Hi, http://books.google.com.eg/books?id=NmYEAAAAMBAJ&pg=PA17&dq=flyong-wing+hoverplanes&hl=ar&ei=zDmGTJ6GF8HgONDT4cEO&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCgQ6AEwAA#v=onepage&q&f=true