The Pobjoy R is a British seven-cylinder air-cooled radial aircraft engine designed and built by Pobjoy Airmotors.[1] Introduced in 1926, it was a popular engine for ultralight and small aircraft in the 1930s. A notable feature of the Pobjoy R was the propeller reduction gear which allowed the small engine to operate at more desirable higher speeds.

R
Preserved Pobjoy R at the Shuttleworth Collection
Type Piston radial aero-engine
Manufacturer Pobjoy Airmotors
First run 1926
Major applications BA Swallow
Comper Swift

The engine was license produced in Czechoslovakia by Walter Aircraft Engines as the Walter Mira.[2]

Variants

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Walter Mira R
License produced version of Pobjoy R.
Walter Mira I-R
Renaming of Mira R.
Walter Mira II-R
Developed version of the Mira R producing 95 hp (70 kW).

Applications

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Walter Mira

Engines on display

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A preserved Pobjoy R engine is on display at the Shuttleworth Collection, Old Warden, Bedfordshire.[citation needed]

Two Pobjoy R engines, one installed in the remains of Comper Swift (R222 / LV-FBA) will be soon on display at the National Aviation Museum in Buenos Aires Province, Argentina.[citation needed]

Specifications (Pobjoy R)

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Data from Lumsden.

General characteristics

  • Type: 7-cylinder air-cooled, radial, left-hand tractor
  • Bore: 3.03 in (77 mm)
  • Stroke: 3.43 in (87 mm)
  • Displacement: 173.05 cu in (2.84 L)
  • Diameter: 25.5 in (647.7 mm)
  • Dry weight: 135 lb

Components

  • Oil system: Dry sump
  • Cooling system: Air-cooled

Performance

See also

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Related development

Comparable engines

Related lists

References

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Notes

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Bibliography

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  • Guttery, T.E. The Shuttleworth Collection. London: Wm. Carling & Co, 1969. SBN 901319-01-5
  • Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.