Scratch Built Hannibal

Hi Brian - I have pull - pull on my Extreme Flite "Vanquish" rudder , this is the standard 2 wire system & works well.
If you stand the model on its wing tip & pretend the rudder is the elevator it works just fine, the servo would need
mounting on its side to avoid an awkward twist in the cables.
If you want a vintage look you could have the servo horns mounted externally with servos inside the model.
Hope this helps.
Colin

Hi Brian
The common closed loop method by attaching each wire directly to a 180deg servo horn works well. The minute you add extra mechanical parts, the more chance of failure. In particular with the method demonstrated (which is only a mock up) would be susceptible to the wire slipping off the turnaround pulley and jamming. If the method was good, it would be adopted by expensive production models. Some designs introduce a lay pivot for the closed loop elevators which is then operated by a short servo link. I had a DB models biplane with that method which was awful. Unless you engineer ball raced auxiliary mechanisms there is no way they will be as smooth as attaching the control wires directly to a ball raced servo.
There is no reason why you cannot mount rudder and elevator servos normally (horizontal ) and run the elev closed loop thru 90deg. However, i do recommend you trial such an installation before covering to optimise the control runs and start with a large servo disc. Then experiment with the attachment points + / - 90 deg to minimise any slack at full surface deflection.

Me again
Subsequent to above post, i recalled you had already provisioned for two elevator servos in the vertical plane so using dual standard closed loops for each elevator half is the logical way. If you have searched the internet you may have found something like this attachment. On my large Decathlon (and others) i find that crossing the cables gives a neater installation (especially where the wires pass thru the fuselage) and is better geometrically - minimising slack on full deflection.
Has your radio got the capability to link / mix a 2nd elevator servo - far more preferable to an in line servo reverser

Tail unit and control surfaces fitted. Decided to use the system shown in the video. The servos drive intermediate servo arms via pushrods. The rudder was very easy to set up, a single loop of wire passing from one horn, through the connector on the servo arm and round the pulley and back to to the opposite horn. The rudder was centred as was the rudder servo, the connector was clamped to the wire . A short length of alloy tube crimped to the wire stops the wire being damaged by the clamp screw. On test equal throws each way, and no sign of binding, made it all seem worth while. A bit time consuming to make and assemble the bits, but a doddle to set up. At the moment the wires cross each other at about mid-point in the run. I'll stop them rubbing against each other by running each one through a short length of hard plastic tube where they cross . Each elevator will be fitted up in the same way, The wire runs for the upper elevator horns will be interesting due to the broad chord of the tail plane. Running the wires over small brass pulleys set in the top rear of the fuselage in front of the tail plane might work..

If the wire is nylon coated there would be no reason for stopping the wires rubbing against each other. And even if not, the metal to metal rubbing would not be an issue over the lifetime of the model. It's not like the old FM days when metal to metal noise was a problem.
In your first photo I cannot see a crimp...how are you securing the wire?

Hello Mike, the wire is fed through a piece of alloy tube which is crimped in two places. I'll try to get a better shot of the whole thing.