The main window of the setup software is broken down into three areas:
- The menu bar provides access to the program’s features and functions.
- The Live Data region is updated in real time whenever the gyro is connected to your computer with a USB cable.
- The Offline Setup Values tabs display the values for your gyro’s current helicopter setup file settings.
NOTE: This section is for reference only. You do not need to read or understand everything that is in it to use your SK720.
Items in the File menu include:
- Load Setup
- Click this menu item to load a setup from your computer’s hard drive. The Offline Setup Values tabs will be updated with newly loaded setup. Any setup sent to the gyro will be labeled with the first 16 letters of the configuration file’s Windows filename.
- Save Setup
- Use this menu option to save a setup to your computer’s hard disk. This feature is useful if you want to experiment with different settings or backup your current settings to disk.
- Reset to Sport Setup
- Use this menu item to reset the SK720 settings to the default sport setup.
- Reset to Scale Setup
- Use this menu item to reset the SK720 settings to the default scale setup.
- Reset to Basic 3D Setup
- Use this menu item to reset the SK720 settings to the default basic 3D setup.
- Upgrade From SK360
- Use this menu item to import a stored SK360 configuration file into the SK720 configuration program. The imported SK360 configuration can then be tweaked and loaded onto your new SK720.
- Replay Flight Log
- Select this item from the File menu to replay your flight logs in the 3D viewer. See Skookum Robotics Data Viewer Help of this manual for detailed description of how to use the 3D viewer.
Items on the Utility menu include:
- Bind Sat RX on Power Cycle
- use this option to bind any Spektrum/JR satellite receivers that are connected to your SK720. Connect the SK720 to your computer using a USB cable and then select this option. All connected satellite receivers will go into bind mode the next time that the SK720 is power cycled (i.e. turned off and then on again).
- Reset Log Counter
- When flight logging is enabled (see the Control Tab section below), selecting this option causes the log index number to be reset to zero. Thereafter, log file names will be “LOG0.BIN”, “LOG1.BIN”, etc.
- Reset Gyro
- Selecting this item on the Utility menu causes the gyro to reset immediately. The unit will disconnect and then reconnect to Windows in the process. Ensure that all open files on the SK720 flash drive are saved and closed before selecting this option. This option is useful when binding satellite receivers because it allows the unit to be reset without having to disconnect it from your computer.
- Format MicroSD Card
- This option will permanently erase the contents of your SK720 mass storage device. Be sure to back up any important files (such as the SK720 setup software directory) before selecting this option. Note that the format is done by the SK720 itself. Use this option periodically to improve the speed of writes to the SK720’s flash drive. The gyro will disconnect and then reconnect to Windows in the process and it may take 30 seconds or more to complete.
- Update SK-720 Firmware
- SK720 program (firmware) updates will be provided from time to time by Skookum Robotics. Select this option and follow the on screen instructions to update your SK720 with the latest software improvements.
- Update SK-LCD Firmware
- Choose this option to load the latest software revision (firmware) onto your SK-LCD accessory. The SK-LCD must be connected to your SK720 before starting the update.
This area displays live telemetry from the gyro, including your radio Inputs from Receiver and Gyro Motion. Remember that while in setup mode, all elevator, aileron and rudder stick motions are sent directly to the helicopter’s servos to allow for easy mechanical setup. See Figure 19.1.
Under Inputs From Receiver, the Pilot Elevator, Aileron, Rudder and Collective command percentage is given as a guide for setting up your radio. See the Step 29 Initial Setup Wizard for details about how this data is used to help setup your SK720.
The Control tab is found in the Offline Setup Values region of the main SK720 setup software window, as shown in the image below.
- When the Satellite Receivers option is selected in this field, the SK720 will look for control inputs from the “SAT RX” ports and servo ports IO-A to IO-C will become outputs. Otherwise, ports IO-A to IO-E will be set to receive signals from a traditional radio receiver’s outputs.
- Auto Trim at Init
- With this feature enabled, the gyro will use the aileron, elevator, and rudder stick centers it receives at initialization as neutral cyclic and rudder (as applicable). If disabled, the gyro’s inputs will need to be trimmed at the radio for each flight due to drift in the stick’s sensors.
- Stick Dead Bands
- To avoid drift due to small errors in stick centering, a dead-band can be set for the cyclic (elevator and aileron) functions as well as the tail (rudder). 1 to 2 percent is a good value for most radios (note your radio’s centering may change with temperature). For scale models, larger dead band can give a solid control feel while in stationary hover. Note that all helicopters should have some dead band on rudder.
- Mounting Orientation
- These settings can be changed to allow the gyro to be mounted in a variety of orientations in your helicopter. See Step 31 of the Initial Setup Wizard for details on how to use these options.
- Low Voltage Alarm
- Use this box to set the low voltage alarm level. Options are BEC or 2S LiPo servo battery. Low voltage will trigger a “Voltage” error to be recorded and will cause the SK720’s LED to blink red.
Drive System Tab
The Drive System tab is found in the Offline Setup Values region of the main SK720 setup software window, as shown in the image below.
- Set Throttle Failsafe
- After setting up your ESC or throttle servo, use this button to tell the SK720 what your throttle channel idle setting is. This sets the fail-safe if you lose the radio link, and helps improve autorotations.
- RPM Sensor
- Click this checkbox to tell your SK720 that an RPM sensor is connected to port IO-C. If selected, the SK720 will record RPM data in the flight logs. The Gear Ratio box will be enabled when the RPM sensor is selected on. Enter a value in the Gear Ratio box to calibrate your sensor to your main rotor RPM.
- Counter-Clockwise Rotor
- Click this checkbox to tell your SK720 that your helicopter’s main rotor rotates counter-clockwise.
