Guy Norris/LOS ANGELES
McDONNELL DOUGLAS Helicopter Systems (MDHS) has surprised the rotary world by unveiling a flying prototype of the MD 630N, a stretched version of the MD 520N, at the Heli-Expo '95 exposition in Las Vegas, Nevada.
The seven- to eight-seat helicopter has been developed in great secrecy by MDHS, which flew it for the first time at Mesa, Arizona, on 22 November, 1994 - just 14 days after the MD 630N concept was first announced and 138 days after the programme was approved.
Equipped with MDHS' no-tail rotor (NOTAR) anti-torque system, the 630N turbine single is aimed at bridging the gap between the five-seat MD 520N and the twin-engine Explorer just entering service.
If MDHS enters production of the MD 630N, it will compete against makers of other large single-turbine machines such as Bell, with its 206L-4 LongRanger IV, and Eurocopter, with the AS.350B Ecureuil. The company says that it "...expects to make a 'go/no-go' production decision in the second quarter of this year. A 'go' decision would mean delivery of the first MD 630Ns before the end of 1996."
Early test flights have shown, that the aircraft is expected to be able to run, at a direct operating cost of about $234/h. Andy Logan, vice-president of commercial programmes for MDHS says, "The performance data we have gathered so far shows, we are on track to have a very special helicopter, including exceptional direct operating costs."
Powered by an Allison 250-C30 turbo-shaft rated at 485kW (650shp) and fitted with a six-bladed rotor, the MD 630N has a maximum cruise speed of 135kt (250km/h) and a maximum permitted speed (Vne) at sea level of 150kt. A fuel tank of 454l capacity gives a maximum range at 5,000ft (1,500m) of around 780km (400nm). Useful load is almost 990kg internally and 1,250kg externally with the hook able to take up to 1,360kg.
The MD 630N is capable of hovering at 10,500ft in ground effect and 6,800ft out of ground effect. Maximum operating altitude is 20,000ft and maximum rate of climb is 1,700ft/min (8.6m/s). The aircraft has already amassed more than 20h of flight tests and was expected to increase this tally with a flight from Arizona to the Heli-Expo show in Nevada.
Source: Flight International
