EntityQ3785791· pop 6· linked from 65 articlesHirth HM 504Sign in to save1930s German aircraft engineConnectionsInternational Standard Book NumberEntitygas turbineEntityoctane ratingEntitytwo-stroke engineEntityaircraft engineEntityreciprocating engineEntitycompression ratioEntityengine displacementEntityHeinkelEntityvalvetrainEntityBü 131 JungmannEntityaerospace manufacturerEntitypower-to-weight ratioEntitystrokeEntityBü 181 BestmannEntityboreEntityelektronEntityAr 79EntityKlemm Kl 35Entitypower densityEntityCategories1930s aircraft piston enginesAircraft air-cooled inline piston enginesHirth aircraft enginesInverted aircraft piston enginesStraight-four engines