While Convair (based in San Diego like the Classic Airliner Page) was quite successful with its piston powered CV-240/340/440 series of twins, it recognized as early as 1950 that turboprop engines ... offered some clear advantages over the "round engines". Instead of building a new plane, Convair decided that those very Convair-Liners could be re-engined instead. An experimental installation of Allison T56 engines into a CV-240 in 1950 was quite successful, but the first commercial conversion did not take place until 1954, and then with British Napier Elands.
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