Futaba CGY750 V2 3-Axis Gyro and Governor Manual

Introduction

The Futaba CGY750 is a combined 3-axis heading hold AVCS gyro and head speed governor. It features a MEMS sensor, high-speed processing, and advanced PID control, optimized for flybarless helicopters.

Warranty and Repair Service (in U.S.A.)

For assistance, consult the manual, your hobby dealer, or contact the Futaba Service Center at www.futaba-rc.com, www.hobbyservices.com, Fax (217)-398-7721, or Tel (217) 398-0007.

Features

Gyro Section

• Developed for flybarless helicopters.
• Preset parameters for helicopter types (450-550, 600-700, 750+) and control feel.
• Supports H3-120, H3-140, H3-90, H4-00, and H4-45 swashplate types.
• Advanced and adaptive PID control.
• High speed operation and low latency for stability.
• Sensing angular velocity up to +/- 1,200 deg/sec.
• Compatible with 1520S Analog (70Hz), 1520S Digital (280Hz), and 760S Digital (560Hz) tail rotor servos.
• 3D and Sports flight modes.
• Feed Forward Option for precise corrections.
• Cutting-edge control algorithm for consistent pirouette rate and smooth yaw control.

Governor Section

• Advanced and adaptive PID control loop.
• High speed operation and extremely low latencies.
• Governs head speeds from 700 RPM to 4000 RPM.
• Compatible with 1520S Analog (70Hz) and 1520S Digital (280Hz) throttle servos.
• Feed Forward Option for precise governing.
• Governor or Revolution Limiter mode selectable.
• Supports gear ratios from 1.00 through 50.00.
• Cutting edge control algorithm for consistent RPM governing.
• Revolution sensor compatible with GV-1, optional back plate, and brushless phase sensors.

Other Functions

• Maximum RPM memory.
• Cumulative engine operation timer.
• Power saving OLED display.

Contents

Your CGY750 includes:

• CGY750 Control Box
• Gyro Sensor
• Revolution Sensor
• R6303SB Receiver (in Gyro & Governor set w/R6303SB and Gyro set w/R6303SB)
• Extension Cord
• Mini Screwdriver
• Dust Covers (x3)
• Mounting Pads (x3)
• Sensor Mounting Hardware
• Magnets (x2)

Precautions

Pay special attention to safety indicated by:

• DANGER: Procedures that may lead to death or serious injury if not followed.
• WARNING: Procedures that may lead to dangerous conditions, death, serious injury, or significant physical damage.
• CAUTION: Procedures where the possibility of serious injury is small, but injury or physical damage may occur.
• Prohibited: Actions that must not be performed.
• Mandatory: Actions that must be performed.

General Precautions:

• Read the entire manual before operating.
• Before Each Flight: Check transmitter and receiver battery voltage. Exit programming mode before flying.
• Use only with 2.4GHz (FASST™) or PCM systems; FM systems are discouraged due to interference risk.

Gyro Operating Precautions:

• Allow 5-10 seconds for initialization. Do not move the helicopter or sticks during this period.
• Verify gyro operating and compensating direction before each flight. Incorrect direction can lead to loss of control.
• Verify the operating mode.
• Ensure gyro mounting pads are in good condition and wires do not contact the frame.
• Servo type parameters must match installed servos to prevent damage or loss of control.
• Allow slack in gyro cables. Use supplied mounting pads; do not use straps that encompass the sensor.
• Allow gyro to adjust to ambient temperature before flight to prevent drift.
• Avoid contact between power leads and the electroconductive coating on the sensor/control box.
• When switching between Normal and AVCS modes with transmitter trim changes, re-memorize the center position by flipping the gain switch three times (Normal-AVCS-Normal-AVCS) within one second.
• In AVCS mode, disable transmitter compensation and offsets.
• In AVCS mode, servos will not re-center when sticks are released. Visually center the swashplate and tail rotor pitch slider before takeoff using transmitter sticks. A centering procedure is available: move stick full left, full right, full left, then allow to center within one second.
• Do not drop or shock the gyro sensor.
• Always use supplied or Futaba replacement mounting pads.

