Rolls-Royce Corp.’s Indianapolis operations will manufacture 78 turboshaft engines for U.S. Navy and Air Force helicopters under the terms of a mammoth $160.6 million military contract the government awarded late last week.

The Navy will account for 62 engines in the order for its MV-22 Osprey tilt-rotor transport, for a total of $128 million. The Air Force will take the remaining 16 engines for $32.5 million. Work is expected to be completed by December 2011.

The Department of Defense announced the contract on Dec. 18. Rolls-Royce officials were not immediately available for comment.

The work will be performed at Rolls Royce’s Indianapolis manufacturing facility, which employs about 4,300—making the British aerospace firm the city’s second-largest manufacturer behind Eli Lilly and Co.

The local operation has accumulated several meaty military contracts in recent months. In November, it received an $11.1 million contract to make gas turbine engines for the Army’s OH-58D Kiowa reconnaissance helicopters and an $8.5 million contract to provide spare engine parts for the Air Force’s C-130J military-transport aircraft.