The HEEWING Ranger T1 VTOL is a unique aircraft that combines the vertical takeoff and landing ability of a multirotor with the speed and efficiency of a fixed-wing plane. It offers a lot of flexibility but also requires some careful setup to get it flying right.

In this detailed guide, we’ll take you step-by-step through how to configure the INAV flight controller for the Ranger T1, covering everything from setting up mixer profiles, calibrating your ESCs and servos, to managing smooth transitions between multirotor and airplane modes.

Whether you’re new to VTOL flying or just want to make sure your Ranger T1 is set up perfectly, this guide will help you understand the key steps to get your plane in the air and flying well.

Chapter 1: Introduction to VTOL Aircraft and INAV Flight Controller (Beginner’s Guide)

1.1 What is a VTOL Aircraft?

VTOL stands for Vertical Take-Off and Landing. This type of aircraft can take off, hover, and land vertically like a multirotor drone or helicopter, but it can also transition to fly forward with fixed wings like an airplane. This hybrid capability combines the best of both worlds:

• Vertical Takeoff and Landing: You don’t need a runway. The aircraft can lift off vertically from confined spaces.

• Efficient Forward Flight: Once airborne, it transitions to fixed-wing mode for higher speed and longer flight times.

VTOL Flight Modes:

• Multirotor Mode: The aircraft uses multiple rotors to hover, ascend, descend, and perform lateral movements. This is similar to a drone’s flight style.

• Fixed-Wing Mode: The aircraft uses aerodynamic control surfaces (ailerons, elevator, rudder) to fly like a traditional airplane, which is more efficient for covering longer distances.

• Transition Mode: This is the process of shifting between multirotor and fixed-wing modes, usually by tilting motors or control surfaces gradually to gain forward speed before switching fully to airplane flight.

VTOLs are popular for drone delivery, search and rescue, aerial photography, and hobbyist RC flying because they combine vertical takeoff convenience with the speed and endurance of planes.

1.2 Overview of INAV Flight Controller

INAV is an open-source flight control firmware designed to support a wide range of aircraft types including multirotors, fixed-wing planes, and VTOLs. It is well-known for its flexibility, advanced flight modes, and strong community support.

Key Features of INAV:

• Multi-Aircraft Support: INAV supports different airframes and allows switching between flight modes on the same vehicle.

• Mixer System: Allows detailed configuration of how control inputs map to motor and servo outputs, essential for VTOL transition control.

• GPS-Enabled Flight Modes: Supports Position Hold, Return to Home, Waypoint Navigation, and Loiter.

• Advanced Sensor Fusion: Combines accelerometer, gyroscope, barometer, and GPS data to provide stable and accurate flight control.

• Open Source and Extensible: Constantly updated by developers and users worldwide, with plenty of tutorials and documentation available.

1.3 Essential Hardware Components for VTOL with INAV

To build and fly a VTOL aircraft using INAV, you need several key hardware parts working together:

• Flight Controller (FC): The main processor running INAV firmware. It reads sensor data and outputs commands to motors and servos.

• Motors and Electronic Speed Controllers (ESCs): Brushless motors powered and controlled by ESCs, responsible for thrust and movement.

• Servos: Small motors that actuate control surfaces such as ailerons and elevators or tilt mechanisms for the motors during transition.

• Battery: Usually a lithium polymer (LiPo) battery providing power to motors and electronics.

• GPS Module: Provides location data for navigation and advanced flight modes.

• Radio Receiver (RX): Receives pilot control inputs from the transmitter.

• Propellers and Control Surfaces: Physical parts that generate thrust and aerodynamic control.

1.4 Understanding Flight Modes in VTOL

VTOL aircraft rely on switching between several flight modes controlled by the flight controller:

• Multirotor Mode: Controls the aircraft as a drone, using rotor thrust vectoring for hovering and maneuvering. No aerodynamic control surfaces needed.

• Fixed-Wing Mode: Uses traditional airplane flight controls (ailerons, elevator, rudder) for efficient forward flight.

• Transition Mode: A blend of the two, where motors tilt forward gradually to gain airspeed and control surfaces start taking over flight control. This mode ensures smooth switching and avoids stalls.

1.5 Introduction to the INAV Configurator Software

The INAV Configurator is a PC application used to configure, calibrate, and monitor your flight controller.

