PW120

Pratt & Whitney Canada PW120

The PW120 is the founding member of Pratt & Whitney Canada's PW100 turboprop family — one of the most commercially successful engine families in regional aviation history. Rated at 2,000 shaft horsepower (SHP), the PW120 entered service in 1984 on the de Havilland Canada Dash 8-100, marking a generational leap in regional turboprop performance and efficiency over the engines it replaced. Although no longer in production, the PW120 established the architecture and design philosophy that would underpin 60-plus variants serving millions of passengers annually.

Technical Specifications

Design and Architecture

The PW120 introduced a free-turbine, two-spool design that would define the entire PW100 family. The gas generator (core) runs at its own optimum speed, while a separate power turbine drives the propeller reduction gearbox. This arrangement allows the propeller speed to be optimized for efficiency independently of the core thermodynamics — a fundamental advantage over single-shaft turboprop designs of the era.

Compression is achieved through centrifugal compressor stages rather than axial stages, a Pratt & Whitney Canada hallmark. Centrifugal compressors are more robust and tolerant of foreign object ingestion, and they maintain higher efficiency across a broader operating range — critical for regional operators who frequently fly in challenging environments including icing conditions and hot-and-high airports.

The PW120 also provides bleed air for cabin pressurization, anti-icing, and environmental control systems, a standard function for turboprop powerplants on pressurized aircraft like the Dash 8.

Historical Significance

The PW120's 1984 entry into service on the Dash 8-100 launched the regional turboprop renaissance of the 1980s. Its combination of reliability, fuel economy, and modernity compared to older Dart and TPE331 engines convinced airlines that turboprops could be genuinely competitive on routes up to 400 nautical miles. The engine's success attracted ATR as a second launch customer for derivatives, creating the commercial foundation for the entire PW100 program. Every subsequent PW1xx variant — from the PW127M to the PW127XT — traces its lineage directly to the PW120's core architecture.