ORIGINAL: bubbagates
ORIGINAL: Rush7
I am by no means an expert on any of this but could you not put matchbox's on them and solve the whole problem.
The idea is to basically eleminate any matchboxes or radio setting that changes the mechincal advantage. You would be surprised just ow much servo arms are "off" and simply changing it to the other side of the servo gets it to line up correctly or even placing it on another servo and in the case of elevators, just placing it on the other elevator servo.
This happens with good aluminum arms to the Hitec thick fiberglass arms to the standard plastic arms on JR servos.
I just had this on a AW Yak I just finished with JR8611's. I eneded up replacing one servo arm with a new one because no matter where I put it, in relation to the elevator halves, I could not get equal throw all the way through the surface movements on both halves, I went to the LHS, grabbed another arm and it lined up. I needed no matchbox no subtrim, no Dual rate setting changes for all 3 flight modes.
I used a very simple method to check elevator halves that someone here told me about something like 2 years ago
Get 2 spring type clothes pins, glue a very stright stick of balasa to each one, I use 20 inch pieces so that they fit almost all planes up to 40%. Clip them to the exact same spot on each elevator halve and line them up so they meet exactly behind the rudder, now slowly move the elevators with the radio, they key being slowly, and watch the sticks, they should remain exactly equal the whole way through the travel. If not, then start looking at mechanical setup. Sometimes you can have to exactly the same servos but one is faster than the other and no matchbox or any other radio setup will fix that.
That is what I think Alan was talking about when he said about matching servos
As Alan said, but is a pretty experienced pattern pilot, so truth be told, I was pretty shocked by this question. It must have him pretty flustered
"Flustered" doesn't QUITE get it, Bill..... this is driving me NUTS. You see, the pattern experience does not prepare one for 35* travels, and triple rates with 70% expos.... and trying to get all three rates to be perfect and identical travels on both elevator halves... well.... it's a new "Learning Experience"
I use 1/8" CF rods that are glued to spring clamps with rubber pads to prevent slippage on the trailing edge. They are 12" long, so quite sensitive to the most minute changes.
At this point, I'm concluding there is something mechanical amiss....my bet is that my servos arms are aligned to the CASES but not "square" to chordline, so I'll be trying to figure that out next.
Yes, I *do* know my way around linkages and geometry and radio setups.... thanks for the compliments, guys, but this is a WHOLE different ball-game. And clearly not as intuitive as one might think.