Ma'anar ƙamus na kalmar "babban rotor" yana nufin ainihin juzu'in juzu'i na rotorcraft, kamar helikofta ko autogyro, wanda ke haifar da ɗagawa da kuma samar da babban tushen motsa jiki. Babban na'ura mai juyi yawanci ya ƙunshi babban taro mai jujjuyawar juyi a kwance tare da ɗigon rotor masu yawa waɗanda ke juyawa a kusa da mast ko cibiya. Babban injin na'ura mai juyi yana motsa shi ta hanyar injin (s) kuma yana haifar da ɗagawa ta hanyar samar da kwararar iska akan ruwan rotor, yana ba da damar rotor don samar da ɗagawa da samun jirgin sama. Babban na'ura mai juyi muhimmin abu ne na tsarin jirgin na rotorcraft kuma yana da alhakin samar da ɗagawa, sarrafawa, da kwanciyar hankali yayin aiki.