setting up dual elevator servos?
 

I have purchased a plane that uses dual elevator servos and need to know the best way to go about doing this. I have a JR 600 radio. Do I use the elevon mixing option? I am not sure my radio will even work with dual elevator servos? If the radio will not work with dual elevator servos what are my options other than redesigning the airframe for a single elevator servo?

RE: setting up dual elevator servos?
 

I do not know anything about the transmitter. Assuming it does not support this there are two simple options.

1. Many JR servos are available 'reversed' and they are noted with an R at the end of the part number. An example is DS821 and DS821R. The DS821R costs about $10 more than the DS821. Here is a search with several results
http://searchrc.horizonhobby.com/ind...reverse&N=5519

2. Buy a reversing Y harness and plug both elevator servos into it. I found these for $14
http://www.radicalrc.com/shop/?keywo...h&cart=2129213

I would choose option 1 rather than adding a bunch of extra connectors.

RE: setting up dual elevator servos?
 

I am not familiar with the JR600 radio. I just looked up the specs on the JR SX600. It looks like an Entry Level computer radio. It does not appear to have Programmable Mixing.

You need to tell us what type of aircraft you are planning to use with this radio.

Normally, a typical 6ch plane would have Throttle, Ailerons, Elevator, Rudder, Retracts, and Flaps. If you have a servo for each Aileron half and a servo for each Elevator half, you would join the Aileron servos together, with a Y harness and plug that into the Aileron channel. You would join each Elevator servo together, with a Y harness, and plug it in to the Elevator channel. You could also use a Matchbox, instead of a Y harness. This would allow you to not only join pairs of servos together, on one channel, but you can Reverse one of the servos ( usually necessary with Dual Elevators), and you could Match the servos for Neutral and Endpoints.

Your Tx does not appear to have any Programmable Mixing. If it did, you could put one Elevator servo on the Elevator channel and one Elevator servo on the Retract channel. This would allow you to mix the two channels so that the Elevator was the Master channel and the Retract channel was the Slave channel. This would allow you to Reverse one channel and adjust the Endpoints so the Elevator servos match one another.

Delta Wing (Elevons) is designed to use the Aileron halves as both Ailerons and Elevators. It usually defaults to mixing just the Aileron and Elevator channels
Flapperons are designed to use the Aileron halves as both Ailerons and Flaps. It usually defaults to mixing just the Aileron and Flap channels. Some people use this mixer to just to have more control over each Aileron half and they turn off the Flap component so the Flap Knob or Switch does not work. Others like to use Ailerons as Flaps because they plane does not have separate Flaps.

Vtail mixing defaults to mixing the Elevator channel and the Rudder channel.

Either way, without Programmable Mixing (which lets you pick any two channels and mix them), you can't really set up Dual Elevators, with this radio, unless you use a Y harness, or a Matchbox.

If you plane is a Delta Wing or a Flying Wing, where Ailerons and Elevators are the same control surfaces, you could use Delta Wing mixing.

RE: setting up dual elevator servos?
 

The plane is a Fliton Edge 330 Freestyle. I guess I will either have to upgrade radios or convert the plane to a single elevator servo. I have heard that it is impossible to get the elevator haves in sync using a Y-harness.[:o]

RE: setting up dual elevator servos?
 

If you are using Hitec Digital servos, you can program them to be identical and track one another. Even with a Y harness, you can still get close, with mechanical adjustments.

A Matchbox type device replaces the Y harness and allows you to adjust each servo to Match. It is about $60. It can accept up to 4 servos, so it can be used in more advanced planes when the need arises.

RE: setting up dual elevator servos?
 

To be honest if I have to spend money, even just $60, I will probably use that as an excuse to upgrade radios (I can buy a good used 72mhz radio right now for little or nothing). It seems there is an option on the ARF build to use a single elevator servo. If I am happy with the single servo set-up I will wait to purchase a better radio, if I fell the dual elevator set-up is much better I may try with only a Y-harness and if that does not give me the precision I need I will look about purchasing a radio with elevator mixing capabilities.

RE: setting up dual elevator servos?
 

I worked in IT for many years. I still do it on the side. There reaches a point where upgrading Old equipment is too expensive and buying New makes more sense, financially, not to mention the increased performance. So I understand your dilemma.

