Boeing–Sikorsky RAH-66 Comanche

RAH-66 Comanche
The first RAH-66 prototype
Role	Reconnaissance and attack helicopter Type of aircraft
National origin	United States
Manufacturer	Boeing Helicopters/Sikorsky Aircraft
First flight	4 January 1996
Status	Cancelled in 2004 by U.S. Army
Primary user	United States Army
Number built	2

The Boeing–Sikorsky RAH-66 Comanche is an American

During the early 1980s, the U.S. Army started to formulate requirements for the replacement of its helicopters then in service, which resulted in the launch of the Light Helicopter Experimental (LHX) program. Nearly a decade later, following the refinement of requirements, evaluation of submissions, and the rebranding of the program as the Light Helicopter (LH) program, during April 1991, the Army announced the selection of the Boeing–Sikorsky team's design as the contest winner, shortly after which a contract for construction of prototypes was awarded. The Comanche was to incorporate several advanced elements, such as stealth technologies, and a number of previously untried design features. Operationally, it was to employ advanced sensors in its reconnaissance role, in which it was intended to designate targets for the AH-64 Apache. It was also armed with one rotary cannon and could carry missiles and rockets in internal bays and optionally on stub wings for light attack duties.

Two RAH-66 prototypes were constructed and underwent flight testing between 1996 and 2004. On 1 June 2000, the program entered its $3.1 billion engineering and manufacturing development (EMD) phase. However, during 2002, the Comanche program underwent heavy restructuring; the number of Comanches that were to be purchased was cut to 650. At the time, the projected total cost for the full production of the Comanche in such numbers stood at $26.9 billion. As early as the late 1990s, the Government Accountability Office (GAO) had reported that it had "serious doubts" about the program, observing that the Comanche would "consume almost two thirds of the whole Aviation budget by Fiscal Year 2008". Multiple government agencies had acted to cut the number of Comanches on order, but, as a consequence of the heavy reductions to the numbers to be procured, the unit costs soared.

On 23 February 2004, the U.S. Army announced the termination of the Comanche program, stating they had determined that the RAH-66 would require numerous upgrades to be viable on the battlefield and that the service would instead direct the bulk of its rotary systems funds to renovating its existing attack, utility, and reconnaissance helicopters. The Army also announced new plans to accelerate the development of unmanned aerial vehicles (UAVs), which could also perform the scouting role intended for the Comanche, but with less risk. Since program cancellation, both of the prototypes have been placed on public display.

Development

Origins and LHX

During 1982, the U.S. Army initiated the

During November 1993, assembly of the first prototype commenced at Sikorsky's facility in Stratford, Connecticut and at Boeing's manufacturing plant in Philadelphia, Pennsylvania. Later all of the rotorcraft's sub-assemblies were transferred to the former location where final assembly occurred. In December 1994, the Department of Defense reduced the number of planned prototypes to two as the services shifted budgets to pay for increased troop salaries.^[6] On 25 May 1995, the first Comanche prototype was formally rolled out at Sikorsky's production facility, after which it was transferred to West Palm Beach, Florida to commence flight testing activities.^[7][8] On 4 January 1996, the prototype Comanche, flown by test pilots Bob Gradle and Rus Stiles, performed its 39-minute maiden flight.^[9] The first flight had been originally planned to take place during August 1995, but had been delayed by a number of structural and software problems that had been encountered.^[7] On 30 March 1999, the second prototype conducted its first flight, before joining the flight test program shortly thereafter.^[4]

Prototype testing

The flight test program was conducted using the pair of prototypes produced, which had been assigned the

