Nelson H-59
The Nelson H-44 was an American single ignition, four-cylinder, horizontally opposed, direct drive, two-stroke aircraft engine that was developed by the Nelson Engine Company for use in motorgliders. It was designed in 1945 and a specially designed motor glider was created by Hawley Bowlus to utilize the engine, the Bowlus/Nelson Dragonfly.
The engine was not certified. Under the regulations then in place in the USA for gliders, a certified auxiliary power glider could be flown with a non-certified engine and propeller. The engine is instead described on the Dragonfly type certificate. The four-cylinder engine ran on a 12:1 mixture of 80 octane gasoline and SAE 30 oil. It was equipped with a single Carter WA1 carburetor and a recoil starter that could be used for inflight starts.
Employed in the Dragonfly, the H-44 proved underpowered, which led to the design of the H-49 version. This upgraded design had E-225 cylinders giving a 2.375 in (60 mm) bore and 2.75 in (70 mm) stroke, producing 28 hp (21 kW) at 4000 rpm.
A further development in 1949 was the H-59 with increased bore of 2.625 in (66 mm) and an output of 40 hp. The engine was designed for use in the Nelson Hummingbird glider, where the engine could be retracted in flight. It was tested in the Bensen Gyro-Copter, an experimental Rotocycle for the U. S. Navy and the Pawnee flying platform for the U. S. Army. This is the model on display at the Museum.
The engine family was not a success and few were produced.
Technical Details: (H-59)
Engine Type: Four-cylinder, two-stroke, single-ignition
Power: 40 hp (29 kW) at 4000 RPM
Weight: 60 lb (27 kg)
Cylinders: 2.625 in (66 mm) bore and 2.75 in (70 mm) stroke
Displacement: 60 cu in (0.975 litres)
Compresson ratio: 9:1