Open-source gas-powered patrol autogyro using RCGF 10cc engine with ArduPilot flight controller
This project aims to develop a long-endurance patrol/surveillance autogyro platform powered by a gasoline engine. Autogyros offer unique advantages for patrol missions:
- Long endurance: Gas engines provide 2-4+ hour flight times
- Low stall speed: Safe, stable flight characteristics
- Simple mechanics: Unpowered rotor means fewer failure modes
- Quiet operation: Lower noise signature than multicopters
| Parameter | Value |
|---|---|
| Model | RCGF 10cc RE (Rear Exhaust) |
| Displacement | 10cc (0.61 cu in) |
| Type | Single cylinder, 2-stroke |
| Power Output | ~1.2 HP @ 9,000 RPM |
| Weight | ~350g (engine only) |
| Fuel | 87-93 octane gasoline + 2-stroke oil (25:1 to 32:1) |
| Ignition | CDI electronic ignition |
| Carburetor | Walbro-style diaphragm |
| Starting | Pull start / Electric starter optional |
| Propeller Range | 12x6 to 14x7 (pusher configuration) |
- Rear exhaust design keeps exhaust away from fuselage
- Lightweight aluminum construction
- Reliable CDI ignition (4.8V-6V input)
- Easy carburetor adjustment (H/L needles)
This project uses ArduPilot firmware on a Pixhawk-compatible flight controller. ArduPilot's robust autogyro and ICE (Internal Combustion Engine) support makes it ideal for this application.
- Flight Controller: Pixhawk 4, Cube Orange, or Matek H743
- GPS: M8N/M9N with compass
- Telemetry: 915MHz/433MHz SiK radio or LTE modem
- RPM Sensor: Hall effect or optical
- Kill Switch Relay: 5V relay module for CDI kill
| Function | ArduPilot Output | Notes |
|---|---|---|
| Kill Switch | AUX5 (SERVO13) | Relay to CDI ground (kills spark) |
| RPM Sensor | AUX6 (SERVO14) | Hall effect on propeller |
| Throttle Servo | MAIN1 | Standard servo to carburetor |
| Choke Servo | AUX1 (optional) | For cold start automation |
| Starter Motor | AUX2 (optional) | Electric starter relay |
# ICE (Internal Combustion Engine) Configuration
ICE_ENABLE = 1 # Enable ICE support
ICE_START_CHAN = 7 # RC channel for engine start
ICE_OPTIONS = 0 # Options bitmask
ICE_PWM_STRT_ON = 1800 # PWM to start engine
ICE_PWM_IGN_ON = 1800 # PWM for ignition on
ICE_PWM_IGN_OFF = 1100 # PWM for ignition off (kill)
# RPM Sensor Configuration
RPM1_TYPE = 2 # 2 = Hall effect sensor
RPM1_SCALING = 1.0 # Pulses per revolution
RPM1_PIN = 55 # AUX6 pin number (varies by FC)
RPM1_MIN = 800 # Minimum valid RPM
RPM1_MAX = 12000 # Maximum valid RPM
# Throttle Configuration
SERVO1_FUNCTION = 70 # Throttle function
SERVO1_MIN = 1000 # Throttle closed
SERVO1_MAX = 2000 # Throttle full open
SERVO1_TRIM = 1100 # Idle position
# Kill Switch (Relay on AUX5)
SERVO13_FUNCTION = 0 # Disabled (manual control)
RELAY_PIN = 54 # AUX5 pin number
RELAY_DEFAULT = 0 # Default off (engine can run)
# Autogyro-specific (if using Plane firmware)
Q_ENABLE = 0 # Disable QuadPlane
ARSPD_TYPE = 1 # Airspeed sensor type
THR_MIN = 0 # Allow zero throttle
THR_MAX = 100 # Maximum throttle %
See hardware/wiring_diagram.md for detailed pinout.
┌─────────────────┐
│ Pixhawk 4 │
├─────────────────┤
│ MAIN1 ──────────┼──► Throttle Servo ──► Carburetor
│ AUX5 (RELAY) ───┼──► Kill Relay ──► CDI Ground
│ AUX6 (RPM) ◄────┼─── Hall Sensor ◄── Propeller Magnet
│ RC IN ◄─────────┼─── Receiver
│ GPS ◄───────────┼─── M9N GPS/Compass
│ TELEM1 ─────────┼──► Telemetry Radio
└─────────────────┘
- Kill Switch: MUST have reliable kill switch that grounds CDI to stop engine
- Failsafe: Configure RTL or engine-kill on RC signal loss
- Fuel Safety: Use appropriate fuel lines, no leaks near ignition
- Propeller Guard: Consider prop guard for ground operations
- Fire Extinguisher: Always have extinguisher on-site
- Pre-flight Checks: Verify kill switch function before every flight
# Recommended failsafes for gas autogyro
FS_THR_ENABLE = 1 # Throttle failsafe enabled
FS_THR_VALUE = 950 # Failsafe PWM threshold
FS_SHORT_ACTN = 0 # Short failsafe: continue
FS_LONG_ACTN = 1 # Long failsafe: RTL
FS_GCS_ENABLE = 1 # GCS failsafe enabled
| Category | Requirement |
|---|---|
| Part 107 | Commercial operations require Remote Pilot Certificate |
| Registration | Required for aircraft >250g (this exceeds) |
| Marking | Registration number must be visible |
| Airspace | LAANC authorization for controlled airspace |
| Visual Line of Sight | Required unless Part 107 waiver obtained |
| Maximum Altitude | 400 ft AGL (or higher with waiver) |
| Operations Over People | Requires waiver for rotating parts |
- Always file LAANC authorization via Aloft, Airmap, or DroneZone
- Carry proof of registration during operations
- Log all flights with date, time, location, and duration
- Consider liability insurance for patrol operations
patrol-autogyro/
├── README.md # This file
├── docs/ # Documentation
│ ├── assembly.md # Assembly instructions
│ ├── tuning.md # Engine and flight tuning
│ └── operations.md # Operational procedures
├── hardware/ # Hardware documentation
│ ├── BOM.md # Bill of Materials
│ └── wiring_diagram.md
├── firmware/ # ArduPilot configuration
│ ├── params/ # Parameter files
│ └── lua/ # Lua scripts (optional)
└── .gitignore
- ArduPilot Documentation
- ICE (Internal Combustion Engine) Support
- Autogyro Setup
- RPM Sensor Configuration
Contributions welcome! Please:
- Fork the repository
- Create a feature branch
- Submit a pull request with clear description
MIT License - See LICENSE for details.
This project is for educational and hobbyist purposes. Building and operating gas-powered aircraft involves significant risks. Always:
- Follow all applicable laws and regulations
- Prioritize safety in design and operation
- Test thoroughly in controlled conditions
- Maintain appropriate insurance coverage
The authors assume no liability for damages or injuries resulting from use of this information.