In February, the US Air Force revealed its 21st century bomber, the Northrop Grumman B-21. This week, the US Army edged closer to defining what could be its first truly new rotorcraft type of this century.
Locked away somewhere, behind a government firewall, is one “initial capability set” that will lead the army’s Future Vertical Lift (FVL) programme, an initiative that will introduce a next-generation family of rotorcraft to succeed everything from the now-retired Bell Helicopter OH-58 Kiowa to the Boeing CH-47 Chinook beginning in the coming decades.
Once at full speed - delivering five different classes of rotorcraft with common architectures to soldiers, sailors, marines and special forces - it will be the Pentagon’s second-largest arms buy, topped only by the $379 billion acquisition of the Lockheed Martin F-35 Lightning II.
The government is now considering which “capability set” to pursue first: a light reconnaissance, attack and assault/lift type with a cruise speed greater than 200kt (370km/h) and 229nm unrefuelled range; or a mid-weight, general-purpose aircraft with a top speed of 230-310kt and 229-450nm range.
Those two capability sets, defined by US Army Training and Doctrine Command, the service’s requirements authority, were communicated in two request for information, released in February.
The response period closed yesterday. The army expected submissions from across the vertical lift industry, including prime manufacturers in America and abroad as well as specialist designers and fabricators.
Richard Kretzschmar, director of the army’s joint Improved Turbine Engine/Future Vertical Lift programme office, and FVL product director Leslie Hyatt told Flightglobal this week that responses will help the army solidify its requirements and the acquisition strategy that will be considered by a Pentagon board in October.
Attack variant of Bell V-280 Valor. Weapons are housed internally to reduce drag.
It is not exclusively an American endeavour, since input has been welcome from vendors in Europe and elsewhere. “It as broad as possible,” confirms Kretzschmar.
“There’s quite a lot of helicopter vendors in the world that aren’t participating in [the Joint Multi Role technology demonstration] that have capability that might be suitable for those capability sets,” says Kretzschmar. “We wanted to really understand where they stood, the investments they’ve made and what they could mature from a cost and time perspective toward our needs.”
Kretzschmar and Hyatt would not say which aircraft type might come first – light or medium. That billion-dollar question seems to have puzzled and even frustrated some industry teams, because of the surprise release of “Capability Set 1” - or FVL Light - in February. It was assumed that FVL Medium would come first.
“We are working right now on the initial capability set,” says Kretzschmar. “Yes, there is one.”
Whichever is proposed in October will direct industry's focus. An analysis of alternatives will begin once a materiel development decision is made. A request for proposals is expected in 2018, followed by an extensive source-selection phase and downselect for the technology maturation phase in 2021, or sooner depending on resourcing and requirements.
Sikorsky-Boeing SB-1 Defiant
via Swift Engineering
The foundation for this future development and production effort is an extensive science and technology project known as JMR. This started in 2013 and will continue through 2019, with first flight of the participating Bell V-280 Valor and Sikorsky-Boeing SB-1 Defiant planned for August or September 2017.
“That’s moving along on schedule and on time," confirms JMR programme chief Dan Bailey, who says the V-280 wing is now being mated to the Spirit Aerosystems-built fuselage. Swift Engineering in San Clemente, California is nearing completion of the SB-1 structure.
JMR is also funding functional trials of Karem Aircraft’s optimum speed tiltrotor system and wind tunnel tests of AVX’s twin ducted fan, coaxial-rotor compound helicopter.
Bailey says Congress added funds in 2015 and 2016 for additional experiments, and full-scale dynamic testing of Karem's wing and rotor system is planned for late 2018 or early 2019 from a tower.
"It’s resource dependent," he says. “Later this year will be our Karem functional test. We’ll have their full [rotor] hub integrated solution on a test stand. It won’t have blades, but that’s a very unique hub. To see if it functions or does not function will be an interesting demonstration.”
Karem Aircraft optimum speed tiltrotor
Bailey says it’s “vitally important” that America moves forward with a new rotorcraft design for this century, one with greater speed, range, and capability compared with today's types.
The most recent innovations are the US Marine Corps CH-53K King Stallion, based the CH-53 series, and its Bell Boeing V-22 Osprey, which is derived from the XV-3 and XV-15 and first few in 1997. Sikorsky self-funded its X-2 and larger S-97 Raider prototypes.
There has not been radically new vertical lift project from the army since the Boeing-Sikorsky RAH-66 Comanche, which was terminated in favour of upgrades to existing designs.
“I think we’ve done all the right things to prepare ourselves for a successful [FVL] programme of record and hopefully, the resources will align and the need will stay,” says Kretzschmar.
“We’ve spent a tremendous amount of effort looking at the lessons learnt from other programmes [like Comanche], not only what went wrong but also building the benchmark from some of the models of success and things that went right with different programmes,” adds Hyatt. “We continue to feed those lessons learned into our acquisition strategy so we don’t repeat those past mistakes.”
AVX JMR concept