P51p

Hi all,
I just got a goldberg 67" edge540 as a third plane and need some help setting up the servos for the elevator. The instructions require two servos mounted inside the plane connected by pushrods to each half of the elevator. The problem is that when i use a y-harness to connect the two servos to the reciever, the servos move in opposite directions therefore the two halves of the elevator also move in opposite directions. But this is the way the instructions has described to install the servos and pushrods. So how do I reverse only one servo and not the other that are connected by a y-harness to the reciever? I don't think I can do this from my computer radio or can I?

Graham

deckerv

My Feedback: (21)

What transmitter do you use? I just used the Ailevator mixing on my Futaba 9CHF to do that on my GP Soucy 300. I think one elevator on CH2, one on CH 8 I believe


The alternative would be something like this
http://www2.towerhobbies.com/cgi-bin...&I=LXAFN1&P=ML

manks7477

You have a couple of choices. If you have a computer radio with open channels you could set it up so that two channels are mixed and set the Ele to that.

If you have to go with the Y harness you can fix your current problem by turning one of the servos around, or moving the throw rod to the other side of the servo arm

MikeL

My Feedback: (3)

Both of those might introduce a problem. Turn the servo around, and you've just changed the length of the pushrod. That'll make it difficult to get the same travel, which is likely to be just a little important. Using the other side of the servo arm may not be a great option, either.

There are two real solutions. The less expensive and less ideal solution is to by a servo that has been reversed, so that you can use it with a Y-harness. The much better solution is to buy a radio that supports dual elevator servos. Why is that a better solution? Because you then have the ability to independently adjust each servo. It's tough to get two linkages to be exactly the same physically.

bruce88123

Turn the servo around?????? That doesn't change the direction of rotation.

Moving to the other side might be a valid option if there is room.

Question is: Why are they turning in different directions in the first place if they are the same servo types on a simple Y-harness??

RCKen

My Feedback: (9)

MikeL is spot on with his advice. You don't want to turn the servo around because it will change the geometry of the elevator throws. You only have two options to set this up. The cheapest of the two is to get a reversing Y-harness which will cause the servos to turn opposite each other. The other option is to use a computer radio that can control 2 elevator servos.

Ken

P51p

I have a 6ch Futaba computer radio so ch mixing might be the simple way to do this. The elevator is on ch 2 and I guess I could use any other open ch the mix with ch2 ?

Graham

bruce88123

Which Futaba?

P51p

Can I just reverse the pins (+ & -) on the y-harness that connect to the servo. Will this also reverse the servo.

By the way I don't want to move the pushrod to the other side of the servo because this might change the throw.

David Cutler

If there isn't enough room to mount the servo arm on the other side, you will have to buy a reversing Y harness. They are quite expensive and have an adjuster so that the servos are matched.

If you use a different channel for each and couple them together in the transmitter, be careful that the trim works on both channels. In a Hitec transmitter (and probably others too) the trim will only work on channel 2, the original elevator channel, and not on, say channel 7 or whatever channel you use for the other elevator half.

-David C.

daveopam

My Feedback: (9)

Turning the servo around does nothing. They will still work opposite. Post what radio model you have. Someone will be able to tell you if it can be programmed. The reverse Y will work but you may here some horror stories about them. I have a bad story which I why I wont use one again. Sisnce you are getting into bigger and better planes think hard about getting a 9C. It is the best money I ever spent in this hobby.

David

David Cutler

If you just reverse the servo connections like this, you haven't reversed the position sensing on it. There is a wiper connector that provides a feedback and if you just reverse the motor connections it will provide the opposite direction position sensing and it won't work.

This might help:-

http://www.fatlion.com/sailplanes/servos.html

-David C.

MikeL

My Feedback: (3)

You can buy a reversed servo from places such as Servo City.

If your radio doesn't explicitly have a function for dual elevator servos, you're likely going to run into a problem when mixing an auxiliary channel to your elevator channel: trim. Trim changes you make to the elevator channel won't be properly matched to the auxiliary channel.

I suppose another option would be tying the two elevator pushrods together and using just one servo (that'll be strong enough to meet the torque requirements). Depending on the layout of the model, this might be very difficult to do.

Having to move up to a better radio is often just one of those things that comes with running a more complex model. It really would be the best way to address the problem if your current radio doesn't have the necessary capabilities.

P51p

I am using the Futaba 6EXAS radio with (4) S3004 servos.

Graham

MikeL

My Feedback: (3)

That model won't support dual elevator servos.

P51p

Do you think I will have a problem with the trim adjustments after mixing two channels

MikeL

My Feedback: (3)

Yes, but if you'd like to see for yourself just set up the servos on a bench. Program your mix, and watch what happens when you use the trim. That'll take all of ten minutes to do, and you'll have first-hand knowledge of the results. There's really nothing better than that.

bruce88123

Yep, hook em up, set the mix, then move the trim and watch only one servo move.[:@]

P51p

Thanks, I will try it tonight.


Graham

Mr67Stang

I just did this with a H9 Cap 232 and a H9 FuntanaX 100 with the same radio... I used a reversing Y-Harness. Very easy and inexpensive.

P51p

Where did you get the reversing Y-harness from?

Graham

Mr67Stang

I got it from my local hobby shop but it can be seen here. http://www.maxxprod.com/mpi/mpi-5.html#Miracle%20Y

bruce88123

http://www2.towerhobbies.com/cgi-bin...&I=LXAFN1&P=ML
another one

P51p

I tried the ch mixing last night and the trim adjustments do not work. But I did solve my problem last night by mounting the servo on its side, this gave me access to the other side of the servo arm without having to extend the pushrod and change the throw.

Graham

bruce88123

As long as it's secure and you're happy.