The idea of a thrust vectoring system is to statically build propulsion in the vehicle and then use one of several different methods to obtain airflow and thrust. JetX is testing plain pipesfan, and a fluid propulsion device similar to the “bladeless fan” that Jetoptera is using.
JetX does not appear to have settled on a specific thrust vectoring method. In fact, it is designing and testing systems that use ventral flaps, external flaps, “rotating” thrust vectoring, cascading blades and buckets to do the job. As the company plans to collaborate with other aircraft designers, it has kept the options as broad as possible, largely independent of the power source or propulsion system, except that they require relatively small diameter fans to accommodate the thrust vectoring of the JetX system.
There are also aircraft that use thrust vectoring on non-tilting propulsion systems for VTOL purposes. Lockheed Martin’s F-35B fighter jet is an example, although it has a Pratt & Whitney F135 turbofan engine capable of producing about 40,000 pounds of thrust.
Closer to the JetX terminal may be the extended-range, nine-seat hybrid electric eVTOL proposed by Odys Aviation. This design used 16 medium-diameter propellers, mounted rigidly forward along the diamond-shaped box-shaped wings. The rear of each wing has flaps that extend downward to allow thrust to be anywhere between 75 and 85 degrees down from the horizontal.
The question here, of course, is how much energy is wasted pushing thrust rather than simply tilting the propulsion unit. Odys is reluctant to reveal any numbers right now – when asked about the efficiency of the system, Odys co-founder James Dorris said: “Of course it’s not 100 percent. But it’s high enough, given the reduction in complexity and transition The simplicity of this technology is well worth it.”
JetX’s solution looks pretty neat and could be packaged in an airframe in interesting ways, but even without knowing what fans it will use or how to redirect thrust, in New Atlas’ view it will be less efficient than the Odys design , simply because of the inability to fit a medium or large diameter fan into its propeller housing. Small diameter fans, due to their higher disc loads, tend to consume more energy than larger diameter fans under a given thrust.
Still, it’s an interesting idea, and it could also be used effectively with other VTOL propulsion systems if the numbers are high enough to make it worthwhile.
JetX has not yet reached the stage of making its own aircraft prototype to demonstrate the system; in fact, so far, it has primarily focused on prototyping and testing the vector system. The company, which hopes to work with other aircraft designers to bring the system to market, is working on the idea of a scalable, modular platform on which any number of different aircraft can be designed.
Such a platform would expand to include batteries, propulsion options, avionics and a flexible framework capable of supporting many different aircraft configurations. It will enable different designs to share pre-approved components, reducing the cost of certification, in a way somewhat similar to what REE has pioneered on its hyper-configurable electric vehicle platform.
The certification fee for JetX itself can be absolutely prohibitive, and anything like that would be a very long process. The company is currently self-funded, although it was selected as one of 36 companies selected by AFWERX for its high-speed VTOL showcase. JetX has applied for a small business innovation research program through NASA, as well as the Leonardo accelerator program, and is now working to stand up as a commercial entity.
“Until recently, most of our work last year was patenting,” co-founder Bryan Welcel told eVTOL.com. “That’s our main focus and takes up most of our time. Our goal now is to seek funding.”