Engine Alliance hopes to roll out a retrofit kit for its GP7200 engine by year-end. The U.S.-based partnership between GE Aviation and Pratt & Whitney is targeting at least a 1 percent improvement in fuel burn for the powerplant, which powers around half the fleet of Airbus A380 widebodies.
Ahead of this week’s Dubai Airshow, Engine Alliance president Dean Athans told AIN that the company has yet to precisely determine exactly which upgrades should be included in the new kit (in terms of the value they deliver to operators) and at what cost. It also has yet to determine how the remaining research and development work will be funded as it attempts to offer upgrades that would be available both for new production engines and as retrofits.
One item that has been successfully evaluated is a durability upgrade for the GP7200’s high-pressure turbine (HPT). Contrary to its early concerns, Engine Alliance has found that this has not had a detrimental impact on the engine’s performance. In fact, it has slightly improved power output by increasing the flow of cooling air through some gaps in the HPT.
Also close to approval is an upgrade that uses bleed air from the compressor to cool the HPT case. This improvement, which is achieved through software changes, also reduces the exhaust gas temperature.
The Engine Alliance engineering team has developed improved lobe-grinding techniques for the GP7200’s advanced HPT stator. “This creates better clearances during the cruise phase of flights and further incremental benefits to overall performance,” explained Athans.
In July, an engine fitted with the new HPT configuration completed endurance testing that ran for 2,500 cycles at temperatures that simulated 3,500 cycles. This testing also used a dust rig to analyze how the turbofan copes with dust ingestion—a significant concern for operators based in the Middle East.
Looking to further potential improvements for the GP7200, Athans said that Engine Alliance is studying technologies developed by its parent companies for the GEnx, Leap and Geared Turbofan (GTF) engines. These upgrades might include a new stage-one HPT blade and new blade-tip technology in stage two (from the GE9X engine). Also under consideration is a new HPT stage-one shroud made from ceramics and new lower pressure turbine airfoils based on those developed by Pratt & Whitney for the GTF (but adapted to accommodate the GP7200’s slower-spinning LPT).
“The earliest the new package could be available would be around year-end,” said Athans. “We want to create an upgrade kit that is efficient for our customers at the right price.”
Meanwhile, Engine Alliance (Stand 1246) has created a maintenance burden index for the GP7200 to help work with airlines, the better to manage and improve the efficiency of supporting the engine in service. This initiative was prompted by the fall-out from earlier upgrades that slightly increased the maintenance burden.
As of last month, there were 438 GP7200 engines in service on 96 A380s worldwide. These have logged more than 4.6 million flight hours and 610,000 cycles.
In April, Emirates Airline opted to have its next batch of 50 A380s powered by Rolls-Royce Trent 900 engines, instead of the GP7200s selected for its existing fleet. The $9.2 billion deal covers 200 Trent 900s for the A380s. Deliveries are due to begin in 2016.