Governor Operating Precautions:

• Setup and enable the battery failsafe function within the CGY750 when the throttle servo is connected.
• Set transmitter throttle failsafe to turn the governor OFF.
• When using transmitter condition hold, set the throttle servo maximum operating point below the governor activation point.
• Ensure throttle remains below the governor activation point when preparing for flight or starting the engine. Do not select flight modes that activate the governor.
• If activating the governor on the ground, ensure at least -5 degrees of pitch to prevent unexpected lift-off.
• Periodically check RPM sensor output. Verify magnet and sensor mounting every 10 flights.

Specifications

Dimensions:

• Controller Width: 1.14in [29mm]
• Gyro Sensor Width: 0.83in [21mm]
• Revolution Sensor Width: 0.30in [7.5mm]
• Controller Length: 1.73in [44mm]
• Gyro Sensor Length: 0.83in [21mm]
• Revolution Sensor Length: 0.63in [16mm]
• Controller Height: 0.47in [12mm]
• Gyro Sensor Height: 0.33in [8.5mm]
• Revolution Sensor Height: 0.39in [10mm]

Weight:

• Controller: 0.459oz [13g]
• Gyro Sensor: 0.282oz [8g]
• Revolution Sensor: 0.141oz [4g]

Electrical:

• Operating Voltage: 3.8V to 8.4V DC*
• Current Drain: 70mA

Servo Compatibility:

• Selectable Servo Frame Rate: 70Hz, 280Hz, 560Hz (Rudder Gyro only)
• Center Pulse Width: 1520µS (70Hz & 280Hz), 760µS (560Hz)

Governor:

• Governor Resolution: 0.1Hz (6rpm) (Engine RPM)
• RPM Accuracy: 1%
• Head Speed Range: 700-4,000rpm

Environmental:

• Operating Temperature: 14°F to 113°F (-10°C to +45°C)

Control System: Digital advanced control

Sensor: Micro Electromechanical Systems (MEMS) Gyro Hall effect sensor

Angular Velocity Range: ±1,200 Degrees Per Second (Gyro)

*Verify that receiver, servos, and other components are compatible with the chosen operating voltage.

Replacement & Optional Items

• Futaba PC Interface CIU-2: FUTM0951
• Extension Cords: 55 mm, 80 mm, 130 mm, 200 mm, 350 mm
• Mounting Pad: 1x22x22 mm (10)

WARNING: Ensure regulators, wiring, and switches can handle high current demands from modern servos. Servo current draw can increase by up to 50% on flybarless helicopters. Always ensure the receiver battery is fully charged.

Helicopter Mechanics Requirements:

• Use with a rigid tail rotor drive system (torque tube or belt drive). Wire-driven systems are not supported.
• Ensure drive gears, torque tube, pulleys, belt, bearings, and shafts are in proper working condition.
• Tail rotor linkage, bell crank, pitch slider, and grips must operate without friction. Binding reduces performance and servo lifespan.
• Balance all rotating components to minimize vibration. Ensure engine/motor runs smoothly.

Gyro Sensor Replacement:

• Each CGY750 control box is calibrated for its specific sensor. Do not mix sensors. Calibration must be done by an authorized service center.
• If replacement is needed, send the complete unit to the regional support center.

Gyro Sensor Installation

Mount the gyro sensor on a rigid platform, at least 6 inches [152mm] from a Nitro Engine. Ensure the mounting area is rigid and the sensor is aligned with the helicopter's roll and pitch axes. The cable should exit toward the front or rear (pitch axis). Misalignment reduces performance.

Alignment Details:

• Elevator (Pitch) axis
• Rudder (Yaw) axis
• Aileron (Roll) axis

Important: The gyro sensor's roll and pitch sensing axes must align with the helicopter. Misalignment over 0.5 degrees will cause performance loss. The bottom of the sensor must be perpendicular to the main shaft. The roll axis must be parallel to the tail boom, and the pitch axis perpendicular to the side frame.

Mount the sensor using a supplied gyro pad. Route the lead to the CGY750 control box and plug it in, ensuring the connector is locked.

Troubleshooting

1. Verify tail rotor and swashplate mechanisms operate correctly.
2. Consider electromagnetic interference (EMI). Move the gyro sensor away from servos, ESCs, or motors if issues persist despite correct setup and vibration-free operation.
3. Vibrations degrade gyro performance. Eliminate vibrations by balancing components. Mount the gyro sensor rigidly; avoid soft foam pads that allow bouncing on roll/pitch axes, which can cause instability or loss of control.

