BELL HELICOPTER Textron and South Korea's Samsung Aerospace are planning joint development of a new light twin-turbine helicopter, tentatively designated the Model 427. Certification is scheduled for late 1998. The 427 is intended to be a rival for the Eurocopter EC 135 and McDonnell Douglas MD Explorer, says Bell chairman Webb Joiner.

The 427 is a derivative of the new light single-turbine Bell 407, deliveries of which began at Heli-Expo '96, one year after the aircraft was launched. The new aircraft has a 2,725kg gross weight and includes the 407's four-blade composite main rotor, with diameter increased by 600mm, to 11.3m. The 407 fuselage is being stretched, by 330mm to provide room for a larger, 720litre, fuel tank. The aircraft accommodates a pilot and seven passengers, or two pilots and two medical litters arranged lengthwise in the main cabin, Joiner says.

Three manufacturers were due to have responded to a request for engine proposals by the end of February. Allison is offering its Model 250-C22+, Pratt & Whitney Canada is tendering its PW206 and Turbomeca is bidding with its Arrius 2. The 427 will meet demanding new international requirements for one-engine-inoperative performance, Joiner says.

The South Korean company will manufacture the cabin and tail-boom and will assemble 427s for sale in South Korea and China. Bell's Canadian plant will be the main final-assembly site. A new, low-cost, 520kW (700shp), direct-input transmission will be developed by Bell and Samsung.

Development will cost less than $100 million, Joiner says. A 1995 price of $1.9 million has been set, compared with $2.35 million for the EC 135 and $3.6 million for the Explorer. Payload will be about the same, as the Explorer's and greater than the EC 135's, the company claims.

Bell originally planned a twin-turbine version of the 407, dubbed the 407T and based on the present 206LT, but says that the aircraft did not offer sufficient payload/range performance. The 427 has been substantially redesigned to increase gross weight, fuel capacity and cabin volume.

Source: Flight International