You will find that a Matchbox is not a total waste of money. I am using two in my H9 P47-150. I have an AR9000 Spektrum Rx and a JR XP9303 with a Spektrum module. Even with 9 channels, I still needed the Matchbox for Flaps and Elevators. I mix Retract halves, on two channels, so I can slow one down to make it scale. I mix Aileron halves on two channels. I use one channel for Fiber Optic Kill switch.

I have a friend who was using a Spektrum DX7 radio, in a BVM T33 jet, and still had 4 Matchboxes. This was reduced when he bought a JR X9303 2.4.

Bottom line is you can always use them in the future or sell them.

I can understand the cost factor. Try the Y harness, however, you will probably need a Reversing Y harness as one Elevator servo will need to be Reversed. The same would be true for Flaps. On 72Mhz, I was having problems with RF noise being picked up by the Reversing Y. I replaced it with the Matchbox and the problem went away.

RE: setting up dual elevator servos?
 

Dual elevator (Ailevator mixing) is not supported with that TX
Servo - DIY Reverse Rotation
Servo - DIY Reverser, Driver, Direct Controller and other mods.
Servo - Reverse operation . DIY pictorial
More umder sub section "'Servo - Modify for Retracts, Number of Turns, Ganging, Reverse & Continuous Rotation" at
Alan's Hobby, Model & RC FAQ Web Links
Regards
Alan T.

RE: setting up dual elevator servos?
 

Your case is why most new people buy better radios. They get a plane that need the higher end software in the better radios. You will not like the Y-harness set up. you'll never get them to work right. And your other idea about buying a used second radio will cost you more money in the long run then you'll save now. Find a radio that will do more then what you need now and grow into it has your planes get more advanced. Buying a used 72 now will only get cheaper later when you what a 2.4. It will cost you more later. Look at the Futaba 7C or the DX_7. If your budget allows maybe even the 10C or 9303 and not need a radio for many years. Dennis

RE: setting up dual elevator servos?
 

Hi gentlemen,So are you all saying that on my new 1/4 scale Super Decathlon i will not be able to match the split elevators enough with just manuel adjusting?I was going to mount the servos oposite sides of oneanother and have one arm pointing north and the othe south.I realize that the control rods will be alittle different in length but i just thought it could be done.If anyone has more ideas please let me know.I am useing the DX6 and have for some time and really dont use mixing at all.Do i have to change if i am used to flying straight stick out of the box?My last plane was 7.5 lbs and 65inch Decathlon.I dont want to put this new beauty in the ground so guys let me know what to do.Thanks DEAN

RE: setting up dual elevator servos?
 

Dean - you can certainly fly your decathlon with your approach. You can get pretty close by making mechanical adjustments. On a plane like the Decathlon, if one elevator goes up (or down) a little more than the other it will still fly fine. I have a plane with one elevator on the fuselage side ABOVE the elevator (horn is on top of the elevator) and the other side the elevator servo is on the fuselage BELOW the elevator (control horn is on the bottom). I can then use a simple "Y" connector.

RE: setting up dual elevator servos?
 

Thank you for the response.I keep asking and getting alot of info so that i have know misshaps on her maiden.I believe ive made up my mind to go with the y connect and adjust as close as possible.The Decathlon is a pretty forgiving plane in RC not quite as good as the Cub but i know it will be fine.Thanks again and a recent pic on Rc Universe under member photos.Thank you,Dean Borchin

RE: setting up dual elevator servos?
 

When you use Dual Elevators and Dual Flaps, you almost always have to Reverse one of the servos. Putting the Servo Arm on the Opposite side of the servo, especially when the servos are on the side of the aircraft, like in your case, causes a mismatch in the geometry and the surfaces track a little differently.

Since there are other options available to you, why settle for an out of whack aircraft. If you have enough channels in your Tx and Rx, mixing the Elevator servos on separate channels is the easiest choice. If not, using a Matchbox device is the next best choice. You can match Neutral, End Points, and Servo direction. If you are using Hitec Digital servos, you can borrow a Hitec Servo Programmer from someone and match a number of different parameters.

You may be able to get away with just mechanical adjustments in this plane, but at some point, putting servo arms on opposite sides of the servo will get you into trouble.