Main Sections:

• Setup Tab: Basic calibration for accelerometer, compass, and radio input.

• Mixer Tab: Defines how inputs from your transmitter and sensors mix to control motors and servos.

• Modes Tab: Assigns flight modes to switches on your transmitter.

• Configuration Tab: Configure ports, sensors, and other system-level options.

• CLI (Command Line Interface) Tab: Allows advanced users to manually enter configuration commands and parameters.

1.6 Basic Steps to Set Up a VTOL with INAV

1. Hardware Assembly: Connect motors, servos, GPS, receiver, and battery to the flight controller.

2. Initial Calibration: Calibrate sensors like accelerometer and compass to ensure stable flight.

3. Mixer Configuration: Set up mixing for multirotor and airplane flight modes and configure transition motor tilting.

4. Mode Setup: Assign switches to toggle between multirotor, transition, and airplane modes.

5. ESC Calibration: Calibrate ESC throttle ranges for smooth motor response.

6. Control Checks: Verify motor and servo directions, flight modes, and control responses on the bench.

7. Flight Testing: Start with vertical takeoff in multirotor mode, transition to airplane mode, fly forward, and return to vertical landing.

Summary

In this chapter, we introduced the concept of VTOL aircraft and the capabilities of the INAV flight controller system. We reviewed the essential hardware components, explained flight modes, and gave an overview of the INAV Configurator software used for setup and tuning. This foundational knowledge prepares you for deeper configuration and safe flight testing in the upcoming chapters.

Chapter 2: Setting Up and Configuring Your VTOL Aircraft with INAV Flight Controller

2.1 Hardware Assembly and Connections

Before diving into software setup, make sure all your hardware components are correctly connected:

• Motors and ESCs:
  Connect each motor’s ESC signal wire to the corresponding output port on the flight controller (found in the Outputs tab).
  Verify ESC power connections are solid and ESCs support your motor specs.
  Note: Some ESCs (like the tail ESC) may not support digital protocols such as DSHOT, so use PWM mode for those.

• Servos:
  Connect servos controlling control surfaces (e.g., ailerons, elevator) to designated servo outputs, such as servo ports 5 and 6 for motor tilt.

• GPS Module:
  Connect GPS to the appropriate UART port. Ensure the antenna has a clear line of sight to the sky to maximize satellite lock.
  Wrap GPS signal wires in aluminum foil and cover with wire harness tape to reduce electromagnetic interference. Although not grounded, this method improves GPS performance significantly.

• Receiver:
  Connect receiver signal (SBUS, PPM, DSM, etc.) to the flight controller’s receiver input.

• Power System:
  Connect your battery to ESC or power distribution board ensuring stable power delivery.
  Use anti-slip battery pads or sticky velcro to secure battery and prevent shifting during flight, which could affect the aircraft’s center of gravity (CG).

• Other Mechanical Fixings:
  Use rubber washers and mounting plates to secure the flight controller firmly to reduce vibration effects on sensors.
  Make sure USB ports and connectors are accessible for firmware updates and tuning.

Safety Note:
Always remove propellers during assembly and tuning or use a smoke stopper device which cuts off power automatically if a motor unexpectedly spins. This protects both the pilot and equipment.

2.2 Sensor Calibration

2.2.1 Accelerometer Calibration

The accelerometer is critical for attitude sensing. Follow these steps to calibrate it properly:

1. Open INAV Configurator and connect to the flight controller.

2. Navigate to the Setup tab and click Calibrate Accelerometer.

3. Follow prompts to hold the aircraft in six orientations (right-side up, upside down, left side, right side, nose down, tail down).

4. Press the calibration button for each orientation until all six positions are completed. The status indicators will turn blue upon successful calibration.

5. Perform calibration in a vibration-free and interference-free environment.

Tip: Start calibration with the aircraft upside down to avoid resetting previously calibrated orientations.

2.2.2 Compass Calibration (Optional)

• Compass calibration may be skipped for many VTOLs due to metal interference.

• If used, perform compass calibration in a magnetically clean environment, rotating the aircraft as prompted.

2.3 Mixer Setup

The mixer defines how flight control inputs are translated to motors and servos for different flight modes.

2.3.1 Multirotor Mixer

• Assign motor outputs and verify motor spin directions for stable hover.

