Helicopters Will Provide Close Air Support

Advanced technology promises to give helicopters the speed, range, and endurance to provide close air support to our troops around the world from the sea.

A helicopter's responsiveness, agility, and ability to operate in diverse conditions are distinct advantages over a fixed-wing aircraft. Its ability to fly under adverse weather conditions and maintain substantial time on station give it untapped potential as a close air support (CAS) platform. The U.S. Navy has not used its helicopters in this way since the Vietnam conflict. Used effectively in roles including logistics, search-and-rescue (SAR), antisubmarine warfare (ASW), antisurface operations (ASU), and combat search-and-rescue (CSAR), Navy helicopters rarely leave their familiar blue-water area of operations.

With the rise in asymmetric littoral threats, the Navy is arming its helicopters with additional weapons; but even with advanced firepower, a fully armed HH-60H or SH-6OB Seahawk lacks the punch to be a formidable CAS force. Without forward-firing guns, the Seahawk is vulnerable in a gunfight; it must turn its nose away from the target to aim its door-mounted guns downrange, placing it in a defensive posture and increasing its vulnerability.

To accomplish the CAS mission, a Navy helicopter would have to be heavily armed. An effective CAS platform would require forward-firing rockets, .30-mm cannons, and added stores for air-to-ground missiles comparable to the highly successful Army, Navy, and Marine Corps' family of AGM-114 Hellfires. With the ability to land in most unprepared landing zones, a Navy gunship, operating in close proximity to a forward area refueling point, could rearm itself quickly, thereby increasing the critical time ordnance is on target. Compared to Navy tactical aircraft, which must fly back to the aircraft carrier to rearm, a helicopter's outstanding endurance and loiter time could be exploited in the CAS mission area.

According to the Navy's Helicopter Master Plan, the new MH-60R, a hybrid of the SH-60B and the carrier-based SH-60F Seahawk helicopters, will assume the vital roles of ASW and over-the-horizon identification and tracking of targets. As the aircraft carrier's S-3 Viking starts to phase out of service, the MH-60R will become the primary armed surveillance/reconnaissance platform for the carrier strike group. With plans to fit the MH-60R with torpedoes, Hellfire missiles, and machine guns, the helicopter will be a lethal platform in the maritime environment—but it still will be inadequate in the CAS mission area. The Navy's newest MH-60S, a U.S. Army Blackhawk variant without the SH-60R's critical sensors, will replace the aging H-46 Sea Knight for logistics support and SAR, and eventually will replace the carrier-based HH-60H as the primary Navy CSAR aircraft. There are no plans for active-duty Navy gunships to conduct CAS or dedicated Naval Special Warfare support while operating in any theater from an aircraft carrier or Navy vessel.

Critics of Navy attack helicopters and gunships quickly point out that the biggest disadvantage of any helicopter is its slow speed and limited range. An aircraft carrier loaded with high-performance jets, they argue, typically operates hundreds of miles off the coast of the hostile nation or rogue state, relatively safe from asymmetrical littoral threats and busy shipping lanes. With limited range, slow airspeed, and lack of air refueling capability, a standard Navy helicopter cannot augment the carrier-based fixed-wing aircraft in the close air support arena.

The Marine Corps has used its helicopters in both support and attack roles with great success. Although the Corps' naval infantry mission is much different from the Navy's, the Marines successfully exploited the AH-IW Cobra, and demonstrated the lethality of the aircraft during Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq. Limited range and slow air-speed, however, did restrict the effectiveness of this conventional helicopter.

In the mid-1960s, Piasecki Aircraft Corporation successfully demonstrated the world's first shaft-driven compound helicopters, the 16H-1 and 16H-1A "ring-tail." These and other compound demonstration efforts eventually led the Army to select the compound AH-56A Cheyenne for its advanced aerial fire support system requirement. After some initial difficulties, this program successfully completed technical development but never went into production because of a roles-and-missions battle over the CAS mission with the Air Force and its A-IO development program.