The Swashplate tab is found in the Offline Setup Values region of the main
SK720 setup software window as shown in the image below.
- Swashplate Type
- Select your swashplate and mechanical mixing type. Options are 120 eCCPM, 135/140 degree eCCPM, 90 degree mechanically mixed (separate servos for each of elevator, aileron and pitch control), and 90 degree 3 or 4 servo eCCPM where servos are directly connected to the swash but 90 degrees apart.
- Swash Ring
- Limits motion of the swashplate to prevent binding when large amounts of both elevator and aileron cyclic are used (i.e. assume the swashplate is round, not square).
- Piro Comp
- Compensates for the effects of rapid yaw rates on cyclic stability. This is important for 3D stunts and when flying in wind.
- The inputs to the gyro must be separate channels for elevator, aileron and pitch (collective) control because the SK720 does its own swashplate mixing. This gives the full precision of your radio set rather than losing half of its precision with in-transmitter mixing. It also allows for extra mixing features normally only available on high-end radios such as Swash Ring and Servo Equalizing.
- Elevator Cyclic
- Percentage of full swashplate motion at full stick deflection for elevator cyclic. You can reverse the elevator servo using the Rev checkbox.
- Aileron Cyclic
- Percentage of full swashplate motion at full stick deflection for aileron cyclic. You can reverse the aileron servo using the Rev checkbox.
- Collective Pitch
- Percentage of full swashplate motion at full stick deflection for collective. You can reverse the collective servo using the Rev checkbox.
- Phase Trim
- Rotates the plane of cyclic action about the main shaft, to allow correction for gyroscopic and aerodynamic effects. It also allows the use of 3 or 4 blade rotor heads. For example, setting phase trim to 90 degrees would make full left aileron stick deflection tilt the swashplate fully forward. Note that the phase angle will vary with rotor rpm and load so a “happy medium” value must be sought when setting this value. See Section 12 of this user’s manual for a step-by-step description of how to check the cyclic phasing.
Swash Servos Tab
The Swash Servos tab is found in the Offline Setup Values region of the main
SK720 setup software window as shown in the image below.
- Servo Type
- Digital uses higher frame rates than analog servos can handle which, along with their better holding power, improves performance. Do not use digital frame rates for analog servos.
- Servo Speed
- Take this value from your servo manufacturer’s specifications. Units are in seconds per 60 degrees of motion. This helps the gyro move the swash evenly. This field only matters if Equalize Servo Speeds is on.
- Servo Travel
- Scales the amount of motion each servo has on either side of centre (endpoints). The servo travels can be set individually to trim the swash to be level at max, zero and min collective pitch.
- Servo Trims and Reversing
- Here each servo’s center point can be set and each can be reversed if needed. This is the same idea as sub-trim on your transmitter. Be careful that the servo doesn’t bind.
Tail Servo Tab
The Tail Servo tab is found in the Offline Setup Values region of the main SK720 setup software window as shown in the image below.
- By Name / Custom
- The tail servo type can be selected by either model number and manufacturer, or if your servo type is not in the list, by its specifications.
- Freq / Pulse
- If you have chosen to specify custom servo options, then you can use this field to select the pulse-type and update rate (frequency). Note that the wrong setting could cause the servo to bind and overheat! This field will be greyed out if the By Name option is chosen.
- Servo Travel
- Amount of servo motion on either side of centre (endpoints).
- Servo Trims and Reversing
- Sets the tail servo’s centre point and direction.
- Setup Servo with Rudder Stick
- This button starts a wizard that allows you to easily set up the tail servo’s centre point and travel. Just press the button and follow the prompts.
NOTE: This section explains the Basic User Interface’s Cyclic tab. See the Advanced Tuning Options section (Section 19.1) for details on the Advanced Cyclic tab.
The Cyclic tab is found in the Offline Setup Values region of the main SK720 setup software window as shown in the image below.
- Control Rates
- The roll or pitch rate of the helicopter at maximum cyclic stick deflection. This setting has a similar effect to changing the area of a flybar’s paddles.
- Hiller Decay
- A value of 100% here can help smooth out rapid tic-tocks, piros or other 3D manoeuvres, especially repeated ones. However, high values for Hiller Decay will also limit the gyro’s ability to hold steady in gusty wind or trim the helicopter precisely in hover. A noticeable effect of higher Hiller Decay values is the need for more forward cyclic (down elevator) to keep the helicopter moving in forward flight.
- Sets how strongly the helicopter tends to pull itself towards level in elevator and aileron. Set the Self-Leveling value to a higher value (i.e. 80%) in one of the two Cyclic tabs to enable a “bail-out” switch. Activate the bailout mode by switching to that bank.
- Lock Cyclic Gain
- This allows you to lock in the value for overall cyclic gain. The SK720 will then ignore the end point setting in your transmitter and use the value you set here instead.
NOTE: This section explains the Basic User Interface’s Cyclic tab. See the Advanced Tuning Options section (Section 19.1) for details on the Advanced Tail tab.
The Tail tab is found in the Offline Setup Values region of the main SK720 setup software window as shown in the image below.
- Control Rate
- Sets the maximum allowable yaw rate of the helicopter at maximum rudder stick deflection. One rotation per second is 360 degrees per second.
- Tail Expo
- Positive values make the rudder stick less sensitive near centerstick, negative values make it more sensitive near center.
- Lock Tail Gain
- This allows you to lock in a value for overall tail gain. The SK720 will then ignore the end point setting in your transmitter and use the value you set here instead.
- Small Heli
- This option increases the response delay that the system expects the tail servo to have. It is useful for helicopters 450 size and smaller.
- Blur Piros
- Select this option to make your helicopter jump to a piro rate of 900 degrees per second (very fast) when you hold the rudder stick at full