My CGY750 Setup for 450PRO
- FLT MODE 5
- AIL & ELE expert menu , remove all EXPO for AVCS & NORMAL
- AIL & ELE expert menu , AIL AVCS. DMP to either 98 or 99 & ELE AVCS.DMP to 100%.
- SWASHPLATE AFR's in CGY750 Amp. be set ELE 50% ALI 50% PIT 53% ( Tarot rotor head & 10mm SERVO horn)
- AIL & ELE expert menu , default value is 30%. Especially on the ELE axis, suggest I GAIN to at least 60%. Increasing the I GAIN as noted markedly improves the straight line tracking of the model and reduces any tendency for the model to pitch up during the inverted portion of rolling maneuvers. ( I Gain setting , Placed the previous menu of the D Gain )
- AIL and ELE gyro EXPERT menus is a function called Control Feel (Cnt.feel). suggest that you increase this value from the default 5 to 10 instead on the ELE axis at least.
- The suggested value of 16 for ROT.His is arguably too high for slow, precision pirouettes. Start with a value of 6 an increase from there until the model pirouettes as flatly as possible. Use the Rotational Tracking to further refine this trim. Pirouette compensation is optimized around a given pirouette speed. I would suggest you find and set you best pirouette rate for precision hovering first and then adjust the ROT.His and Rotational Tracking around that pirouette rate.
CGY-750 Control Amplifier Settings and Hints
- flight mode 4 to start
- 2. EXPERT menus for the AIL and ELE gyros, remove all EXPO for AVCS and NORMAL. You’ll set the exponential to suit your own tastes in your transmitter.
- SWASHPLATE AFR’s in the CGY-750’s amplifier be set to somewhere between 50 and 65%. The higher the AFR’s are within that suggested adjustment range and corresponding to your desired collective and cyclic throws, the greater the system’s resolution and the more electronic you will be able to run on the AIL and ELE gyros. We do not want to exceed 65% for any of the three AFR’s or the CGY-750’s linkage compensation mixers will not have sufficient extra travel to do their job. If you find your swash AFR’s are at 50% or lower, I would suggest that you reduce your servo wheel diameters.
- Gains should be adjusted to the point the model start to wobble in hover and then backed down until the wobble disappears.
- run less AIL and ELE gyro gain for your autorotation/HOLD flight condition since headspeed often get quite low near the end of an autorotation.
- AIL and ELE EXPERT menus, find and AVCS. DMP menu. AVCS. DMP adjusts the heading hold characteristics of the AIL and ELE gyros. For the greatest resistance to the effects of wind in hover and for the best performance in rolling maneuvers, I suggest that you set the AIL AVCS. DMP to either 98 or 99 and the ELE AVCS.DMP to 100%.
- SWASHSET BASIC menu is a useful item called I GAIN. The default value is 30%. Especially on the ELE axis, I suggest increasing the I GAIN to at least 60%.
- AIL and ELE gyro EXPERT menus is a function called Control Feel (Cnt.feel). I would suggest that you increase this value from the default 5 to 10 instead on the ELE axis at least.
- The suggested value of 16 for ROT.His is arguably too high for slow, precision pirouettes. Start with a value of 6 an increase from there until the model pirouettes as flatly as possible. Use the Rotational Tracking to further refine this trim. Pirouette compensation is optimized around a given pirouette speed. I would suggest you find and set you best pirouette rate for precision hovering first and then adjust the ROT.His and Rotational Tracking around that pirouette rate.
Ben Minor
Team Futaba, Helicopter
Preface
From its inception, the CGY-750 represented a landmark achievement in flybarless helicopter stabilization technology. Though well optimized for the most amazing 3D helicopter performance, the CGY-750 possesses tremendous capability for precision hovering and aerobatics. Below I will provide some set up guidelines to achieve the best possible performance from the system in these two areas of interest.
Model Considerations and Other Set Up Hints
The CGY-750’s performance is no better than the servos it directs and the radio’s power supply that drives the whole system. For cyclic servos, the optimal choices in the Futaba product line include the new BLS255HV, the BLS252, and the BLS253. For tail rotor control, the best choices are the BLS-251 and the new BLS-256HV. The BLS255HV and BLS256HV are rated for 2S lithium voltage. The BLS-252/253 should not be run on voltage in excess of 6 volts. Failure to power these two servos and others with similar voltage ratings with a 4.8-6V regulated supply will result in excessive servo temperatures in use. When using a regulated power system, employ only the highest quality products well capable of supplying the power demands of the entire flight control system. All linkages in the model should be tight and free of play. Rotor head dampening should be biased for stiffness. Pitch curve settings will be similar to what you may be used to running for a flybarred model. Cyclic pitch setting for hover will be noticeably less and will also likely incorporate more negative exponential for a softer feel around center stick. This reduced travel is important for your ability to precisely control the model over fixed points and to execute other precision hovering maneuvers. Aerobatic cyclic pitch ranges will once again be similar to what you may be used to using with a flybarred model. I suggest that you run at least 1600 rpm in hover for a typical sport and even competition model. Running a slightly higher headspeed in hover narrows the control loop of the flight control system, eases the work load of the gyros and servos, and overall makes the model noticeably more stable. Finally, a good set of rotor blades is very important for optimum system performance. In my opinion, the heaviest set of blades you can obtain for your model size with well forward chord wise and well outboard span wise centers of gravity contributes dramatically to maximum CGY-750 flight performance in precision hover and aerobatics.