During 2002, the Comanche program underwent heavy restructuring; consequently, the planned number of Comanches to be purchased was decreased to 650 rotorcraft. At the time, the projected total cost for the full production of the Comanche in such numbers stood at $26.9 billion.[12] Originally, the EMD phase was to last for six years with five Comanches to be constructed for the testing regime. During 2003, production on the third RAH-66, which was to be the first EMD-conformant helicopter, was started. Subsequently, eight RAH-66s were to be constructed for operational testing purposes.^[4] The initial production RAH-66s were to be completed in a Block I configuration that included the majority of the rotorcraft's planned weapons and sensors. From the 16th Comanche onwards, deliveries would have been made to the Block II standard with all of the planned capabilities.^[14]

Cancellation

On 23 February 2004, the U.S. Army announced that they had decided to terminate all work on the Comanche program. At the time, it was stated that the Army had determined that a number of upgrades would be necessary in order for the RAH-66 to be capable of surviving on the battlefield in the face of current anti-aircraft threats; however, the Army had instead decided to re-direct the bulk of its funding for rotary development toward the renovation of its existing helicopter fleet of attack, utility, and reconnaissance aircraft. Specifically, the Army also had plans to reuse the funds allocated to the Comanche program to speed up development of unmanned aerial vehicles (UAVs), which could also perform the scouting role intended for the vehicle.^[15][16] At the time of its termination, the Comanche program had reportedly spent US$6.9 billion.^[17] The contract termination fees involved were estimated to total US$450–680 million for the main program partners Sikorsky and Boeing.^[16][18]

Subsequently, the Army decided to pursue development of another battlefield scout helicopter under the Armed Reconnaissance Helicopter program; this resulted in another rotorcraft, designated as the

A multitude of reasons contributed to the ultimate cancellation of the RAH-66 program. According to aviation author James Williams, efforts to speed up the program via the elimination of risk-mitigation measures and the stream of continuous adjustments to account for annual budget cuts to the rotorcraft resulted in the formation of a negative cycle that functioned to greatly extend the rotorcraft's development schedule.[20] Over the course of the Comanche's development, multiple government agencies had acted to cut the number of helicopters that were intended to be ordered; one particularly common basis for such curtailments was that the Cold War had ended and thus such quantities were unnecessary (a phenomenon known as the "peace dividend"). However, significant reductions in volume directly resulted in the rapid climbs in the projections of the Comanche's unit cost; in turn, this stimulated and gave validity to critics of the program, such as the Army Acquisition Executive James Ambrose, who had prominently declared that the Army would not receive any aircraft "costing a dollar over $7.5 million".^[20]

As early as 1995, it is claimed by Williams that the Comanche had been facing complete cancellation as a choice between which defense development programs were to be scrapped.^[21] During mid-1999, the Comanche was subject to substantial governmental scrutiny; the Government Accountability Office (GAO) reported that it had "serious doubts" about the program and noted that the Comanche would "consume almost two thirds of the whole Aviation budget by Fiscal Year 2008". In addition, wartime experiences, such as from the Kosovo War, had led to some senior figures within the Army to place a greater emphasis on the use of unmanned platforms for conducting many of the same roles for which the Comanche was being developed to perform.^[22] By 2000, Williams postulates that the primary reason for retaining the program was out of concern for the state of the helicopter industry—Sikorsky's production and employment figures were at their lowest for decades and the contract was considered critical.^[23]

Author Fred Brooks criticized the program's requirement for the Comanche to be capable of ferrying itself across the Atlantic as an example of excessive requirements being present in a project's design phase and of their costly repercussions.^[24] Williams observes that the Comanche's weight requirements were unachievable, and claimed that this was due to poor management, in which no party was allegedly aware of or in control of the rotorcraft's final weight; there were concerns that, when outfitted with actual equipment required for operations, the Comanche's engines would be incapable of lifting the total weight of the helicopter.^[23] Additionally, it has been claimed that it proved difficult to convince the Army that the program suffered from serious troubles while key individuals failed to realize the existence of insurmountable technical problems. Prized elements of the program, such as certain software capabilities and its integration, failed to foster confidence with Army overseers; several capabilities were viewed as having been unproven and risky, while the anticipated consumption of up to 40 percent of the aviation budget by the Comanche alone for a number of years was considered to be extreme. According to Williams, it was concluded that the Army's aviation budget would be better spent on the delivery of less risky and more critical needs.^[25]