Connecting the CGY750

The CGY750 connects to the receiver, servos, and sensors. It requires an S.BUS receiver or the optional PWM Receiver to S.BUS adapter.

Connections:

• (1) Gyro Sensor: Connect the gyro sensor lead. Ensure the connector is fully inserted until it clicks.
• (2) Rsen (Revolution sensor): Connect the revolution sensor.
• (3) S.BUS: Connect to the S.BUS output of the receiver.
• (4) AIL Output: Connect the aileron servo.
• (5) ELE Output: Connect the elevator servo.
• (6) PIT Output: Connect the pitch servo.
• (7) TH Output: Connect the throttle servo or ESC with BEC (in Gyro+THR mode).
• (7) E2 2nd ELE Output: Connect the second elevator servo (for H4-xx swash modes; governor is inhibited).
• (8) RUD Output: Connect the rudder servo.

Important Notes:

• If the governor and limiter functions are disabled in [Gyro+THR] mode, the throttle signal is sent directly to the TH/E2 connection. The throttle servo can connect to the receiver or the CGY750 TH/E2 port.
• When H4-xx swash mode is selected, the TH terminal becomes the 2nd elevator output, and the governor function is inhibited.

General Connection and Setup:

• Mount the receiver and CGY750 control box using vibration-absorbing pads.
• Route servo leads and extensions carefully, avoiding contact with metal or carbon fiber.
• S.BUS Channel Setting: Assign functions (AIL, ELE, etc.) to channel numbers (1-16) within the CGY750's S.BUS menu. Set unused functions to [INH]. Default assignments usually work with Futaba transmitters.
• If transmitter channels are insufficient, functions like GV On/Off, Ail Gain, and Ele Gain can be set to [INH] in the S.BUS menu, with settings controlled internally by the CGY750.
• When the GV On/Off channel is unused, governor control is handled by the [Stick Switch] function.
• When remote gain channels are unused, operating mode and gain are set in the AIL/ELE Basic menus.

Using the CGY750 with an Electric Helicopter:

DANGER: Remove the pinion gear or disconnect the motor from the ESC before powering up to prevent injury from the powerful electric motor.

• If using the ESC's internal governor, connect the ESC to the [TH/E2] port.
• Set the gyro mode to [GYRO+THR]. The CGY750 will pass the throttle signal from the receiver.
• Complete necessary transmitter setup (ATV/EPA/REV) per ESC instructions.

TX Set-up

Condition Selection: Use the transmitter's digital channel "1" (DG1) to assign a switch or flight mode, allowing two adjustable values for parameters (c1/c2).

• Rotor Head Gyro Gain ("RotHd.Gn"): Assign to a channel (default CH9) for TX adjustment. If using 6CH or less TX, setting to [INH] defaults gain to "BaseGain" in Flight Tuning.
• Tail Rotor Gain ("RGn"): Assign to a free TX channel (default CH5) for TX adjustment.

Initial Setup: Set transmitter dual rates, pitch curve, and endpoint values to 100/100.

Governor Installation

Modify the cooling fan to embed the accessory magnet. Attach the magnetic sensor to the engine, ensuring a 1-2mm gap between sensor and magnet. Balance the cooling fan if necessary.

Sensor Mounting: Select a mounting method that prevents the sensor from touching the frame or other parts. Temporarily mount the sensor and select the magnet position. Tighten securely and recheck sensor output (should be at least 60% in "Revolution sensor testing" menu).

Magnet Operating Side Check: Ensure the magnet's operating side faces the sensor for optimal output.

Governor Fuselage Setting Precautions

Throttle Servo Linkage: Maximize servo operating range. Set transmitter EPA/AFR functions close to 100%. Adjust needle for smooth engine reaction. Ensure mixture is not too rich or lean.

Fuselage Vibration: Address engine vibrations from weak frames or improper engine mounts, as they cause unstable speed and reduce governor performance. Ensure the carburetor provides linear throttle control.

Tuned Silencer: Adjust needle and pipe length for throttle response proportional to opening. The governor requires linear carburetion.

First Map

This section illustrates the menu navigation flow using MODE and DATA keys.

Opening Screen

Verify connections. For electric models, remove the pinion gear. For first power-up, remove servo arms/linkages to prevent damage. Power up the transmitter, then the helicopter. Keep the helicopter motionless during CGY750 initialization. The display shows the ID and firmware version, followed by an initialization animation.

