The Wright R-3350 Turbo-Compound was a hybrid radial piston engine, which was used to power the Lockheed Super Constellation aircraft for civil airliners. It had eighteen cylinders, which was arranged in a twin row, and three power recovery turbines (PRT). Originally, it was developed from the Wright Cyclone R-1820 radial engine, which powered the Boeing B-17 Flying Fortress. It was massively produced by Curtiss-Wright Aeronautical Corporation after WW2.
Technical Description
The Wright R-3350 Turbo-Compound engine was composed of three sets of six cylinders, with a total of eighteen, and three power recovery turbines. The exhaust from these cylinders drove the turbines, which was connected to the engine crankshaft. The recovery of this otherwise wasted heat energy returned approximately 20 percent of the engine power.
Each set of six cylinders fed each of the three power recovery turbines, while a fluid coupling would feed rotational power of the turbine wheel to the crankshaft of the piston engine. Wright claimed it produced a 20 percent increase in engine power. This allowed to meet the design goal envisioned for the Super Constellation aircraft.
The 1049C Super Constellation aircraft was the first civilian version to use the Wright R-3350 Turbo Compound. To be precise it was the R-3350-872TCC18DA-1. Although not much larger than previous versions of the engine, this model was able to pump out a staggering 3,250 horsepower, driving a three-bladed propeller.
Below, exterior view of the Wright R-3350 Turbo-Compound engine. Exhaust from a set of six cylinders spun one turbine.
Below, a side view of the Wright R-3350 Turbo-Compound engine shows the exhaust ducting to two of the three power recovery turbines.
Installation of a Wright R-3350 Turbo-Compound engine on the Lockheed assembly line.
