Flying and controlling the model

From BEASTX Wiki
(Redirected from Help:FAQ:FlightPerformance)
Jump to: navigation, search
This page is a translated version of the page Help:FAQ:FlightPerformance and the translation is 100% complete.

How can I increase rotation rate for roll, pitch and rudder?

The rotation speed of the helicopter is only determined by the length of the stick output signal. The gyros measure the actual rotation rate and the system will move the servos until the helicopter reaches the rate that is commanded by the stick position. So simply increasing/decreasing the stick throw (mostly done by increasing/decreasing servo throw or using DualRate in the TX for the specified function) will increase/decrease rotation rate.
The presets at Parameter menu point B are nothing else than different preset DualRate/expo curves inside MICROBEAST / MICROBEAST PLUS making the heli rotate slower or faster at a given stick input and making the stick contol more or less sensitive around stick center position. Choose the preset that fits your preferences best and that gives you a good amount of rotation rate. Using the presets (except for the "Transmitter" preset) it is recommended to not change the output signal in the TX significantly as especially when using expo this will bend, compress or stretch the internal curves, leading to very strange flight behavior (anyhow, doing small adjustments in stick throw, i.e. for slightly increasing the roll rate should work without any issues).

If you want to create your own control style easiest thing to do would be to switch Parameter menu point B to preset blue (="Transmitter") and adjust the curves in your transmitter just as you like. Therefor we suggest to start with a setting of 70% D/R and 25% expo on cyclic and 85% D/R and 40% expo on tail in the transmitter and adjust the curves accordingly. When setting parameter B to "blue = TX" the internal curves in MICROBEAST will be "disabled". Here 100% stick input will give a rotation rate of apprx. 600deg/s on the rudder axis and apprx. 300 deg/s for the cyclic movements (this may vary depending on TX brand as any manufacturer use another signal output as maximum, so this also can be 107, 110% or 95%).

We are often asked which percentages of expo or dual rate corresponds to the different presets. As manufacturers calculate expo curves different, we can't tell you what our preset curves correspond to which TXs expo values as we use our own expo calculation and there is no data available for comparing. We did out fly these values and programmed them in the source code so we can't tell what these are in Futaba or JR percentages. If you want to use a specific preset as your starting point we suggest to connect your MICROBEAST to the StudioX software. Here you can see the different values for each control behavior preset and you can save a custom preset for which you may use the given values and adjust them with StudioX until they perfectly fit your flying style.

  • Note that the rotation rate in first line has nothing to do with your cyclic pitch adjustments at Setup menu points J or L and also has nothing to do with the cyclic pitch when steering cyclic on the ground! Especially when controlling slow rates do not get confused when the system will move the servos to full cyclic deflection. This is normal behavior of the system as the heli when the heli is standing on the ground and can't move. In flight the system will automatically control the pitch as high as necessary to maintain the given rate. So always setup the cyclic pitch as mentioned in the manual and do not rely on what you see when moving the sticks on the ground!

  • If the heli does not flip / roll / rotate fast enough even if you've fully increased the stick throw in the transmitter check the maximum amount of cylic pitch at Setup menu point L and the maximum rudder servo deflection at Setup menu point E. When the cyclic pitch or tail pitch is not sufficient of course the system can't rotate the heli faster than the pitch allows.

The helicopter wobbles on aileron and elevator axis.

Reducing the swashplate gain does not help to suppress this effect completely.

  • The helicopter's linkage ratio is not suitable for flybarless usage. In Setup menu point J adjust the cyclic pitch to exactly 6 degrees and make sure the color of the Status-LED lights up “blue”. If this is not the case change the mechanical linkage ratio of the helicopter (i.e. by moving the linkage balls further inwards on the servo horns, by mounting longer linkage balls on the swash plate outer ring or by mounting shorter linkage balls on the swash plate inner ring).
  • The servo-blade combination is not good. Use faster and stronger servos and/or specific flybarless blades.
  • Some linkages aren’t moving smoothly and freely. Check the mechanics for any hard points (ball linkages, blade grips). Check if the dampers are greased and that the thrust bearings in the blade grips are correctly mounted.
  • Imbalance of the main rotor head. Firstly, do not tighten rotor blade bolts to much. The blades must be able to align themselves by centrifugal force. Then check blade balancing and/or try a different set of rotor blades.

