The U.S. Defense Advanced Research Projects Agency (DARPA) has moved its SPRINT experimental aircraft program into the construction phase, with Bell Textron beginning work on the X-76 demonstrator following the completion of a critical design review.
The aircraft is part of DARPA’s SPeed and Runway INdependent Technologies (SPRINT) program, developed in partnership with U.S. Special Operations Command. The effort aims to demonstrate technologies capable of combining the high cruise speed of fixed-wing aircraft with the vertical takeoff and landing flexibility of helicopters.
The X-76 designation places the aircraft within the long-running U.S. X-plane series used to test advanced aviation concepts. According to DARPA, the designation also references the United States’ upcoming 250th anniversary in 2026.
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Bell was selected to build the demonstrator in 2025. With the design review completed, the program will now shift to manufacturing, integration and ground testing of the prototype aircraft before flight testing begins later in the program.
The SPRINT concept targets cruise speeds above 400 knots while retaining the ability to hover and operate from unprepared surfaces, capabilities that could allow military aircraft to deploy without relying on traditional runways.
DARPA says the program is intended to address a long-standing operational trade-off between speed and operational flexibility. Conventional fixed-wing aircraft can fly faster but require runways, while helicopters can operate from austere locations but at significantly lower speeds.
Flight tests of the X-76 demonstrator are expected to begin during the program’s third phase, currently planned for early 2028.