• Reverse motor directions in the flight controller if necessary to ensure correct yaw, pitch, and roll response.

2.3.2 Airplane Mixer

• Assign servos controlling ailerons, elevator, etc., to correct outputs.

• Set servo directions to ensure stick inputs correspond to expected control surface movement.

• Set control surface influence weight to around 50% in multirotor mode to avoid destabilizing hover flight while still providing some control authority.

2.3.3 Transition Mixer

• Assign tilt servos (e.g., servos 5 and 6) controlling motor tilt to a mixer mode that gradually tilts motors forward during transition.

• Initially set tilt servo outputs to max values to find correct angles (around ±45°), then adjust weights to fine-tune tilt amount.

• Avoid tilt angles beyond 50° to prevent servo actions interfering with yaw control.

• This mixer only activates during transition mode.

2.4 Flight Mode Switch Configuration

Use a 3-position switch on your transmitter to manage flight mode changes:

• Multirotor Mode (VTOL): Default startup mode for vertical takeoff and hovering.

• Transition Mode: Intermediate state where motors tilt forward, gaining airspeed for fixed-wing flight.

• Airplane Mode: Motors fully tilted forward; wings provide lift and the aircraft behaves like a plane.

In INAV Configurator’s Modes tab:

• Bind the 3-position switch to a channel (commonly channel 9).

• Map each switch position to a mixer profile: Profile 2 for multirotor, Transition for transition mode, Profile 1 for airplane.

• Verify the flight controller switches profiles correctly based on the switch position.

2.5 ESC Calibration

Proper ESC calibration ensures that the motors respond linearly to throttle commands.

Calibration steps:

1. Remove propellers or use a smoke stopper for safety.

2. Power off the system.

3. In the Configurator Outputs tab, move the throttle slider to 100%.

4. Power on the ESCs and listen for calibration tones indicating ESCs have entered calibration mode.

5. Immediately move throttle to 0%, confirming calibration completion with tones.

6. Save and reboot the flight controller.

Note: Recalibrate ESCs after replacing ESCs or the flight controller.

2.6 Servo Travel and Motor Direction Checks

• Check servo endpoints to avoid mechanical binding or propeller strikes with the airframe or control surfaces.

• Adjust channel min/max values (e.g., reduce from 2000 to 1980) to limit servo travel if necessary.

• Reverse servo directions via mixer weight signs if control surfaces move opposite to stick inputs.

• Confirm motor spin directions match yaw control logic; reverse motors or adjust settings if incorrect.

2.7 Battery Placement and Center of Gravity (CG)

• Battery position strongly influences CG; move battery fore or aft along the centerline to balance aircraft.

• Use sticky pads or velcro to prevent battery movement in flight, maintaining a stable CG.

• Begin with the battery centered and make incremental adjustments after test flights.

2.8 Wiring and Antenna Setup

• Wrap GPS wiring in aluminum foil and cover with harness tape to reduce EMI.

• Position GPS antenna with clear sky view; orientation matters for optimal satellite lock.

• Receiver antennas should ideally be arranged at 90° angles for best diversity, but practicality may require compromise.

• Avoid antenna placements that could be damaged during landing.

2.9 Final Checks and First Flight Preparation

• Secure all screws and hardware.

• Install propellers with correct orientation and pitch.

• Verify mode switching via transmitter switch works as intended.

• Test motor directions and yaw mixing in both multirotor and airplane modes.

• Unlock the flight controller using yaw stick override if no GPS is present.

• Select a safe, open flying area.

• Perform hover, transition to forward flight, and transition back to VTOL mode for the maiden flight.

Summary

This chapter covers everything from hardware assembly, sensor calibration, mixer setup, mode configuration, ESC calibration, to wiring and first flight prep. Following these steps will enable your VTOL aircraft to transition smoothly between multirotor and fixed-wing flight modes, giving you a stable and controllable platform ready for advanced flight testing.

Chapter 3: Flight Testing, Tuning, and Advanced Flight Modes

3.1 Pre-Flight Checklist

Before the maiden flight of your VTOL aircraft, go through this checklist:

• Confirm all hardware connections are secure and correctly installed.

• Ensure battery is fully charged and firmly fixed to maintain CG.

• Verify flight modes switch properly on your transmitter (VTOL, Transition, Airplane).

• Remove propellers or use a smoke stopper for initial motor tests.