In a report published during 2008, the GAO recorded that an Army spokesperson had stated that "the program's costs could no longer be justified".^[26] Author Cindy Williams stated of the Comanche: "The rationale for cutting Comanche... is twofold. First, the doctrinal niche that the Comanche occupies is unnecessary in the near term and probably not viable in the longer term. Secondly, as with all rotary-wing aircraft, the Comanche is a voracious consumer of strategic airlift."^[27]

The manufacturing team, Sikorsky and Boeing, have attributed factors that were outside of their control, such as budget cuts, "

The Comanche was intended to be an advanced armed reconnaissance and attack helicopter. The Comanche was specifically tailored to the role of armed scout to replace the U.S. Army's

In 2001, the Army sought to procure a "heavy attack" variant of the Comanche, which was intended to begin replacing Apaches in 2025.[34]

Aircraft on display

Both prototype airframes 94-0327, 95-0001, are located at the United States Army Aviation Museum at Fort Novosel, Alabama.^[35]

Specifications (RAH-66A)

Data from Jane's All the World's Aircraft 2005–2006,^[36] Frawley,^[2] Boeing and Sikorsky,^[29] Bonds and Miller^[33]

General characteristics

• Crew: 2
• Length: 46 ft 10.25 in (14.2812 m)
• Width: 6 ft 8.25 in (2.0384 m) maximum fuselage width
• Height: 11 ft 0.75 in (3.3719 m)
• Empty weight: 9,300 lb (4,218 kg)
• Gross weight: 12,349 lb (5,601 kg)
• Max takeoff weight: 17,408 lb (7,896 kg) maximum fuel for self-deployment
• Fuel capacity: 301.6 US gal (251.1 imp gal; 1,142 L) internal fuel + 2x 450 US gal (370 imp gal; 1,700 L) drop tank + 2x 112 US gal (93 imp gal; 420 L) optional side weapon bay tanks; Total 1,201.6 US gal (1,000.5 imp gal; 4,549 L) / 1,425.6 US gal (1,187.1 imp gal; 5,396 L) with weapon bay tanks
• Powerplant: 2 ×
  LHTEC T800-LHT-801 turboshaft
  engines, 1,563 shp (1,166 kW) each
• Main rotor diameter: 40 ft 0 in (12.19 m)
• Main rotor area: 443 sq ft (41.2 m²) 5-bladed main rotor with fenestron tail rotor
• Blade sections: - root: Boeing VR-12; tip: Sikorsky SSC-A09[37]

Performance

• Maximum speed: 175 kn (201 mph, 324 km/h) without mast radar

166 kn (191 mph; 307 km/h) with mast radar

• Cruise speed: 165 kn (190 mph, 306 km/h) without mast radar

149 kn (171 mph; 276 km/h) with mast radar

• Range: 262 nmi (302 mi, 485 km)
• Combat range: 150 nmi (170 mi, 280 km) internal fuel
• Ferry range: 1,200 nmi (1,400 mi, 2,200 km)
• Endurance: 2 hours 30 minutes on internal fuel
• Service ceiling: 14,980 ft (4,570 m)
• g limits: +3.5 -1
• Rate of climb: 895 ft/min (4.55 m/s) without mast radar

500 ft/min (152.4 m/min) with mast radar

• Disk loading: 71 lb/sq ft (350 kg/m²) YRAH-66
• Power/mass: 0.13 hp/lb (0.21 kW/kg) at MTOW, take-off power

Armament

• 1×
  Turreted Gun System with a 20 mm XM301 three-barrel rotary cannon
  (capacity: 500 rounds)
• Internal bays: 6×
  AIM-92 Stinger air-to-air missiles, or 24× 2.75 in (70 mm) Hydra 70
  air-to-ground rockets
• Optional stub wings: 8× Hellfires, 16× Stingers, or 56× Hydra 70 rockets

