Pratt & Whitney Canada (P&WC) has revealed details of previously confidential work with NASA's Glenn Research Center on high altitude performance tests of a PW545 turbofan for possible development as an unmanned air vehicle (UAV) powerplant.

"We think we should get into the UAV market, so we are working closely with NASA to test the PW545", says PW500 series senior programme manager Maurice Weinberg. The objectives are to evaluate a commercial off-the-shelf, small high-bypass turbofan at altitudes up to 65,000ft (19,800m), investigate performance and operability under the range of conditions, and define a production UAV configuration.

The first phase of the programme - which complements a broader Pratt & Whitney initiative with Teledyne to enter the UAV market (Flight International 16-22 May) - was undertaken last year. With minimal modifications made only to the fuel control unit, a baseline PW545 engine was tested from 50,000ft to 65,000ft and M0.5 to M0.8. It also included a test at 70,000ft and M0.8.

P&WC says the engine performed well at high altitudes. "Before we ran it out with NASA, we flew it up to 45,000ft on our Boeing 720 testbed to see how it would operate up there. In the tests up to 70,000ft [made in a NASA test chamber], the thing didn't even burp," says Weinberg.

The next phase will test an optimised configuration. "We will look at how it works with more loads, as well as things like inlet distortion. It will include measurements of low Reynolds numbers and will be data we've never had before," he says.

Source: Flight International