• Perform a control surface check: confirm servos move in correct directions and do not bind or hit props.

• Check motor directions and yaw mixing in both multirotor and airplane modes.

• Calibrate accelerometer and verify sensor readings are stable and accurate.

• Ensure GPS lock if using GPS-dependent flight modes, or prepare to arm without GPS by yaw-stick override.

• Verify ESC calibration is fresh and motors respond smoothly to throttle inputs.

3.2 Initial Hover and Transition Flight Tests

3.2.1 VTOL Multirotor Mode Hover Test

• Power up the aircraft and enter VTOL multirotor mode.

• Arm the motors and slowly raise throttle to hover.

• Observe stability: the aircraft should hover steadily with minimal drift or oscillation.

• Use yaw, pitch, and roll inputs to confirm correct motor and servo responses.

• Adjust motor directions or mixer weights if control inputs do not correspond to expected movements.

3.2.2 Transition to Forward Flight

• Gradually engage the transition switch to activate motor tilt servos.

• Watch motors tilt forward to about 45°, increasing forward thrust.

• The aircraft should begin accelerating forward, gaining airspeed and airflow over control surfaces.

• Ensure the flight controller smoothly manages control surface inputs during transition.

• Monitor for any stalls or abrupt attitude changes; reduce tilt angle or adjust mixer weights if needed.

3.2.3 Fixed-Wing Airplane Mode Flight

• Once sufficient forward airspeed is established, switch fully to airplane mode.

• The aircraft should fly like a traditional fixed-wing plane, controlled primarily by control surfaces.

• Use pitch, roll, and yaw inputs to test responsiveness and control authority.

• Verify differential thrust yaw control works smoothly due to lack of a rudder.

• Adjust servo travel endpoints or mixer weights to optimize control effectiveness.

3.2.4 Transition Back to VTOL Mode

• Activate the transition switch to tilt motors back to vertical position.

• The aircraft should slow forward speed and gradually switch control authority back to the multirotor motors.

• Confirm a smooth and stable change in flight mode with no sudden attitude or power changes.

• Land the aircraft vertically using VTOL mode controls.

3.3 Troubleshooting Common Issues

• Stalling during Transition:
  If the aircraft stalls immediately upon tilting motors forward, reduce tilt angle or increase throttle during transition phase.

• Control Surface Binding:
  Recheck servo endpoint limits and mechanical clearances to avoid props or airframe contact.

• Yaw Control Issues:
  Verify correct motor spin directions and yaw mixer weights. Reverse motors or invert yaw mixer weights if yaw responds opposite to control stick inputs.

• ESC or Servo Malfunctions:
  Recalibrate ESCs and servo endpoints. Confirm signal protocols (PWM vs DSHOT) compatibility.

• GPS Lock Problems:
  Improve GPS antenna placement and shielding. Avoid metal interference near GPS module.

3.4 Advanced Flight Modes with INAV

Once basic flight control and transitions are stable, explore advanced INAV features:

• Position Hold:
  Allows the aircraft to maintain a fixed GPS position in multirotor mode. Useful for stable hover or loiter.

• Loiter:
  Combines GPS hold with wind compensation to keep the aircraft steady in the air.

• Auto Launch:
  Automates vertical takeoff and transition to forward flight without pilot input.

• Auto Landing:
  Guides the aircraft for a controlled vertical landing using GPS and barometer data.

• Return to Home (RTH):
  Automatically returns the aircraft to the launch point, ideal for failsafe situations.

3.5 Flight Data Logging and Tuning

• Use INAV’s black box logging feature to record flight data.

• Analyze logs post-flight to diagnose issues like oscillations, control lag, or sensor errors.

• Adjust PID controllers for pitch, roll, and yaw to optimize flight smoothness and stability.

• Tune servo mixer weights and transition angles for seamless mode changes.

• Update firmware regularly to benefit from bug fixes and new features.

3.6 Safety Considerations

• Always conduct initial flights in open areas, away from people and obstacles.

• Start with low throttle and short flights to familiarize yourself with aircraft behavior.

• Use failsafe settings to disarm motors or initiate safe landing if signal is lost.

• Wear eye protection and ensure bystanders keep a safe distance.

