Manuals:MB Plus:Flying

Tail gyro gain adjustment with transmitter

The tail gyro gain is adjusted by one of the transmitter‘s auxiliary channels. The more servo throw this channel produces, the higher the tail gyro gain will be. Additionally the direction of servo throw determines whether the gyro works in Normal-Rate mode or in HeadingLock mode. The color of the Status-LED indicates the selected mode when MICROBEAST PLUS is ready for operation. Purple indicates Normal-Rate mode and blue indicates HeadingLock mode. Additionally while adjusting the gain or shortly after the first start up, the current amount of gain is displayed by one of the menu LEDs for about 10 seconds. When the gain channel is centered, this will correspond to 0% gain indicated by LED A. In both modes, the maximum adjustable tail gain is 100% and will correspond to LED N. Please note that the actual percentage and sign of servo throw in the transmitter will depend on its brand and/or type.

For the first flight we suggest to start with medium gain not higher than LED G (LED D for 450 size helicopters and smaller) in HeadingLock mode. Low gain will cause the tail rotor control to feel weak and it will stop with overshoots. Increase the gain step by step and you will feel the tail having more and more precise stops, and hold better and better on jerky pitch inputs. If the gain gets too high, the stops will bounce back quickly and wagging will appear in fast forward or backward flight. In this case immediately 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.

• Operation without using the auxiliary channel for tail gyro gain is not possible!
• When gain is close to point A (0% gain) the rudder servo will not perform full servo travel as the gyro is switched off. Do not attempt to fly in this condition!

Menu-LED	N	M	L	K	J	I	H	G	F	E	D	C	B	A		B	C	D	E	F	G	H	I	J	K	L	M	N
Gyro gain	100%	96%	88%	80%	72%	64%	56%	48%	40%	32%	24%	16%	8%	0%		8%	16%	24%	32%	40%	48%	56%	64%	72%	80%	88%	96%	100%
Auxiliary channel	-100	-96	-88	-80	-72	-64	-56	-48	-40	-32	-24	-16	-8	0		8	16	24	32	40	48	56	64	72	80	88	96	100
Gyro mode	Normal-Rate mode														HeadingLock mode

In Normal-Rate mode the tail gyro of MICROBEAST PLUS 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 D). 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.

We recommend to use the HeadingLock mode. Here 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.

Adjusting the dials

To adjust the dials please only use the supplied plastic BEASTX adjustment tool to prevent damage to the dials!

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Dial 1: Cyclic gain
The swash gyro gain (cyclic gain) can be set by dial 1 from 50% up to 150%. Turn dial 1 clockwise to increase the gain. The factory setting is horizontal which corresponds to 100% swashplate gain. For your first flights we suggest not changing this setting. However, when using very small helicopters (such as 250 or 450 size), reduce the cyclic gain by 3 marks (=75% gain) as with such small helicopters the control loop tends to overcompensate more easily.

In general the higher the gain the harder the helicopter will stop after cyclic moves and the helicopter will fly more stable and exact in the air. If the gain is too high, the helicopter will tend to oscillate at high frequency especially on the elevator axis. Due to their low mass, this behavior will occur sooner on small helicopters, so typically these do not need as much gain as large helicopters.

If the gain is too low the helicopter does not stop precisely and overshoots the more or less after a cyclic movement. Additionally it feels unstable and sluggish in fast forward flight and when hovering. In general low gain will allow the helicopter to have more life of its own and so it will not react to stick inputs as precise and immediate as the pilot expects it.


Dial 2: Cyclic feed forward
This part mixes some amount of stick input directly to the servos, bypassing the control loop. If correctly adjusted, this relieves the control loop which will work more efficiently by only having to make residual corrections. Factory setting of the dial is horizontal which provides a good setup in most cases. Turn dial 2 clockwise to increase the cyclic feed forward. This will cause more cyclic stick input going directly to aileron and elevator on the swashplate. Decreasing the direct stick feed forward will do the opposite.

If the cyclic feed forward is too high the stick input will over control the cyclic input. Eventually the control loop needs then to steer back and compensate the unwanted cyclic movement. Even though you get the impression to have a more direct and immediate control over the servos with high feed forwared values, unwanted side effects may appear, like pitch backs on cyclic stops and imprecise fast forward flight that show the control loop not working properly.

If the direct cyclic feed forward is too low, the helicopter will feel softer, slower and less direct. The optimal point depends of many factors like blades, servos, head speed, size and mass of the helicopter. Ideally you can increase the feed forward just as high as possible without any side effects happening. So you get a quite natural stick feeling and on the other hand the control loop is supported as good as possible. At delivery the dial is in the middle which should be a good starting point for most helicopters. Before adjusting the cyclic feed forward you should try to find the optimal maximum cyclic gain first (dial 1). Then adjust the cyclic feed forward and after that, you may have to adjust the cyclic gain once again, as both parameters interact to each other.

The cyclic feed forward does not affect the maximum rate of rotation! If the helicopter turns too slow, you should check the settings of the swashplate limiter in Setup menu point L, change the control behavior at Parameter menu point B or increase the servo travels or “Dual Rate“ setup of your transmitter.

Also to get a quicker and more aggressive response, increase the control behavior at Parameter menu point B (reducing expo and increasing the maximum rotation rate) and increase the cyclic response at Parameter menu point G. It is not recommended to increase the feed forward in this case, although it may produce a quicker servo movement and more direct stick feel at first glance. As described above this value is part of the control loop and you will get side effects as the control loop will not perform optimally, if you do not adjust this part as intended.

Dial 3: Tail gyro response
Turn dial 3 clockwise to increase the tail gyro response. Turning dial 3 counter clockwise will decrease it. Increasing the tail dynamic will lead to harder stopping behavior and more aggressive response to rudder stick inputs. If the response is too high the tail will bounce back shortly after a hard stop and feel spongy when making fast direction changes. If the dynamic is set too low the tail feels dull and stopping might be too soft. Ideally the tail should stop perfectly to the point without making any flapping noises.

Factory setting of the dial 3 is horizontal which provides a good setup in most cases. You have to make sure the maximum possible tail gyro gain has already been determined (see above) before adjusting the tail gyro response. Then after adjusting the tail gyro response you may have to adjust the tail gyro gain once again, as these parameters interact to each other.