High Quality Content by WIKIPEDIA articles! The Pobjoy Niagara is a British seven-cylinder, air-cooled, radial, aero-engine first produced in 1934, with an unusual offset-from-centre propshaft due to its engine reduction gearing. The Niagara was a popular engine for light and experimental aircraft. The entire series of Pobjoy motors were seven-cylinder radials with compact dimensions and very high rpm. The entire Pobjoy range was well regarded due to its small diameter, smooth operation, low noise and innovative engineering.