Translations:Manuals:AR7210FblV5:Gains/5/en

Tail gyro

Gyro gain and operation mode
The tail gyro system of the AR7210BX receiver helps to keep the helicopter's tail in position while flying around. It makes the rudder only react to stick inputs but not to external effects. Before the first flight, you have to set the correct amount of gyro gain in order to adapt the reaction of the gyro system to your specific helicopter model. Additionally, you have to choose between two different operation modes:

• Normal-Rate mode - here the tail gyro of the AR7210BX only acts as dampening that decelerates sudden rotations caused by external influences. Slow, constant rotational movements will not be compensated. Thus the tail does not drift in hover due to the main rotor torque, a perfect mechanical adjustment of the tail rotor is essential (see the section to Setup menu point E & F). But even with perfect mechanical adjustment you will always encounter some drift on the rudder axis due to crosswinds and the pilot has to constantly perform corrections when doing hovering flight. In high-speed flight on the other hand the tail will be aligned in flight direction by the wind, so curves can be flown very dynamically and the pilot doesn‘t have to constantly concentrate on controlling the rudder.
  

• HeadingLock mode - in this mode the tail is actively controlled by the gyro system. You will barely feel any external influences. By giving rudder stick input, the pilot only commands the gyro how fast it has to turn the tail. When the stick is in center position the tail gyro will ensure that the tail keeps locked into position by any means. This simplifies the control significantly. In hovering flight the beginner can fully concentrate on the control of cyclic and collective pitch and the advanced pilot can perform 3D - flight maneuvers such as backwards flying quite easily. The only disadvantage of HeadingLock-Mode is that the rudder must be steered by the pilot when flying curves. Otherwise the gyro will try to keep the tail aligned with the initial direction.
  

When setting up the system for the first time, start with medium gain in HeadingLock mode. Then readjust the gain as necessary:
Low gain will cause the rudder control feel weak, the tail will break out on collective pitch inputs and it will stop with overshoots. Increase the gain step by step. You will feel the tail having more and more precise stops and hold better and better on jerky pitch inputs. But watch out! If the gain gets too high, the stops will bounce back quickly and wagging will appear in fast forward or backward flight (or even on take-off). In this case land immediately and reduce the gain! For optimum performance set the gain as high as possible, just before the tail rotor starts to wag in fast forward flight.


Tail gyro response
In addition to the gyro gain adjustment there is a parameter called gyro response which helps to optimize the precision of the gyro. Increasing the gyro response will cause a harder stop and quicker response to rudder stick inputs. But if the response is too high, the tail will bounce back after a hard stop and feel spongy when making fast direction changes. If the response is set too low on the other hand, the rudder control feels dull and stopping might be too soft. Ideally the tail should stop perfectly to the point without making any flapping noises.

Before adjusting the gyro response make sure the maximum possible tail gyro gain has already been determined as described above! The gyro response can be considered as some sort of fine-tuning and adjusting this parameter will not have any significant effect if the gyro is not operating correctly in general. Also note that after adjusting the tail gyro response you may have to readjust the tail gyro gain once again, as these parameters interact to each other.

For better tail gyro performance also check for correct servo horn length. In case you can set the gyro gain only to a very low value and the rudder tends to oscillate very easily, move the linkage ball further inwards to the center of the servo horn. If on the other hand you have a very large amount of gain and the gyro still does not seem to be capable of holding the tail rotor in any flight condition, move the linkage ball on the servo horn further out from the center, to get faster response speed when the gyro controls the rudder servo. Also you may use different (larger) tail rotor blades or higher tail rotor speed to achieve better holding force.