Split Elevators and Dual Servos
 

On another Plane I have with Split Elevators/Dual Servos, I put each Servo on a separate Channel so I could adjust each Servo separately; on my newest project, it also has Split Elevators/Dual Servos. However, because of Radio limitations, I am trying to free up a Channel for another function. In order to be able to adjust each servo separately yet only use one channel for Elevator, will a JR Matchbox work in this situation?

I bought one and tried it out on the bench with 2 Servos attached, and when I tried to adjust the endpoint on one of the Servos, I noticed that the servo movement of adjustments in either direction of rotation, was made in such minute or small increments with a very small overall range; I know that through Push Rod and Servo Arm geometry that this may be sufficient to make a difference in Control Surface alignment, unified movement and have the same identical End Point. Are these small Increments of movement Normal for these JR Matchboxes, or is there a better method to be able to adjust each Servo separtely without having to use 2 Channels; I have a servo programmer but I wouldn't think that would work because the Servos have to be mounted in the Plane to observe and measure actual control surface movement and end points. Also, joining the push rods into one pushrod for single servo is not possible.

For reference, not sure if it makes a difference, the servos are Hitec and are Standard, the manual states that the Matchbox will work on Standard or Digital; or will these just work better with Digital Servos?

Thanks.

To use the programmer,, All you have to do is bring the plane close to the computer,, or a laptop close to the plane and use a long servo extension or long USB cable,,, I've done them while in the plane several times.

If you have minor mechanical differential,, the most important thing to cure that is servo arm angle at center, if those 2 angles are off you will have some differential,, being able to set the center point with the programmer is key to matching them.

I've never used a match box,, so I don't know how to set that up

good luck

Scale only 4 me;

Appreciate the reply, I guess you are talking about a computer based Servo Programmer; the one I have is an Older Version hand held Hitec Programmer, your suggestion is something I had not considered, and that is to get one of those Computer Based Programmers if the JR matchboxes don't work out like I want.

Thanks.

The matchbox should work. The Hitec programmer is a good tool also, but you will need Hitec digital servos that can be programmed. I don't think your analog servos will work with it. The last choice would be a reverse Y or changing brands on one servo. I did not have good luck with either of the two reverse Ys i used in the past, hence my hesitation. Futaba servos run the oposite way of Hitec servos. So while it may be hard to find two that match up it is possible to run one of each brand on a normal Y and do what you want.


BTW these suggestions are listed with the best option first and poorest option last :-)

David

I missed the standard servo part, just read programmer, yes only digital servos are programmable.

Yes, my programmer is the hpp-21+, works either with the computer or not,, but the fine tuning of center and end points is useless without the computer interface.

good luck

I liked the hit ec programmer option also. just make sure the control horn and pushrod geometry is as close to identical to get best results. I have had them on the same surface and when they were programmed they matched perfectly no fighting. you can even match a programmable servo to one that is not programmable just make sure you program the hitech servo to the regular servos true end points and center max endpoint setting on radio and no subtrim on centering. make sure mechanically everything is close then the trim will move both servos to the same points. you also have to balance the servo speed to be close to the regular servo. close counts.

I have the spectrum DX7 and you can center to match servos using the sub trims, there is a limit to how far you can go and the only place I may have to do this is on flaps and split elevators on separate servos both tied to a Y harness and un plug the one your going to match to.

I have always just used the match box. Been a while but I don't recall it being so slow but the only one I have left is an older unit.