 The F.5 (standing for Fabrizi 5) had a two-row 14-cylinder Fiat A.74 R.C.38 radial engine, unlike its cousin the F.4, which Fabrizi and his design team intended to be powered by a water-cooled engine.The F.4 project was not pursued immediately because the Italian Air Ministry held its proposed engine in disfavor, but development of the F.5 continued.