SME Spotlight: Orbital - Little engines with big plans

In December 2016 Perth-based Orbital Corporation announced it had signed an agreement to provide engines for Boeing’s Insitu UAV division, maker of the ScanEagle UAV.

Philip Smart | Adelaide

In a deal worth up to $120 million, Orbital’s UAV business will supply its small piston-engine N20 propulsion system, co-developed with Insitu, for the next three years. But all involved are confident this is just the beginning of a longer-term relationship, underlined by Orbital’s intent to establish an operating base near Insitu’s Oregon plant to support, refurbish and perhaps later manufacture the engines.

“It’s inevitable that if that’s where the customer is, that’s where the requirement is,” Orbital CEO and managing director Terry Stinson said to ADM. “We want to be strategically close, logistically close to them so we can address any issues that arise and make sure we are providing the best level of customer satisfaction.

“But also these propulsion systems can be rebuilt two or three times. The UAV will come back to Oregon from wherever it is deployed so we want to be close there, because taking that engine unit and shipping it all the way back to Perth doesn’t make any sense. But from an Australian industry perspective, our plan is to keep our core here. We’ll have capabilities in both places.”


“Orbital is the descendant of the company started by inventor Ralph Sarich in the 1970s to develop his radical ‘orbital engine’”


Both companies see good reason to establish a relationship for the future. The US Department of Defence estimates that between 2015 and 2035 the fleet of drones operated by US Government agencies alone will grow from a few hundred to around 10,000. The global market is expected to be worth US$28 billion by 2022, with the military sector tipped to grow at around 38 per cent per year to US$13.9 billion by 2026.

Orbital bills its N20 propulsion system as the first reciprocating internal combustion engine designed specifically for UAV applications.

“The new technology delivers enhancements not available on other aircraft in the same class, including real-time monitoring and diagnostics of all critical systems, sensor and actuator redundancy and extensive ‘black box’ recording ability,” Stinson said.

“The engine is integrated with Orbital-designed and supplied compact fuel and oil tank modules into a complete stand-alone propulsion system, simplifying the assembly of the UAV and allowing easy in-field servicing.”


Orbital is the descendant of the company started by inventor Ralph Sarich in the 1970s to develop his radical “orbital engine”. Rather than reciprocating pistons, Sarich’s design saw a prism-shaped rotor orbiting inside a housing, with the rotor’s motion alternately sealing off sections of the chamber that would be charged with an air/fuel mixture for combustion to produce power. Rather than rotate like a rotary engine, the rotor would “orbit” inside the chamber.

Technical difficulties, including issues of cooling and lubrication, prevented the engine from ever reaching production. But feeding an air/fuel mixture to such a precisely-controlled system required a fuel injection unit that was way ahead of its time. Ironically, it was the fuel injection unit that helped the company prosper.

“At the time it was radical in the sense that it mixed air with fuel and injected it directly in to the cylinder,” Stinson, who came to know Orbital as head of advanced product and process development for Mercury Marine engines, said. “Today many engines have that, but back then direct injection was state of the art. You have to have a quantum leap in processing power to be able to put the fuel and air in to the cylinder with such precise timing to be able to do it every cycle. And if you look at what that can deliver from an efficiency point of view it’s very significant.”

Mercury wanted the system on its engines, but Orbital didn’t have the manufacturing capability to supply, so the two companies formed a joint venture. The system was a success, in some cases demonstrating up to 50 per cent improvement in fuel economy on Mercury’s high-end outboard engines. It also proved very adaptable, as shown by a later project to convert a US military Polaris all terrain vehicle to run on heavy fuel and in motorcycle and jet ski applications for companies such as Aprilia, Piaggio and Seadoo.

Orbital then expanded in to lightweight engines of its own design as well as research and development for customers. Ironically, its first big break was to Insitu competitor Textron for its Aerosonde UAV.

“We did a system for Textron that performed very well, and that got the attention of Insitu, so it evolved from one customer to the next.”

“We’re experts at small, lightweight two-stroke engines,” Stinson said. “We’ve designed many of them, some for customers which they brand name themselves.”

Orbital’s fuel injection system has also solved traditional fuel consumption and efficiency issues with the humble two-stroke engine, putting the company at the front of the pack for the ever-growing UAV market.

Orbital UAV head of engineering John Tubb (L) and CEO and MD Terry Stinson with an N20 propulsion unit destined for an Insitu ScanEagle UAV. Credit: OrbitalOrbital UAV head of engineering John Tubb (L) and CEO and MD Terry Stinson with an N20 propulsion unit destined for an Insitu ScanEagle UAV. Credit: Orbital

“If you’ve got the best combustion system then you’re going to get the endurance,” Stinson said. “But there are other factors related to that, such as a good power-to-weight ratio.

“The control we have over our fuel injection also allows us to have state-of-the-art altitude compensation. We run great at 3,000 feet, we run great at 5,000 feet and at 10,000.

“And another is the ability for cold start. With many of these applications, especially in defence, you end up in a very cold place and you have to launch the UAV. To start a spark-ignited piston engine that is running on heavy fuel when it’s below zero is difficult when the fuel is so thick. Our competitors’ technology doesn’t allow them to start in, say, 20 below zero. We can.”

Future growth

Orbital has plans to pursue other market sectors, including larger UAV aircraft.

“We’re now on very small engines, but our technology will scale up to larger engines. The Mercury Optimax (marine outboard) engine goes up to 400 horsepower. So the next segment of the market is the planes that are larger. One of the most famous of course is the Predator from General Atomics.

“The other market we are actively pursuing is vertical takeoff and landing, which is the fastest growing part of the market.

“We’re inquisitive and we’re looking at other high-value, high-tech niche type products where we can add value. Just in the UAV, we’re on the cusp of a few different product launches. UAV is well on its way now, and the plan is to grow Orbital and to realise what it was always expected to realise, to be a big, successful Australian company.

“But we don’t want to lose our Australian core. We have the largest small-engine test facility in the southern hemisphere. We’re going to keep the capability to do the current product that we have, where we can build both products for current customers. We want to keep that capability in Australia.”

This article first appeared in the February 2017 edition of ADM.

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