The Nelson H-44 is an American single ignition, four-cylinder,

horizontally opposed A flat engine is a piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct from the less common opposed-piston engine design, wh ...

, direct drive,

two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of ...

aircraft engine that was developed by the Nelson Engine Company for use in motorgliders.

Design and development

The H-44 was designed in the period following the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

and a specially designed motor glider was created by Hawley Bowlus to utilize the engine, the Bowlus/Nelson Dragonfly. The engine was not

certified Certification is the provision by an independent body of written assurance (a certificate) that the product, service or system in question meets specific requirements. It is the formal attestation or confirmation of certain characteristics of a ...

. 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. 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 A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meteri ...

and a recoil starter.

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.Said, Bob: ''1983 Sailplane Directory,

Soaring Magazine ''SOARING'' is a magazine published monthly as a membership benefit of the Soaring Society of America. It was first published in 1937. The headquarters is in Hobbs, New Mexico. The magazine's article topics include safety issues and accounts of in ...

'', page 118. Soaring Society of America, November 1983. USPS 499-920

Variants

;H-44 :Original design with a bore and stroke, producing at 3900 rpm. ;H-49 :Upgraded design with E-225 cylinders giving a bore and stroke, producing at 4000 rpm.

Applications

* Bowlus/Nelson Dragonfly

Specifications (H-44)

References