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The Army Takes Another Look at VTOL UAS

Given the rapidly expanding tactical capabilities of unmanned aircraft systems, few observers would question the U.S. Army’s tightening embrace of these platforms. As outlined in the foreword to the recently released “U.S. Army Roadmap for Unmanned Aircraft Systems: 2010-2035,” “The U.S. Army began combat operations in October 2001 with 54 operational Hunter and Shadow unmanned aircraft. Today, the Army has over 4,000 unmanned aircraft systems (UAS) in various sizes and capabilities with still more programmed. After nearly 9 years of continuous combat operations, we have significantly evolved the way we employ UAS in support of our warfighters. These adaptations are reflected in the tremendous growth of platforms and the expanded capabilities in the current UAS force. …”

One area of expanded capabilities being explored by the U.S. Army involves vertical takeoff and landing (VTOL) UAS designs. Service planners see various VTOL design applications in a wide range of roles and missions, ranging from surveillance to resupply to personnel medical evacuation.

In light of this continuing VTOL interest, it is perhaps ironic that the Army appears to have had procurement challenges with two VTOL UAS designs over the last few years.


A gMAV in flight. The similar Class I VUAV was canceled by the Army due to weight, bulkiness, and aerial signature concerns. U.S. Army photo

The first involved the “Class IV” UAS envisioned under the Army’s Future Combat Systems (FCS) program. In late January 2004, Northrop Grumman Corporation announced that its MQ-8B Fire Scout VTOL UAS had been selected to provide the Class IV UAS capabilities sought for the FCS architecture.

Designated by the Army as the XM157, the RQ-8B air vehicles improved upon the earlier RQ-8A Fire Scout design with a new, four-blade rotor system (versus the RQ-8A’s three-blade design), improved airfoil blades, and several performance enhancements that enabled more than eight hours endurance with a specification payload weight of 130 pounds.

By linking into the existing U.S. Navy contract, the Army was able to obtain eight air vehicles with initial planned first flight scheduled for 1st quarter of FY 11, followed by long lead for low-rate initial production in 2013 and initial operational capability (IOC) in 2015.

The second VTOL experience, also introduced as part of FCS, involved the “Class I” (Block 0) UAS, later designated XM156 by the Army and “T-Hawk” by manufacturer Honeywell Aerospace, but referred to by some soldiers as the “flying beer keg.”

In late May 2006, The Boeing Company and partner Science Applications International Corporation (SAIC), then serving as the lead systems integrator for the FCS program, awarded the Class I contract to Honeywell Defense and Space Electronic Systems. The man-packable VTOL system introduced a “hover and stare” capability with potential applications like “pattern of life” monitoring. In addition to its inclusion in the FCS architecture, an additional quantity of the gasoline-powered micro air vehicles (gMAV) were also deployed to Iraq with two different Stryker brigade combat teams.

Both VTOL systems got a boost in early 2007 when Army leadership announced a series of adjustments to the FCS modernization strategy “to accommodate reduced funding and an unexpectedly high operational tempo.”

RQ-8 Fire Scout

The Army’s Class IV VUAV, the RQ-8 Fire Scout, was also canceled based on the conclusion that similar capabilities could be delivered by an improved Shadow UAV. Image courtesy of Northrop Grumman

FCS program adjustments for fiscal years 2008-2013 reduced the total number of planned FCS systems from 18 to 14, but accelerated the fielding of the FCS network to the Army by two years. In addition, the announcement noted service intent to procure more Class IV UAS and add a laser designator to the Class I system.

But funding and other challenges continued, and a June 23, 2009, acquisition decision memorandum formally cancelled the FCS Brigade Combat Team program while also directing the Army “to transition to a modernization plan consisting of a number of separate but integrated acquisition programs …”

The initial “Increment 1” of this plan included the Small Unmanned Ground Vehicle (SUGV), the Class 1 Block 0 UAS, both Tactical and Urban versions of Unattended Ground Sensors (T-UGS /U-UGS), the Non-Line-of-Sight Launch System (NLOS-LS), and an early increment of the FCS network in the form of vehicle-mounted Network Integration Kits.

Subsequently, on May 13, 2010, the Department of Defense announced that it authorized the Army to cancel the NLOS-LS element of the Increment 1 package.

