The V-280 Valor. Bell Photo.
The Bell V-280 Valor advanced tiltrotor has met all U.S. Army Key Performance Parameters (KPPs) for the Joint Multi-Role Technology Demonstration (JMR-TD) program in flight testing, and the company plans to continue such testing to reduce risk, Bell said on May 20.
An Army request for information from industry last month on the Future Long-Range Assault Aircraft (FLRAA) component of Future Vertical Lift lays out a desire for 280 knots maximum continuous cruise speed at max power.
The two most likely competitors for FLRAA are the Boeing-Sikorsky SB-1 Defiant and the V-280. Both aircraft are participating in the Army’s ongoing JMR-TD program.
"Our team has now completed all of our KPPs through flight testing as far as JMR-TD for speed, range, payload capability, and agility," Paul Wilson, Bell's chief engineer for the V-280, said in a phone interview on May 20.
The most recent and final KPP demonstrated by the V-280 was the low-speed agility KPP, according to Bell.
"The V-280 Valor has now demonstrated in flight testing that it has the raw control power in pitch, roll, and yaw maneuvers to meet the Army’s Level 1 Handling Qualities requirements, which is the highest performance standard for agility," the company said. "This flight testing validates Bell’s engineering models and development processes to design, build, and test an air vehicle on an aggressive aircraft development schedule that meets Army performance requirements and delivers revolutionary capabilities to war fighters."
Ryan Ehinger, Bell's V-280 program manager, said that Bell's meeting of the latest KPP flight milestone "proves that the V-280 Valor tiltrotor delivers first-rate handling for pilots during low-speed maneuvers without sacrificing speed, range or payload that the military needs for multi-domain operations."
Last month, Lockheed Martin also flight tested its pilotage distributed aperture sensor (PDAS) on the V-280. PDAS is a multi-function sensor system for vertical lift aircraft that generations and fuses high-resolution, 360-degree real-time imagery with a goal reminiscent of the sensor suite and data fusion on Lockheed's F-35. Ultimately working with the company's multi-modal sensor fusion (MMSF) system, PDAS is intended to improve situational awareness for pilots and let them share that data.
The Army's desires for FLRAA focus on a replacement for the Sikorsky UH-60 Black Hawk--the FLRAA assault mission--and no longer seem to include a FLRAA attack version--a replacement for the Boeing AH-64E Apache.
The Boeing/Sikorsky SB-1 Defiant features a coaxial, rigid-rotor design and eight rotor blades, four each on two counter-rotating main rotors and a rear 11-foot wide eight-bladed pusher-propulsor — basically a backward propeller — to provide forward thrust. The blades' pitch is variable to maximize thrust and perform quietly at high speed. That rear propulsor will increase aircraft agility in a low-altitude environment and thus survivability, as the rotor craft will be able to dive quickly coming over a hill when facing possible threats, Boeing said.
Boeing has said that the Defiant is "a 160-knot aircraft" with the propeller not turning and that with the propeller turning, "it's a 260 knot machine."
The company plans to start rear propeller testing this year, including possible "reverse feather" testing to show that the aircraft can rapidly decelerate.
Sikorsky and Boeing officials said that they will be able to meet the Army's FLRAA goal for 280 knots maximum continuous cruise speed at max power through modifications, which would likely mean bigger engines and transmissions and a larger air frame and more horsepower going through the rear pusher prop, a higher horsepower generation that would mean higher drag and less efficiency.
While the maximum gross weight of a Black Hawk is 23,000 pounds, and the aircraft costs about $19 million a copy, the SB-1 is 32,000 pounds, and the V-280 is 57,000 pounds. Boeing has said that the overall footprint of the SB-1 is smaller than that of a Blackhawk.
Want more Future Vertical Lift? R&WI’s Dan Parsons was recently interviewed on a podcast about FARA, FLRAA, and the future of Army helicopters. Check it out here.