It’s been a long time coming, but finally actual build work has begun on a new kind of airplane engine, one that might revolutionize the industry. NASA calls it the Hybrid Thermally Efficient Core (HyTEC), and it stole the headlines several times before.
Despite aviation being around for more than a century and engine designs constantly progressing, it is only in recent years that the industry’s focus is falling on making these pieces of hardware more fuel efficient and less harmful to the environment.
There are several ways the big players of the industry go about this, but NASA’s is unlike anything else currently being done. That’s because the agency is looking to downsize the core of the engine, while keeping the same thrust output. A tough nut to crack, but the agency is getting there.
A core is one of the most important parts of an engine. It is there where compressed air is mixed with fuel and ignited, giving the aircraft forward motion. It is also the place from where significant fuel savings can come from. The best way to do that is give it a much higher bypass ratio than it is possible with current engines.
The bypass ratio is a number that describes the relationship between how much air flows through the engine core to be used for combustion and how much of it moves around the core and is transformed into thrust.
At the time of writing the airplane with the best bypass ratio is the Boeing 787 Dreamliner, which comes in at a respectable figure of 9. Translated into words, that means the aircraft allows nine times more air around the core, to be turned into thrust , than the amount of air allowed in for combustion.
Photo: NASA
NASA plans to take that ratio much further, to as much as 15. Doing so would mean less fuel is needed for the plane to operate, thrust levels remain the same, and everyone is happy.
There are several ways of going about the business of increasing the bypass ratio, including by increasing the size of the fan, and thus, of the engine. NASA’s approach is however opposite to that, as it will go for a smaller engine core.
The biggest challenge the agency had to overcome on its road to making the HyTEC a reality was to come up with the proper materials for the engine. You see, a smaller core and the same thrust levels translate into more internal pressure and higher temperatures. The dimensions of everything else, and even the new aerodynamics, also had to be considered.
NASA started the HyTEC program back in 2021, and much of the work conducted since focused on finding the proper materials. They found them in the form of stuff like ceramic matrix composites.
At the end of 2023 the American space agency announced that Phase 1 of the HyTEC program, meant to select the components that will go into the engine, concluded. Phase 2 was announced back then, but several months had to pass before NASA actually started this stage of the program.
The official start of the HyTEC Phase 2 was announced last week. It is now when engineers will look into the actual design of the engine and start building it. Most importantly, though, we will soon get to witness the first actual test of the engine, which will be conducted together with partner GE Aerospace.
Photo: NASA
We’re not told the specifics of the test other than that it will be a ground run. Its results are crucial because they will prove whether such a design can be adopted for use in the real world.
It is NASA’s hope that the HyTEC program will result in a powerplant that could deliver a ten percent reduction in fuel consumption compared to today’s engines of similar power, as well as a cut in fuel consumption.
It’s unclear exactly how much lower that will be, but given how the engine is made to be compatible with sustainable aviation fuels (SAF), and it will also be suitable for hybridization, that will probably be a lot.
NASA calls the HyTEC engine the world’s first mild hybrid-electric engine and plans to allow it to also be used to provide power for other systems aboard the aircraft. That’s something that already happens today, when about five percent of the engine’s power is used for that (in the so-called Dreamliner, at least), but the agency hopes to bring that number to at least 20 percent.
NASA is running the HyTEC program under the Sustainable Flight National Partnership, and plans to have it ready for the industry to use as soon as 2030. If it makes it, the engine design will become the first hybrid-electric powertrain of any kind to be used in actual airliners.
We’ll keep an eye out for more on this topic as we’re particularly hyped about seeing the engine in the metal for the first time, but also about the upcoming ground tests.