The 2009 reorganization and guidance also directed the Army to continue testing of these Early Infantry Brigade Combat Team (E-IBCT) Increment 1 assets over the next two years, under a process of Limited User Tests in the fall of 2009 (LUT 09) and the fall of 2010 (LUT 10).

In spite of service efforts to fast-track the Class IV in the early 2007 FCS reorganization, in a Jan. 11, 2010, information letter sent to members of Congress, the Army noted that it had terminated the Fire Scout portion of its FCS contract because analysis had indicated that an improved Shadow UAS could meet future Army requirements and therefore the Fire Scout was no longer required.

Fire-X VUAV cargo

An artist’s conception of two Fire-X VUAVs transporting cargo. Fire-X is a likely candidate for the MRMP program. Image courtesy of Northrop Grumman

As part of his own March 9, 2011, testimony before the United States House of Representatives Armed Services Subcommittee of Tactical Air and Land Forces, Dr. J. Michael Gilmore, director of the Operational Test and Evaluation Office in the Office of the Secretary of Defense, also offered a somewhat negative assessment of the resulting user experience with the remaining Class 1 Block 0 VTOL system.

“The Class I UAS was most useful when employed from a static defensive position such as the company combat outpost (COP),” he noted. “It was less useful in offensive operations due to its weight and bulkiness. The Class 1 UAS has a loud aural signature and the unit did not use it when tactical surprise was desired. The unit showed a preference for the Raven UAS over the Class I UAS because the Raven was easier to deploy, had longer endurance, and was quieter. The Class 1 UAS fell well short of its reliability requirements, demonstrating a 3.1-hour MTBSA [mean time between system abort] versus a 23-hour requirement. Unlike the other E-IBCT systems, the Class 1 UAS showed little reliability growth from LUT 09.”

A stop work order was reportedly issued in January 2011.

Nevertheless, the U.S. Army has continued to express significant interest in VTOL UAS capabilities. Recent confirmation of that interest emerged during a “UAS Warfighter Forum” panel discussion on June 23, 2011.

According to U.S. Army Deputy Product Manager for UAS Modernization Donna Hightower, the Army is focusing on two new VTOL UAS efforts during the second half of 2011.

The first, dubbed “Army Argus A160,” is a quick reaction capability (QRC) that will be introduced into a “yet to be determined orbit area” in Afghanistan during the 2nd quarter of FY12 (a preceding round of U.S. flight testing is likely to start late in 4th quarter of FY11). The QRC program will involve three YMQ-18A VTOL UAS – called A160T “Hummingbird” by manufacturer The Boeing Company – one aircraft already owned by the Army and one each being loaned to the Army by both the Defense Advanced Research Projects Agency (DARPA) and United States Special Operations Command (USSOCOM).

Outlining some of the 2010-2011 industry A160T program activities at a recent defense exhibition, Jeff Shelton, A160T Business Development lead at Boeing, pointed to the recent movement of early A160T manufacturing activities from Irvine, Calif., to Mesa, Ariz., with the initial vehicles – slated for a Marine Corps cargo demonstration – coming off the new line in March of this year.

Lockheed Martin/Kaman K-MAX

The Lockheed Martin/Kaman K-MAX at Yuma Proving Ground, Ariz., in January 2010. The K-MAX is likely to be a competitor in the MRMP program. Photo by Chad Slattery

In terms of envelope expansion and demonstrated platform capabilities, Shelton pointed to a recent demonstration in which the company flew the platform for 18.7 hours with a 300-pound payload, landing with 90 minutes of fuel remaining.

“So we know we can fly over 20 hours with a 300-pound payload,” he said. “That being said, the exact endurance would be dependent on what our customer wanted on the platform. Anything they would put on there additional would add weight, which would reduce that endurance time.”

Emphasizing the design’s multi-mission platform capabilities beyond logistics or electro-optical missions, he noted that the aircraft has also been flown with “dummy” Hellfire missiles mounted on the stub wings “to demonstrate center of gravity and aerodynamics. We know we can do it aerodynamically and weight-wise, but have not yet integrated and tested the weapon system on it.”

