US Army reveals details of Joint Multi-Role fleet vision

Washington DC
Source:
This story is sourced from Flight International
Subscribe today »

When the US Army aviation community looks into the future, it sees a radically different helicopter fleet that could turn the domestic helicopter industry upside down.

Instead of more than 20 helicopter types spread across the services, there are only three basic models, plus a new "ultra" category extending vertical take-off and landing aircraft into the domain of medium-sized fixed-wing transports.

In the army's vision, no aircraft will be slower than today's fastest conventional helicopter, which is limited to 170kt (314.5km/h). In all three basic categories - light, medium and heavy - the future aircraft are not merely larger than the conventional helicopters they are replacing; the next generation could be powerful enough to carry their predecessors as external payload.

v-22 osprey, usaf
  © USAF
With the exception of the V-22, the helicopter industry has been building improved models of exisiting aircraft for more than three decades

And it could all become reality relatively quickly for a military rotorcraft programme. With the notable exception of the Bell Boeing V-22, the industry has been building improved models of existing aircraft for more than three decades. The army's vision would swiftly break with that tradition. Four new aircraft types superior in every way to the existing fleet would enter service during a 10-year period, beginning in 2025.

A total of 25 existing aircraft types, including conventional aircraft and tilt rotors, would be phased out as the more advanced replacements arrive.

The transition would begin in the ultra-sized category, under a plan that envisions building a vertical lift aircraft with performance somewhere between a Lockheed Martin C-130J and Airbus A400M. It is the most extreme of the four new airlifters but, perhaps counter-intuitively, it is to enter service first, around 2025.

The next step would introduce the so-called JMR-Medium, a fast-moving utility-and-attack aircraft that could insert a platoon-sized unit up to 424km (263 miles) from a base, or launch a deep-strike assault on a column of enemy tanks well behind the front lines. According to a May presentation by Colonel Doug Rombough that was posted on the internet, it could enter service by 2027 or 2028.

The next generation of scout helicopters would arrive a few years later, around 2030. It is called JMR-Light, but it would be able to carry the full weight of the 5,500lb (2,500kg)-class Bell Helicopter OH-58 Kiowa Warrior as either internal or external stores. Finally, the schedule for JMR-Heavy anticipates fielding a replacement for the Boeing CH-47 Chinook, which achieved first flight in 1961, by 2035.

piasecki x-49a, piasecki aircraft
 © Piasecki Aircraft
Piasecki Aircraft's X-49A is a modified YSH-60F with a 200kt speed capability

The vision has been known for several months, but details of the performance attributes and timing called for by the army's so-called joint multi-role (JMR) study have only recently appeared. Industry officials interested in competing for the JMR projects were briefed by the army in December. However, the information still was not disclosed or leaked until late July or early August, when Col Rombough's presentation surfaced online.

How real the army's commitment to realising the vision of a four-tiered fleet of rotorcraft will be discovered within a few years.

The task is not simple in a new era of inevitable budget cuts, given that the programme seeks to introduce advanced technology, exotic rotorcraft configurations and all-new supply chains. At the same time, it supports the army's "mounted vertical manoeuvre" strategy, which calls for the rapid deployment of small groups of forces over widely dispersed areas.

However, the thing propelling the army aviation community forward is the fear of the alternative - another cycle of performance upgrades of existing helicopters.

"I don't want my grandchildren flying the [AH-64] Longbow Block 80," Major General Anthony Crutchfield told the Army Aviation Association of America conference last April.

However, it is not yet clear which direction the army will proceed. Like gamblers hedging bets, both the army and the rotorcraft industry are supporting parallel tracks to support the JMR vision as well as the path that lead's towards Crutchfield's worst-case scenario - the AH-64 Block 80.

joint multi-role helicopter specs

This is true even for the underlying technologies at the heart of any new rotorcraft modernisation programme. Two companies - GE Aviation and the Advanced Turbine Engine Company (ATEC), a joint venture between Honeywell and Pratt & Whitney - are competing to develop a 50% more powerful successor to the 2,000shp-class T700 turboshaft. The new engine - called the advanced affordable turbine engine (AATE) - could be applied in different ways.

The new powerplant could simply be inserted into the next generation of remanufactured or newly-built versions of the Sikorsky UH-60 Black Hawk or Boeing AH-64 Apache. But industry officials have also confirmed the engine is being designed with oil-sump pumps that can articulate vertically or horizontally. This often-overlooked feature is not found on the T700, and means the next generation of rotorcraft designs could support advanced, high-speed configurations, such as tilt rotors.

Meanwhile, fly-by-wire technology developed for the cancelled RAH-66 Comanche has now been demonstrated on the high-speed Sikorsky X2. It, too, is necessary to support a leap to a new generation of high-speed rotorcraft with much higher vibration levels. Or, the army could choose to apply it to bolster the handling and agility of its existing fleet of conventional helicopters in the next upgrade cycle or even sooner.

For industry, the implications of making the transition to JMR are stark. The military services currently support three large rotorcraft companies based in the USA, as well as two relatively recent entrants from Europe with the army's EADS North America UH-72A Lakota and the US Coast Guard's AgustaWestland MH-68. At least 25 basic helicopter and tiltrotor models are in service across the fleet, which include trainers, cargo, utility, scout and attack systems.

Under the army's JMR vision, the rotorcraft inventory would be consolidated into four basic types. At least the three smallest and perhaps all four types could be based on a single design by one of the five helicopter suppliers. By the mid-2040s, the last of the conventional helicopters would be retired from service, leaving an industrial base for rotorcraft not unlike the tactical aircraft industry, with one dominant supplier and one or two suppliers struggling to hang on.

The JMR vision also asks the industrial base to break the mould of two decades of remanufacturing programmes and compete with all-new designs and advanced performance.

Some industry officials, led especially by Bell, Boeing and EADS, pushed the army to consider alternative approaches to the acquisition plan. The normal path starts when the army establishes a requirement for a new weapon system. Bids are accepted to compete for a technology maturation phase, with two or three winners selected to compete for a winner-takes-all development contract leading to production.

Instead, these companies formed the vertical lift consortium (VLC). This sought to have the army incentivise investments by the prime helicopter suppliers in potential breakthrough technologies by smaller, more entrepreneurial companies.

The goal was to produce a wider range of experimentation for the same amount of funding, with the potential for finding the kind of "disruptive" technology changes difficult for a mature industry to bring forward on its own.

However, the army chose to bypass the VLC earlier this year, preferring the conventional path. At least $300 million has been budgeted for a technology demonstration phase in three years, with two or more competitors for the JMR-medium class of rotorcraft. Meanwhile, VLC members intend to continue a parallel demonstration programme, although it is not clear if the army's budget can support both tracks simultaneously.

Nothing, however, is certain in a budget environment expected to only decline during the next decade. Even the army's fall-back strategy to modernise its existing helicopters with new engines and fly-by-wire controls could be in doubt in that scenario.

But industry officials still see opportunities even beyond the JMR technology demonstration.

Sikorsky intends to develop and fly two S-97 Raider prototypes by 2014, leveraging the coaxial-rotor and pusher-propeller combination of the recently retired X2 demonstrator. The S-97 is designed to be a 10,000lb-class vehicle that could lift its own weight in payload. This falls somewhere between the performance of the army's JMR-light and JMR-medium classes.

Sikorsky is likely to offer the S-97 instead for a separate requirement now emerging for the US Special Operations Command (SOCOM). The roughly 50 Boeing/MD Helicopters MH-6 Little Birds flown by the 160th special operations aviation regiment were intended to be replaced by the Bell ARH-70 Arapaho, but the army terminated the contract.