Dash 8 Q400 engines are twin PW150A turboprops. Learn their power rating, propeller pairing, controls and differences from earlier Dash 8s.
In real-world aviation, the De Havilland Canada Dash 8 Q400 is powered by two Pratt & Whitney Canada PW150A turboprop engines. Each is rated at up to 5,071 shaft horsepower for take-off and drives a six-bladed Dowty R408 propeller through a reduction gearbox. The Q400 name does not denote a different propulsion type.
What is the Q400 engine and propeller combination?
The complete installation pairs each PW150A engine with a large, slow-turning Dowty R408 propeller.
- Engines: Two Pratt & Whitney Canada PW150A free-turbine turboprops
- Maximum take-off rating: Up to 5,071 shp (3,781 kW) per engine; general references often round this to 5,000 shp
- Propellers: Six-bladed Dowty R408 composite propellers
- Propeller diameter: Approximately 13 ft 6 in (4.11 m)
The PW150A is the engine; the R408 is the propeller. Confusing those names is a common error. Published power is expressed in shaft horsepower because the engine turns a propeller shaft, so it cannot be compared directly with the pounds or kilonewtons of thrust quoted for a turbofan.
The propellers have variable and reversible blade pitch. Reverse thrust after landing comes from changing the blade angle—not from making the engine or propeller rotate backwards.
How does the PW150A turboprop work?
The PW150A burns fuel in a gas generator and uses the resulting gas flow to turn a mechanically separate free power turbine.
That power turbine drives the propeller through a reduction gearbox, allowing the internal turbine machinery to run much faster than the propeller. Most of the aircraft's useful thrust comes from the propeller rather than directly from the exhaust, which is why the PW150A is classed as a turboprop rather than a turbofan. Our primer on aircraft-engine operation explains the wider differences between piston, turboprop and jet installations.
Full-authority digital engine control manages engine fuelling and operating limits, while electronic propeller control governs blade angle and commanded propeller speed. The quoted 5,071 shp is a maximum take-off rating, not a guarantee that identical power will be available under every temperature, altitude and operating condition.
Do all Dash 8 models use PW150A engines?
No: the PW150A is specific to the larger Series 400/Q400 family, while earlier Dash 8 versions use lower-powered PW120-series engines.
| Dash 8 family | Typical engine family | Key distinction |
|---|---|---|
| Series 100/Q100 | PW120/PW121 | Original short-body Dash 8 |
| Series 200/Q200 | PW123 series | Short body with improved performance |
| Series 300/Q300 | PW123 series | Stretched earlier-generation model |
| Series 400/Q400 | PW150A | Larger, faster and substantially more powerful installation |
Exact suffixes vary among earlier airframes, which is why we use engine-family names for those models. The Q400 NextGen branding did not introduce a replacement engine; it retained the PW150A.
What does the “Q” in Q400 mean?
The “Q” was marketing shorthand for the quieter cabin produced by the Q Series' noise- and vibration-suppression measures.
It does not mean four engines, identify a propeller type or signify a special PW150A version. Dash 8-400, Q400 and DHC-8-400 family references describe the same basic Series 400 aircraft despite changes in manufacturer branding. Many individual aircraft are formally identified as DHC-8-402 variants.
Why can a simulated Q400 sound like another turboprop?
A flight-simulator sound set does not necessarily identify the engine being represented.
An add-on can correctly label the aircraft as PW150A-powered while reusing generic or substitute turboprop audio. Its aircraft description, flight-model power values and sound package are separate layers, and one can be accurate while another is simplified. Our FSX Q400 aircraft reference records the real PW150A designation and power rating for comparison.
The distinction is especially clear in the MSFS package documentation for the Q400, which identifies the real engine while explaining its substitute simulator sound set. When checking any add-on, do not use sound alone to decide which engine the real aircraft carries.