Nelson H-44

The Nelson H-44 is 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.[1]

Nelson H-44
Type	Two-stroke aircraft engine
National origin	United States
Manufacturer	Nelson Engine Company
Designed by	Ted Nelson
Major applications	Bowlus/Nelson Dragonfly
Produced	circa 1947

Design and development

The H-44 was designed in the period following the Second World War and a specially designed motor glider was created by Hawley Bowlus to utilize the engine, the Bowlus/Nelson Dragonfly.[1]

The engine was not certified. Under the CAR 5 regulations then in place in the US 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.[1]

The four-cylinder engine runs on a 12:1 mixture of 80 octane gasoline and SAE 30 oil. It is equipped with a single Carter WA1 carburetor and a recoil starter.[1]

Operational history

Employed in the Dragonfly the H-44 proved underpowered, which led to the design of the H-49 version. The engine family was not a success and few were produced.[2][3]

Variants

H-44

Original design with a 2.25 in (57 mm) bore and 2.75 in (70 mm) stroke, producing 25 hp (19 kW) at 3900 rpm.[1]

H-49

Upgraded design with 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.[1]

Applications

• Bowlus/Nelson Dragonfly[2][3]

Specifications (H-44)

Data from FAA Type Certificate Data Sheet[1]

General characteristics

• Type: Four-cylinder, two-stroke, single-ignition aircraft engine
• Bore: 2.25 in (57 mm)
• Stroke: 2.75 in (70 mm)
• Displacement: 44 cubic inches
• Dry weight: 40 lb (18 kg)
• Designer: Ted Nelson

Components

• Fuel system: Carter WA1 carburetor
• Fuel type: 80 octane gasoline
• Oil system: premixed oil in fuel, SAE 30 oil mixed at 12:1 fuel to oil
• Cooling system: air
• Reduction gear: none

Performance

• Power output: 25 hp (19 kW) at 3900 rpm
• Compression ratio: 9:1

See also

• List of aircraft engines

References

1. Federal Aviation Administration (April 1947). "Aircraft Type Certificate Data Sheet GTC19" (PDF). Retrieved 10 March 2011.
2. Activate Media (2006). "Dragonfly Bowlus Nelson". Archived from the original on 15 July 2011. Retrieved 10 March 2011.
3. Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 118. Soaring Society of America, November 1983. USPS 499-920