LOS ANGELES — Flight tests of a fuel-saving upgrade to the Rolls-Royce T56 are set to begin at Edwards AFB, Calif., in July.

The modified engine will be fitted to an Air National Guard-operated Lockheed Martin C-130H and is aimed at demonstrating flying qualities data as well as verifying overall improvements in performance. Flight tests are expected to run through August.

Tom Hartmann, Rolls-Royce vice president for customer business, says flight tests mark the final qualification stage for the upgrade kit, which is attracting interest from domestic and international C-130 operators. The T56-15 Series 3.5 “enhancement” kit originally was launched in response to U.S. government calls for reduced dependence on foreign oil, and if adopted could extent the operational life of the C-130H to 2040.

Hartmann says the kit is designed to reduce fuel burn by 8% and increase overall engine life by around 10%. Alternatively, as a trade-off against the extended-life option, he adds the upgrade also can be used to generate up to 9% more power for improved hot-and-high performance. The overall performance of the kit was recently verified in a test cell in Indianapolis, Hartmann says.

The kit, which can be fitted as part of a standard overhaul, consists of remanufactured compressor blades, single-crystal first-stage high-pressure turbine blades, and aerodynamically redesigned blades and vanes throughout the low-pressure turbine. According to an Air Force analysis report, the Series 3.5 upgrade could contribute to overall long-term savings of $3.5 billion over the lifetime of the fleet. Rolls has previously stated that the kit also could be potentially adapted for the T56-14 version that powers the P-3 maritime patrol aircraft.

Flight tests also will assess if the engine can deliver on estimates that it will increase the range of the C-130H with a 20,000-lb. payload to more than 3,180 nm, from 2,845 nm, compared with a standard Series 3-powered aircraft under identical conditions.