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Reversing Y-harness use

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Reversing Y-harness use

Old 06-06-2015, 11:06 AM
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Sander35
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Default Reversing Y-harness use

Are '"reversing Y-harnesses" safe to use to control split elevator servos? Thanks.

Sander35
Old 06-06-2015, 11:49 AM
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Steve Percifield
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You are going to get 100 responses telling you why not. But I have used them for years with never a failure. And I mean on multiple models for years of use.. You will have to use your own judgement on this one.
Old 06-06-2015, 12:48 PM
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BarracudaHockey
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Sure, unless you're flying Spektrum, where they specifically warn against using amplified or reversing harnesses in their systems.
Old 06-06-2015, 07:15 PM
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Sander35
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Thanks Andy. That explanes my problem. I am using the Spectrum module in my JR xmtr. 😃
Old 06-07-2015, 03:02 AM
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Rodney
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I think it depends on the design of the reversing circuit. If all it does is amplify the signal (the output of most of the 2.4Ghz systems is only about 2.7volts), there should be no problem. Now , there will be a very slight shift (in the order of one or two microseconds) in the time the pulse goes to the servo due to rise and fall times of the pulse but that would be nearly undetectable by the operator or plane. If you are using some of the very old servos, some required that the signal to the servo be 1/2 the voltage of the power source so, if using 6 volts you had to have a 3 volt minimum amplitude on the servo signal thus requireing that you use an amplifier. The answer to your original question depends on the compatibility of the entire system you are using, not a cut and dried answer.
Old 06-07-2015, 03:03 AM
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BarracudaHockey
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https://www.spektrumrc.com/Experienc...Practices.aspx

Under "DONT"
Old 06-07-2015, 04:37 AM
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Originally Posted by BarracudaHockey View Post
+1 Why even risk it?

Mike
Old 06-07-2015, 05:13 AM
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Instructor
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If the radio being used has the ability to slave a separate servo to the master, reverse the slaved servo. Problem solved....

Larry/Instructor
Old 06-07-2015, 05:16 AM
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ltc
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Originally Posted by Instructor View Post
If the radio being used has the ability to slave a separate servo to the master, reverse the slaved servo. Problem solved....

Larry/Instructor
Or if your radio doesn't offer reversing, just buy a reversed travel servo or open up a standard servos and modify it for reverse travel.
Old 06-07-2015, 09:17 AM
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Rodney
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The only way a reversing Y could foul up a system is if it were radiating or creating electrical noise itself and feeding it back through the signal or power lines ( a not very likely scenario) as they usually consist of having the leading edge of the servo signal creating a 3 millisecond pulse and then inhibiting the first part of it by the duration of the original servo signal The remaining portion then is past to the second servo as it is the proper duration to give the same servo rotation in the opposite direction. The only possibility of such a circuit causing a problem is that the rise and fall times of the pulses is so fast that it is creating noise that is being fed back to the receiver (a highly unlikely situation). I would like to see what could possibly cause the Spectrum receiver to not work with such a circuit. I think they are just trying to cover their you know what should someone say that a reversing Y is causing their system to fail .
Old 06-07-2015, 09:54 AM
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Kim Couturier
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I've used them for years..no issues. You can get top quality, heavy duty ones from electrodynamics...
Old 06-07-2015, 12:20 PM
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Most radios have dual elevator servo mixing, I would check into that first. If no mixer in the TX then I would suggest a Smart Fly equalizer. The equalizer will allow you to reverse a servo if needed but also lets you adjust each servos center and end points so your elevators track evenly. It could also be used on any aplication that requires more then one servo.
Old 06-07-2015, 01:43 PM
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j.duncker
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Regardless of the method used, reversing Y or slaved reversed servo check carefully that the elevator halves move in synch.

DO NOT JUST ASSUME THEY WILL.

I can remember at least two cases where we found they did not.
Old 06-07-2015, 03:59 PM
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Instructor
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Originally Posted by ltc View Post
Or if your radio doesn't offer reversing, just buy a reversed travel servo or open up a standard servos and modify it for reverse travel.
Buying a reverse servo would be better than going inside and making a normal travel servo into a reverse servo, unless you know what you are doing. I have done that and it's only possible if you don't have a "surface mount" servo. With a surface mount servo, you don't have any wires running from the pot to the motor or amp.....

Larry/Instructor
Old 06-08-2015, 03:54 AM
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JR Matchboxes are always coming up in the classifieds on the cheap because people now have radios that do the same thing.

So if your radio does it, thats the easiest way.

Some Hitec servos are programmable, that will accomplish both the direction and matching

or a Matchbox

are probably the best way to accomplish what you're trying to do
Old 06-09-2015, 11:31 AM
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Sander35
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Originally Posted by Instructor View Post
If the radio being used has the ability to slave a separate servo to the master, reverse the slaved servo. Problem solved....

Larry/Instructor
Thanks for the suggestion Larry. I've tried mixing the ELEVATOR channel with theAUX1 channel, designating the servo driving L half of the elevator as Master and the servodriving the R half as Slave. This seemsto work fine except that the elevator Trim only trims the Master servo or left half of the elevator; theSlave servo is unaffected by the elevator trim even though the Slave servo tracks the Master servo perfectlywith elevator stick movement. Go figure !! My transmitteris a JR XP8103 with a Spektrum DM9 RF module. Any suggestions to that problem? Thanks
Old 06-09-2015, 01:28 PM
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daveopam
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There should be a place in the mix page to turn on the trim link. Just not sure where on that radio.


David
Old 06-09-2015, 03:54 PM
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Instructor
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Originally Posted by Sander35 View Post
Thanks for the suggestion Larry. I've tried mixing the ELEVATOR channel with theAUX1 channel, designating the servo driving L half of the elevator as Master and the servodriving the R half as Slave. This seemsto work fine except that the elevator Trim only trims the Master servo or left half of the elevator; theSlave servo is unaffected by the elevator trim even though the Slave servo tracks the Master servo perfectlywith elevator stick movement. Go figure !! My transmitteris a JR XP8103 with a Spektrum DM9 RF module. Any suggestions to that problem? Thanks
Hi Sander35,

First off, I am a Futaba user and I really don't know much about JR radios. I have a friend that flies JR and he said "if the radio has a dual elevator setup, use that. When you are using the dual elevator setup, both servos will trim the same"......

Larry/Instructor
Old 06-10-2015, 02:56 AM
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speedracerntrixie
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There is a dual elevator setting in the wing type menue on the TX if I am not mistaken.
Old 06-10-2015, 07:52 AM
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Sander35
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Originally Posted by Instructor View Post
Hi Sander35,

First off, I am a Futaba user and I really don't know much about JR radios. I have a friend that flies JR and he said "if the radio has a dual elevator setup, use that. When you are using the dual elevator setup, both servos will trim the same"......

Larry/Instructor
Hi Larry,

Thank you for your response. A local JR XP8103 user informed me that TRIM functions are only coupled to MIX5 and MIX6. I was using MIX1. Switched to MIX6; problem solved.
Old 06-10-2015, 08:24 AM
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Oh yea, thats right! The DX-7 did the same damn thing when it came out.

They fixed that in the 9303 and went with mating instead of having to use a P-mix
Old 06-10-2015, 12:37 PM
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Originally Posted by Sander35 View Post
Hi Larry,

Thank you for your response. A local JR XP8103 user informed me that TRIM functions are only coupled to MIX5 and MIX6. I was using MIX1. Switched to MIX6; problem solved.
Hi Sander35,

Glad to hear everything worked out for you. This is what RCU is all about, helping out others........

Larry/Instructor

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