Summary

This chapter guided you through initial flight tests, troubleshooting, and exploring advanced INAV flight modes for your VTOL aircraft. Successful flight testing and tuning are essential steps before advancing to complex autonomous missions. Remember to prioritize safety and take gradual steps to improve your aircraft’s performance.

Chapter 4: Practical Guide to Autonomous Flight and Camera Integration with INAV

4.1 Preparing for Autonomous Flight

4.1.1 Firmware and Software Setup

• Ensure your flight controller is running the latest stable INAV firmware version (7.x or later).

• Connect your flight controller to the INAV Configurator via USB.

• Back up your current configuration before making major changes.

• Verify that all sensors (accelerometer, gyroscope, barometer, GPS) are properly calibrated.

4.1.2 Setting Up GPS and Compass (Optional)

• If using GPS for autonomous modes, mount the GPS module away from power wires and metal parts to minimize interference.

• Use aluminum foil shielding and proper wire twisting as described in Chapter 2 to improve GPS signal quality.

• In INAV Configurator, enable and configure the GPS and compass.

• Calibrate the compass carefully using the provided calibration tool.

4.2 Configuring Autonomous Flight Modes

4.2.1 Enabling GPS-Based Modes

• Go to the “Modes” tab in INAV Configurator.

• Add flight modes such as “Position Hold,” “Loiter,” “Return to Home (RTH),” and “Auto Landing.”

• Assign switches on your transmitter to toggle these modes.

• Confirm the modes activate correctly in the configurator and on the transmitter.

4.2.2 Programming Waypoints (If Supported)

• INAV supports waypoint missions through the Mission Planner or similar ground control software.

• Plan your flight path by selecting waypoints on the map interface.

• Upload the mission to the flight controller.

• Ensure the aircraft’s GPS fix is strong before starting the mission.

4.3 Camera and Video Transmitter Setup

4.3.1 Selecting and Mounting the Camera

• Choose a lightweight FPV camera compatible with your aircraft.

• Mount the camera securely on the nose or another stable part of the airframe, minimizing vibration.

• Adjust the camera angle to suit your forward flight view—typically angled slightly downward.

4.3.2 Installing the Video Transmitter (VTX)

• Install the VTX in a location with good airflow to avoid overheating.

• Connect the VTX to the camera and flight controller power supply as per the manufacturer’s instructions.

• Attach the antenna firmly and route it away from power wires to reduce interference.

4.4 Binding and Testing the Video Link

• Power on the VTX and your FPV goggles or monitor.

• Set the VTX channel and band to match your goggles/monitor receiver.

• Verify a clear video feed without interference or static.

• Perform a range test by moving the aircraft away and ensuring the video feed remains stable within expected distances.

4.5 Integrating Camera Controls with Flight Controller (Optional)

• Some flight controllers support camera controls such as pan/tilt or switching video channels.

• Connect camera servo inputs to the flight controller channels if supported.

• Configure camera control channels in INAV Configurator under “Output” or “Camera” settings.

• Assign transmitter switches or sticks to control camera functions.

4.6 Executing Autonomous Flights with FPV

• Arm the aircraft in a safe, open area with good GPS signal.

• Activate “Position Hold” or “Loiter” to verify GPS stability in hover.

• Start waypoint missions if programmed, monitoring via ground control software and FPV feed.

• Practice “Return to Home” and “Auto Landing” functions, understanding how the aircraft behaves during these modes.

• Always keep manual override ready on your transmitter to regain control if needed.

4.7 Troubleshooting Autonomous Flight Issues

• Poor GPS Signal: Check antenna placement and shielding, reduce interference sources.

• Video Feed Drops: Check antenna connections, adjust channels, reduce power output if required.

• Flight Controller Not Switching Modes: Verify transmitter switches and mode assignments.

• Unexpected Aircraft Behavior: Review logs, check PID tuning, confirm sensor calibration.

4.8 Tips for Safe and Successful Autonomous Flights

• Always conduct autonomous flights in open spaces free of obstacles.

• Start with short, low-altitude missions before attempting complex waypoint paths.

• Monitor battery voltage and flight time closely during autonomous operations.

• Use failsafe settings to ensure safe landings on signal loss or critical errors.

Summary

This chapter provided a step-by-step practical guide for setting up and flying your VTOL aircraft autonomously with INAV, including GPS configuration, flight mode programming, and integrating FPV camera systems. Following these instructions will help you confidently explore autonomous flight capabilities and enjoy immersive FPV experiences safely.

