PAUL LEWIS / WASHINGTON DC
World's first civil tiltrotor unlikely to achieve conversion to aircraft mode this year
The Bell Agusta Aerospace (BAAC) BA609 civil tiltrotor has made its long-awaited first flight, kick starting a cautious and conservative development and test schedule with a full conversion from helicopter to aircraft mode not expected before the year-end. Partner AgustaWestland in the meantime has begun assigning extra engineers to the programme to accelerate work.
BAAC has mapped out a 4,000h flight-test programme between now and planned type certification in early 2007. The initial prototype will focus on aero stability and handling qualities, while a second machine due to follow within the year will be used for avionics systems testing. A further two machines will follow at a yet-to-be-determined point for power and altitude testing up to a design ceiling of 25,000ft (7,600m).
"The first aircraft is primarily focused on making sure the software is doing what we want it to do and when we want it to," says Jack Gallagher, BA609 programme manager. There are at least another five fly-by-wire flight-control software downloads being developed by BAE Systems to follow the initial block 5.5, each adding more functionality.
With the first flight having slipped by over two years and initial planned deliveries running around five years behind the original schedule, AgustaWestland recently indicated it wants more involvement in the programme to speed development (Flight International, 18-24 February). It has added 12 engineers and will supply 12 more over the next year to strengthen Bell's team and assist with transmissions, flight controls and rotor blades.
During its 36min first flight, the BA609 hovered at a height of 50ft, performing left and right pedal turns and low-speed manoeuvres forward and aft with nacelles tilting -10° and +5° respectively from the 90° vertical position. The first 10h of testing will focus on basic stability; the nacelles will be rotated forward to a maximum of 75° with the vehicle reaching a forward speed of up to 110kt (200km/h).
BAAC is also planning to perform a hover-out-of-ground effect and testing with one engine inoperative, shutting down one of the BA609's two Pratt & Whitney Canada PT6C-67A turboprops and engaging the cross shaft drive.
Source: Flight International
