BELL HELICOPTER Textron Canada is modifying two Model 206L-4 LongRangers into certification-test aircraft for the new Model 407 light turbine.

The first 407 is scheduled to be flown at Mirabel, Quebec, in the third week of June. Certification, is planned by the end of 1995, says programme manager, Dale Cato.

Bell has orders for more than 60 single-turbine 407s and is now taking orders for the twin-turbine 407T, which will be certificated in the second half of 1996. The 407 features a four-blade composite main-rotor, up-rated engine and transmission and wider fuselage, compared with the 206L (Flight International, 8-14 February, P8).

Design of the 407 began in January 1994 and a concept demonstrator was first flown on 21 April, according to Cato. This was a 206L-4, modified with the dynamic system and tail-boom of the military OH-58D and with sidewall fairings simulating the wider fuselage.

Compared with the 206L-4, the 407 is faster and heavier. Cruise speed at maximum gross weight and maximum continuous power is 128kt (240km/h), up from 110kt for the 206L-4. Take-off weight is increased by 250kg to 2,270kg, hover ceiling out-of-ground effect by 1,500-2,000ft (450-600m) and range by 90-110km (50-60nm), but the 407 costs only $125,000 more than the 206L-4, Cato says.

Flying qualities of the 407 "equal or better" those of the 206L, which is regarded as one of the smoother-riding helicopters, he says. The four-blade rotor is quieter, Cato adds, as it eliminates the characteristic blade slap of the 206's two-blade rotor.

The 407 and 407T will be certificated under amendments to the existing 206L/LT approvals, he says. Design work on the 407T is getting under way at Bell and at Soloy, which provides the combining gearbox. This will be up-rated by 105kW (140shp) from the design used in the 206LT, Cato says, and the 407T will have an almost 2,500kg take-off weight.

The 407 and 206 will be assembled on separate lines at Mirabel, he says, although there is significant commonality in detail parts. The 407 and 407T airframes will be common below the roofline. The new sidewalls, which provide 180mm more width in the aft cabin, plus larger windows and doors, are load bearing, carbonfibre-composite structures.

Source: Flight International