turnigy 9x rudder-throttle mix

[RClearningpilot]

I have used Turnigy 9X TX/Rx combo for about 4 years with excellent results. However, mixing channels is a mystery, so I follow what I've seen on Youtube. Works with a Flitetset Bronco and a Hobby King Lancaster, except - one side starts before the other! How do I balance this? Using rudder trim does not seem to work, so is it something to do with the even more mysterious "Offset" parameter?

 

[Arcfyre]

I'm not sure what you mean by "one side starts before the other"

Am I correct in assuming that when you're applying throttle to your Lancaster (4 motors), the motors on one wing start spinning before the other wing? If this is the case you can usually fix it with a simple ESC recalibration:

TX on, throttle on full
Power on your RX and wait for the beeps
Move throttle to idle and wait for more beeps
Power off the RX and recycle the power

I'm working on a custom 4 engine plane right now and that's how I got all 4 to spin together. Hope this helps.

 

[RClearningpilot]

I'm not sure what you mean by "one side starts before the other"

Am I correct in assuming that when you're applying throttle to your Lancaster (4 motors), the motors on one wing start spinning before the other wing? If this is the case you can usually fix it with a simple ESC recalibration:

TX on, throttle on full
Power on your RX and wait for the beeps
Move throttle to idle and wait for more beeps
Power off the RX and recycle the power

I'm working on a custom 4 engine plane right now and that's how I got all 4 to spin together. Hope this helps.

Thank you for such a quick and insightful response. It worked on the bench, so now for some taxi trials! Do you happen to know if setting dual rates/expo on rudder will work with this setup?

 

[Arcfyre]

Thank you for such a quick and insightful response. It worked on the bench, so now for some taxi trials! Do you happen to know if setting dual rates/expo on rudder will work with this setup?

I don't see why it wouldn't work. That being said, you probably won't need rudder expo or dual rates with a differential thrust setup. In my experience the differential throttle is way more powerful than the rudder control surface. Try it out and let us know how it goes!

 

[RClearningpilot]

That's the crux of the matter - throttle is way more powerful, and unless limited with a percentage rate or tamed down with expo results in wild swings from side to side when taxying or on take-off run. This particular Lanc has no rudder control except on the tail-wheel. I guess this was because of the model size, control rods, horns and ell-cranks would have been too complicated (or expensive) with the end-plate vertical stabilisers. I also suspect that as dual rate/expo is not accessible on the throttle channel, only one side is affected. I''l try going back to full rate/linear setting and learn to be VERY gentle with the rudder!
Thanks, I'll pass on interesting results - other than a crash!

 

[Arcfyre]

That's the crux of the matter - throttle is way more powerful, and unless limited with a percentage rate or tamed down with expo results in wild swings from side to side when taxying or on take-off run. This particular Lanc has no rudder control except on the tail-wheel. I guess this was because of the model size, control rods, horns and ell-cranks would have been too complicated (or expensive) with the end-plate vertical stabilisers. I also suspect that as dual rate/expo is not accessible on the throttle channel, only one side is affected. I''l try going back to full rate/linear setting and learn to be VERY gentle with the rudder!
Thanks, I'll pass on interesting results - other than a crash!

It's always going to be touchy. I have the same problem with twins. I have yet to maiden my 4 motor transport, but I'm sure it won't be easier. It will probably just come down to practice and developing a slow and smooth throttle thumb.

 

[RClearningpilot]

It's always going to be touchy. I have the same problem with twins. I have yet to maiden my 4 motor transport, but I'm sure it won't be easier. It will probably just come down to practice and developing a slow and smooth throttle thumb.

Latest mod: dual rate 100%, expo 0, but end point of rudder servo cut down to 40%. Gives me better control in taxi and take off run (haven't maidened it yet - continuing to practice the slow and smooth throttle thumb!)

 

[Merv]

Latest mod: dual rate 100%, expo 0, but end point of rudder servo cut down to 40%.

I hope that works for you.
If is doesn't there is a difference between rates and end point. End points are something you set that you never want to exceed, perhaps due to a physical limitation. Something like you can't move the servo beyond this point or it will bind. End points can not be changed in the air. Rates on the other hand, are on a switch. You may prefer low rates to taxi with but in the air, just flick the switch and now you have high rates.

If you never want to change, then end point and rates will accomplish the same thing, less throw. If you want the ability to change the throw in the air, you should use rates, not end points.