In the 1990s, the Piasecki ring-tail compound helicopter concept reemerged in the face of Army and Marine Corps concern about the threat of Soviet helicopters being developed as antihelicopter helicopters. The early Piasecki design has matured to a second-generation configuration, vectored thrust-ducted propeller (VTDP) compound helicopter technology. In 1992, wind tunnel testing confirmed a 46% improvement in hover efficiency over the ring-tail. In 1994 and 1996, piloted simulations of the AH-IW/VTDP showed significant performance, handling, and survivability improvements. These successes led to the awarding of a Navy contract in October 2000 for the design, fabrication, and flight testing of the X-49A, a VTDP-configured SH-60F helicopter, as an advanced technology demonstration program initiative. Sponsored by the Office of Naval Research (ONR), the primary objective of this flight demonstration program is to show the potential improvements in mission capability the VTDP technology provides.¹

This concept involves substituting a VTDP unit for a standard tail rotor and adding a lifting wing with short stub wings called flaperons to increase forward speed and improve maneuverability. The lifting wing unloads the rotor in forward flight, delaying the onset of blade stall, an aerodynamic certainty that limits the airspeed of most helicopters to approximately 150 knots. By comparison, the maximum speed of the VTDP-configured helicopter exceeds 200 knots. The technology dramatically increases the aircraft's range, a critical component in missions such as CSAR, personnel recovery, ASW, ASU, and medical evacuation. An HH-60H compound helicopter, for example, has a 520-nautical-mile radius when making a vertical take-off, and a 762-nautical-mile combat radius when using a rolling take-off from a carrier deck or runway. The latter is triple that of the standard HH-60H and is well matched with the Navy's newest F/A-18E/F Super Hornet's 665-nautical-mile radius.²

Georgia Institute of Technology, under an ONR contract sponsored by the Air Force, has completed an independent assessment of the technology applied to Air Force CSAR requirements. The results are impressive. Compared to a standard Air Force HH-60G Pavehawk, Georgia Tech estimated, the VTDP variant could achieve a 50-knot increase in speed, a 110% increase in range, and a 71% increase in endurance.³

The VTDP technology offers improvements in the ASW mission area as well. In a report generated by Piasecki illustrating a typical ASW scenario, the increment in speed between the conventional and compound helicopter gives a 30% reduction in the time to determine the last known location of a submarine, with a corresponding reduction of 50% in the required search area, greatly diminishing a submarine's ability to evade. The enhanced mission effectiveness provided by the speed increment allows the limited number of helicopters in the task force to be more responsive to their multimission demands.⁴

In addition to increased airspeed, range, maneuverability, and survivability, one of the greatest advantages of the VTDP compound technology is its applicability to existing and future helicopter platforms. By reducing airframe vibrations and excessive load on the airframe, lifecycle costs of the aircraft will be reduced. This equates to long-term savings and makes a compound helicopter a cost-effective solution.

At the Precision Strike Association's 2003 Summer Precision Engagement Operations Forum, retired Vice Admiral Arthur Cebrowski, now director of the Office of Force Transformation, stated the importance of joint war fighting: "Forces being projected from the sea must also be able to support special operations force-like capabilities. We are going to have to position forces forward around the world in different ways than we ever have before. It will call on different organizations, it will call on different platforms; we're going to see changes in operational maneuvering."⁵

The Navy is transforming from its archaic Cold War paradigms. No longer can we predict when aircraft carriers will deploy. As a result of secretary of Defense Donald Rumsfeld's transformation philosophy, the Navy is projecting power with carrier strike groups, combined Navy and Marine Corps expeditionary strike groups, and maritime prepositioning force platforms. These joint forces combine their strengths into a seamless sea base. The compound helicopter exploits the craft's advantages while overcoming its inherent disadvantages and gives the commanders another capable and lethal option in the close air support mission area.