Home Screen

After initialization, the Home Screen displays:

1. Axis Indicator: Cycles through AIL, ELE, RUD and their gain values.
2. Gyro Operation Mode: [A] for AVCS, [N] for Normal. Inverted color indicates neutral offset. AVCS centering procedure involves moving the stick twice to its full extent and returning to center within one second. Memorizing neutral position requires changing the operating mode twice within one second.
3. Gyro Gain: Displays current gain for the indicated axis.
4. Operating Condition: [ON] or [OFF] for the Governor.
5. Yaw Rate Comp: Indicates if Governor feed forward is enabled.
6. Battery Voltage: Displays voltage; changes to [LOW BAT] if below fail-safe voltage.
7. Setting Menus: Access to the main configuration menus.

The display cycles through AIL, ELE, and RUD gains. If the governor is disabled ([Gyro+THR] mode or H4-xx swash type), the display shows gains only.

Home Screen Options (accessed via MODE [+] or [-] keys):

• Engine Runtime: Cumulative engine run time. Reset by holding DATA [+] or [-] for over one second.
• OLED Display Options: [Saver] (dims after 60s) or [Light] (always full brightness).
• Setup Style: Select between 3D and F3C modes. Changing style initializes AIL/ELE/RUD settings.
• Condition Menu: Enable/disable for using two sets of parameters via a transmitter switch (DG1).
• Roll Rate Maximum Display: Shows maximum roll rate recorded. Resets on power-up.
• Elevator Rate Maximum Display: Shows maximum elevator rate recorded. Resets on power-up.
• Maximum RPM: Displays maximum recorded RPM. Cleared by holding DATA [+] or [-] for at least one second.
• Condition #: Indicates the current condition number.

Warning Display

• Governor Warning: Displayed if the governor is activated during power-up. Disable governor via flight condition and start the engine with the governor OFF.
• Sensor Error: [SensorER] indicates a calibration error, possibly due to a defective sensor. Remain motionless during initialization. Contact support if error occurs.
• Low Battery: [Low Batt] warning if receiver battery voltage drops below the [BAT/FS] setting. If sustained for over one second, Battery Fail Safe activates, returning throttle to idle. Land immediately. Throttle can be temporarily reactivated by moving the stick to idle.
• Memory Writing Indicator: Do not power off the CGY750 while this indicator is displayed, as settings may be lost.

Setting Menus

Access menus like [RUD.Gyro], [AIL.Gyro], [ELE.Gyro], [SWASHset], [Governor], and [S.BUS]. Press MODE [+] or [-] to show next/setting items. Hold MODE [+] or [-] for one second to enter/exit Expert menus. Return to Home Screen by navigating back to the Basic menu and cycling through.

Note: The [Governor] menu is not displayed if Operating Mode is [Gyro+Thr] or Swash Type is H4-xx.

S.BUS Basic Setting

Assign CGY750 functions to S.BUS channels. Set unused functions to [INH]. Verify assignments match transmitter function assignments.

Channel Assignments:

• (2) Aileron channel: Default 1ch.
• (3) Elevator channel: Default 2ch.
• (4) Throttle channel: Default 3ch.
• (5) Rudder channel: Default 4ch.
• (6) Pitch channel: Default 6ch.
• (7) Rotor head gain (AIL/ELE): Default 9ch.
• (8) RUD gain channel: Default 5ch.
• (9) RPM channel: Default 7ch.
• (10) GOV. on/off channel: Default 8ch.
• (11) Condition change channel: Default DG1.

(12) S.BUS data reset: Resets assignments to defaults.

Swash Servo Installation and Setup

Supports 6 swashplate types: H3-120, H3-140, H3-90, H4-00, H4-45.

