T56 3.5 Engine upgrades and Winglets

[Jansen]

The Rolls-Royce series 3.5 development program for the T56 engine uses existing technologies from commercial and industrial variants, including compressor inlet housing, compressor blades, single crystal 1st stage turbine blade and compressor wheel knife seals. The changes don't require aircraft installation or interface changes, making 3.5 a low-risk technology solution for P-3 operators.

The updates improve engine fuel consumption, hot-day take off performance and turbine life. Rolls-Royce is in the last month of development for the 3.5 upgrades for the U.S. Air Force C-130H aircraft. Flight tests will be in 2011. The work done for U.S. Air Force aircraft will be leveraged for the P-3 fleet. Low rate production will begin later this year.

-From P-3 International Operators Support Conference

Compared with the gains realized for commercial airline applications, the performance benefits provided by wingtip modifications on the C-130 would be less. For one thing, the C-130’s wing is already very efficient because its aspect ratio of 10 is relatively high. Another reason for the lower gain in expected winglet efficiency is the C-130’s unswept wing with its lower tip loading. In addition, since winglets are more effective for longer ranges and with the higher wingtip loading realized at higher altitudes, the potential benefit of winglets for the C-130 is limited.

-Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft (2007)