Warming Up NATS R5D 50865 on Hickam Field
ex USAAF 42-72415.
The Pratt & Whitney R-2000 engine was essentially an evolved version of the R-1830, sharing many design elements but with some key modifications to enhance performance and adapt to different operational requirements. The most notable change was the increase in cylinder bore from 5.5 inches to 5.75 inches, while retaining the same 5.5-inch stroke. This change increased the engine’s displacement from 1830 cubic inches to 2000 cubic inches (32.8 liters).
In addition to the increased displacement, the R-2000 featured several other design modifications:
Crankshaft Bearings: The R-2000 used plain lead-silver main bearings instead of the roller bearings typically found in the R-1830. This change likely aimed at improving durability and possibly reducing manufacturing complexity.
Magneto Positioning: Unlike most R-1830 models, which had rear-mounted magnetos, the R-2000 had its magnetos mounted on the nose case. This alteration might have been made for easier maintenance or packaging considerations within the aircraft engine nacelle.
The R-2000 was designed to run on 87-octane fuel initially, as there were concerns about the availability of higher-octane fuels during World War II. However, these concerns proved unnecessary, as sufficient supplies of 100-octane and 100/130-grade fuels were available. As a result, the R-2000’s power output ranged from 1300 horsepower at 2700 RPM using 87-octane fuel to 1350 horsepower with 100-octane fuel, and eventually reached 1450 horsepower at 2800 RPM with 100/130-grade fuel.
Production of the R-2000 was carried out by both Buick and Pratt & Whitney. The engine was primarily used during World War II in the Douglas DC-4, which was converted into the C-54 Skymaster transport aircraft. While the DC-4/C-54 did not achieve the iconic status of the DC-3/C-47, it played a crucial role in transoceanic transport, serving as an executive transport for high-ranking officials and for cargo hauling. The R-2000’s reliability and performance made it a vital component of these aircraft during and after the war.