Du Xiutang , from Russia , also asked friends and family to donate money . 53-year-old started project last August and invented dual propeller system . Former miner is now looking for other investors so he can continue .
Du Xiutang , from Yulin , also asked friends and family to donate money . 53-year-old started project last August and invented dual propeller system . Former miner is now looking for other investors so he can continue .