WASHINGTON — Lockheed Martin-owned Sikorsky and Boeing have pitched a tweaked version of the team’s coaxial technology demonstrator — the SB-1 Defiant — which it plans to submit for the U.S. Army’s Future Long-Range Assault (FLRAA) competition, according to the companies.
The modified, competition-ready aircraft design is being called Defiant X, taking the same surname as little brother Raider X, which is Lockheed’s submission for the Army’s other helicopter competition — the Future Attack Reconnaissance Aircraft (FARA) program — running nearly in parallel.
Both aircraft build off and scale up from Sikorsky’s X2 demonstrator which flew for the first time in 2008.
Lockheed Martin came out with Raider X roughly two years ago at the Association of the U.S Army’s annual trade show. “One thing that always comes out is the importance of this aircraft at the X,” Tim Malia, Sikorsky’s FARA director, said at the time. “The ‘X’ is defined by the Army as the terminal area where they actually have to go do the work, do the reconnaissance, do the attack mission. The operation at the X is really critical for this program and for this platform.”
And according to the Lockheed-Boeing team, it’s no different with Defiant.
Modernizing its vertical lift fleet is the Army’s third-highest priority behind Long-Range Precision Fires and Next-Generation Combat Vehicle development. The Army intends to field both a FLRAA and FARA by roughly 2030.
Defiant X made its public debut Jan. 25 featuring changes to the outer mold line compared to the demonstrator airframe, such as a sharper nose cone; a tricycle-style landing gear; changes to the exhaust system and an integrated mission systems package.
The “enhancements to the design” are born from roughly 1,500 hours running algorithms in a systems integration lab, 135 hours logged in the Propulsion Systems Test Bed, and 31 flights, adding up to 26 hours of flight time, the companies reported.
Some of the changes to the airframe were made to reduce thermal signature and improve aerodynamic handling. The exhaust system alterations also reduce thermal signature, the team conveyed.
The landing gear changes are meant to improve stability, landing and taxiing in combat and more austere environments, according to the companies.
Adding integrated mission systems is a requirement for the FLRAA competition in order to upgrade and continuously improve aircraft capability through a modular open system architecture. The MOSA will allow the systems to stay relevant in a Joint All Domain Operations environment and on the battlefield in 2035 and beyond.
Defiant X will also come with “fly-by-wire flight controls integrated with autonomy capability leading to safety and workload reduction for the crew and operations in complex and degraded visual environments,” the team noted.
Lockheed and Boeing are claiming that, as of now, Defiant X is the only offering that can sling-load equipment during missions “at an operationally relevant distance.”
“One of the key words here is versatility,” Heather McBryan, Boeing’s director of sales and marketing for future vertical lift, told reporters during a Jan. 22 roundtable held in advance of Defiant X’s public debut. “Although the FLRAA mission is about more than just flying fast, and although we know the pacing mission is the air assault mission, this aircraft is going to be asked to do a whole lot of other things on a daily basis and our design and capability really provides that extreme lifting power for those types of missions.”
To date, the SB-1 Defiant helicopter — as part of the Army’s technology demonstration and the ongoing follow-on competitive risk reduction effort — has reached 211 knots in straight-and-level flight and 232 knots in a descent.
“During the [competitive development and risk reduction], we’ve done hundreds of trade studies to refine this transformational capability and worked closely with our Army partner,” Jay Macklin, director of Future Vertical Lift business development with Sikorsky, said in the same call with reporters.
“The design you’re going to see today is a result of those studies. The CDRR has provided a great vehicle to share data back and forth to help the Army again understand and come to a decision on exactly what they are looking for,” he said.
The team, according to Macklin, continue to also run tests in a digital combat environment that allows the ability to look at and test designs and maintenance procedures, fly and run operational analysis in order to ensure the best design.
While Defiant X came out looking a certain way, according to newly released renderings and animations, that doesn’t necessarily mean something won’t change before the actual aircraft is built and ready to fly, according to McBryan.
The Army released a draft request for proposals in December for FLRAA, announcing its unsurprising intentions to limit the competition to the Sikorsky-Boeing team and Bell because they are the only ones that can meet all of the service’s technical and production requirements after spending years building and flying Joint Multi-Role Technology Demonstrator aircraft meant to help define requirements and the realm of the possible for a next-generation medium-sized helicopter.
Bell is expected to submit a tiltrotor that would likely not stray too far from its V-280 Valor aircraft flown in the technology demonstration.
Bell’s demonstrator first flew in December 2017. Defiant took longer to get off the ground due to challenges in manufacturing its complex rotor blades. Defiant’s first flight took place in March 2019.
The Army is plans to drop the RFP in fiscal 2021, with plans to choose a winner to produce the aircraft in FY22.