(3) The Next Generation UAV Engines: Alec Shkolnik, Liquid Piston

What might the next generation UAV engines look like?

For that question, we turn to Alec Schlonik, co-founder and CEO of LiquidPiston, a Connecticut based company that is revolutionizing next-generation engine development. The company develops and licenses compact & efficient power solutions based on an optimized thermodynamic cycle and a new type of rotary engine architecture. The patented high-efficiency cycle is the biggest leap forward in combustion engine technology over the last 85 years, and holds great promise as the preferred future propulsion solution for both military and heavy commercial drones. Alec has a PhD in Computer Science and Artificial Intelligence from MIT, and has spent a decade-plus reinventing the rotary engine that Felix Wankel created in 1960 and Mazda is bringing back to life in 2019. In this edition of the Drone Radio Show, Alec talks about Liquid Piston, it’s revolutionary engine and the potential value and impact on the military and commercial UAV sectors.

In This Episode

• Introduction. Alec Shkolnik is co-founder and C.E.O. of liquid piston, a company that is developing a new kind of rotary diesel combustion engine that can power UAV systems. The company was incorporated in 2004. In 2007, the company got a small army contract , they were awarded a small business innovation research grant and then some venture capital unding. Since then, the company has been refining the design of their engines.
• Entry Into The UAV Space. Liquid Piston has always focused on smaller engines, and it was looking at smaller engine applications. That’s one the reasons for entering the UAV space. Energy and power are fundamentally limiting items for anything mobile and especially something like a UAV, which has to carry its own weight and the weight of its propulsion system. Smaller drones can capitalize on electric systems, but for larger commercial and military drones the batteries are not very energy dense. Consider that 50 lbs of battery can be displaced by just one pound of fuel. It made sense for Liquid Piston to look at how their engines can be used.
• Market Focus. Liquid Piston is concentrating on the military sector, as it has an immediate need for heavy fueled propulsion systems. The military is restricted to using ____ fuel, which also limits propulsion options. It is seeking more powerful and efficient alternatives. Two engines are currently in development, a large engine funded by DARPA and a smaller version. The smaller engine was placed in a “go cart” to demonstrate its capability. For other applications, the engines are suitable for any application that requires larger payloads or longer durations.
• Benefits. Liquid Piston’s engine much smaller and lighter than typical combustion engines, so it can lighten the weight of a vehicle significantly. This can increase payload size and/or duration of flight. For surveillance missions, that could reduce the amount of drones in the air, directly translating into cost savings.
• Engine Simplicity. There are two primary moving parts in the Liquid Piston engine – a rotor and a shaft. As a rotary engine, there’s no oscillating mass caused by pistons moving back and forth. The engine behaves like a three cylinder four stroke engine. There’s much less vibration, lower noise and greater efficiency.
• Current Status. The engines are still in development. Later this year, Liquid Piston hopes to conduct a demonstration of the technology. That would involve a low altitude flight test of the engine on a simple platform. The company will continue to work with government and partners on maturing the technology and identifying the key applications it will support.
• The Thermodynamic Cycle. Alex discusses how the thermodynamic cycle of the Liquid Piston engine is more efficient that gasoline or diesel cycles. The latest engine architecture has just two moving parts (the rotor and the shaft), and it has a total of five gas seals. Compare this to a typical 3-cylinder four stroke engine, which might have hundreds of parts and several seals. The design results in a thermodynamic efficiency of about 75% which is much more efficient than a traditional auto or diesel cycle.
• Advice To Entrepreneurs. Alec’s advice to other entrepreneurs is just because something seems impossible or others may think that it is impossible, just keep going and solve the problem. That’s what successful game changing innovators do.
• Closing. Alex believes that Liquid Piston has a solution that provides the power and energy requirements for future applications that are not possible with current technology. He looks forward to demonstrating the technology and very excited to be a part of this space.