The U.S. National Aeronautics and Space Administration (NASA) on Nov. 4, unveiled the X-70 Fractal, a crewed experimental aircraft meant to speed up the development and testing of advanced aviation technologies. The agency announced the airplane at the UP.Summit at Kennedy Space Center in Florida. NASA Administrator Jared Isaacman said he expects the aircraft’s first flight under the NASA banner within the next two years.
Image: NASA
The X-70 is built around flight-control technology that NASA describes as rapidly reconfigurable. According to the agency, that capability will let researchers explore aircraft maneuverability in ways that have not been demonstrated in crewed flight. The airplane can also carry up to 2,000 pounds of experimental payloads, mounted either inside the airframe or on external stations.
What NASA says the aircraft can do
NASA lists a takeoff weight of 10,000 pounds. The aircraft is designed to cruise at Mach 0.75 and reach altitudes of up to 45,000 feet. Its operational range exceeds roughly 2,778 kilometers, or 1,500 nautical miles. NASA says those numbers will let the agency run demanding flight research across a broad range of operating conditions.
Two design choices stand out. The first is the flight-control system, which can be reconfigured quickly. In flight research, changing control laws or hardware between experiments is often slow, so a system built for fast changes could shorten the time between one test campaign and the next. The second is the payload arrangement. Because instruments and test articles can be swapped inside and outside the aircraft, a single airframe can serve several different experiments without major rework.
The X-70 is also crewed, which matters for this kind of research. A pilot on board can judge how an aircraft feels and responds in real flight conditions, something that is harder to capture with an uncrewed vehicle or in simulation.
Agency leaders frame it as a return to hands-on flying
Isaacman described the X-70 as a platform for testing advanced flight-control, maneuverability and other technologies in real flight. He said the modular design and the ability to swap payloads quickly will keep NASA teams moving from one experiment to the next, and that the aircraft is one part of what he called a new beginning for aeronautics. People come to NASA, he said, “to build, to learn, and most importantly, to fly.”
Laurie Grindle, director of the Aeronautics Division within NASA’s Research and Technology Mission Directorate, pointed to the agency’s long use of X-planes to develop technologies that advance aviation. She said adding another X-plane will help accelerate and drive aeronautics research.
A long line of maneuverability research
NASA’s own press release places the X-70 alongside the Bell X-1, the X-15 and the X-59 quiet supersonic demonstrator. For this aircraft, though, a narrower history may be more useful, because the X-70 is aimed at how airplanes are controlled and how they maneuver.
That story starts in the 1970s with the F-8 Digital Fly-By-Wire research aircraft, the first to fly with a fully digital flight-control system and no mechanical backup. Later projects built on that foundation. The Highly Maneuverable Aircraft Technology (HiMAT) vehicle, a remotely piloted subscale aircraft, let researchers test hard turns without risking a pilot. The X-29, with its forward-swept wing, was aerodynamically unstable and could fly only because fly-by-wire computers made constant corrections.
NASA/DFRC, Public domain, via Wikimedia Commons
The next wave explored thrust vectoring, which steers an aircraft by redirecting engine exhaust. The F/A-18 High Alpha Research Vehicle (HARV), the X-31 Enhanced Fighter Maneuverability demonstrator and the F-15 Advanced Control Technology for Integrated Vehicles (ACTIVE) aircraft all looked at control at very high angles of attack, where conventional surfaces lose effectiveness. After that came adaptive and flexible-structure work. The F-15 Intelligent Flight Control System (IFCS) tested neural-network controls meant to help an aircraft compensate for damage or failures, and the X-53 Active Aeroelastic Wing used the flexing of the wing for roll control instead of resisting it.
NASA, Public domain, via Wikimedia Commons
NASA is no longer the only organization working on new ways to maneuver. The Defense Advanced Research Projects Agency (DARPA) is developing the X-65 under its Control of Revolutionary Aircraft with Novel Effectors (CRANE) program. Aurora Flight Sciences, a Boeing subsidiary, is building it to test active flow control, a method that uses jets of air in place of flaps, rudders and other moving surfaces. The X-65 is uncrewed and modular, and it carries conventional control surfaces as a backup. Its first flight has slipped more than once from an original target of 2025, and recent reports point to 2027 or later.
https://www.darpa.mil/news-events/2024-01-03, Public domain, via Wikimedia Commons
The contrast with the X-70 is useful. The X-65 asks whether an aircraft can be controlled without moving surfaces. The X-70, as NASA describes it, is a crewed and reconfigurable platform meant to test a range of control concepts and other technologies, one after another.
What NASA has not said yet
The announcement leaves a number of basic questions open. NASA has not said who built the aircraft, what powers it, or what its configuration looks like. It has not named the first technologies it plans to test, or the program and budget behind the effort. The agency has also not said where the X-70 will be based and flown, how outside partners can apply to fly experiments on it, or why it carries the name Fractal.
Schedule is another point to watch. A first flight within two years is a broad window for a new crewed aircraft, and experimental programs often move more slowly than planned. The X-65 is a recent example.
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