Brian Everstine After years of flying, one potential Black Hawk replacement will stay in the air as the other is broken down to inspect wear and tear.
Brian Everstine
The Sikorsky-Boeing SC-1 Defiant demonstrator will keep flying as the team further develops its Raider X entrant for the Army’s Future Vertical Lift program. Credit: Lockheed Martin
As source selection continues for the U.S. Army’s Black Hawk replacement, the two teams vying for the future contract are taking different approaches to their demonstrators and pitches to the Army.
The Future Long-Range Assault Aircraft (FLRAA), one-half of the Army’s Future Vertical Lift effort, has come down to a competition between the Bell V-280 Valor and the Sikorsky-Boeing team’s Defiant X. Demonstrators flew for years to help the Army refine its requirements for the aircraft, and service officials say that effort has put the service in a better position compared to previous, failed rotorcraft programs.
“The risk brought down with tech demonstrators is different than anything we’ve ever done in the past, and we will have better-informed requirements for Future Vertical Lift [FVL] than for any other platform we’ve ever had,” says Brig. Gen. Walter Rugen, director of the Army’s Future Vertical Lift Cross-Functional Team. “And so I think we’re going in with a great deal of confidence. A great deal of risk has been brought down because industry has come to the table and demonstrated the capabilities that we’re looking for.”
The Army wants to award a contract in the third quarter of 2022, with a prototype of that aircraft to follow in 2025, then delivery of production aircraft to units in 2030.
During the second phase of the two-phase competitive risk-reduction efforts, Bell has grounded its V-280 demonstrator and begun forensics to study its strengths, while Sikorsky and Boeing are pressing their SB-1 Defiant demonstrator to fly faster and operate more Army-representative missions.
The V-280 ended its three-year flight-test program in June after 214 hr. of flight that included a 305-kt. high-speed flight. Five Army test pilots flew 15 sorties as well.
Bell has taken apart the aircraft’s tiltrotor to inspect how it fared over the demonstration period. The results indicate a shift the company made from the V-22 Osprey’s design has proven useful. The V-22’s Rolls-Royce T406 engines rotate with the rotors, which introduces more possibility for wear on the aircraft and complications within the engine. The V-280’s engine remains stationary when the rotors tilt, and initial data shows this is helpful for the engine’s—and aircraft’s—health, says Ryan Ehinger, vice president and program director of V-280 at Bell.
Additionally, the inspection found that the proprotor’s gearbox has also performed well. Engineers drew Sharpie lines on the gears, and the lines remained after the flights, demonstrating how smoothly it runs.
In October, Bell and Rolls-Royce announced they would replace the V-280’s General Electric T64 engine, used in Sikorsky H-53 helicopters, and install an upgraded version—designated the 1107F—of the V-22 Osprey’s Rolls-Royce engine. That engine will make for a “more sustainable approach to the powerplant of the V-280,” Rolls-Royce Defence President Tom Bell said at a Defense One event.
Meanwhile, Sikorsky and Boeing are keeping the SB-1 Defiant demonstrator flying even though they already submitted their proposal for FLRAA in September. The rigid coaxial rotor helicopter, with a pusher propeller in the rear, is built for lift and agility, and test pilots are pushing the aircraft to fly as fast as it can.
In October, Lockheed Martin-Sikorsky’s Principal Test Pilot Bill Fell announced that the SB-1 Defiant recently flew to a speed of 247 kt. in dash flight, and there is some limited power to go even faster. The companies have said they want to exceed 250 kt. During the 247-kt. flight, pilots set out to reach 240 kt. and decided to pull back after the 7-kt. overshoot.
Bell has stopped flying its V-280 Valor demonstrator to assess the aircraft’s performance. Credit: Bell/U.S. Army
“We were designed to achieve the Army goal of 230 kt.,” Fell said. “We’ve already significantly exceeded that. I think anything above 250 kt. will put a smile on my face when I get home. There’s not a lot of speed remaining in it, but we have some.”
The Honeywell T55-powered helicopter also flew 56 kt. in side flight and lifted a 5,300-lb. sling load. Sikorsky says the Defiant’s lift capability is a big advantage over the tiltrotor V-280. As of mid-October, the SB-1 Defiant demonstrator has flown 41 flights totaling 39 hr., along with 42 ground-run hours. Sikorsky and Boeing plan to keep the SB-1 flying into next year to further push its limits and fly other Army-representative missions.
The second component of FVL, the Future Advanced Reconnaissance Aircraft (FARA), also has a tight schedule, with a fly-off due to start in 2023. The prototype of Sikorsky’s entrant, the S-97-based Raider X, recently passed 60% completion, the company announced Oct. 12.
“Our team is working hand in hand with the Army, and we continue to make great progress. We are leveraging a very robust—and ongoing—FARA flight-test program with our S-97 Raider tech demonstrator, and production on Raider X is over 60% complete,” Jay Macklin, Sikorsky’s FVL business development director, said in an announcement. “It’s the success of the flight-test program that has allowed our team to optimize and mature our Raider X design.”
Bell’s 360 Invictus recently underwent a major design change, based on the Army’s requirements for mission systems. Instead of a ducted fan as the tail rotor, the company shifted to an unducted tail rotor, says CEO Mitch Snyder.
“It’s not that the other tail [rotor] didn’t work. We wanted to make sure, as a risk reduction for the Army, that our competitive prototype aircraft was as close as possible to the Increment 1 aircraft,” Snyder says.
Both helicopters will use the GE Aviation T901 engine, developed for the U.S. Army’s Improved Turbine Engine Program, which will also be used in Sikorsky UH-60 Black Hawks and Boeing AH-64 Apaches.
The Army used financial incentives as part of a $517 million contract, signed in 2019, to accelerate delivery of the first two engines to this past June. A GE Aviation official said the company will achieve the “first engine to test” (FETT) milestone by year-end or early 2022, which is earlier than the original schedule but later than the Army’s goal. The slowdown is due to problems with some equipment and COVID-19 pandemic-related disruptions, says Mike Sousa, GE’s business development leader for advanced turboshaft engines.
In early October, the Center for Strategic and Budgetary Assessments (CSBA) think tank in Washington published an extensive report on the Future Vertical Lift program, against the backdrop of the Army’s previous failures in helicopter procurement, such as the Boeing–Sikorsky RAH-66 Comanche and the Bell ARH-70 Arapaho.
Key to the program achieving success, according to the report, is adoption of a Modular Open Systems Approach (MOSA)—the capability to plug and play new avionics, defensive systems and other features into the helicopters from any provider at any time, instead of going back to the original equipment manufacturer for expensive and slow procurement of updates. The Army sees MOSA as a critical way to keep life-cycle costs down, with operations and sustainment historically responsible for 55-85% of program costs. While MOSA may require additional up-front investment, long-term savings will make it worth it, the report’s authors assert.
“By allowing for increased clarity and adaptability, FVL can be one of the first major programs to achieve this virtuous cycle and break the common trend of substantial cost growth in defense acquisition programs,” the report states.
The FLRAA and FARA will be the first new Army helicopters in a generation; the last clean-sheet helicopter the service fielded was the AH-64 Apache in the mid-1980s. The FVL may face problems in development, the CSBA report notes, but it also has potential based on the progress so far, if the Army does not try to do too much with the designs and requirements and if the costs do not grow too much.
“The FVL effort may face roadblocks, but it also could be one of the first major programs to drive an open ecosystem of affordable designs,” the CSBA authors write. “If the Army can live within well-estimated means, stick to its plan and pace advancing threats, FVL could become one of the most successful defense acquisition programs of the 21st century.”
