Designing a successful human-powered aircraft is difficult because a very large power to weight ratio must be achieved. This has been the reason why many of these aircraft use advanced composite materials in their construction.
d ɪ z aɪ n ɪ ŋ WORD_BOUNDARY ʌ WORD_BOUNDARY s ə k s ɛ s f ə l WORD_BOUNDARY h j uː m ə n p aʊ ə ɹ d WORD_BOUNDARY ɛ ɹ k ɹ æ f t WORD_BOUNDARY ɪ z WORD_BOUNDARY d ɪ f ɪ k ə l t WORD_BOUNDARY b ɪ k ʌ z WORD_BOUNDARY ʌ WORD_BOUNDARY v ɛ ɹ i WORD_BOUNDARY l ɑ ɹ d̠ʒ WORD_BOUNDARY p aʊ ə ɹ WORD_BOUNDARY t ə WORD_BOUNDARY w eɪ t WORD_BOUNDARY ɹ eɪ ʃ ɪ oʊ WORD_BOUNDARY m ʌ s t WORD_BOUNDARY b iː WORD_BOUNDARY ʌ t̠ʃ iː v d WORD_BOUNDARY ð ɪ s WORD_BOUNDARY h æ z b iː n WORD_BOUNDARY ð ə WORD_BOUNDARY ɹ iː z ə n WORD_BOUNDARY w aɪ WORD_BOUNDARY m ɛ n ɪ ə v WORD_BOUNDARY ð iː z WORD_BOUNDARY ɛ ɹ k ɹ æ f t WORD_BOUNDARY j uː s WORD_BOUNDARY ʌ d v æ n s t WORD_BOUNDARY k ə m p ɑ z ɪ t WORD_BOUNDARY m ə t ɪ ɹ i ə l z WORD_BOUNDARY ɪ n WORD_BOUNDARY ð ɛ ɹ WORD_BOUNDARY k ə n s t ɹ ʌ k ʃ ə n WORD_BOUNDARY