Basic operation and flying

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When the initialization has finished the Status LED flashes red/blue on my AR7210BX. Is it defective?

Flashing red/blue LED means the throttle lock is engaged. Usually this happens when you switch on the transmitter after powering up the AR7210BX and/or the throttle is not in low position. The system then keeps the throttle in the stored failsafe position (which is teached when doing the bind process) in order to prevent from starting the motor by accident. Now to unlock the throttle you have to move the throttle on the radio into this failsafe/off position, then the LED display will change to the usual status display. So always make sure that you bind the system to the radio with correct low throttle position and do a rebind if you need to change this position later!

The gyro sensors do not seem to work correctly.

The rudder servo does not react or reacts very slowly to rotation of the helicopter.

  • Maybe the gain of tail gyro is too low. Check assignment of gain channel and adjust the gain in the transmitter as described in the manual.
  • 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.

Please note: With AR7210BX and firmware version 4.x.x or greater the setting of device orientation has changed compared to older devices/firmware and there are more options now. Do not use the same LED color as before as it is very likely this will be wrong. READ THE MANUAL!

How to increase rotation rate for aileron, elevator 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 helicopter as fast as it is determined 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. Or you also can change the rate by choosing a different Control style (PARAMETER MENU point B) or directly editing the rate by software with StudioX or the StudioXm App.

Please note: The rotation rate in first line has nothing to do with your cyclic pitch adjustments (SETUP MENU points J and L) and also has nothing to do with the cyclic pitch you see when steering cyclics on the ground! In flight the system will automatically control the pitch as it is necessary to maintain the given rate. So always setup the cyclic pitch as mentioned in the manual (set the throw to exact 6.0 degrees at menu point J and limit as less as possible at point L so the system has enough range of motion) and do not rely on what you see when moving the sticks on the ground.

Paramter menu point B (Control style) - How does this work? Can is use DR/Expo in the radio?

The presets at PARAMETER MENU point B are nothing else than different DualRate/Expo curves inside the device. Choose the preset that fits your preferences best and that gives you a good amount of rotation rate. When using the presets (except for the "Transmitter" preset) it is recommended to not change the output signal in the radio significantly as especially when using expo this will bend, compress or stretch the curves, leading to very strange flight behavior. It just is not like adding 5% of expo as the curves between TX and AR7200BX/AR7210BX/AR7300BX will multiply and not sum together! Anyhow you may do small adjustments in stick throw, i.e. for slightly increasing the roll rate. This will not significantly deform the internal curves of AR7200BX/AR7210BX/AR7300BX.

If you don't like the presets and/or you do want to adjust the rate with your radio go with preset blue (="Transmitter") and start with a setting of 70% D/R and 25% expo on cyclic and 85% D/R and 40% expo on rudder in the transmitter and adjust the curves accordingly. When setting parameter B to "blue = TX" the internal curves will be "disabled". Here 100% stick input will give a rotation rate of apprx. 600deg/s on the rudder axis and apprx. 400deg/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, Jeti, Spektrum or JR percentages. If you want to use a specific preset as your starting point we suggest to connect your AR7200BX/AR7210BX/AR7300BX to the StudioX software. Here you can see the different values for each control style preset and also you can create a custom preset using the given values and adjust them until they perfectly fit your flying style. When you have an AR7210BX receiver with firmware version 5.x.x even you can adjust the rate in exact values of degrees per second!

Note for AR7200BX/Ar7300BX (not AR7210BX): If Parameter menu point B is set to preset "blue" and the tail gain is switched to heading lock mode you can see in operation mode by the Status LED state at which tail stick position the maximum possible rotation rate on rudder will be reached: At that specific tail stick position the Status LED will start to flash. Moving the stick to this point in flight the rotation rate of the helicopter will be as high as the gyro can control. Increasing the stick throw further the LED will go off. At this point the rate control is switched off and the rudder axis will spin uncontrolled. Here the only limit is the tail pitch throw and normally the tail will spin ultra fast. This can be used for performing tail slides or turns with very fast spinning tail. For normal flying around you should not use this as you may accidentally steer into the uncontrolled area and the tail may spin too fast or very uneven. So please check on the ground that the Status LED will not go off when giving full rudder stick deflection in your default flight modes.

