Guy Norris/HARTFORD
Pratt & Whitney has started building the first flight test PW6000 engines in preparation for trials in August on the company's Boeing 720 testbed. The tests are a vital step towards certification in October 2001 and the maiden flight of the Airbus A318 in January 2002.
The 107-seat A318 is offered with the PW6000 and the CFM International CFM56. The PW6000-powered version has secured 113 firm orders, and according to P&W large commercial engines single-aisle aircraft marketing manager, March Young, competitions are under way at the moment for several contracts which could extend the orderbook by up to another 150 over the next 18 months.
The engine maker has also started a new phase of high-altitude tests of the first PW6000, X-872, in its Wilgoos test site in Connecticut to prove high-pressure compressor (HPC) stability at simulated altitudes of up to 44,000ft (13,400m) and cruise speeds of Mach 0.78. On-going tests will also evaluate redesigns made to the engine as a result of initial runs. These include a strengthened retaining ring in the HPC which was revised after the platform seal in the sixth stage "opened up" and parts were forced into the gas path.
Changes have also been made to the oil tank static draintank after oil began draining into the gearbox after each engine run. Other modifications being examined include a series of tests of three different fan blade configurations.
"We will be running tests on different blades and mapping the results, though structurally we are happy," says Young. The wide-chord fan, with 24 titanium blades, has passed crucial 0.68kg (1.5lb) and 1.14kg (2.5lb) bird strike tests, as well as a fan containment test. The revised blade will face a 2.72kg (6lb) bird ingestion test.
Test engine X-871, which has been used for initial high and low rotor stress surveys, is being prepared for new fan, low-pressure (LP) compressor and HPC stress tests in June. Engine X-873 is to continue endurance tests.
Source: Flight International
