What was the name of Rolls-Royce’s first turboprop engine to enter production?

Rolls-Royce’s first turboprop engine to enter production was the Rolls-Royce Dart.

The Dart originated in the late 1940s as Rolls-Royce developed gas-turbine power for propeller-driven aircraft. It was a free-turbine turboprop, meaning the turbine driving the propeller was mechanically separate from the gas generator. That arrangement helped provide useful flexibility for aircraft such as the Vickers Viscount.

The Dart’s success made it one of the defining engines of the first commercial turboprop era. It powered not only the Viscount but also later aircraft including the Fokker F27 Friendship, Handley Page Herald and Grumman Gulfstream I.

The answer is sometimes confused with the Proteus or Tyne because both were important Rolls-Royce turboprops. The Proteus was developed for larger aircraft, while the Tyne was a later, more powerful engine. The Dart’s association with the Viscount is its best-known legacy.