The growth variant AE 3007H engine was tested in a Northrop Grumman RQ-4 aircraft and both aircraft and engine performed in line with expectations.
The engine, which improves the turbine and fuel nozzles, began development in 2008.
"This is another major milestone for a system, which has been flying for 13 years and amassed more than 60,000 flight hours," said Stephen Fairbairn, Rolls-Royce vice president-Customer Business.
"We continue to enhance our engine performance and capabilities for our customers with these types of improvements."
The Block III enhancement provides significant increases to the life of the turbine and nearly doubles its time on wing. It will become the production configuration for U.S. Navy MQ-4C Broad Area Maritime Surveillance Unmanned Aircraft System and the Air Force Global Hawk program, as well as future variants.
The RQ-4 is powered by a Rolls-Royce AE 3007H turbofan engine.
Rolls-Royce made the announcement at the annual Air Force Association Air and Space Conference near Washington.