Tuning Guide

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Spirit Tuning Guide

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This guide should help you in tuning your helicopter to fit your flying style exactly.

First from all, you should try default settings that are recommended. There are basic parameters that you have to set first (for example in the wizard) but other are usefull so you can adjust stick feeling, flight behavior. Basically, you can set the behavior so that it is very similar to any known flybarless or flybared system.

If you are in the state that the helicopter is flying, but you need to do some corrections, you should start with the rudder settings first.

1 RUDDER TUNING

Prerequisite step - You can verify that the rudder servo limits are not too low or either not too high.

If the value is less than 70, than it is too low. That mean that servo precision vs mechanical gain is not good. You can fix the issue with putting ball link on the rudder servo horn closer to the center so that limit can be higher. In case the value is more than 170 there is mostly too high servo precision vs mechanical gain. You should put longer tail horn, so the ball linkage can be farther. Be sure you have configured limits that tail slider is moving from end to end, but without any mechanical binding (servo is buzzing). In case your tail mechanism allows blades pitch higher than 45°, do not set limits higher. It is not needed that limits for both sides are equal.

1. Set Rotation Rate for the rudder - this parameter determine how fast the rudder will rotate around its axis. Values between 8-11 are used by allmost all pilots.
2. Set your Rudder Delay accordingly for your servo type. For Futaba BLS servos and ultra fast servos it is fine to set 0. Slower the servo is, higher value should be configured. If you are not sure, leave this parameter (value 15 should fit for average digital servos).
3. Set your Gyro Gain (mostly in your transmitter) to the value, that tail is holding well, but not oscillating in any maneuver. This value should be as high as possible always. If you are obserinvg tail oscillation, you should decrease the gain to eliminate it.
4. Now, when your gain is configured, your tail can still not hold the position exactly. That's because your mechanical gain is not that high. You can fix it with increasing Piro Consistency parameter. You can increase it by 5 gradually until this can be eliminated. The value should be nearly all cases between 155 - 190. When increasing too much, it could be needed to decrease Gyro Gain little bit and vice versa. With higher values the rudder should rotate more constantly and so can be even more sharp. With bigger size helicopter the value is often higher. It depends mostly on the helicopter construction (manufacturer) and servo type. For Futaba BLS servos or similar, it is needed to increase value even more (in rare cases to value of 200). You shouldn't set the parameter too high if not necessary, else tail oscillation in high extent can occur. You can verify it in Fast Forward Flight or Pitch Pumps whether the value is too high and if you can see a tail oscillations.
5. When above steps are done, you can tune Stopping Behavior. For this there is Rudder Dynamic parameter. Value determines how agressive the rudder stops and whole steering is. If you like sharp stops, you should set value between 5 to 8. If you like extra sharp behavior, than value higher than 10 are intended for you. But high values are very demanding for servos and mechanics, so you should be carefull. If you like smooth stopping so that steering is also very smooth, you should set values between 3-5. If value is too low, the rudder reaction can be even delayed. In case tail stopping is not equal or overshooting in one side, you can lower servo limit for such side (mostly closer to the tail boom) by 0,5-1mm.

2 CYCLIC TUNING

Be sure your Cyclic Ring - Aileron/Elevator range is as high as possible without binding even in min/max collective pitch. Ideally it should be equal angle with your max. collective pitch.

1. Increase your Cyclic Gain if you can observe cyclic is not level during pitch pumps, flight is not precise. Mostly with values around 60% it should be good. You shouldn't set the gain as high as possible always, if it is too high, steering can be even delayed little bit and not that comfortable. Mostly values above 80% are unwanted. If gain is too high, you can see Aileron Oscillations, especially when descending slowly. Sometimes it is caused by too soft head dampening or non-flybarless blades. But if you can achieve values higher than 50% than it is good. In some cases, if you want very natural feeling, you can set Cyclic Gain to even 40%, but you will loose some precision.
2. Set Rotation Rate parameter to the extent that flips and rolls are fast enough. Be carefull to not set it higher than your mechanics can handle. The highest value for most models is between 11 - 13. If the value is too high, steering is not precise and sometimes you can observe that rate is not constant (Post-input movement can also occur).
3. If input reactions are delayed, you want likely to increase Cyclic Feed Forward which plays very important role in overall behavior. If you are switching from e.g. Microbeast, you will be comfortable with values between 4 - 6. If you are switching from V-Bar you will like 6 - 8. If you are switching from Bavarian Demon, you will love values of 8 - 10. The highest value is than demand for the servos is growing too. In bigger helicopter you can even risk Boom Strike with too high values, so be very carefull. Too high value will induce too sharp movements and also elevator bounce-back. Too low value will cause very delayed (smooth) steering.
4. Now it is time to set your Flight Style. This is last parameter that determines flight characteristics. If you like very constant movements from the stick center to full stick deflection than you will like low values. If you like flybar bevarior, so that feeling around center is smooth but with faster input you will get sharp movements, than you want to set high values. With various combinations of Flight Style and Cyclic Feed Forward you can change Cyclic feeling a lot. If you are switching from e.g. Microbeast, you will be comfortable with values between 4 - 6. If you are switching from V-Bar you will like 6 - 8. Difference between settings can be seen in piro maneuvers, tic tocs. If value is too high, than blades efficiency can decrease and motor can be overloaded. But sharp movements are transfered faster to the servos. Also if you are doing sharp maneuvers, it will stop faster when stick is returned to the center. If the value is too low, then your tic tocs can't be done fast enough, piroflips can't be done precisely, etc. For beginners it can stay in its default value.This parameter is only about your preference and both low and high value has its positives and negatives. For example, if you want smooth feeling around center with natural characteristics, you can set value of 8 there and Cyclic Feed Forward to 6-10.
5. Lastly, you want to eliminate possible Elevator Bounce-Back. This can occur if your Cyclic Feed Forward is too high, but can be reduced with Elevator Filter parameter. Value between 2-3 should be enough for almost all helicopters. For some agressive blades you will need value of 4. Especially for bigger size helicopter, value can be higher. In case of too high value, elevator movement can be so smooth and in some cases elevator can oscillate with low RPM during hovering. So you should set it only to minimum necessary value.