ɐ vˈɛɹɪəbəl sˈaɪkəl ˈɛndʒɪn vˌiːsˌiːˈiː, ˈɔːlsoʊ ɹᵻfˈɜːd tʊ æz ɐdˈæptɪv sˈaɪkəl ˈɛndʒɪn ˌeɪsˌiːˈiː, ɪz ɐn ˈɛɹkɹæft dʒˈɛt ˈɛndʒɪn ðæt ɪz dɪzˈaɪnd tʊ ˈɑːpɚɹˌeɪt ɪfˈɪʃəntli ˌʌndɚ mˈɪkst flˈaɪt kəndˈɪʃənz, sˈʌtʃ ɐz sʌbsˈɑːnɪk, tɹænsˈɑːnɪk ænd sˈuːpɚsˈɑːnɪk.
A variable cycle engine (VCE), also referred to as adaptive cycle engine (ACE), is an aircraft jet engine that is designed to operate efficiently under mixed flight conditions, such as subsonic, transonic and supersonic.