Rotorcraft Programs: Tiltrotors and Compounds

 - February 22, 2010, 6:20 AM

Cutting-edge research takes an enormous amount of time and while the BA609 tiltrotor still shows signs of life, it may end up a solely AgustaWestland project. Sikorsky’s X2 compound helicopter hasn’t broken any speed records, yet, but it remains a fascinating program.

Bell/AgustaWestland
BA 609 Civil Tiltrotor

Now entering its 12th year of development, the Bell/Agusta BA609 program appears to be headed for a divorce. For nearly three years AgustaWestland CEO Giuseppe Orzi has made no secret that he is displeased with the glacial pace of the 609’s development and it now appears that negotiations are taking place that would either give AW a majority interest in, or outright ownership of, the program. Neither AW nor Bell will formally comment on the status of these negotiations, but last year Orzi told an Italian business conference that AW’s parent, Finmeccanica, had authorized him to negotiate for control of the program as a means to accelerate development and certification. Even under the most ideal outlook, airworthiness approval is unlikely until at least 2014.

The 609 first flew in 2003, and only two prototypes are now flying. Two more prototypes that has been scheduled to join the test program for several years have yet to materialize. However, in December an AW spokesman told AIN that both aircraft are under construction and will join the test program in 2011 and 2012.

However, commercial interest in the 609 has waned as development deadlines repeatedly slipped and the unit price has climbed from an estimated $8 million to $10 million in 1998 to more than $29 million today, making it considerably more expensive than the 19-seat Sikorsky S-92A or AgustaWestland’s own three-engine AW101. But AW is believed to be pursuing an order for the 609 from the Italian government for up to 50 of the aircraft configured for coastal patrol and search and rescue. Officially, orders for the 609 stand at 77, but the status of many of those is tenuous at best. Two years ago some order holders told AIN that they could not justify continued interest in the 609 at a price near or above $20 million.

Yet, the twin P&WC PT6-67A-powered 609 would seem ideally suited for a less price sensitive, government-backed overwater SAR role. The Bell/Agusta 609 has an mtow of 16,800 pounds. Preliminary data indicate the aircraft has an unrefueled range of 700 nm (boosted to 950 nm with auxiliary fuel tanks), a cruise speed of 275 knots (maximum forward speed 310 knots) and a service ceiling of 25,000 feet. In utility configuration it could carry up to 12 passengers plus crew, and in SAR mode it could rescue up to six by hoist.

Pier Guargualini, CEO of AW parent Finmeccanica, sees a big future for the 609, predicting demand for up to 500 aircraft during its first decade of production.

Sikorsky X2
Technology Demonstrator

The Sikorsky X2 first flew in 2008, but 2009 came and went without its achieving Sikorsky’s stated goal of beating the world helicopter speed record of 249 mph (216 kt), held since August 1986 by the Westland Lynx).

Sikorsky announced the self-financed X2 in 2005. The compound coaxial helicopter features fly-by-wire flight controls and combines components from existing Sikorsky aircraft, including the S-76, Black Hawk and CH-53, and other manufacturers’ aircraft.

Power for the 6,500-pound X2 comes from a single LHTec (Light Helicopter Turbine Engine Company) T800 turboshaft rated at up to 1,680 shp. Sikorsky had previously flown the LHTec engine on the RH-66 Comanche scout and attack helicopter prototype developed for the Army. That program was canceled in 2004 after expenditures of $6.9 billion and 20 years of development. LHTec has developed a successful civilian variant of the T800, the CTS800. The T800 drives the twin four-blade Eagle Aviation contra-rotating rigid main rotors and the Aero Composites six-blade pusher propeller, or auxiliary propulsion system, mounted at the end of the tailboom.

Sikorsky claims its X2 technology is suitable for military missions such as assault, armed reconnaissance, close air support and combat search and rescue, and unmanned applications.

One way Sikorsky might cash in on the X2 was revealed in May last year, when it displayed a mock-up of a possible X2 military light tactical helicopter (LTH) design at the Army Aviation Association of America annual convention. The LTH mock-up was widely seen as a precursor to a potential Sikorsky bid for the Army’s armed scout helicopter program.

However, Sikorsky would face substantial competition for the contract from both Boeing and an EADS-Lockheed Martin partnership. Both are offering solutions featuring commercial, off-the-shelf airframes that, while slower, likely present less technical risk and lower unit costs.