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 6.0 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 of the heli turns around instantly when doing backwards flying.

  • Tail gyro gain too low. Increase tail gyro gain as described in the manual and make sure you're using the tail gyro in HeadingLock mode (using "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 larger tail rotor blades or from another brand and increase the rotor speed.

The tail oscillates in horizontal position with very low frequency or irregularly while hovering.

  • The HeadingLock gain of the tail gyro is too high. Reduce the HeadingLock gain (PARAMETER point D) by one step and increase the tail gain 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.

  • AR7200BX/AR7300BX: Adjust the pirouette optimization (SETUP MENU point N).
  • AR7210BX: Here the direction of pirouette optimization is set automatically from the selected mounting orientation! So check if mounting orientation is set correctly (SETUP MENU point A).

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!
  • When using an AR7210BX with PROEDITION firmware this has the bailout rescue option (AttitudeControl). So make sure the stabilization is not active by accident when you try to takeoff. This will not work out (unless the helicopter is in exact leveling position) because as mentioned above the system will move the servos to full deflection when the helicopter doesn't follow the movement.
  • 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 then almost certainly this is a vibration issue which affects the sensors of your device. Trying different adhesive mounting pads might help (smoother or firmer mount) or installing the device in another location. But usually this is caused by a mechanical fault of your 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 (high-frequent) vibration. On electric helicopter you normally should not hear, feel or see any major vibration (no vibrating tail fin or skids). Then it should normally be possible to attach the AR7200BX/AR7210BX/AR7300BX 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 AR7200BX/AR7210BX/AR7300BX device 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 by 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 AR7200BX/AR7210BX/AR7300BX did perform 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 do not confuse: A slight tilt of the swash plate when the heli is standing on the ground is absolutely normal when the so-called integrators are not fully discharged. Especially when carrying the heli or steering the sticks this can happen as the system tries to perform the necessary commands. But as the helicopter will not move as intended the system tries to keep the servo movement until the helicopter may turn. 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 will not see any of these effects as now the control loop can operate as intended. As described in the manual to center the swashplate you can also move the cyclic stick(s) to full deflection once as this will clear integrator instantly. 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.

  • 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 AR7300BX with high power input.
  • A reset can be triggered due to a transfer of high voltage. Take measures to prevent static discharges.

My servos are getting warm/hot, is this normal?

Similar to a tail gyro a flybarless system is constantly working and correcting. So the servos are moving much more frequently than if they're controlled manually. Additionally the servos are usually driven with higher frequency, which means the system gives commands to the servos more often than usually (which will improve performance drastically). And because of the abolition of mixing levers and the support of the auxiliary rotor plane the servos have to resist higher forces in flight. This results to a higher power consumption and a stronger heat generation which usually is not critical. However under adverse conditions this can reach a critical range (e.g. at very high air temperatures or even if the servos are installed near other heat sources such as electric motors). In this case try reducing the driving frequency and/or the input voltage.

Servos react somehow "notchy" at high frame rate. Is AR7200BX/AR7210BX/AR7300BX damaging my servos?

If the servos are approved by the manufacturer for the chosen update frequency, this is a normal effect. The servos get new positioning signals four times faster than if they are connected to a conventional remote control receiver. Especially servos with brushless motors run very hard and direct which causes slightly jerky movements in modes with high servo frame rate. This is totally harmless to the servos and you will not notice in flight operation.

Why do the swashplate servos run very slow when testing on the bench?

This is absolutely normal. The movement of the stick only give a rate command to the system which actually controls the helicopter. The pilot no longer controls the servos directly by stick input (except for collective). So you can't say exactly what the system will do with the servos when you push one of the sticks.

The servos move to full deflection even when reducing the stick throw in the radio

I don't want to have so much cylic pitch and try to reduce the pitch using Dual Rate in the radio. This is absolutely normal and doesn't say anything about the rotation rates you will see in flight. Similar to the tail gyro in HeadingLock mode the system measures rotation rates and tries to maintain the rotation rate that is commanded by stick input. Now if you move the stick while the heli is standing on the ground you tell the system to rotate the heli with a certain speed. The system measures the speed and sees that nothing is happening. So it will apply more and more servo input in order to move the heli but as the heli can't move the servos will be driven to the maximum allowed deflection. You can't control the pitch by stick input and you don't need to!