Nelson H-44

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

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]

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

References

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

[GTC19-1] ^ ^a ^b ^c ^d ^e ^f ^g Federal Aviation Administration (April 1947). "Aircraft Type Certificate Data Sheet GTC19" (PDF). Retrieved March 10, 2011.

[SD-2] Activate Media (2006). "Dragonfly Bowlus Nelson". Archived from the original on July 15, 2011. Retrieved March 10, 2011.

[SoaringNov83-3] Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 118. Soaring Society of America, November 1983. USPS 499-920

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