Heavy Fuel Engines for Group 2 & 3 Tactical UAS

Orbital's engines have been selected by leading defense primes including Insitu and Textron By Mike Ball / 10 Jun 2024
Follow UST

Orbital UAV is a world-leading developer of integrated heavy fuel engine systems for military drones, with a focus on Group 2 and 3 tactical UAS (unmanned aerial systems). UST is delighted to welcome Orbital on board as a supplier partner, and we will be highlighting their unique solutions and capabilities across our channels over the next 12 months.

We’ve just launched Orbital’s UST supplier profile, which has been written and built by our team in collaboration with the company. The Silver profile showcases their innovative propulsion systems, which enable global defense forces to field the state of the art in unmanned ISR (intelligence, surveillance and reconnaissance) and battlefield logistics.

Read on to find out more:

Orbital’s spark-ignited heavy fuel engines are based around the company’s proprietary FlexDI technology, featuring a spray-guided direct fuel injection system that utilizes injected air to atomize the fuel. The extremely fine level of atomization results in increased surface area and improves vaporization.

The engines are designed to provide highly efficient and reliable combustion of a range of heavy fuels including JP5, JP-8 and Jet-A1, allowing them to satisfy single-fuel policies that are currently being enacted by many defense forces around the world today. All Orbital heavy fuel engines are also able to run on gasoline, making them highly versatile.

Orbital 50cc Heavy Fuel UAV EngineThe Orbital 50cc Heavy Fuel Engine utilizes an air-cooled two-stroke single-cylinder design, and is capable of delivering 3.7 hp (2.8 kW) at 6500 RPM. Weighing just 3 kg, it can provide 250W of electrical power.

The real-world capabilities of the 50cc HFE have been rigorously proven, with over 150,000 service hours in the field with Insitu. This engine is the propulsion system of choice for the Insitu ScanEagle 3, a long-endurance tactical ISR drone in service with the U.S. and Australian armed forces.

Orbital 75cc Heavy Fuel UAV EngineThe Orbital 75cc Heavy Fuel Engine utilizes an air-cooled two-stroke single-cylinder design, and is capable of delivering 5.2 hp (3.9 kW) at 6500 RPM. Weighing just 4.4 kg, it can provide customizable levels of electrical power from 300 to 500W, to suit customer-specific requirements.

The 75cc HFE was selected for the Aerosonde MK4.7, a tactical hybrid VTOL sUAS designed for land-based and maritime ISR. It has undergone over 650,000 hours of in-field service with Textron.

Orbital 150cc Heavy Fuel UAV EngineThe Orbital 150cc Heavy Fuel Engine is Orbital’s latest engine to enter full production, and features a horizontally-opposed twin-cylinder two-stroke boxer design. Weighing 6.4 kg, the MIL-STD-810H qualified engine can deliver 11.5 hp (8.5 kW) at 6500 RPM with customizable levels of electrical power from 300 to 1000W.

This engine has completed over 5000 hours of ground testing, as well as multiple 3x 150-hour FAR33.49b durability tests and 500-hour mission profile durability tests. It has been selected for Textron Systems’ Aerosonde MK4.8, a tactical hybrid VTOL UAS that has been purpose-built to meet the U.S. Army’s Future Vertical Lift requirements. It is also being provided to a leading Singaporean defense company.

To find out more about Orbital UAV and their heavy fuel engines for tactical UAS, please visit their profile page:

Posted by Mike Ball Mike Ball is our resident technical editor here at Unmanned Systems Technology. Combining his passion for teaching, advanced engineering and all things unmanned, Mike keeps a watchful eye over everything related to the unmanned technical sector. With over 10 years’ experience in the unmanned field and a degree in engineering, Mike’s been heading up our technical team here for the last 8 years. Connect & Contact