Parameter menu point F

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The advantage of always knowing the pitch and cyclic load on the flybarless system, allows MICROBEAST PLUS to precompensate for the torque variations on the tail rotor, just before any noticeable deviation occurs. This method of torque precompensation (RevoMix) relieves the tail control loop and improves the tail performance, especially when using MICROBEAST PLUS on helicopters with insufficient tail authority and/or extreme motor torque (e.g. well powered electric helicopters) where the tail does blow out shortly when applying a sudden pitch or cyclic input.

To see the compensation direction, you can move the collective pitch, aileron and elevator control stick at Parameter menu point F. With precompensation activated the tail rotor has to produce a deflection which must counteract the rotor torque. Since at 0° pitch the least torque is applied by the main rotor, also the tail rotor makes the least deflection and the tail slider is in center position. If you pitch in positive or negative direction or move aileron or elevator control, a deflection will be added to the tail rotor which will act against the torque of the main rotor.

For helicopters with clockwise rotating main rotor, the precompensation has to always push the tail to the left (nose of the heli to the right). For helicopters with the main rotor turning anti-clockwise, the precompensation has to push the tail to the right (nose of the heli to the left). The deflection will be to the same direction, whether positive or negative pitch, as the torque only increases. So first of all check which direction is needed for your helicopter and determine the necessary Status-LED color (red or blue). Then you have two options to set the precompensation (low or high = Status LED flashing or constant lighting). The choice is made by moving the rudder stick into one direction until the Status-LED lights in the desired color.

Status-LED Torque precompensation (RevoMix)
purple off
red flashing low - normal direction
red high - normal direction
blue flashing low - reverse direction
blue high - reverse direction
off user defined

Use torque precompensation when the tail does go away in torque direction when applying a sudden pitch input, even if the tail gyro gain is properly setup. Increase the amount of precompensation stepwise until the tail holds well. If the tail is moving against torque direction, the amount of precompensation is too high already. If the tail is blowing out even worse when torque precompensation is active, probably the direction of torque precompensation is wrong! If you can't find a good adjustment check the mechanical conditions. Use different (larger) tail rotor blades or higher tail rotor speed to gain better holding force. Also check your tail gyro gain. If the tail gyro gain in general is very low and the rudder tends to oscillate very easily move the linkage ball on the servo horn further inwards to the center. If on the other hand you have a very large amount of tail gain and the tail gyro still does not seem to be capable to hold 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 needs to control the rudder.

  • Torque precompensation can only be used if you have 0° of pitch at the servo center positions (adjusted at Setup menu point G)!
  • The amount of servo throw in the ratio of cyclic to collective pitch adjustment depends on the setting of the maximum collective pitch angle at Setup menu point K. The larger the maximum collective pitch angle, the greater the rudder servo throw due to the collective pitch input will be, while the servo throw through cyclic control commands will remain the same.

The option “user defined” allows you to choose your own setting that can be edited by using the StudioX software bundle and the separately available USB2SYS interface. With this you can also change the ratio between cyclic and collective pitch compensation.

Push the button to save the configuration and to proceed to Parameter menu point G.