured out.

I reversed the wires on the servo motor and the servo pot.

Everything works great. Servo travel between the two is identical. I don't think I'll ever buy another reversing Y-harness again.
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Old 11-28-2002, 12:58 PM
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Default Reversing Y-harness and different travel on elevators

I reversed the wires on the servo motor and the servo pot.
Yea that's it. Simple, fewer failure points and my favorite, cheap. The only better way is to plug the two servos into different ports in the receiver and control things from the radio, but if like me you have an Eclipse you can't do this.
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Old 12-03-2002, 04:20 AM
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Default Reversing Y

I had a reversing Y purchased from Max products in a brand new airplane. It flew beautifully for the first 3 minutes, then suddenly everytime I input up elevator, the aircraft would roll to the right.
The only way to gain altitude was to roll either left or right onto a knife edge and apply rudder. Try flying an airplane with this going on. When you applied up elevator, you could hold it level with the ailerons; however, you could not gain altitude unless you rolled to one side and then applied high side rudder. Needless to say, it was only a matter of time before I got tired of flying rolling circles and the inevitable crash resulted.
A friend of mine had one installed in another 1/5 scale warbird and on his taxi to the runway, he noticed that one elevator was up and the other was down. If this had occurred a few minutes later, he would have lost his aircraft.
I will not install another one of these reversing Y's in any of my airplanes. If I can't reverse a servo internally or with a mixing radio, then I will not use any type of installation that requires two servos to go in the opposite direction.
When I contacted Max Products about this problem, he said "no problem", end of conversation.
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Old 12-15-2002, 12:37 PM
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Default Which Wires to swap

Good Morning. you've got some good info going here. I disassembled my airtronics servo and found three wires, Just to verify, which wires do I swap? The + & - or something else. Thanks. Moose.
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Old 12-15-2002, 12:43 PM
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Default Normally

You would reverse the positive and negative on both the motor and the pot.
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Old 12-15-2002, 03:11 PM
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Default Reversing

Yep thought so.
Thanks BOB-NJ You've helped me solve the problem. I really did'nt want to use a reversing y-harness. Thanks again. Moose
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Old 04-24-2003, 03:57 AM
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Default Reversing Y-harness and different travel on elevators

Hi, I am new to the forums, and I came across this subject in reversing a servo without a reversing Y harness. I need to be able to do this to enable 4 wheel steer on an R/C truck. Sorry if this is the wrong forum, but I saw the subject and wanted to know how to do it. So to do it, I just reverse the red and black wires on the servo motor, and the pot. What exactly is the "pot." Is it the connector that connects into the receiver or part of the Y... etc?

Thank you for your time.

Thmaxxer
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Old 04-24-2003, 03:10 PM
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Default Reversing Y-harness and different travel on elevators

"Pot" is short for potentiometer. I don't mean any disrespect but if you can't identify it maybe you should get some one to help you. I did this on a Hitec servo but I'm not sure you can do it on all brands. Do a search on the subject and you will probably get more responses / more help. That's how I learned to do it.
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