After completing more than 75h of testing of the fan and gearbox of its geared turbofan engine, Pratt & Whitney plans to start tests of the powerplant's first core by the end of 2009.
Since PW used an existing core from a PW6000 engine, the company had to configure the test powerplant used on the A340 with a bypass ratio of 11:1 instead of the planned ratio of 12:1 for the Bombardier CSeries.
Noting the slight drop was not a "big difference" Pratt & Whitney VP of next generation product family Bob Saia explains once you understand technology tested on the A340 you can "scale up or down pretty easily".
Speaking to ATI at the MRO Americas conference Saia says PW can take the noise signature of the engine used in the A340 tests "and then look at the design we have for the CSeries, and with that, take that data and either extrapolate it or interpolate it, depending on the measurement that we're taking, to go and do the engine properly for the CSeries".
The fan sized used for the A340 testing was 80-inches, and Saia says the value of those tests is "looking at the installation of the engine and nacelle on the pylon and how would you optimize it as it integrates to the wing or aircraft systems".
PW is "very comfortable now that we know how to best optimise a bigger fan, with a pylon" Saia explains, to keep the pylon weight down, to optimise the wing weights and also optimise both the air flowing through the engine and over and under the wing.
For the testing of the first PW1000G core, the company plans to use a test cell to place large fans in front of the core and draw air into the chamber "to bring the front end of that core to an engine operating condition", Saia says, adding heat and pressure will be added to the air.
He says those conditions allow for testing in a real engine environment to examine efficiency, stability and mechanical strength of the airfoils.