Bell Textron has been selected to proceed to Phase 2 of the US Defense Advanced Research Projects Agency (DARPA) Speed and Runway Independent Technologies (SPRINT) X-plane programme.
The award will see the company complete detailed design, construction, ground testing and certification of a demonstrator capable of combining high-speed flight with short takeoff and landing performance.
The aircraft will use Bell’s high-speed vertical takeoff and landing (HSVTOL) technology and is intended to cruise at 400 to 450 knots while retaining the ability to hover and operate from unprepared surfaces.
“Bell is honored to have been selected for the next phase of DARPA’s SPRINT program and is excited to demonstrate a brand-new aircraft with the first-ever stop/fold technology,” said Jason Hurst, Bell’s senior vice president for engineering.
“This is an achievement we’ve been working towards for over 10 years, as we’ve leveraged our nearly 90-year history of X-plane development to bring new technology to our warfighters.”
Bell completed its conceptual and preliminary design work during Phase 1A and 1B, and enters Phase 2 with a mature approach informed by recent risk-reduction trials. These have included tests of folding rotors, integrated propulsion and flight control systems at Holloman Air Force Base, along with wind tunnel validation at the National Institute for Aviation Research in Wichita.
The programme continues Bell’s long history of experimental VTOL aircraft. Its past contributions include the X-14, X-22, XV-3 and XV-15 for the US military and NASA. The company also developed the Bell X-1, the first aircraft to break the sound barrier in level flight.
Bell is a subsidiary of Textron, which also owns Cessna, Beechcraft and Lycoming. The company said the SPRINT demonstrator would support the US military’s push for aircraft that can survive and operate in dispersed and contested environments.
I hope this works out, it’s a nice concept. However considering the long drawn out gestation and issues in perfecting tilt rotor generally, it does instil a little concern about adding even more complexity to the mix.
From the graphic it looks like it will need to fold and unfold the rotor blades in-flight to transition between vertical and horizontal modes. That has to be a major engineering challenge.