Often fascinated because of the strategy of flight—he even sketched out crude concepts for a parachute as well as a helicopter—the artist and inventor’s notebooks specially reference his tries at building a design airplane out of parchment. ( Critics argue that China's C919, the plane produced by state-owned business, COMAC, https://telegram-chinese-version60471.bloguerosa.com/28024763/manual-article-review-is-required-for-this-article