The tail rotor turns around instantly when doing backwards flying.

  • Tail gyro gain too low. Increase tail gyro gain as described here and make sure you're using the tail gyro in HeadingLock mode (using Normal-Rate mode it is nearly impossible to perform backwards maneuvers!).
  • No sufficient thrust produced by the tail rotor. Check tail pitch angles. Reduce the maximum amount of available tail pitch throw at Setup menu point E to prevent the tail blades from stalling or increase the tail pitch angle if it's too small. Use different (larger) tail rotor blades or increase the rotor rpm.

The tail oscillates in horizontal position slowly and irregularly while hovering.

  • The HeadingLock gain of the tail gyro is too high. Reduce the HeadingLock gain in Parameter menu point D by one step and increase the tail gain on your transmitter instead.
  • Due to mechanical issues the tail gyro can not work precisely. Check the linkage and mechanics for absolute free movement without hard points and use a dedicated rudder servo that is fast and accurate and that allows a high control frequency.

During slow hovering pirouettes the helicopter is rolling out.

The pirouette optimization setting may be wrong:

  • MICROBEAST/AR7x00BX: Adjust the pirouette optimization at Setup menu point N correctly.
  • MICROBEAST PLUS: Check if mounting orientation is setup correctly at Setup menu point A. Note that mounting orientation is setup differently compared to older devices!

Apart from this also make sure the helicopter is well balanced (center of gravity setup correctly?) and servos are trimmed properly.

Helicopter tips over when trying to take off or tilts to one side in flight.

  • Please check whether everything works properly on the ground. When giving collective pitch input the swash should move up and down properly. When giving cyclic input it should return to zero after a few seconds. This is also especially after turning on Idle up or switching between flight conditions in the transmitter. Make sure that there are no trims, mixers, etc. in any flight condition and also make sure that the sensor directions for aileron and elevator are setup correctly (Setup menu point M)!
  • When taking off do not use too much cyclic input. Just let the motor come up to speed and then quickly give pitch input. Only when the helicopter is airborne the system can operate and control commands. If the helicopter sits on the ground, however, a stick input(= command to rotate the heli) would have no effect and the system would increase the cyclic pitch more and more desperately to perform a rotational movement. As soon as the helicopter will get "light" by increasing the collective pitch it will tip over abruptly. So always make sure that the swash is aligned straight during starting procedure!
  • Tilting in flight: Remove the main rotor blades and let the helicopter run in all speeds on the ground (beware of the rotating parts!). Again the swash should move straight up and down when giving pitch inputs. If at a certain speed it starts to tilt in one direction and this will depend on the rotor speed then that is almost certainly a vibration problem which confuses the sensors in the MICROBEAST. Trying different adhesive pads might help (smoother or firmer mount) or installing the unit in another location. But especially in the electric helicopter that brings in most cases nothing and there certainly is an error somewhere on the helicopter.
This can be: slightly bent hub of the tail rotor, jammed or defective ball bearings, tail blades / tail rotor is not properly balanced, engine bell not balanced / comes at a certain speed to vibrate or motor bearings damaged making the motor shaft vibrate, slipped ball bearings in the torque tube tail drive system or installed in the wrong position, main gear wobbles / unbalanced; motor shaft bends and runs rough, ... actually everything that rotates on the helicopter can be the cause of such a vibration. On electric helicopter you normally should not hear, feel or see any mayor vibration (no vibrating tail fin or skids). Then it should normally be possible to attach the MICROBEAST only with a very thin adhesive pad on electric helis. On nitro helis the situation can be slightly different as the motors do shake the more or less. This can lead to shaking of the MICROBEAST unit itself and will make the rotor pane wobble. So here trying different pads or a sandwich made of two pads and a metal plate may help to stabilize the unit better. Also the wiring can be the cause of such a shaking. But when the swash tilts as explained above the cause normally is some very high frequent (abnormal) vibration and trying around with different kinds of gyro pads only disguises the real cause and may not help 100%.
  • Is the movement, however, abruptly or suddenly (similar to the twitch in a radio interference) this can especially be caused by static charges from the rear belt. Here a uniform electric potential across the entire helicopter should be done. The use of graphite spray, using a different rear belt or simply changing the belt tension can help.
  • One could also consider a voltage fluctuation of the receiver power supply. It is necessary that this is stable enough, especially in terms of duration and whether the cable cross-sections and the connecting system are of sufficient size. The power supply should be dimensioned at least twice or three times as strong as expected since very high current peaks can occur in milliseconds which make the voltage sag dangerously low. In this context it may happen that the helicopter flies normally for a few minutes and then suddenly turns or rolls away in flight or even after landing the swash plate turns by itself to one direction. This is a sign that the MICROBEAST made a quick reboot in flight but because of the severity or duration of power failure it could not completely reload all calibration and sensor data. In this case the cause must be found and rectified and it mustn't/shouldn't be flown anymore since the receiving system was apparently close to a total failure.

