Pratt & Whitney tightens grip on bizjet market with Gulfstream win

Pratt & Whitney Canada lifted the veil on its 16,000-pound-class PW800 engine, which has been selected to power the new Gulfstream G500 and G600 large-cabin business jets, thus finding a new application for its PurePower family. The engine manufacturer said that the PurePower engine brings major improvements in fuel burn and maintainability. The program is well advanced, as certification of the new turbofan is expected by year-end.

“We have nine engines in the development program,” Mike Perodeau, v-p of corporate aviation and military engines, told AIN on the eve of the NBAA show. These engines have run a combined 2,500 hours. This can be added to more than 4,400 hours of experience with the core engine, as the PW800 shares its high-pressure spool–an eight-stage compressor and a two-stage turbine–with the PW1500G that powers Bombardier’s CSeries. On the company’s Boeing 747SP flying testbed, the PW800 has run more than 250 flight hours in over 35 flights since April 2013, Perodeau said.

The 50-inch diameter fan is a titanium, single-piece design. Linear friction is used to weld the blades to the hub. The turbomachinery is the same on the two variants: the G500’s PW814GA (15,100 pounds of thrust) and the G600’s PW815GA (15,680 pounds).

Asked how the new Gulfstreams’ high-cruise speed influences engine design, Perodeau answered that the engine has to provide more thrust in cruise. “Speed is a factor of thrust and drag,” he pointed out.

This was one of the factors that led to the Gulfstream’s PW800 employing direct drive, rather than the geared turbofan design used by other members of the PurePower family that are intended for commercial aircraft such as A320neo, Bombardier CSeries, Embraer E2 and Mitsubishi MRJ.

Perodeau noted that his company is in charge of the integrated powerplant system and therefore has responsibility for nacelle aerodynamics.

Specific fuel consumption is reduced by “two digits” over previous-generation engines. The Talon X combustor yields “a double-digit margin” to anticipated CAEP/8 regulations for reduced nitrogen-oxide (NOx) emissions. It provides “ultra-low” levels of unburned hydrocarbons and smoke.

Pratt & Whitney Canada has designed the engine to be more efficient and ergonomic from a maintenance standpoint. The PurePower PW800 introduces a 10,000-hour time between overhauls and scheduled maintenance requirements are reduced by around 40 percent. Scheduled inspections are reduced by 20 percent.

Ease of access was a key driver in the design, resulting in four large access panels being provided in the nacelle, which is supplied by Nordam. Each panel is large enough for a technician to comfortably work inside the engine, and the lower panels incorporate steps for a safe foothold. It is also possible to remove the inner cowls for deeper access.

Numerous borescope ports are incorporated in the engine for internal inspections. Engine accessories are placed singly around the engine, rather than being stacked, allowing one to be removed in a typical time of less than 30 minutes.

Furthermore, the PW800 features a new Fadec system that offers expanded recording of engine parameters, in turn allowing more sophisticated fault analysis and trend monitoring. Pratt & Whitney Canada has yet to finalize its engine support plans and how retrieved in-flight data will be processed, but it is working on this support aspect as the engine moves toward a 2018 entry into service.

On Pratt & Whitney Canada’s turboprop front, Perodeau announced the PT6 family has reached the 400-million-flight-hour milestone.

Additional PT6 models or upgrades may be expected. Asked if one possibility would be to add a Fadec, Perodeau answered positively. “The Fadec would have to be developed for the engine and integrated at the aircraft level,” he said, but ultimately it would be a cost-benefit question.

(Thierry Dubois - Aviation International News)