Hi,

The plan for my 1/4 scale sopwith pup,shows the split elevator,is controlled using two servos,one for each side.
What i would like to know,is it safe to link the two elevators,and only use one servo,i intend to pass on the push rods,and try and install a closed loop system instead.
Any thoughts and advise very welcome

Cheers
Eindecker

But, are you trying to save weight, money, or just possibly have a radio that doesn't provide for split elevators?

Hi,

Edge, i thought it might be easier to setup,ive not tried two servos before,but was wondering if its possible to get away with it .
Radio will allow two servo operation if need be!!

Eindecker

sent you a note...

just use a 'y" harness with a reverser. i like them because you can dial them in perfectly with the dial built in to the harness.

Yep..."servo reversing Y-harness" is what makes it a piece of cake. I also have capability to mix, when using an 8 or 9ch receiver. For 7ch I just get the above reverser, it has micro adjustment, and only runs about $10 through horizon. I've used several without a prob. Expert part# EXRA325 (I hope that's right) just double check me if your interested. It makes it a snap to do.

Hi,

Thanks guys,ive just discovered that my tranny is not able to mix two servos for elevator,so it looks like i will have to go for the y connector with servo reversing,is it possible to make sure they travel at the same rate,or will the reverser take that into account,from what i can gather as a newbie,does this mean i must find two servos that are travelling at the same speed,or very near to each other?
Your input always welcome

Cheers

Eindecker

Don't bother with the reversing Y-harness.

The problem with them is this: Many servos travel more in one direction than the other.

For example: Lets say a servo travels 60degrees at positive throw and 55degrees at negative throw.

Now that you have reversed the servo on one side of the elevator, you have created a problem wherein one elevator half will move up; let's say 1" and down 3/4". The other elevator will EXACTLY mirror the first, BUT backwards. It will move up 3/4" and down 1".

I had this problem with a 1/4 scale Cap 232. Not pretty when you try to do a loop for IMAC. The plane will corkscrew through the loop because one elevator moves up more than the other.

A simple solution to this is this: Take the servo apart and reverse the wires on the MOTOR and the two OUTSIDE WIRES on the pot.

This makes the servo work backwards, and the throw will mirror the other servo in the same direction.

Hope this helps out.

Hi All,

I admit it,not reading the instructions doesnt help matters!!!,i spent an hour or so,searching for my tranny instructions last night,and read them from front to back,now when i came to the very last page,guess what,two spare mixing channels are available!!!!,so it looks like my problems could be solved.
I still have alot of work to do yet before i install radio gear etc,so i reckon i will have more questions for you all in due course!!!!,i have another problem to overcome,which i will ask your help for in a new thread!!!,but many thanks for your advise sofar,things are looking much more possible now!!!

Cheers

Eindecker

You can also try one Hitec and one Futaba servo. The rotate in opposite directions. If the speed is the same (or close) you should be OK.

kis keep it simple use 2 same brand servos and put a "y' with a reverser. has never failed me.

Yes, there is an adjustment pot on the y-reverser I named above. It allows fine tuning if your servos are not equal. It's the most reasonable on the market right now, and it is considered heavy-duty as well, so it's very applicable to larger planes with powerful servos, and/or 6volt systems.

And for sure use same brand servos, there's really no reason not too.

If I counld not mix with my radio, I would get a different radio before the servo reverser, accident waiting to happen.
If you have a futaba, plug inti 2&5 go to Ailevators. 0 out ailerons
adjust your elavator, this way your trim will work as well.
Servo reverer will work for a while but seen far more trouble with them.

lucas, it won't work with the 6ch's. You can't mix ch5. Unless I'm mistaken here, and I missed something in my experiments, I've tried it several different ways with a 6XAS and I couldn't get it to work, at least the exact way that it needs to. Sure, I could get servos to move, but the lesser radios don't have parameters for an advanced mix. Please explain the steps here, and your experience at doing this, at least with anything less then an 8UA. Even on that radio, or the 9C you can't mix ch5. I have it set up on my 9C with no prob at all, that's using a 9ch radio though, and it calls for ch2 and ch8 for mixing.
I'm using the same Y-harness that I recomended, for my H9 Edge, and also have one on a CG Sukhoi. I always eliminate the Y's where possible, and I have had my shares of prob's with them, almost lost a DagoRed due to one.
I ran across this brand, and to look at it, you can tell it's not of the same variety of the flimsy "brand name" harness's. It has a real solid feel to it, and the wiring, and make-up look well above average. Not everyone can afford a new radio, and really there's no need to, as one can have just as much prob with a new radio as everything else. New radio does not guarantee a thing. I wouldn't recomend anything that I dont' have experience with, and this Y-harness, I do have plenty of experience with no problems.

What's your experience here lucas?

I have the 9 zap it works just fine on 2 & 5 There are alot of guys setting there elevators up like this but they do all have 9zap.

I had a brand new Y-harness with reverser by futaba last summer for a new 1/4 Extra that had dual elevator servos. I'm not sure if it is only designed for 4.8 volts, or what pack I was using for that matter. I use a 6 volt pack now, but during the time of set up, I think I was using a 4.8 pack. Anyhow, right after I got it all set up right, I was tieing my wires in so they wouldn't move, and it went dead....I don't think I even pulled the wires that tight. but if it had failed during my maiden flight, I would have been very upset. I took it off and mixed them on the ailevator menu. Futaba sent me a new one, I am saving it to use for my P-40 on its flaps.
If your still working on the elevators, you could tie the elevators together, making sure the hinge line is in-line, else they would bind, and ganging 2 servos together using a servo to servo to pushrod setup, or just going for one of futaba's $35 1/4 scale servos. You would loose the independently adjustable feature, but it would be ok as long as you took the time to make sure everything was lined up. If you Y-yoked split elevators together,and ran a single pushrod down the center, (regardless if it were to 2 servos or 1 big one), you have to watch that the pushrod doesns't move from side to side, otherwise it will yank one elevator up and down more than the other, which is what your trying to avoid in the first place. A fix for that being the case, mount the servo on it's side, so the vertical arcing woun't have any change in the pushrod's geometry. Any arching becomes more drastic the more throw you have. So keep that in mind. Happy Building!

Why not try this: Split the elevstor halves as designed. Set up a tiller bar driven via a short wire rod, located just behind the elevator servo, which needs to be a "large" one, maybe 100 oz-in or so. Then connect pull-pull (closed loop) wires, 2 on one side to both elevator tops and the 2 on the other side to the bottom of both.

Run the wires thru the covering at the tail through fabric grommets. That'll make it look just like the full size plane.

Lots of adjustments, but very sturdy and a lot less weight than 2 servos plus a reverser plus 2 pushrods. Less chance of problems too.

Ditto to Mr. Pettit's suggestion!

check this link out. I like this idea better than a servo reverser. This is picture of what pettit is talking about.

http://www.centralhobbies.com/contro.../Bellcrnk.html


I am going to do this on my H9 edge.

Just buy you a strong enough servo.

Use Hitec digital servos. Reverse one with the programmer and then Y them together. Done.

Craig.