Hi guys,
im trying to sort out the tail kicking out on my Raw 500 with Brain 2. It kicks out quite violently on large pitch pumps and despite going up from default up to 75 on Pitch precomp I’m not really getting any different results, any suggestions on what else I should look for? I’m running around 2900 hs on this and all mechanical set up is sound.
thanks in advance
As always, in order to try to understand the cause of the problem and make a remote diagnosis, we need as much data and information as possible as explained in this sticky forum post:
when-you-ask-for-support
and also here in the FAQ:
FAQ #01
If the maximum thrust of the tail rotor is not sufficient to counteract the torque generated by the main rotor, then the described phenomenon of tail position loss occurs.
In fact, the flight controller cannot give a command greater than the maximum tail rotor blade tilt command.
If the Events 106 ‘Rudder output limit reached’ is present, it means that the flight controller, in an attempt to counteract a tail displacement, has come to send the maximum command of 100% because lower commands (80%, 90% etc.) were not sufficient to stop the tail.
This indicates that the aerodynamic thrust of the tail rotor was not sufficient.
Usually this happens when very low RPMs are used for the rotor. In this case, however, the RPM for a 500-class model (2900rpm) is more than sufficient.
The causes that can be hypothesised can therefore be many others.
Just a few examples:
- The minimum and maximum excursion values of the tail blade tilt were not adjusted just before the mechanical limit of the tail.
- Instead of the tail blade tilt control being smooth and free without any friction (by releasing the uniball from the tail servo, the control should be able to be moved with the thrust of a feather), it instead has friction that slows down the movement of the tail servo (which always has little thrust power to be able to achieve high speeds).
- The actual rpm is much lower than the measured rpm because the wrong values were entered for the motor speed dividers ‘Pulses For Rotations’ and ‘Main Gear Ratio’.
- The blades used in the tail are too small and short.
- The tail pulley and/or belt slip reducing the actual rotation speed of the tail blades.
- The thrust bearings of the tail blade holders have been mounted upside down and the centrifugal force generated by the fast rpm of the tail blades blocks their rotation/inclination.
- When the maximum collective pitch is given, the RPMs collapse because the maximum pitch is too high compared to the maximum power supplied by the motor, the battery ‘C’ are too low and limit the maximum current supplied by the battery, the maximum Amperes that can be supplied by the ESC are too low compared to what is required, the cables are too thin and/or long and therefore generate a sharp drop in the supply voltage, the connectors are undersized for the maximum current flowing causing a drop in the supply voltage, faulty soldering of the connectors, etc.
In this case, in addition to the files mentioned at the beginning, we also need to know:
- Brand, model and length of the blades used in the tail.
- Maximum degrees set for the collective pitch of main rotor.
- Two photos of the tail rotor, one with the tail stick all the way to the right and the other with the tail stick all the way to the left.
Thanks