PWC: Roomier fuselage key for next generation turboprop

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Pratt & Whitney Canada this summer will begin assembling portions of its next-generation turboprop engine in anticipation of a launch platform for a clean sheet 90-100-seat turboprop potentially as early as 2012.

"Most sales today are for 70-seat aircraft," says Richard Dussault, P&WC vice-president of marketing. "We definitely see a place for 90- to 100-seat aircraft and that's where we're aiming for with a 5,000-7,000shp engine. We could easily do 8,000shp as well."

Rather than linear extensions of current product lines dominated by ATR and Bombardier aircraft powered by PWC engines, Dussault says there's a "clear push" for aircraft that are more spacious in cabin size than today's turboprops, a trend exhibited in the evolution from small-cabin first generation regional jets to the larger Embraer EJets and Bombardier CSeries families.

"The size of the aircraft relatively speaking might be a bit larger than today's turboprop, with larger overhead bins," he adds.

In terms of speed and altitude, Dussault says 300-350kt (555-647km/hr) is the "most likely goal of that market" with similar cruise altitudes to today's turboprops - in the mid-20,000ft (6,096m) range.

Fastest in today's turboprop fleet is the Bombardier Q400 with a maximum cruise speed of 360kt. The 68-78-seat aircraft is powered by two Pratt PW150A engines, each rated at 5,070shp (3,780kW), and connected to six-bladed Dowty Aerospace propellers.

"The big question is speed," says Dussault. "To preserve the economy of turboprop, you have to have the right speed. Though higher speed gives longer routes and more turns for the aircraft per day, it comes with higher fuel costs. When turboprops became very popular in end of the 1990s, [lower] speed was the tradeoff."

PWC is working with sister company Hamilton Sundstrand to develop an integrated propulsion system offering which will include the propeller, engine, nacelle and associated components. However Dussault says PWC will offer an engine-only option if a launch airframer decides to perform that work in-house.

Dussault expects the clean sheet aircraft to have "sixed-bladed or more" propellers that use "conventional" propeller technologies. "A lot of the technology will come in the way we integrate the engine and propeller control into single integrated system," he adds. Target reduction in fuel burn for the centreline engine is 20%.

Dussault says PWC will be ready to launch the new engine next year, timing that suggests a possible position on the 90-seat turboprop that ATR partner Alenia says it is committed to developing. Bombardier has been considering a derivative of the Q400 for the 90-seat sector.

Meanwhile, PWC is building a prototype engine which Dussault says will be ready for full-up testing next year, probably in Montreal. Dussault says the company has received "some raw materials" for the engine and is starting detailed manufacturing, with the first compressor unit to be ready for testing potentially later this year.

Once a launch customer is identified, PWC, per its usual process, will build 8-10 test engines and begin a flight test campaign on the company's Boeing 747SP testbed from its Mirabel facility. The most recent new engine test campaign for PWC took place in 1998 with the certification of the Q400's PW150 engine on the company's Boeing 720 testbed, an aircraft that is being retired.