By: Scott Way
The internal combustion engine may be at a crossroads. It has been the backbone of economics and industry for over a hundred years, and it has served us well. Even more, the marine industry is still developing exceptionally powerful engine platforms with more horsepower with less maintenance than we ever thought possible. It's not that the internal combustion engine doesn't work, it's just that some new competitors have arrived.
Now, that's not to say gas-powered engines are going to disappear tomorrow. We're simply in a transition between reliance on the old system and the potential of a new one. As far as boating is concerned, the turbine engine has the potential to not only exceed the performance of piston-driven engines, but also offer lower emissions, better fuel economy, and in a perfect world, a lower price point.
A small company out of Wichita, Kansas named Astron Aerospace has developed a small turbine engine called the Omega 1. It still burns fuel like a traditional internal combustion engine, but it operates in a way that's unlike anything the marine world has seen. The company claims it can serve as a viable alternative for cars, trucks, planes, and boats, and that certainly seems to be the case.
Now, a quick clarification. Yes, a turbine engine is technically an internal combustion engine. However, the two most popular combustion engines in history are the spark ignition gasoline engine and the compression ignition diesel engine. Most of these are four-stroke cycle engines (two-stroke engines are being phased out), meaning four piston strokes are needed to complete a cycle. The cycle includes four distinct processes: intake, compression, combustion and power stroke, and exhaust. For example, the Chevrolet V8 small block is one of the most popular engines in history. Both the spark ignition and compression ignition engine have been the foundation of boating since it ditched sails in favour of propellers.
A turbine engine, meanwhile, operates by compressing air to high pressure, then combusting fuel inside the air stream to increase pressure and temperature. Then the expanding high-pressure exhaust gases through a turbine to produce work. You've seen turbine engines in commercial aircraft, natural gas pipelines, and various industrial applications.
How is this relevant to boating? I'll explain.
Turbine engines are extremely lightweight. The Omega 1 weighs only 35 pounds but produces 160 horsepower. For comparison, a 150 horsepower marine outboard engine weighs about 450 lbs. That's 13 times heavier than the Omega 1. The weight savings on a small vessel, like say an 18' aluminum fishing boat, would create noticeable performance improvements and better fuel economy simply due to the weight reduction. Acceleration, holeshots, getting on plane, and the physics of hull shape would all be affected. A standard outboard engine with 150 hp running at 4000 RPM produces about 190 lb-ft of torque. The Omega 1 produces a comparable 170 lb-ft of torque.
And therein lies the second factor. RPMs.
Piston driven engines and turbine engines have vastly different RPM ranges. The Omega 1 idles around 1000 RPM and red lines at 25,000 RPM, which creates a wider range of performance from low to high speed. Most marine outboard engines cruise around 3000-4000 RPM redline around 5000-6000 RPM. With the ability to run at higher RPM, turbine engines can produce faster acceleration while simultaneously 'working' less (burning less fuel and producing fewer emissions) than their piston-driven counterparts due to less friction inside the engine.
Turbines like the Omega 1 can also be stacked, which means you can add multiple units together to increase power. To match the 450 lbs of engine weight from a 150 hp outboard, you could conceivably stack 13 Omega 1 turbine engines, which would generate 2,080 horsepower. Even if you ran a single turbine, the weight savings relative to a single outboard would produce better fuel economy. Couple that with the fact a turbine itself burns less fuel, and you get considerable savings.
The combustion cycle of a turbine is also mechanically less destructive than a piston engine. It uses a rotation setup, and Astron claims that the loss of power through friction, like you see with a piston engine, is minimal. This means the cross-contamination of oil like you see in a piston engine doesn't occur, which potentially means lower maintenance costs and longer service intervals.
Now, of course there are downsides. If you've ever been on a plane, you know how loud a turbine engine is. The idea of a high RPM turbine without major sound dampening on a transom is problematic. Turbines are also often air cooled, which presents another set of issues for a water vessel. But, if a turbine can be encased inside an engine bay while still having access to air-cooling, the possibilities are almost limitless.
The Astron turbine is already making waves in the automotive industry, and the company claims it is applicable for boats as well. It's not that new of a concept either. The first turbine car was the Chrysler Turbine Car in 1964. Modern companies like Jaguar have also tinkered with the idea in the C-X75 Concept.
Perhaps a boat is next.
You can get an in-depth look at how the Omega 1 works in the video below: