Syncronizing/Balancing Multiple Servos

[Naughty Monkey]

Unless the geometry is correct you get binding. After a while I ended up just setting up proper geometry

This is the one time in my life since school that geometry was ever important. If you get the control horns set up right, it makes everything else so much easier. The pivot point of the control horns need to be in the same spot. They need to be the same distance from the hinge line, not the control surface and directly over the hinge line unless you want differential, then they need to be the exact same distance behind or forward of the hinge line. This keeps the throw equal throughout the full range of travel, not just the endpoints.

 

[Lojik]

Good informative thread, got this on fav's for the 40% build.

 

[jamesrxx951]

This is the one time in my life since school that geometry was ever important. If you get the control horns set up right, it makes everything else so much easier. The pivot point of the control horns need to be in the same spot. They need to be the same distance from the hinge line, not the control surface and directly over the hinge line unless you want differential, then they need to be the exact same distance behind or forward of the hinge line. This keeps the throw equal throughout the full range of travel, not just the endpoints.

With Arfs the exact distance numbers always seem to be a little different. Thats why a custom build plane would likely be easier to set up. I usually don't do any measuring. I eye ball it where the arm is parallel or close to the hinge line and set in my turnbuckle. Thats where I just use my angle meter to determine the rest. The next connection I will kinda match up to the first to get me close but again just let the meter determine the geometry.

With one of my Arfs the control horns were not glued in equal at the factory and made set up a little harder. Servo balance really helped on that one.

 

[Bartman]

i'm trying to force myself to do this. i can opt out and go pull-pull on the rudder and split the ailerons which is something i've been wanting to try since i first heard about it in Pistolera's Krill thread

but balancing servos is a necessary skill in giant scale so i might as well get to it (maybe)

 

[Pistolera]

Well....I was going to mention those, but it still doesn't help for push/pull rudders, etc. I agree with the other guys.....first and foremost is getting the most accurate mechanical setup you can achieve. Then use whatever capabilities your radio/matchbox/EQ6/Booma intellimatch can give you to try and eliminate any mismatch during travel.

I use a Futaba 14MZ and usually can get things very close at centers and either end of the throws using its travel programming.

Even so, when servos start getting a teeny bit of play and the ailerons start chattering at center, I will give one of the servo's links a small adjustment to put it on a very slight bind (at center) with the other one. Not enough to change any trim, just enough to stop the chatter at center. Is it perfect....no. Does it use a little bit more battery...yes. does it affect the way the plane flies....no. But....I digress

 

[dhal22]

I like my Fromeco Quad meter. Just feels better seeing the power usage variances and adjust to identical.

 

[AEROSHELDON]

I have a QCM also, but I did read that with brushless servos they use less current and are harder to match with current. Anyone know if that is true or not?

 

[jamesrxx951]

I have a QCM also, but I did read that with brushless servos they use less current and are harder to match with current. Anyone know if that is true or not?

At least with my JR brushless servos a current meter is pretty useless. The current draw is so low it is very difficult to find a bind. I balance by eye with my brushless servos. One servo connected and one not. I match up the bolt hole to determine binding.

 

[Jlc]

At least with my JR brushless servos a current meter is pretty useless. The current draw is so low it is very difficult to find a bind. I balance by eye with my brushless servos. One servo connected and one not. I match up the bolt hole to determine binding.

The same with my BLS152's. They have to be in a hell of a bind to draw much current.