Transmitter sub trim limits

[Bill Eilers]

Wana know what's the max. Sub trim a person should input,before they should start looking for a different way to get what they want. (Different spline location and or different pushrod geometry)

 

[rhomodel]

2-4 clicks out of 10. The more you offset a horn to get the output straight the more bias you get if you apply any steering or throttle. Ideally should be 90 degrees on neutral.

 

[Mark Anderson]

Before using any electronics, get the mechanics right.

 

[Wasted wages]

^^^^ This ^^^^

 

[Bill Eilers]

Flying helicopters I know about differential geometry.,

 

[Bill Eilers]

2-4 clicks out of 10. The more you offset a horn to get the output straight the more bias you get if you apply any steering or throttle. Ideally should be 90 degrees on neutral.

Thanks for the reply. Out of a 100 up or down (sub trim limits) I start to get nervous if I have to input more than 25-30.. your opinion?

 

[Daniel's Racing]

Better to not use any of the subtrim. EPA should also not need to be turned down a huge amount to take out throw. If using less than 80 on the EPA your throwing away torque. A shorter horn(move closer to pivot on servo) so servo rotates fully to turn will make better setup.

 

[rhomodel]

Well it is easy to say it is too much, but I have instances where I had to. Better to lenghten or shorten the rods and ensure all linkage is square so throw each way is the same. For gas engine for example I deliberately have a 25-75 % throw 25 to shut down engine, 75 to throttle, but certainly for steering it is better to have the geometry right as others indicated as well..

 

[SayMikey]

A Jae/Ski type boat will turn on a dime with 10 Degrees of rudder input. I dial almost all the input out.

 

[Daniel's Racing]

A Jae/Ski type boat will turn on a dime with 10 Degrees of rudder input. I dial almost all the input out.

If you are already running a very very short servo horn dialing out some EPA on the rudder is what it is but you should strive for the servo to rotate fully in each direction to give you only what you need.
If you have to turn it down much you should usually have a shorter control horn on the servo.

That is your torque going out the window and the strength of the servo gears and the amount it uses of the final gearing. You don't want it wearing out one little spot in the drivetrain of the servo and you want all the torque there getting to the rudder so less chance to break servo parts if you hit something.

Many reasons for setting the servo up mechanically first to limit rudder movements to only what you need. Yea sure you may need to fine tune your endpoints a little less than you set them up but if you are turning down the EPA more than 80% you surely have used too long of a servo horn.

 

[Mark Anderson]

What Daniel said with the addition of a long rudder horn added to the short servo horn if needed. On my JAE style boats, I grind the side of the clevis to clear the servo shaft and drill a hole closer in. Always Sulivans with the lock in place.