Chapter 5: Final Adjustments, Calibration, and First Flight Testing

In this chapter, we will focus on the crucial final steps before taking your VTOL aircraft for its maiden flight. These steps include calibrating ESCs and servos, adjusting servo endpoints to prevent mechanical interference, installing GPS and antennas properly, performing control checks, and finally, conducting the first flight tests with safe procedures.

5.1 ESC Calibration

Electronic Speed Controllers (ESCs) must be calibrated to correctly interpret throttle signals from the flight controller. Calibration ensures the ESC understands what the minimum and maximum throttle inputs correspond to in motor speed.

Steps to calibrate ESCs:

1. Power off your aircraft and remove the props for safety — unless you have a smoke stopper installed.

2. Open your flight controller configuration software and navigate to the Outputs tab.

3. Slide the Master throttle slider to 100%.

4. Power on the ESCs; you should hear a sequence of tones indicating calibration mode.

5. Smoothly slide the throttle down to 0%.

6. Wait for confirmation tones indicating calibration completion.

7. Power cycle the ESCs or reboot the flight controller.

Note: Whenever you replace ESCs or the flight controller, recalibrate the ESCs.

5.2 Servo Endpoint Adjustment

Proper servo endpoints prevent mechanical collisions, such as propellers striking the wing or servo arms over-rotating.

How to adjust:

• Place your aircraft in VTOL mode and command a full yaw to one side.

• Identify which servo channel is at its max travel and verify if the prop or wing is contacting the servo arm.

• If contact occurs, reduce the maximum servo travel value incrementally (e.g., from 2000 to 1990, then 1980, etc.) and save/reboot.

• Repeat the process on the other side until full yaw is possible without interference.

5.3 GPS and Antenna Installation

Good GPS and antenna placement is vital for reliable flight modes like position hold and return-to-home.

• Wrap GPS wires with aluminum foil or duct tape and then cover with wire harness tape to reduce electromagnetic interference. This has been proven to improve satellite lock.

• Mount the GPS module as flat and forward-facing as possible.

• Install receiver antennas with diversity in mind — ideally, antennas should be at 90° angles to each other for optimal reception, even if that means one antenna pointing up and one flat.

5.4 Control Check Before Flight

Before flying, perform thorough control checks:

• Power on the aircraft and check all control surfaces in both VTOL and airplane modes.

• Verify correct motor directions and yaw mixing.

• Arm the aircraft safely (override GPS arm restrictions if needed by holding yaw stick right).

• Test transitions between VTOL and fixed-wing modes using your mode switches.

• Confirm all servos respond appropriately, and the aircraft responds to stick inputs for roll, pitch, yaw, and throttle.

5.5 Maiden Flight Procedure

When ready to fly:

1. Begin in VTOL mode to perform vertical takeoff.

2. Transition to forward flight mode once safely airborne and establish forward speed.

3. Monitor aircraft behavior and control responsiveness closely.

4. Transition back to VTOL mode for landing.

5. Practice smooth transitions to build confidence.

5.6 Troubleshooting Tips

• If motors or servos move in the wrong direction, adjust mixer settings or invert channel outputs as needed.

• Ensure the flight controller is fully calibrated — accelerometer, compass (if used), and ESCs.

• Use smoke stoppers for safety during initial motor tests.

• Be patient and perform incremental adjustments.

With these detailed final steps, you should be confident to take your VTOL plane into the air and enjoy the unique capabilities of a hybrid multirotor/fixed-wing aircraft powered by INAV.

Chapter 6: Advanced Flight Modes and Future Enhancements

In this chapter, we explore advanced flight modes that INAV offers for VTOL aircraft and discuss potential future enhancements to improve your flying experience. Understanding these modes will unlock the full potential of your VTOL and provide safer, more autonomous flights.

6.1 Overview of Advanced Flight Modes

INAV supports multiple flight modes tailored for different flying conditions and pilot skill levels. Here are some common modes you can enable on your VTOL:

• Position Hold (PosHold):
  The aircraft holds its current GPS position and altitude. Useful for stable hovering and precise positioning during VTOL flight.

• Loiter:
  Similar to Position Hold but generally with more gentle corrections and longer endurance. Great for surveillance or photography missions.