In parallel with the planned QRC fielding, Hightower described the Army’s second current VTOL effort as “the formal program of record.” Noting that the Army had completed the preliminary stages of the acquisition strategy and was working on subsequent approval phases throughout the Department of Defense, she pointed to the imminent release of a request for information (RFI) that would allow service UAS planners “to gain some knowledge about the different systems that are out there … Then we will continue finalizing the acquisition strategy after we have received some of that information from industry. Then we will go on into a full and open competition on that program.”

The RFI for a medium range multi-purpose (MRMP) VTOL UAS was subsequently released on June 27, 2011. Noting that the functional capabilities listed in the RFI were “intended to provide an overview of the Army MRMP VTOL UAS goals and objectives,” program planners explained that the industry responses to the RFI would be used “to support the Army development of the MRMP acquisition strategy and to inform the collaborative Army and Navy Medium Range Maritime UAS (MRMUAS) Analysis of Alternatives (AoA). The MRMUAS AoA will be a joint collaboration between the Navy and Army to specifically evaluate alternatives and determine what components, sub-components, or technologies could be cooperatively and jointly developed to reduce total ownership cost in the Department of Defense (DoD). Respondents to this RFI shall provide information for an Army VTOL solution only. The Navy in parallel to the Army will release an RFI for Navy VTOL solutions and the two services will exchange information.

“The Army intends to move forward with the MRMP VTOL Technology Development phase in FY12 and deploy competitive systems in FY13,” they added. “Deployments of the competitive systems will support down-select to a single vendor in FY14.”

The RFI seeks information on several key attributes of available VTOL UAS, including:

  • primary intelligence, surveillance, and reconnaissance (ISR) role and additional capabilities (i.e. resupply, weapons, high-levels of autonomy, teaming, safety, redundancy, maintainability, reliability, survivability, airworthiness, security, deployability, etc.);
  • operations in adverse weather conditions (rain, icing, high winds, temperature extremes) for all mission profiles; interoperability and net-centric operations;
  • compatibility with U.S Army Universal Ground Control Station (UGCS);
  • training program for UAS Universal Operator and UAS Universal Maintainers;
  • modular, plug-and-play payload functionality capable of supporting a minimum of three payloads, excluding electro-optical/Infrared (EO/IR), simultaneously with simplified integration;
  • system integrity consistent with safe operations over populated areas and in controlled airspace; and,
  • affordability.
Boeing Unmanned Little Bird VUAV

Another VUAV derived from a formerly manned platform is the Unmanned Little Bird from Boeing. Photo courtesy of Boeing

One notional ISR mission profile projects a 300-pound internal payload (not including standard aircraft equipment), travel distance to target area of 300 kilometers (km) at 16,000 feet mean sea level (MSL), and travel 300 km at 16,000 feet MSL back from target.

Several functional capability requirements were also identified for the MRMP VTOL UAS. One example outlined “hard point” requirements, stating, “The VTOL UA will include at a minimum (1.) four non-centerline hard-points capable of supporting 500 lbs. each (2.) a centerline hard-point capable of supporting 5,000 lbs.”

“The VTOL UAS will operate in austere environments,” the RFI notes. “The aircraft will have ground mobility over rough terrain, transportability, and hard-points for munitions or cargo. The payload bay will have adjustable power and racks to accommodate multiple payloads with sufficient external fuselage common mounting points for reconfigurable antennas. The VTOL UA will use sustaining cruising speeds and endurance to perform reconnaissance and surveillance, multi-mission, staring and resupply missions while having standard equipment on board.”

Reflective of apparent interest in future weaponization of any VTOL UAS platform, it also states a desire for the platform to incorporate “DoD and NATO open standard electrical, logical, and mechanical interfaces as governed by PM UAS Weapons Interoperability Profile,” calling for responding contractors to “State the Target Location Error (TLE) which supports the employment of (1.) coordinate-seeking weapons and (2.) small diameter bombs.”

Other visualized capabilities for the VTOL UAS include a capability for autonomous takeoff/landing support for resupply, remote delivery, and recovery operations, capabilities that would allow “an opportunity to use limited skilled operators.”

Industry responses to the MRMP VTOL UAS RFI were requested no later than Aug. 10, 2011.

This article was first published in Defense: Fall 2011 Edition.


Scott Gourley is a former U.S. Army officer and the author of more than 1,500...