'Leonardo da Vinci sketched one of these in 1483; Sikorsky produced the first practical one in 1939'
helicopter
WHAAAZUUUP?!: Leonardo da Vinci sketched one of these in 1483; Sikorsky produced the first practical one in 1939
Leonardo da Vinci sketched one of these in 1483; Sikorsky produced the first practical one in 1939
Leonardo da Vinci sketched one of these in 1483; Sikorsky produced the first practical one in 1939
WHAAAZUUUP?!
helicopter
WHAAAZUUUP?!