Setup Steps:

1. Install servos according to helicopter manual and chosen swashplate type.
2. Reset transmitter to default, set swashplate type to Normal (H-1). Disable CCPM mixing in the transmitter.
3. Power up TX and helicopter. Allow CGY750 to initialize.
4. Navigate to [SWASHset Basic] menu.
5. Select the correct Servo Type (Analog, DG:70Hz, DG:95Hz, DG:140Hz, DG285Hz). Match servo manufacturer recommendations.
6. Adjust AIL.Ntr, ELE.Ntr, or PIT.Ntr to center servos. Gyros are disabled during this. For electric models, remove pinion gear.
7. Check servo direction for collective pitch input (positive stick = increase pitch). If incorrect, use ServoDir Comb#.
8. Center collective stick (0 degrees pitch). Ensure servos are level. Make small adjustments using AIL/ELE/PIT.Ntr.
9. Mount linkage balls and install servo retention screws. Use Loctite if servos have metal gears.
10. Check cyclic stick movements: Forward stick -> forward tilt; Right stick -> right tilt. Reverse direction using ELE.Dir or AIL.Dir if needed. Reverse PIT.Dir if collective pitch movement is opposite to transmitter input.
11. Verify swashplate moves correctly for all stick inputs.
12. Navigate to SWS.Rate. Ensure swashplate is level at 0 degrees collective pitch. Adjust linkage rod lengths if necessary.
13. Set cyclic pitch: Rotate blade to align with tail boom. Apply full right cyclic and measure pitch. Aim for at least 9 degrees. Adjust SWS.Rate. Repeat for aft cyclic.
14. Adjust collective range using PIT.Rate (similar to traditional flybar helicopters). Suggested range: +/-10 to +/-12 degrees.
15. Set transmitter AFR/ATV/D/Rs for cyclic/collective to 100%.
16. Gyro Compensation Direction: In [Swashset Basic] menu, check AGy.Dir and EGy.Dir. Roll helicopter right; CGY750 should add left cyclic. Lower nose; CGY750 should add aft cyclic. Reverse direction if incorrect.
17. Check for interactions between cyclic and collective movements. Refer to Linkage Compensation section if needed.

Swash Basic Setting

Contains functions for swashplate servo and mixing setup.

• (2) Operation mode: [Gyro+Gov], [Gyro+THR] (governor disabled, throttle passed through), [Gyro+H4] (governor disabled, TH/E2 is 2nd elevator output for H4-xx swash). Reset required after changing mode.
• (3) Servo type: Select servo driving frequency (Analog=70Hz, DG=95Hz, DG=140Hz, DG285Hz). Match servo specifications.
• (4) Swash type: Select swashplate type (H3-120, etc.). All swash parameters reset when type is changed.
• (5) Swash servo direction setting: Adjust servo directions for eCCPM models. 8 combinations for H3-xx, 16 for H4-xx.
• (6) Swash direction setting: Selects AIL, ELE, PIT direction. Reverse if stick movement and swash movement are opposite. (Not displayed for Gyro+THR or H4-xx swash types).
• (7) Servo neutral adjustment: Subtrim for each swashplate servo. Adjust to keep linkage balls perpendicular to control linkage at 0 collective pitch.
• (8) Swash Rate: Adjusts throw for roll (AIL) and pitch (ELE) axes. Applies to both. Suggested base cyclic pitch: 6-10 degrees depending on helicopter size.
• (9) Pitch Rate: Adjusts collective pitch travel. Similar to traditional flybar helicopters. Suggested range: +/-10 to +/-12 degrees.
• (10) Swash ring: Prevents swashplate binding at extreme stick inputs.
• (11) Aileron (roll)/ Elevator (Pitch) Gyro direction setting: Controls compensation direction for roll/pitch axes. Verify correct compensation.
• (12) Aileron direction memorizing: Teaches CGY750 aileron swashplate movement direction.
• (13) Elevator direction memorizing: Teaches CGY750 elevator swashplate movement direction.
• (14) Pitch low memorizing: Saves minimum collective pitch point.
• (15) Pitch zero memorizing: Saves zero collective pitch point.
• (16) Pitch high memorizing: Saves maximum collective pitch point.

Swash Detail Setting

For advanced pilots seeking precise swashplate movement to eliminate adverse flight behavior.

