Help:FAQ:Gyro

The rudder servo doesn't respond

I've set up everything: frequency, pulse width, gyro gain. It was working before, but after firmware update it doesn't.

You've updated with wrong firmware! When updating, make sure that the button Tailmotor is disabled. Otherwise you will download firmware specially for helicopters with tailmotor drive instead of servo control.

The gyro sensors do not seem to work correctly.

The rudder servo does not react or reacts very slowly to rotation of the helicopter. (The same happens to the elevator axis.)

Probably the gain of tail gyro is too low.

• Check assignment of gain channel and adjust the gain in the transmitter as described here.
• Check for correct wiring or setup of tail gain cable/channel.

Additionally when the elevator doesn't seem to work either, maybe the wrong mounting orientation has been selected. So select the correct mounting orientation in Setup menu point A.

My gyro gain seems to be very low. What is the best gyro gain value?

The gyro gain value is just the amount of servo deflection the system will add to the rudder servo during one control loop process. So how much gain is needed highly depends on your mechanical servo throw. If the tail pitch makes a huge step even at very little servo throw, then you will only need very little gain. If you have very a short servo arm and/or very long tail pitch control arm which allows to control the pitch in very little steps, you will be able to go very high on gain setting. So from an absolute point of view there is no good or bad setting. Set the gain as high as possible and as high as necessary. When gain is too low in general, the rudder won't be held in position properly. If gain is too high the tail will wag and osscilate quickly, as the servo is making too much pitch deflection and the gyro is overcompensating. Usually you will end up with a gain setting somewhere around 50% as most helicopters have similar tail mechanics in regards to tail pitch throw. But having a different value is no reason to worry about as long as the tail is held in place by the gyro properly.

If you can't find a good setting in between "too high" and "too low" and you have a very low gain value this may be a sign that your servo arm is too long and thus the servo stepping is not precise enough. In this case move the tail linkage closer to the servo center position (shorter servo arm) to get a more precise servo stepping. As a result you will have to increase the gyro gain but also you will be able to adjust the gain more sensitive.

When moving the rudder stick in Heading Lock mode the servo does not go back to center positions but stays somewhere.

This is normal behavior when using the gyro in Heading Lock mode!

Before take off, when the motor is not running, you can clear the control loop and center the servo by moving the rudder stick:

left -> center -> right -> center -> left -> center