EntityQ4650149· pop 5· linked from 42 articlesABC DragonflySign in to saveR-9 piston aircraft engineConnectionsWorld War IConceptcopperEntityInternational Standard Book NumberEntitydigital object identifierEntityRoyal Air ForceEntityresonanceEntitycarburetorEntityarmisticeEntitycrankshaftEntityScience MuseumEntityaircraft engineEntityradial engineEntityengine displacementEntityvalvetrainEntityoverhead valveEntitypower-to-weight ratioEntitystrokeEntityaerospace manufacturerEntityboreEntitySnipeEntityCategories1910s aircraft piston enginesABC aircraft enginesAircraft air-cooled radial piston enginesNine-cylinder engines