• (2) PITAIL mixing rate: Adjusts pitch to aileron mixing.
• (3) PITELE mixing rate: Adjusts pitch to elevator mixing.
• (4) PITELE2 mixing rate: Adjusts pitch to 2nd elevator mixing (H4 swash only).
• (5) AILPIT mixing rate: Adjusts aileron to pitch mixing.
• (6) AILELE mixing rate: Adjusts aileron to elevator mixing (H4-45 swash only).
• (7) AILELE2 mixing rate: Adjusts aileron to 2nd elevator mixing (H4 swash only).
• (8) ELEPIT mixing rate: Adjusts elevator to pitch mixing.
• (9) ELEAIL mixing rate: Adjusts elevator to aileron mixing.
• (10) ELEELE2 mixing rate: Adjusts elevator to 2nd elevator mixing (H4 swash only).
• (11) Linkage compensation aileron: Compensates for swashplate rising/falling on elevator/collective axes during aileron inputs at high/low pitch.
• (12) Compensation direction of the aileron: Sets compensation direction for aileron linkage compensation.
• (13) Linkage compensation elevator: Compensates for swashplate rising/falling on aileron/collective axes during elevator inputs at high/low pitch.
• (14) Compensation direction of the elevator: Sets compensation direction for elevator linkage compensation.
• (15) Speed compensation: For 120 CCPM, matches servo speeds for elevator input to keep swashplate level.
• (16) Swash rotation: Electronically adds rotor head phasing to swashplate controls.
• (17) Data reset: Resets all Swashplate parameters to default.

Linkage Compensation

Detailed adjustment to eliminate eCCPM interactions.

Prior to adjustment: Set transmitter AIL, ELE, PIT to full travel (AFR/DR 100%).

Pitch calibration: Memorize Pit.Zero, Pit.Low, Pit.High in SWASHset Expert menu.

Pitch movement calibration: Ensure swashplate is level at center collective. Adjust linkage rods. Use PIT-AIL and PIT-ELE mixing rates in SWASHset Expert to level swashplate at max/min collective.

Aileron movement calibration: At center collective, check for AIL-PIT interaction. Adjust AIL-PIT mixing rate to minimize. Repeat for left/right AIL. At max collective, adjust SWcp.AIL rate to minimize interaction. Check compensation direction (CpA.Dir). Repeat at min collective.

Elevator movement calibration: At center collective, check for ELE-PIT and ELE-AIL interactions. Adjust ELE-PIT and ELE-AIL mixing rates. At max collective, adjust SWcp.ELE rate to minimize interaction. Check compensation direction (CpE.Dir). Repeat at min collective.

Adjust SpeedCmp to minimize elevator axis "wiggle" during fast elevator inputs.

Flight Tuning Menu Definitions and Adjustment

Refines cyclic gyro performance.

• (2) Gyro base gain setting: Sets cyclic gyro base gain. If remote gain channels are [INH], this sets the actual working gain.
• (3) Cyclic rate setting: Sets maximum cyclic pitch and roll rate (d/s).
• (4) Exponential: Softens or sharpens cyclic control feel around center stick. Negative values soften, positive values sharpen.
• (5) Control Authority Aileron: Changes gyro's reaction rate to stick input for AIL axis.
• (6) Control Authority Elevator: Changes gyro's reaction rate to stick input for ELE axis.
• (7) Flight style: Adjusts model's reaction feel (robotic vs. fluid).
• (8) Elevator pre compensation: Compensates for nose lift/fall during collective pitch changes.
• (9) High pitch authority: Increases control authority during loaded maneuvers at high pitch angles.

Tail Rotor Gyro Setup and Rudder Basic Setting

Transmitter Setup: Enable rudder gyro function, set mode to AVCS. Set remote gyro gain (e.g., 75% AVCS for Normal/Hold, 50% for Idle Up). Set Tail Rotor ATV/EPA to 100%, D/R to 75% (reduces pirouette rate). Use 30% expo on tail rotor channel.

WARNING: Do not connect tail rotor servo until servo type is selected.

Setup: Remove servo arms/linkages. Power up system. Connect tail rotor servo to CGY750 rudder port. Install servo arm, ensuring linkage is perpendicular to pushrod. Confirm servo direction using transmitter reverse function if needed. Install servo arm screw.

• (2) Servo type: Select appropriate type (DG1520, DG760, Analog).
• (3) Gyro direction: Controls yaw axis compensation. Verify correct compensation direction.
• (4) Limit setting: Sets mechanical limits for tail rotor servo. Recommended: 100% in CGY750, adjust servo arm length. Use parameter for fine adjustments (90-110% optimal). Prevent binding.
• (5) Gyro working mode: [CMT] (select AVCS/Normal via TX), [Normal], or [AVCS].

Governor Basic Setting

Sets fundamental governor functions.

