1 servo for each elevator half problem
 

I have 1 ele half plugged into channel 2, and the other half plugged into channel 7. Set up a mix to slave chan 7 with chan 2. All is fine until I go from hi rate to lo rate , then the end point changes. I have reset the end points for both halves at the high and lo rate position , but they always seem to change when I switch from lo to hi or vice versa. If I set the rates at 100 % for hi and lo everything is fine. What am I doing wrong? Thanks.

Mike

RE: 1 servo for each elevator half problem
 

What TX?

RE: 1 servo for each elevator half problem
 

Futaba t9cap. Servos are the same brand and model (futaba). I've done split elevators before, but used a reversing y-cable. I'm guessing this is a programming issue, but I've tried everything I can think of. Any help would be greatly appreciated.

Mike

RE: 1 servo for each elevator half problem
 

The 9C TX has that mix already setup in the programming. The following is copied from the Futaba FAQ section on their web site.

Question: What is the easiest way to do twin elevator servos?

Use the ailevator function, designed for just this purpose.
Plug servos into 2 and 8
Go to AILEVATOR
Make the function active
Test your elevator movement. If one is going the wrong direction, reverse the % for that servo (ie -100%).
IMPORTANT READ ME: Do you want your elevator servos to also act with your ailerons? If NOT, you must reset the AIL3 and AIL4 numbers to 0.

The FAQ page can be found hear
http://www.futaba-rc.com/faq/index.html

RE: 1 servo for each elevator half problem
 

Thanks, I saw that but didn't realize that was the function I wanted. I'll give that a Try. I need to get this aircraft going - the season is short up here!

Mike

RE: 1 servo for each elevator half problem
 

OOPS - disregard my previous reply. I'm using a 7 channel Futaba rx, so I can't use the ailevator suggestion. Any other suggestions?

RE: 1 servo for each elevator half problem
 

Yea, I have the 7CAP too, you have to use the reversing Y cable. If you slave the second servo off the elevator, i.e. 7 is a slave to 2 the trim IS NOT slaved. I used a MPI miracle Y cable, worked great.

RE: 1 servo for each elevator half problem
 

Mike it sounds like a problem with the mix. Go to the mix page. Check to see if the "trim" and "link" tabs are turned on or off. One of these in the wrong position will mess it up. I do not have my TX in front of me or I could walk you through it.

David

RE: 1 servo for each elevator half problem
 

Thanks for the replies guys. I have the 'trim' option in the 'mix' on. This function seems to work fine - ie if you adjust the tx trim for elevator both ele halves move the same amount. I have used the y with success on a different plane, but I read somewhere that you should be able to to plug the elevator servos into channel 2 and 7 and have them function together. Which they do - except when going back and forth between hi and lo rates. I have the have dual rate set at 50% for hi and lo rate on channel 2 and this allows the elevators to work fine, but no hi rate for 3d work.

RE: 1 servo for each elevator half problem
 

What about the link option Mike. Is it on or off?

David

RE: 1 servo for each elevator half problem
 

The link function is 'off' and the trim is 'on'. From what I read in the manual the trim function allows the slave channel to follow trim commands from the master and this works fine. It's beggining to sound like I need the y-cable! Didn't there used to be a 'radio' only section on rc universe? I can't find it anymore. It seems like maybe that would be the place for this question. Thanks again guys.

Mike

RE: 1 servo for each elevator half problem
 

There is a direct support forum for Futaba.

RE: 1 servo for each elevator half problem
 

Mike I have my TX in front of me. I am going to run down my set up in hopes you can fix yours.
For starters I use CH-5 for the second elev servo. The closer the two servos are on the chanels the closer the initial movement of the two. First thing you need to do is in your menu go to BASIC (ACRO) screen (2/2) Go to *AUX-CH ---make CH5>NULL. This will let the gear chanel act normally. Otherwise it will only give full deflection one way or the other like retracts do.
Then go to ADVANCE(ACRO) screen 1/2. Pick a mix here. I use three because I have my spoileron mix on one and two. I like to set the second page up first so go to it. It should read as follows from the **bottom** up. POSI>NULL----SW>H it does not matter what switch.------TRIM>ON------LINK>OFF I also don't thinks this matters for this mix------SLV>GEAR------MAS>ELEV-----MIX>ON. Now on page 1/2 set both your rates on + or - 100% depending on how your servos are set. The offset should be 0%.
This should fix your problem. Unless you have a bunch of sub trim in one of your servo. This can keep it from giving full deflection.

