The Praga B2 was a low powered

aero engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Aircraft using power components are referred to as powered flight. Most aircraft engines are either piston engines or gas turbin ...

suitable for very light aircraft. It dates from the mid-1930s.

Design

The Praga B2 was a dual ignition, air-cooled horizontal twin producing 40

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are t ...

(30 kW) aimed at lightweight aircraft. It was a higher

compression Compression may refer to: Physical science *Compression (physics), size reduction due to forces *Compression member, a structural element such as a column *Compressibility, susceptibility to compression * Gas compression *Compression ratio, of a ...

version (6.7:1 from the earlier 5.72:1) of the original and otherwise very similar Praga B, which provided 36 hp (27 kW). Its cylinders were machined from alloy

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

forgings and had

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

alloy heads. The pistons were of aluminium alloy, with three compression rings and one scraper ring. The connecting rods were of nitrided steel, with divided big ends and

bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...

bushes at the little ends. The one piece

crankshaft A crankshaft is a mechanical component used in a reciprocating engine, piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating Shaft (mechanical engineering), shaft containing one or more crankpins, ...

was also formed from nitrided steel and had two main roller bearings and a single ball thrust bearing. The single piece

crankcase A crankcase is the housing in a reciprocating engine, piston engine that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block. Two-stroke engines typically use a crankcase-compression design, res ...

was cast from an aluminium alloy. 135 units in all, including B and B2 variants were built.Praha history
Jowett Cars Ltd. of Idle,

Bradford Bradford is a city status in the United Kingdom, city in West Yorkshire, England. It became a municipal borough in 1847, received a city charter in 1897 and, since the Local Government Act 1972, 1974 reform, the city status in the United Kingdo ...

in the UK obtained a licence in 1936 to build the Praga B engine, for installation into the licence built Hillson Praga. Immediately after the end of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

the Praga B2 was on display at the 1946 Paris Air Show.Small engines at Paris Show ''Flight'' 21 November 1946
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Applications (B & B2)

* Alaparma A.M.10 Tucano * AVEX Yakstas Racer Yakstas LV-X095

* de Schelde Scheldemeeuw *

de Schelde Scheldemusch The de Schelde Scheldemusch was a single-seat pusher biplane designed in the Netherlands to be easy and safe to fly. It was one of the first light aircraft to use a tricycle undercarriage. Despite a sales campaign in the UK, only six were built, ...

* Hillson Pennine * Mignet Flying Flea * Praga E.114/Hillson Praga

Design

Applications (B & B2)

Specifications (B2)

See also

References

Further reading