Cortex Heavy Fuel Hybrid System
Currawong Engineering has launched the Cortex Heavy Fuel Hybrid System, a two-stroke hybrid engine for heavy fuel unmanned aerial vehicles (UAVs) with industry-leading power density, innovative new fuel and Currawong-developed power electronics.
Cortex Heavy Fuel Hybrid System is a two-stroke hybrid engine for UAVs.
Key features of the engine
The hybrid architecture allows the engine to power the onboard electrical systems and charge the batteries while still providing thrust for flight. In case high power is required, the motor and batteries can work together to increase the overall power. It also reduces the overall weight of the propulsion system by reducing the number of batteries needed to sustain flight duration. Energy can also be directed from the battery system to the engine to increase power during flight and restart the engine in the air.
To balance the flow of energy through the system, Currawong developed what is called “hybrid transmuter» based on the extremely powerful ESC of the Velocity series. The hybrid transmuter manages battery charging, changing UAV load requirements, and is also able to determine whether to supply power from the motor to the batteries or from the batteries to the motor. All of this happens automatically, making the Cortex system an ideal battery replacement.
Triplex fuel pump
Heavy Fuel, or more specifically, stable heavy fuel, is constantly striving to create a safer environment for Currawong’s workforce. The company was able to show that UMAN-VP4F performs well as a spark ignition fuel in a Corvid-50 engine with very clean combustion. The output power of such an engine is comparable to that of a gasoline internal combustion engine. The UMAN-VP4F requires a fuel pressure of 8–10 bar, which is ideal for using the specialized Triplex fuel pump developed by Currawong engineers.
The Triplex’s unique three-piston fuel pump design provides high pressure, smooth fuel delivery, while a tightly integrated control system allows precise fuel delivery. The Triplex pump is self-priming and is able to measure fuel consumption with an accuracy of <1%.
4.7 kg (engine, generator, low noise exhaust system, cooling system, insulating support, EFI including Triplex pump, converter and wiring harness)
heavy fuel UMAN-VP4F
600 g/kWh (electric) at 5000 rpm and 50% throttle* (* This fuel may differ from the above performance figures and depends on the application)
2.4 kW (electric) at 7500 rpm
Converter current (continuous/peak):
Time Between Overhaul (TBO):
Recommended max. weight:
Slave. transducer temperature range:
-20°C to 100°C
Full technical documentation provided by the developer is available here.
Technical drawing of a two-stroke hybrid engine from the developer:
The developer put the following components in the kit with the engine:
- Ignition block
- Spark plug
- fuel injector
- crank sensor
- Throttle servo
- Temperature sensors, including cylinder head temperature (CHT; Cylinder Head Temperature) and manifold air temperature (MAT; Manifold Air Temperature) sensors
- Manifold pressure sensor
- Throttle body and exhaust manifold
- Cooling channel and cooling control servo
Availability and price
The Cortex Heavy Fuel Hybrid System will be available to order from September 2022. At what price it will be sold, the developer has not yet disclosed. Shipping will be worldwide.
With this innovative fuel, the Cortex system will be primarily relevant for naval applications, and the hybrid nature of the engine allows for a wide range of applications in various vehicles.
About the developer
Currawong Engineering Pty Ltd is a global leader in powertrain systems for unmanned aerial vehicles (UAVs) for both military and commercial applications. Currawong’s first offering was a Corvid-29 engine including a custom induction system, fuel injection system, low noise exhaust and power supply. The second Corvid-50 engine system was developed to meet the rapidly growing UAV market with heavier payloads.
Currawong has developed a CAN servo drive that provides a complete closed loop drive system with real-time position feedback. The company has also developed a powerful and reliable ESC Velocity electronic speed controller. These electronic systems are networked via the CAN standard along with the engine control unit, power supply, autopilot and payload. Currawong’s proprietary software, cEQUIP, provides an interface for real-time configuration and data logging of electronic systems. Currawong also offers specialized machining services and engineering design consultancy to local and international clients.
All the best! And safe flights!