Let me know how you make out.
David

RE: 1 servo for each elevator half problem
 

Thanks David. I believe I have mine set exactly as you describe, except I use mix 2. I will have to check the subtrim on both elevator halves. I may change the receiver to a 9 channel and use the ailevator function, although I really don't how that would cure this problem. It actually seems to work the way as a mix so I don't understand how it would cure the hi to lo rate problem. I'm hoping you're right and I have a big difference in my subtrims. Thanks again. It has been windy here and I haven't been able to fly anyway!

Mike

RE: 1 servo for each elevator half problem
 

The radio forum seems to be alive and well. It is called..... RC Radios, Transmitters, Receivers, Servos, gyros.

Good to hear that your problem CAN be solved with the 7 channel tx. I have the 6XEA and have to use the Y cord.... am I understanding Dave correctly that when using channels 1 and 5, that the trims and hi rate switch all work perfectly?

One problem a guy at our field had was that when setting his 6 channel JR up that way with 1 and 5, that if he advertantly hit the Gear switch while flying it would cause one elevator half to quit working right, and this caused him a crash that destroyed the plane.

Ernie

RE: 1 servo for each elevator half problem
 

Thanks Ernie. I would be leary about using channel 5 for that very reason. A mix on channel 7 should be just as good. Again, the hi and lo rates are working but the amount of travel ends up slightly different when going from hi to lo or vice versa. By the way, I did find that radio forum- I was looking for it under the airplane topic.

Mike

RE: 1 servo for each elevator half problem
 

It depends on the TX you are using. I am talking about the Futaba 9C. Once the position switch is set to NULL. The mix cannot be turned off. I also have a JR. It is like Ernie said. Bumping the mix switch will shut down one elev. At least on the cheap JR I have. The 9303 is a different ballgame.
Ernie, on the 9C it will work perfectly as I described. You owe it to yourself to save up and get a 9C. Once you get the programming down you will wonder how you got by without it. Being able to set up a plane in 30 minutes or less from scratch is worth the price alone. I also like the switch assignment. I can make any switch do any function. For example I use a spoileron mix for Waterfalls and Harriers and Elevators. I put this mix on my trainer switch. So when I want the mix I pull the switch. When I am done I just let go. It will spoil you.

David

RE: 1 servo for each elevator half problem
 

I just programmed my brand new 9CAP and QQ 86" Yak last night with a 7 channel Futaba Rec. I used 2 as master and 7 as slave. Channel 7 is a primary auxiliary channel. Channel 5 is for retracts and will take more programming to use it( I used 5 for choke on the engine).
The set up you speak of is possible and the preffered method is as I set it. 2>7 using programed mix #5, but any mix will do.
Adam

RE: 1 servo for each elevator half problem
 

Here's the answer to the problem! BAD SERVO / TOO MUCH SUBTRIM! While checking the subtrims I found 1 of the servos to be weak and strange acting. I could easily move the control surface with the servo at full deflection. This combined with too much initial subtrim was causing my problems. I replaced both ele servos fine tuned the initial trims mechanically and everything works great. I believe the amount of subtrim I had in there was really the root of the problem. Only because I was re-checking things did I find the intermittent servo problem. Thanks for your help. Maidened the plane and it flew great! By the way, this is a Goldberg Matrix 40 with a Magnum .91 4-stroke. 'There is no replacement for displacement!'

Mike -
70 degrees and sunny in Anchorage yee-haw - fly till midnight.

RE: 1 servo for each elevator half problem
 

I'm glad you found the problem Mike. I wish I had thought of the sub-trim sooner.

david