Suggested CGY-750 Control Amplifier Settings and other Hints
I suggest you set up your model using flight mode 4 to start. Even though the instruction manual implies that the higher flight modes are more suitable for advanced 3D aerobatics, appropriate adjustment of AFR/dual rate and exponential produces a model that is stable and predictable both in hover and in aerobatics.
Within the EXPERT menus for the AIL and ELE gyros, remove all EXPO for AVCS and NORMAL. You’ll set the exponential to suit your own tastes in your transmitter. We do not want exponential to be present in the amplifier and the transmitter because the two become additive in effect. Have the exponential in one place only; the transmitter is ideal.
In no uncertain terms, the higher the overall AIL and ELE gain your model will tolerate without starting to wobble or oscillate in hover, the better the model is going to fly. For eCCPM models, we would like to see the SWASHPLATE AFR’s in the CGY-750’s amplifier be set to somewhere between 50 and 65%. The higher the AFR’s are within that suggested adjustment range and corresponding to your desired collective and cyclic throws, the greater the system’s resolution and the more electronic you will be able to run on the AIL and ELE gyros. We do not want to exceed 65% for any of the three AFR’s or the CGY-750’s linkage compensation mixers will not have sufficient extra travel to do their job. If you find your swash AFR’s are at 50% or lower, I would suggest that you reduce your servo wheel diameters .The goal of these exercises is to be able to run AIL and ELE gyro gains in hover at 75% or better, especially on 600-700 class models. Gains should be adjusted to the point the model start to wobble in hover and then backed down until the wobble disappears. Make sure you do this check in breezy conditions. It is entirely reasonable to expect maximum ELE gain to exceed that for the AIL. It is also expected that the lower your headspeed, the less AIL and ELE gain you will able to run. For the most part, the maximum amount of gain you can run in hover is at least what you will be able to run in aerobatics; do not expect the model to become unpleasant or unstable in forward flight with gains similar to what you were able to run in hover. I would however suggest you run less AIL and ELE gyro gain for your autorotation/HOLD flight condition since headspeed often get quite low near the end of an autorotation.
Next, for both the AIL and ELE EXPERT menus, find and AVCS. DMP menu. AVCS. DMP adjusts the heading hold characteristics of the AIL and ELE gyros. For the greatest resistance to the effects of wind in hover and for the best performance in rolling maneuvers, I suggest that you set the AIL AVCS. DMP to either 98 or 99 and the ELE AVCS.DMP to 100%. Increasing these values as described will modestly increase the need for the pilot to have the swashplate reasonably level prior to model lift off, but the model in no way becomes unpleasant or unpredictable to fly.
Within the SWASHSET BASIC menu is a useful item called I GAIN. The default value is 30%. Especially on the ELE axis, I suggest increasing the I GAIN to at least 60%. Increasing the I GAIN as noted markedly improves the straight line tracking of the model and reduces any tendency for the model to pitch up during the inverted portion of rolling maneuvers.
Also within the AIL and ELE gyro EXPERT menus is a function called Control Feel (Cnt.feel). I would suggest that you increase this value from the default 5 to 10 instead on the ELE axis at least. Increasing the control feel noticeably improves the smoothness and predictability of entry and exits (pull ups and pull outs) from aerobatic maneuvers.
The CGY-750 incorporates pirouette compensation. The adjustment features are termed Rotational Equalization, Phase Equalization, Rotation Null (His) and Rotational Tracking. For the Phase Equalization to work correctly, make certain you program your model’s headspeed for the corresponding flight conditions into the governor menu even if you are not using the governor. The suggested value of 16 for ROT.His is arguably too high for slow, precision pirouettes. Start with a value of 6 an increase from there until the model pirouettes as flatly as possible. Use the Rotational Tracking to further refine this trim. Pirouette compensation is optimized around a given pirouette speed. I would suggest you find and set you best pirouette rate for precision hovering first and then adjust the ROT.His and Rotational Tracking around that pirouette rate.
Tail rotor set up of the CGY-750 is conventional and mirrors techniques and suggestions for the GY-701. I suggest that you use SPORTS mode. When paired with the suggested BLS-251 or BLS256HV tail rotor servos, tail rotor gain should be adjusted to at least 75% in hover and 60-65% for aerobatics. Gains of these levels or even higher are possible without generating excess servo heat assuming the model is well tuned and running smoothly. As with the cyclic servos, the tail rotor servo should not be run on voltage above its rated range.
Flying Philosophy
For the most part, flying aerobatics with the CGY-750 is an entirely natural endeavor because the system provides you with a model which flies as well or better than the best trimmed flybarred model. Achieving the best hovering performance takes a bit of practice. It is important to understand that the flybarless control system does not self-center or self-level the model. Rather, the system tries to maintain either the stationary position of the model or, if the model is moving, the model’s current heading. Because of this fact, for best hovering you need to learn to put the model where you want it and then let the gyros do their job to hold that position. The system responds well in hover to small control inputs, but it does not do as well when the pilot attempts to “man handle” or otherwise over-control the model. It is for this reason that I earlier suggested that you run noticeably less cyclic throw and more negative exponential to soften the model’s response in hover to your commands. The gyros do a great deal of the work for you in hover. You simply do not need a great deal of cyclic throw to control the model even in strong winds. Once you learn when, where, and how to leave the model alone and let the CGY-750 do its best work, you will find that the system’s performance even in hover rivals some of the better trimmed flybarred models.
