freestyln

Hi guys,
Currently puting together my CMPro Extra 300 90, and was wondering whats the best option with setting up the elevator, is it better to go dual servo's on seperate channels for each elevator half, or should i fix them and run one servo? It just seems that of this size maybe fixing them might not be as strong on both sides of the elevator and may cause it to roll out of loops etc? Any help is greatly appreciated.

joeb102072

My Feedback: (9)

Given the choice I choose duel elevator servos all day long especially on a plane that size. The issue now becomes connecting them together. IMO I like the duel channel set up but others will argue that with out a digital servo and or a throw meter it is imposible to get them to throw equally and a Y harness is the way to go. Either case is better than joining the elevator halves and using one servo. I made sort of a custom throw meter to establish an acurate throw on my control surfaces no numbers just an adjustable angle where I can fix it and switch it fromone side to the other. Eventually I will get the real 3D throw meter.

Geistware

My Feedback: (16)

If you are able to mix the channels with trim, then go with two servos.
If you cannot, go with one servo and a "Y" push rod.

camss69

My Feedback: (46)

I'm running dual servos with standard JR servos, they seem pretty close, close enough that I can't seem to tell if one is off. If you've got a computer radio use it, that's why you bought it right?

Propwash in Pa

I seem to be in the minority. For planes up to this size, I like to use on servo with two pushrods. Rods are connected together just aft the servo. Have not had any problems. For planes larger than about a 90 size, then I would go with two servos.

freestyln

Thanks guys,
Few things tho i forgot to mention, it wont be running the servo insde the fuse with a push rod, the servo's mount on the tail of the fuse externall which is good fromt he point of view i have no push rods, but makes it harder when deciding my issue, as i can either run two servo's or one, not one with a split pushrod. I am running a JR x2610 radio, so its capable of a fair bit, so it should being the worlds most sophisticated 6 channel 'supposedly'... but i like the idea of dual servo's thats why i asked, more so for the extra grunt due to the load that will be on such a large elevator i couldn't see one doing it efficiently, more to the point i'd see one servo causing the elevator to flex from point to point as the elevator isn't being pushed in the center... But basicall if i run dual servo's it means one servo will have to be in the other direction right? Otherwise they will travel in opposite directions... does this mean having a longer pushrod on one side it will effect the distance the elevator moves on that side? Any help is greatly appreciated guys! Thanks alot.

joeb102072

My Feedback: (9)

You are on the right track with your thinking on why 2 servos instead of one is better. The torque isnt as much of a factor seeing you can always get a bigger torque rated servo to handle the load. What can be a problem is the control surface deflection at the oposote end from the linkage connection. Thats where you can get your most flex and yes it can make your plane snappy on loops and other manuvers. As for running the duel servos put them in as you would to get the arms close to the elevator now you know they are equal distance apart. To run 2 separate channels for the elevator your radio has to have a reversing mode. Just asign one of the servos to reverse and bingo the're swinging the same direction. If your radio cannot then you have no choice but to get a reversing Y harness plug the 2 elev servos into that and run the harness into your elev channel on your reciever. Hope this helps.

*Crash*Johnson*

My Feedback: (7)

I had this same dilema with my CG Ultimate 60. Went with stock hardware and single servo. There seems to be a bit of play on one side so I'm thinking it's definately better to use dual servo's if the option is available.

With my arf it'd be a pain in the arse to do dual servos so I went stock, but may have to redo it to dual down the road.

camss69

My Feedback: (46)

It wasn't too much trouble, I ran two sullivan semi-flex rods, and used the two outside stock servo mounting locations for each elevator half. Make supports for the rods that glue to the formers inside the fuse. Then you just have to relocate the throttle servo, which I placed on the left side just ahead of the other three. Now I have very little play and dual servos for the elevators. I cut the covering out of the holes in the bottom of the fuse to gain access and then recovered the bottom. It's pretty painless actually and the results are worth it.

freestyln

I've decided yesterday that i am definately going dual servo's. The radio i am running is the new JR x2610 6 channel digital, but it doesn't have the 'ailervator' capability like the PC10x or whatever the higher model is. Is there some way you can run one servo off ya normal servo channel on the reciever, then use say the 5th channel on the reciever and somehow assign that channel to the elevator aswell?

But otherwise i did some research when i posted this the other day, and will just go grab one of them reversing 'Y' leads, as it will probably be the easiest. At least that way i know it will work. The best bit is that both servo's can be mounted on the tail of the fuselage externally No mucking around with pushrods and what not, so i'll run some larger gauge rods so basically there will be zero flex Thanks guys, james.

joeb102072

My Feedback: (9)

Yes, if you read my post above i have explained it. You can install the servos as normal in 2 separate channels and reverse one of the throws. The alternative is to not get e Y harness but make sure its a reversing Y harness. Plug them into one channel and your done. Pros and cons to each but both are funtional.