• U.S. Helicopter Armament Subsystems

Aircraft of comparable role, configuration, and era

• Bell 360 Invictus
• Bell OH-58X
• Eurocopter Tiger ARH

References

Citations

Bibliography

• "Comanche EMD Signed".
  ISSN 0015-3710
  . Retrieved 5 October 2013.
• Eden, Paul, ed. (2004). The Encyclopedia of Modern Military Aircraft. London: Amber Books.
  ISBN 1-904687-84-9
  .
• Bonds, Ray and David Miller (2002). "Boeing Sikorsky RAH-66 Comanche". Illustrated Directory of Modern American Weapons. Grand Rapids, Michigan: Zenith Imprint.
  ISBN 0-7603-1346-6
  .
• ISBN 978-0-201-36298-5
  .
• Crawford, Steve (2003). Twenty-First Century Military Helicopters. St. Louis, Minnesota: MBI Publishing.
  ISBN 0-7603-1504-3
  .
• Frawley, Gerard (2002). The International Directory of Military Aircraft. Fyshwick, ACT: Aerospace Publications.
  ISBN 1-875671-55-2
  .
• Government Accountability Office (March 2008). Defense Acquisitions: Termination Costs are generally not a Compelling Reasons to continue Programs or Contracts that otherwise Warrant Ending. Darby, Pennsylvania: DIANE Publishing.
  ISBN 978-1-4379-0335-5
  .
• Harding, Stephen (1997). "Boeing-Sikorsky H-66 Comanche". U.S. Army Aircraft Since 1947. Atglen, Pennsylvania: Schiffer Publishing.
  ISBN 0-7643-0190-X
  .
• Lewis, Paul (9–15 June 1999). "Digital Domain".
  ISSN 0015-3710. Archived from the original
  on 5 November 2012. Retrieved 8 July 2011.
• Lopez, Ramon (11 April 2000). "Paying its way".
  ISSN 0015-3710
  . Retrieved 28 August 2013.
• Siuru, William D (1993). "Boeing Sikorsky RAH-66 Comanche". Future Flight: The Next Generation of Aircraft Technology. New York: McGraw-Hill Professional.
  ISBN 0-8306-4376-1
  .
• Trimble, Stephen (2–8 March 2004). "US Army calls time on Comanche".
  ISSN 0015-3710. Archived from the original
  on 5 November 2012. Retrieved 8 July 2011.
• Williams, Cindy (2001). Holding the line: U.S. defense alternatives for the early 21st century. Cambridge, Massachusetts: MIT Press.
  ISBN 978-0-262-73140-9
  .
• Williams, James W (2005). A History of Army Aviation: From its Beginnings to the War on Terror. Bloomington, Indiana: iUniverse.
  ISBN 0-595-36608-2
  .
• Wilson, Stewart (2000). Combat Aircraft since 1945. Fyshwick, ACT: Aerospace Publications.
  ISBN 1-875671-50-1
  .

Further reading

• Garcia, Stewart (2000). Combat and Firing Aircraft since 2003. Borouge, ACT: Aerospace Publications.
  ISBN 1-875671-50-1
  .

External links

Wikimedia Commons has media related to Boeing–Sikorsky RAH-66 Comanche.

• Boeing RAH Comanche history page on Boeing.com
• RAH-66 Comanche page on Globalsecurity.org
• RAH-66 Comanche site (rah66.com) Archived 16 June 2013 at the Wayback Machine
• RAH-66 Comanche EMD Forges Ahead. Aviation Week, June 2001.
• news/08253news.xml&headline=Comanche%20Weight%20Control%20Gets%20Special%20Attention Comanche Weight Control Gets Special Attention^{[permanent dead link]}. Aviation Week, 24 August 2003.