y-harness on elevator
 

Hi,

I was considering purchasing a Futaba 7CAP transmitter, but realized it did not support two elevator servos (as used on some 3d planes). I understand that two channels can be mixed together and therefore essentially accomplish the same effect, but this allows trimming of only one side of the elevator.

Is it possible to use a Servo Reversing Y-harness off of channel 2 in order to make two Futaba 3151 servos act in conjunction with each other? It is my understanding that doing so will essentially turn the elevator back into a single servo elevator with twice the torque. Is this correct?

Would you recommend any other Futaba transmitters? (I'd prefer stay with Futaba)

Thanks,

Michael

RE: y-harness on elevator
 

If your radio doesn't support running two elevator servos using a reversing Y-harness is the only way that you can do. It will accomplish exactly what you are wanting to do.

Ken

RE: y-harness on elevator
 

The chanel mixing gives you the best control. You can trim out each servo, including sub trim and throw. However the front pannel trim works like a single servo. Give it a go on the bench and I think you will be pleased. Oh yes, just don't set the mixing up as switch activated. The last thing you want is to bump a switch and end up with only one surface for control.

Don

RE: y-harness on elevator
 

Thanks guys... you have been very helpful with quick and precise responses.

Michael

RE: y-harness on elevator
 

You can also use what is called a "match box". They allow for centering and end point adjustment of the individual servos as well as reversal.

RE: y-harness on elevator
 

One of the main draw backs to the 7c is that it does not allow you to mix channels so the other options mentioned are your only choices. If you have not bought your radio, you might want to select a model that does allow channel mixing, such as the Futaba 9c. I know there are others that allow mixing, but I am not familar with all the models numbers as I am a Futaba kinda guy. Good Luck, Dave

RE: y-harness on elevator
 

David,

I'm not trying to correct you but rather learn more about this so please try not to take this offensively. What are the "3 mixes" on the specs from this site and Futaba's site? (links listed below) Do they operate differently?

BTW, I was looking at Futaba transmitters anyway. I'll consider the 9c.

http://www.rcuniverse.com/product_gu...smitter_id=129
http://www.futaba-rc.com/radios/futj69.html

Thanks,

Michael

RE: y-harness on elevator
 

The 3 mixes are any combination of the from the list below the words 3 mixes. What you are looking for is a radio that will allow you to program another unused channel to follow your elevator channel. The mixes that are listed on Futaba's web site are some what typical for most radio's. Here is the specs for the 9C. It has 7 mixes available and elevator mixing is one of them.

http://www.gpmd.com/cgi-bin/wgpinf100p?&I=FUTK9200

Don't get me wrong, the 7C is a great radio and I just love mine. I was not thinking about elevator mixing when I got mine and now that I have planes that need elevator mixing, I am using my older radios that have that feature. I just want you to purchase a radio that is going to do what you want it to do and have the features that you need. I personally believe that if you can eliminate a match box, a reversing Y harness, or a Y harness you are flying with less to go wrong. Good Luck, Dave

RE: y-harness on elevator
 

Ok...So I know we are discussing Futaba radios here, but I have a question along these exact lines for a JR radio. I am looking to get the JR XP7202 as my radio upgrade. Does anyone know if it supports two elevator servos or the type mixing needed to allow this? Everything I have heard about being able to trim each servo individually is important to me, and if this radio won't allow me to mix two servos together for elevator then this radio won't do. If anyone has any experience with the XP7202 I would love some help.

Thanks

RE: y-harness on elevator
 

I own the 7202, as well as the DX7. They both support what you are wanting to do. You will not find an "elevator mix" in the programming that is built in, but you can mix the elevator channel with any of the three remaining channels, mix them with opposite percentages, and then put them as "on" and not on a switch. This will give you exactly what you want. Works like a charm, as I have several planes set up like this.
I even have a P-51 where the elevator halves are mixed together, and then (on a mixing switch) I mixed them to the ailerons, so the elevator halves function with the ailerons (reverse of each other--like an elevon). This gives out of sight roll maneuvers!

RE: y-harness on elevator
 

Thanks for the clarification David, I'll look into the 9c.

Michael

RE: y-harness on elevator
 

2slow2matter, thank you very much for this info, it was exactly what I needed to know. I have spent a lot of time debating radios and finally had settled on the 7202. As much as I would like to go to a 9303, I just can't justify the extra cost. I have put together a list of planes that I want, and I can't find one that will use more than seven channels (this was under the assumption that I can mix dual aileron, elevator, and rudder). The only real challenge will be if I get a plane with dedicated flaps in addition to the channels listed before. I am not really into retracts, and smoke so those are a non-issue. Looking at this list, and what I expect my plane budget to be over the next 2 years (which is the time I expect the radio to last before an upgrade) I don't see myself getting into anything that will require 9 channels.

Anyway, sorry for hijacking the thread. Thanks again for the information!