home *** CD-ROM | disk | FTP | other *** search
/ Inventor Labs: Transportation / InventorLabs - Transportation.iso / mac / Builders / timeline.Dxr / 00237_Text_TFHELE.TXT.txt < prev    next >
Text File  |  1997-05-29  |  196b  |  3 lines
  1. 1843
  2. The Helicopter
  3. An early helicopter, designed by Sir George Cayley, uses two rotors for lift and two propellers for thrust. It is designed to take off and land vertically. It doesnΓÇÖt work.