• Return to Home (RTH):
  Automatically returns the aircraft to its takeoff point using GPS navigation. This is a critical safety feature for lost signal or low battery situations.

• Altitude Hold:
  Maintains a constant altitude using barometric sensors, even when the pilot adjusts throttle.

• Cruise Mode:
  Optimizes flight parameters for efficient, fixed-wing forward flight with stabilized control surfaces.

6.2 Setting Up Flight Modes in INAV

1. Assign flight modes to switches on your transmitter to easily toggle between them mid-flight.

2. Use the Modes tab in INAV configurator to map flight modes to specific AUX channels.

3. Adjust parameters in the Configuration tab to fine-tune each mode’s behavior, such as GPS hold radius, descent speed, and transition sensitivity.

4. Always test modes on the ground or in a simulator before actual flight.

6.3 Using Auto-Launch and Auto-Landing

• Auto-Launch:
  Automatically takes off and transitions the aircraft from VTOL to forward flight without pilot input after throttle up. Useful for smooth, hands-free takeoffs.

• Auto-Landing:
  Allows the aircraft to safely descend and land by itself, reducing pilot workload and enhancing safety during emergencies.

To enable these:

• Ensure your flight controller firmware supports these features.

• Configure and test auto-launch and auto-landing parameters carefully.

• Perform test runs in a safe environment.

6.4 Camera and Video Transmitter Integration

Adding a camera and video transmitter (VTX) transforms your VTOL into a powerful FPV platform.

• Mount the camera with a stable, vibration-free mount.

• Use the video transmitter’s antenna placement tips (90° diversity) to maximize range and signal quality.

• Ensure wiring does not interfere with control signals or moving parts.

• Test video feed on the ground before flight.

6.5 Troubleshooting and Optimization Tips

• Monitor GPS satellite count and signal quality; improve antenna setup if needed.

• Check telemetry data for sensor health (accelerometer, gyroscope, barometer).

• Fine-tune PID values for both VTOL and fixed-wing flight profiles.

• Regularly update INAV firmware for new features and bug fixes.

6.6 Future Enhancements and Customizations

• Explore installing additional sensors like airspeed sensors or LiDAR for better altitude control.

• Experiment with different propeller and motor setups to improve efficiency and flight time.

• Consider upgrading to more advanced flight controllers with built-in GPS and telemetry support.

• Engage with the INAV community for shared tips, firmware updates, and custom scripts.

Mastering these advanced features will help you get the most out of your VTOL aircraft, enabling smoother, safer, and more autonomous flights. As you gain experience, you’ll discover even more ways to customize and improve your setup.

Chapter 7: Troubleshooting, Maintenance, and Best Practices for Long-Term Success

In this final chapter, we focus on common issues you may encounter, how to perform routine maintenance, and best practices to ensure your VTOL aircraft remains reliable, safe, and fun to fly for the long term.

7.1 Common Issues and How to Fix Them

1. Flight Controller Fails to Switch Mixer Profiles:

• Symptom: Transition between VTOL and fixed-wing modes doesn’t engage mixer profiles properly.

• Solution:

  • Confirm accelerometer calibration is complete and accurate.

  • Verify that the mixer transition mode is enabled and assigned correctly in the modes tab.

  • Check that your firmware version supports mixer transitions (some older versions may have bugs).

  • Reboot the flight controller after changes.

2. Motors or Servos Move in the Wrong Direction:

• Symptom: Control inputs produce opposite motor or servo responses.

• Solution:

  • In the mixer tab, invert the sign of the affected channels.

  • Double-check wiring connections for motor and servo plugs.

  • Confirm correct motor spin direction and servo arm orientation physically.

3. Servo Binding or Mechanical Interference:

• Symptom: Servos hit physical stops or propellers strike the wings.

• Solution:

  • Adjust servo endpoint travel limits via the outputs tab.

  • Test full servo throws carefully on the bench before flight.

  • Modify servo arm positions or reposition components as needed.

4. GPS Signal Weak or Unstable:

• Symptom: Poor satellite lock, causing position hold and RTH to fail.

• Solution:

  • Wrap GPS wires with foil and wire harness tape to reduce EMI.

  • Position GPS module away from high-current wires and motors.

  • Ensure receiver antennas are placed with good diversity angles.

5. ESC Calibration Issues:

• Symptom: Motors don’t respond correctly to throttle inputs or ESCs beep inconsistently.

