Multi-Fuel Rotary Engines for UAS

The Cubewano range of UAS engines has been developed from the ground up to meet the demanding requirements of the world’s military and aerospace organisations. All engines are manufactured to AS9100 quality standards, with full traceability to ensure consistent quality levels and to meet aerospace requirements. These are not modified model engines but professional units designed with one requirement in mind: extremely high quality engines for professional use.

The engines have been designed from conception with the following goals:

  1. Multi-fuel compliant with ability to start and run perfectly on heavy fuel (Kerosene, JP8)
  2. High power-to-weight ratio
  3. Extremely low vibration
  4. Full fly-by-wire engine management system to enable complete bi-directional control via the vehicle management system
  5. Altitude compensation to enable fault-free starting and running up to at least 20,000 feet.
  6. A high quality product to meet the world’s military and aerospace requirements
  7. Compact form factor, especially suited to ducted fan installations reducing impingement in fan area
  8. Quiet running, meeting 56db at 500ft requirement
  9. High fuel efficiency compared to other currently available engines.

Due to the central form factor of the rotary engine, Cubewano UAS engines are extremely suitable for loiter, one-trip UAS where tube launch is a requirement. This form factor also means there is much less obstruction in ducted fan installations.
The engines offer both exceptionally low vibration and heavy fuel capabilities to meet the demands of both commercial and military requirements.

Cubewano has utilised the latest material and manufacturing technologies to push the boundaries of rotary engines. For example, Cubewano developed ceramic tip seals and specialist coatings to eliminate the tip wear associated with rotaries in the past.
 Almost every component in the engine has been optimised, including specialist imported steels for the major stress bearing components.

Engines are offered in three basic size configurations with power options from 3.0hp to 16.0hp. 
All engines can be optimised for weight for a given specific power by varying the width of the rotor assembly, providing the lowest possible weight for required power output.

Rotary engines are mathematically free of second order vibrations; they are balanced to make them smooth. Cubewano has invested heavily in equipment to balance the engines to a high level, ensuring almost no vibration. They do not need to be isolation mounted; bolting directly to the vehicle is the standard for Cubewano engines. Torsional vibrations are also much lower: peak torque is 4 times the average torque. This leads to much less stress on the drivetrain and vehicle mounting, which allows the elimination of image stabilising systems. The vehicle can be much lighter and last much longer.

Rotary engines have most of their mass very central to the output shaft. This means minimal obstruction to airflow in any configuration. It also means less obstruction in ducted fan installations and gives a perfect form factor for any tube launched vehicles.

Cubewano engines have a separate oil system which ensures that the vehicle is free of oil residue. The oil system functions on a top up method meaning no oil changes are required – simply maintain the oil level in the small oil tank.

Cubewano, in collaboration with a race car ECU company, has developed its own small, lightweight electronic engine management with altitude compensation. This ECU is a full fly-by-wire system that takes inputs from the VMS and sends all real time telemetry. Simply ask for a desired RPM and the ECU does the rest, informing you of actual RPM along with all other key measurements.

Cubewano chose to use manifold air temperature and pressure to measure mass air flow to self-compensate for altitude – essentially eliminating an operating ceiling. With a low altitude power lapse rate of 18% per 10,000ft, Cubewano engines are able to operate at elevated altitudes compared to anything else on the market.

All engines are available as either air or liquid cooled systems. For installations that require extended run times at peak power, liquid-cooled variants of the engines were developed. This ensures optimal cooling at extended power levels. For simplicity and ease of installation, air-cooled engines would be the preferred choice for fixed wing applications.

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