Bell Helicopter is applying systems designed for its 525 Relentless commercial medium twin to the V-280 Valor third-generation tiltrotor technology demonstrator it is developing for the U.S. Army as part of its Joint Multi-Role (JMR) Program for Future Vertical Lift (FVL).
The Army was expected to decide by the end of last month which two contenders from a field of four–including Bell, Sikorsky, Karem and AVX–will actually build aircraft. Those aircraft would need to fly in 2017 and Bell executives think the company’s experience with the 525 gives it a leg up in the contest.
Keith Flail, Bell’s director for future vertical lift, said systems commonality (including the Moog components on the 525’s fly-by-wire system) “certainly is” reducing Bell’s risk on developing a JMR technology demonstrator (JMR-TD) for the Army. Flail said the commonality extends to the fuselage design of both aircraft. “There is a high degree of commonality, especially in the nose section, between the V-280 and the 525. The front end of the aircraft is similar. The 525 is a great design and we really didn’t need to re-invent the wheel there,” he said.
Chris Gehler, Bell director for military program operations, said, “It has been interesting and helpful to have the 525 precede us. There has been a lot of learning in that design. Doing a clean-sheet [design] such as the 525, having that corporate knowledge, and carrying it on to advancing tiltrotor technology has been helpful to our process.”
Flail said Bell learned many lessons from the V-22 Bell/Boeing tiltrotor currently in service with the U.S. Marines and U.S. Air Force that will make the V-280 a competitive vehicle for the JMR program. “Our definition of success is to look at this program through the lens of affordability. Every technology we are looking to put on this demonstrator is designed to increase performance and reduce cost, weight and complexity. We are providing advanced war-fighting capabilities that are affordable. The goal is affordable and revolutionary. It’s not one or the other. It has to be both. That is our focus.”
Flail said that the V-280’s extensive use of composites will reduce weight while helping performance and maintainability. The new design of the engine and gearbox rotor and prop-rotor interface will also help the V-280 in this regard. On the V-22, the engines, gearboxes and prop-rotors all have to rotate as thrust direction is changed; on the V-280 only the gearboxes and prop-rotors rotate. The V-280 also eschews the forward wing sweep of the V-22. Going to a straight wing on the V-280 eliminates the need for a mid-wing gearbox and makes the wing easier to manufacture. “We spent a lot of time focusing on the maintainability and modularity of the V-280’s components,” Flail said.
While the potential spoils of the eventual winner of the JMR-TD could be as many as 4,000 aircraft under the Future Vertical Lift program, right now much of the technology required on the aircraft, as well as the operational requirements, remains to be defined, and program competitors are fielding their best guesses as to what form it will eventually take. For example, the Army eventually wants FVL aircraft to be fitted with future advanced turbine engines that will post a 35-percent reduction in specific fuel consumption, an 80-percent improvement in power-to-weight ratio, a 20-percent improvement in design life (to more than 6,000 hours) and a 45-percent reduction in production/maintenance costs. The technologies for those engines remain under development and are not scheduled to be demonstrated until 2016. Those engines would not fly on Phase One JMR-TD aircraft in 2017, but could fly on Phase Two or “Model Performance Specification” aircraft in 2019.
“We’re not that far along in future vertical lift that we have all the operational requirements,” said Gehler. “We are doing the best guess of the technologists as to what they think those requirements are going to be.”
The V-280 is designed to carry 11 fully outfitted troops, fly up to 800 nm at a maximum speed of 280 knots and satisfy the Army’s requirement for aircraft operations at up to 6,000 feet at 95 degrees F. Estimated mtow of the V-280 is approximately 30,000 pounds and the aircraft will be configured for utility and attack missions. The V-280 features six-foot-wide sliding side doors and a V tail.