• (2) Revolution setting: Set main rotor revolution (700-4000 RPM).
• (3) Gear ratio: Input main rotor gear ratio (1-50).
• (4) Pole number: Sets motor pole count for phase sensors (2p default for other sensors).
• (5) Servo selection: Select throttle servo type (Analog/Digital).
• (6) Stick switch: Sets desired throttle stick position for governor activation.
• (7) Governor on/off switch: Allows governor ON/OFF via transmitter switch.
• (8) Servo limit point setting: Defines throttle servo travel range (idle and high position). Must be set before other functions.
• (9) Limit point testing: Confirms throttle servo positions.
• (10) Revolution sensor testing: Tests sensor output level (needs >60%).

Governor Speed Setting

Set RPM via transmitter channel or 3-position switch.

Speed setting precautions: Ensure transmitter channel travel is sufficient. Set governor maximum speed approximately 50 RPM below the engine's maximum achievable RPM.

Safety reminder: Configure transmitter failsafe for throttle and governor ON/OFF channels.

Governor Operation

Operates from 700-4000 RPM. Governor is OFF during engine start/idle.

Governor ON Conditions: ON/OFF switch OFF during power-on, stick switch ON, ON/OFF switch ON, setting speed not OFF, engine speed exceeds 60% of set speed, speed sensor working.

Recommended Gyro Gain Settings

• AIL/ELE Gyro: 50-60% for 450-550, 600-700, 750+ size helicopters.
• Rudder Gyro: 50% is a good starting point for all model sizes.

Before Flight Checklist

• Verify transmitter and receiver batteries are fully charged.
• Check gyro mounting tape and ensure firm mounting.
• Verify gyro wiring has slack and is clear of the frame.
• Power on transmitter and receiver; allow gyro to initialize.
• Check and verify servo type parameters.
• Ensure servo arm screws are installed.
• Confirm cyclic and tail rotor servos do not bind.
• Verify gyro operating mode and gains are set correctly.
• Test all controls and verify correct movement direction.
• Verify gyro compensation direction for all three axes before flight.

Adjustments During the Test Flight

• Always level the swashplate with the cyclic stick before applying throttle.
• Make small corrections during takeoff. Large ground corrections can cause tip-overs.
• If resonance/shaking occurs during spool-up, leave the helicopter on the ground until it stops. Address vibrations by balancing components.
• Use a power switch to avoid potential initialization failure when connecting the flight battery.

Tuning Guidelines for CGY750

V2 firmware offers excellent performance with default values. Fine-tuning may be needed for specific models.

• Static cyclic pitch: Measure in SWS.Rate section of SWASHset BASIC. Suggested range: 9-10 degrees. Use transmitter AFR/DR for cyclic rates.
• Total gyro gain: Initially 50-60% for AIL/ELE. Set AIL and ELE gains to matching percentages.
• Bounce: Adjust D gain for elevator axis. If bounce persists, reduce total gyro gain.
• Compensation Mixers: V2 firmware includes AIL, FLT, and ROLL compensation mixers in AIL/ELE Expert menus for advanced tuning (e.g., corkscrewing, rolling off).
• Memorize Directions: Teach CGY750 directions for UP ELE and RIGHT AIL in STK.Dir menu (SWASHset BASIC).

Tips for Using the CGY750 Governor with Electric Models

WARNING: Remove main and tail blades, or disengage motor pinion before electric governor setup.

• Configure ESC for external governor use.
• Use brushless phase sensor or magnetic sensor. Set gear ratio to 1:1 for one magnet.
• For brushless phase sensor, observe CGY750 input signal range and motor pole count. Set pole count to 2 for magnetic sensors.
• Set Governor Working Mode to "Governor" and Response to "Silent" (Expert Menu).
• Set Throttle Mode to FIXED (or OPTIMIZE).
• Calibrate ESC and governor speed ranges.
• To suppress tail "kick" when switching speeds, increase Revolution Up/Down delays (Rv.UpDly/Rv.DnDly) in Expert Menu.
• Optimal gearing for chosen headspeed improves governor function. Excessive governor gain worsens tail kick.
• Activate and adjust PIT-RUD F/F mixing if model yaws nose left with collective input.