• Solution:

  • Repeat ESC calibration procedure carefully.

  • Ensure firmware and hardware compatibility (e.g., ESCs that do not support DShot require PWM).

  • Replace faulty ESCs if issues persist.

7.2 Routine Maintenance Tips

• Check and tighten all screws and fasteners regularly, especially on servo mounts and motor mounts. Vibrations can loosen them over time.

• Inspect propellers for damage or cracks before every flight; replace if necessary.

• Clean dust and debris from servos, motors, and control surfaces to maintain smooth operation.

• Update firmware periodically to benefit from bug fixes and new features.

• Store the aircraft in a dry, cool place to protect electronics and batteries.

• Balance the battery securely with non-slip pads to maintain a stable center of gravity during flight.

7.3 Best Practices for Flying VTOL Aircraft

• Always perform a pre-flight checklist including control surface tests, motor directions, and mode switching.

• Start flying in an open, obstacle-free area to reduce risk during initial tests and transitions.

• Use simulators or smaller scale models to practice flying VTOL transitions and emergency procedures.

• Gradually increase flight complexity — start with simple hover and forward flight before attempting auto-launch or auto-landing.

• Monitor battery voltage and temperature closely during flights to prevent sudden power loss.

• Respect local regulations and fly responsibly to ensure safety for yourself and others.

By following these troubleshooting tips, maintenance routines, and best practices, you’ll maximize your VTOL aircraft’s performance, reliability, and enjoyment for many flights to come.

Frequently Asked Questions (FAQ)

1. Why doesn’t my VTOL aircraft switch properly between multirotor and airplane modes?

• Possible causes:

  • Accelerometer not calibrated correctly.

  • Mixer transition mode not enabled or not properly configured.

  • Flight controller firmware version bugs or incompatibility.

• Solution:

  • Recalibrate the accelerometer in all required orientations.

  • Double-check that mixer profiles and mixer transition are correctly linked and assigned to switch channels.

  • Update to the latest stable INAV firmware version.

2. How do I know if my ESCs need calibration?

• If motors do not respond smoothly to throttle commands, or they start spinning erratically, it’s likely the ESC throttle endpoints are mismatched.

• Calibrating ESCs sets throttle minimum and maximum for accurate motor response.

3. Can I use DShot protocol with all ESCs on a VTOL plane?

• Not necessarily. Some ESCs, especially on tail motors, may not support digital protocols like DShot.

• Test ESC compatibility before setting the motor protocol to DShot. If incompatible, use PWM or other supported protocols.

4. Why do my servos not reach full travel or hit mechanical limits?

• Check and adjust servo endpoints in the flight controller software to avoid physical damage.

• Reduce servo travel limits for tilt servos to prevent propeller strikes or wing damage.

5. What should I do if the yaw control feels reversed?

• Invert the sign of the yaw mixing weights in the mixer tab (switch between positive and negative values) to correct servo direction.

• Also verify motor directions correspond with intended yaw response.

6. How can I improve GPS signal performance?

• Use shielding such as aluminum foil wrapped around GPS wires to reduce electromagnetic interference.

• Twist GPS antenna wires to minimize noise.

• Ensure GPS antenna orientation matches manufacturer recommendations.

7. What are the best practices for battery placement and CG adjustment?

• Place the battery to achieve proper center of gravity (CG) for stable flight.

• Use non-slip pads or sticky battery grips to prevent battery movement during flight, which can destabilize CG.

8. How do I safely perform pre-flight checks?

• Verify motor directions and responses to throttle, yaw, pitch, and roll controls.

• Check servo movements for tilt and control surface deflections.

• Perform range and receiver antenna checks.

• Arm the aircraft in a safe environment, preferably with prop guards or smoke stoppers.

9. What should I do if the flight controller fails to arm?

• Some flight controllers require GPS lock before arming.

• If GPS is unavailable, use the yaw-stick override arming method (holding yaw stick fully right) to arm manually.

10. Can I use INAV flight modes like Loiter and Position Hold on a VTOL plane?

• Yes, INAV supports various flight modes on VTOL aircraft, but functionality depends on proper sensor calibration and tuning.

• Testing each mode in a safe environment is recommended before full mission flights.

If you have other questions or need support, always check the Stirlingkit community forums for updated information and tips.