LuckyArmpit

My U Can Do has dual servos for the elevator. I am running JR 537's all around. I hooked them up and then ran a "Y" connector.
However, this Y connector has an adjustment knob in which that if the elevator halves are different at rest, you can turn the knob to adjust. Would be useful if you have two different servos for the elevator.

Dave...

freestyln

Okay so i have a 6 channel transmitter and 7 channel reciever, but how do i assign the second servo that i plug into say the 5th channel to operate with the elevator stick? Thats what i meant, i know i can reverse it but that doesn't mean its gunna know its being used as a second elevator control lol Thanks dude, james.

camss69

My Feedback: (46)

You just need to do a linear mix, with your elevator channel being the master and one of the aux channels (your second elevator servo) being the slave. It should explain this in the manual that came with your radio. Different mixes handle trim differently so pick one that the trim on the master channel also trims the slave. It's pretty simple and saves you the cost of buying a "Y" harness.

freestyln

Thanks dude! I'll go check the manual now!

freestyln

Good news, i have 4 programable mixes, the 4th being the one that allows digital trim adjust to both master and slave... looks like its $20 i save from the Y lead can go towards CF control rods and top quality horns and servo arms Thanks everyone, ya help was greatly appreciated!

Volfy

My Feedback: (23)

WIth most computer radios, you don't need to use the programmable mixes to do dual elevator. There are usually an "elevon" or "ailevator" mixes you can use. Just set the percentages of "AILERON" to zero with either pre-programmed mix, and you'll have instant dual elevator servo channels.

You can do the same thing for dual aileron servos.

freestyln

Wont "elevon" turn my ailerons into dual elevators? Or is it controlled by the elevator and still has the aileron channel working? Otherwise i have the ability to program a seperate mix anyway. Thanks, james.

P.s. I just finished the plane last night!! Just gotta get me an OS91fx and its off to the runway!

Volfy

My Feedback: (23)

ELEVON = elevators that also work as ailerons

AILEVATOR = ailerons that also work as elevators

These mixes are used on delta wings and such, but can also be used simply for dual elevator servos. I do this all the time for dual elevator or dual aileron servos with my 9C. All you have to do is:

1. First enable the mix, for example ELEVON
2. Set the Elevator percentages to 100%
3. Set the Aileron percentages to 0%

What you are doing is keeping the elevator function across the two servos, while disabling the aileron function. Good thing about this type of preprogrammed mixes is that trim and offset are adjusted automatically on both servos, while subtrim and end points of the individual servos can be adjusted independently.

Any more detail than that, you'll have to consult your TX manual.

freestyln

Thanks!! Thats similar to my pre-mix no.4 which allows me to mix any channel with one of my two spare AUX channels, and allow the trim from the master change the slave also, as well as individually still being able to reverse a channel. But good to know the info! Thanks alot!

*Crash*Johnson*

My Feedback: (7)

I think you mean elevators that also work as ailerons no?

I haven't tried this yet, but it's one of the reasons why I picked up a 9CAP. To make the elevators act as rear ailerons to roll on the axis.

JasonSU78

I am a rookie builder trying to assemble a U Can Do 60. I am totally stumped by the elevator setup though. I am using a Futaba 6EXA with 3004 servos through a regular Y-harness. I got the elevator setup mechanically centered, but then when I go to full deflection with the radio, one side goes higher than the other. And then on the down side the one that was low on the high side goes lower than the other. I cannot figure out how to get the same throw out of it.
I tried switching servos, and adjusting the pushrod location on the control horn to no avail. I even called Great Planes/Futaba for assistance and they were stumped.

If anyone can assist me I would be forever grateful. This silly little problem has brought my project to a halt.

freestyln

Its because either the hinge line from side to side is different or because the control horns on the control surface are in a different location to each other.. think about it.. if 1mm difference on the control horn adjustments itself for the pushrod make that much of a difference on deflection, then the position of the control horn on the surface will affect it too.\
You can adjust this tho.. if you mix into your radio to use each servo on seperate channels then you can adjust the end points. You need to make the elevator channel the master channel, and the second servo on an aux channel or even a gear/flap channel (make sure you inhibit the switch for gear/flap if you chose that channel). Once you have each channel sorted, you need to mix them in 100% each way so it will be elevator->gear/flap/aux (whichever you chose) then 100% for up and 100% for down.. and make sure you use a mix that allows the master channel to trim both the master and slave when you trim the elevator channel. Then from here you can reverse one channel so they both deflect in the correct direction, and also adjust the end point for the slave channel to match you master channels throw.

I'm not sure if your radio has this capability but check your manual.