Expert Gyro and Governor Definitions and Tuning Section

FLT.Tune EXPERT SETTING

• (2) Dead band: Transmitter control dead band (0-25.0µS).
• (3) Head hold: Heading hold gain (0-200%). Improves holding angle and cyclic rate consistency.
• (4) Stop tune A: Cyclic stop tuning for aileron axis. Lowers for harder stop, increases to reduce bounce.
• (5) Stop tune E: Cyclic stop tuning for elevator axis. Lowers for harder stop, increases to reduce bounce.
• (6) Head Response: Gyro control speed matching helicopter reaction capability (1-10).

RUDDER GYRO EXPERT SETTING

• (2) Pirouette speed: Maximum pirouette speed (100-999 deg/sec).
• (3) Control delay In: Tail rotor feel off center (0-20).
• (4) Control delay Out: Tail rotor stop aggressiveness (0-20).
• (5) F/F mixing rate: Feed Forward mixing rate (-100% to +100%).
• (6) F/F mixing acceleration gain: Momentarily increases F/F mixing for abrupt collective changes (0-200%).

GOVERNOR EXPERT SETTING

• (2) Governor working mode: [Governor] (RPM controlled by GOV) or [Limiter] (controls RPM during throttle reduction).
• (3) Rv. Display: Choose to display ROTOR RPM or MOTOR RPM.
• (4) Feed Forward from Cyclic: Adds throttle with cyclic commands for RPM stability (0-100%).
• (5) Revolution change up delay: RPM change speed when increasing RPM (2-20).
• (6) Revolution down delay: RPM change speed when reducing RPM (2-20).
• (7) Start delay: RPM stabilization speed when GOV is turned ON (2-20).
• (8) Low revolution setting: Lowest possible governing RPM (1000 rpm default).

Condition Menu

Allows two sets of parameters adjustable via a transmitter switch (DG1).

Adjustable parameters include Swash Rate, Pitch Rate, Swash Ring, Flight style, Control Authority, Head hold, Stop tune, Cyclic rate, Exponential, Governor gain, and Low limit set.

F3C Style Tuning Section

Exclusive functions for F3C style tuning.

• (Swash Basic) Rotational equalizer: Optimizes pirouette stability.
• (Swash Basic) Equalizer direction: Sets rotational equalizer direction (NORMAL/REVERSE).
• (Swash Detail) Rotational tracking: Tunes rotational equalizer to pirouette characteristics.
• (Flight Tuning) Gyro working mode: [CMT], [Normal], or [AVCS].
• (Flight Tuning) Stability gain setting: Adjusts tolerance for oscillations without wobble (1-10).
• (Rudder Basic) Flight mode: Selects [3D] or [Sports] flight mode.
• (Governor Basic) Response: Selects governor operation response (Middle, Moderate, Quick, Silent).
• (Rudder Expert) Gain tracking: Adjusts tail rotor stop aggressiveness (-20% to +20%).
• (Rudder Expert) F/F mixing: Activates Feed Forward mixing.
• (Rudder Expert) Neutral compensation: Recalls rudder servo neutral point for tail stop motion.
• (Rudder Expert) Yaw smoother: Selects rudder control feeling.
• (Governor Expert) Gyro basic gain: Sets base gyro gain (50%-120%).
• (Rudder Expert) Rudder servo neutral setting: Sets neutral position of the rudder servo.
• (Rudder Expert) Rudder exponential: Sets tail rotor control feel around center.
• (Rudder Expert) Rudder delay mode: [Function] (softer feel) or [Constant] (linear feel).
• (Rudder Expert) Stop delay: Adjusts tail stop aggressiveness (100%-400%).
• (Rudder Expert) Gain change up delay: Sets delay for gyro gain change from low to high (1-50).
• (Rudder Expert) Gain change down delay: Sets delay for gyro gain change from high to low (1-50).
• (Rudder Expert) Rudder hysteresis: Adjusts range around center stick for no rudder servo movement (0µS-50µS).
• (AIL Expert) Integral gain (I gain): Maintains heading (0%-200%).
• (AIL Expert) Differential gain (D gain): Tunes stops following cyclic commands (0%-250%).
• (AIL Expert) Aileron compensation: Mixes pitch to aileron to compensate for rolling off during ascent/descent.
• (AIL Expert) Roll compensation: Mixes aileron to elevator to compensate for corkscrewing or non-axial rolling.
• (ELE Expert) Flip compensation: Mixes elevator to aileron to compensate for rolling off during flips/loops.