Please note: A slight tilt of the swash plate when the heli is standing on the ground is absolutely normal. When carrying the heli or steering the sticks on the ground the system tries to perform the necessary commands. But as the helicopter will not move as intended the system will maintain and even increase the servo movement in order to turn the helicopter. Only after approx. 30 seconds without moving the helicopter or touching the sticks, the swash will return to its normal position as the systems slowly clears its "memory". The exact amount of time for this depends on the position of the thrust stick. In the middle position is the discharge at the fastest. So if possible always keep the thrust stick in center position when the heli is on the ground so that the swash plate stays leveled. Once the helicopter is airborne you won't see or feel any of these effects as now the control loop can operate as intended. As described here to center the swashplate you can also move the cyclic stick(s) to full deflection once. Only if the swash moves downright by itself to full-stop even after correcting with the sticks and only cycling power off and on resolves this problem, check that your transmitter does not send any unwanted control commands (trimming active, stick pots worn out, ...). If this is not the case please contact support as maybe there is some problem with the sensors then.

Status-LED flashes in operation mode, i.e. after landing.

The flashing Status-LED shows that a software-reset occurred during operation. This can have different reasons:

  • The receiver power supply does not seem to be sufficient. The voltage during operation dropped in a critical area (<3.5 Volts). Use a stable power supply and make sure that the wiring and plugs are dimensioned big enough and feature low contact resistance. On large helicopters we recommend to use the MICROBEAST PLUS HD with high power input.
  • A reset can be triggered due to a transfer of high voltage. Take measures to prevent static discharges.

The helicopter drifts slowly around its vertical axis. The rudder servo creeps to maximum deflection slowly.

When using Heading Lock mode the system compares the rotation rate of the helicopter with the commanded rotation rate from the stick input all the time. So basically this can have two reasons:

1) Gyro is measuring a rotation even if there is none. This can happen from hard vibrations disturbing the sensor measurement or also by gyro drift due to high temperature change or a defective sensor. As with other electrical devices make sure to give the system time to acclimatize before powering it up, especially when flying on a cold winter day or during a hot summer.

2) Stick is commanding a rotation even when it seems to be in center position. Check all your trimmings on the transmitter. They must be 0 in all flight modes. Make sure to keep the sticks centered during power up as the system learns stick center positions each time it performs the init sequence. This is necessary because most often stick potentiometer positions vary slightly, i.e. due to different ambient temperature. This issue can solved by using stick deadband but to keep deadband as low as possible and to increase overall performance MICROBEAST / MICROBEAST PLUS learns stick position directly before flying. However, if you see your sticks do not center properly, i.e. when pushing and releasing the stick softly the servo starts to creep into one direction and only will stop when tapping the stick into the opposite direction, then you can increase the Stick Deadband at Parameter menu point E.

After updating MICROBEAST PLUS from Version 3.x.x to Version 4.x.x. the collective pitch does not work correctly anymore

As version 4.x.x can be upgraded with the AttitudeControl functionality it is required to set up thrust stick directions. Firmware Version 3.x.x did not provide such parameters therefore you must set the thrust stick positions by adjusting the collective pitch at Setup menu point K. Otherwise you can only control collective pitch into one direction. Please read the MICROBEAST PLUS ProEdition Addon manual carefully. There are also a few other things that are different to Version 3.x.x and that need to be readjusted.