Quadcopter: Difference between revisions

The [[Convertawings Model A Quadrotor]] was intended to be the prototype for a line of much larger civil and military helicopters. The design featured two engines driving four rotors through a system of v belts. No tail rotor was needed and control was obtained by varying the thrust between rotors.<ref>{{cite web|url=http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%201564.html|title=1956 - 1564 - Flight Archive|work=flightglobal.com|access-date=13 March 2015}}</ref> Flown many times from 1956, this helicopter proved the quadrotor design and it was also the first four-rotor helicopter to demonstrate successful forward flight. Due to a lack of orders for commercial or military versions however, the project was terminated. Convertawings proposed a Model E that would have a maximum weight of {{convert|42000|lb|t|abbr=on}} with a payload of {{convert|10900|lb|t|abbr=on}} over 300 miles and at up to {{convert|173|mph|abbr=on}}. The Hanson Elastic Articulated (EA) bearingless rotor grew out of work done in the early 1960s at Lockheed California by Thomas F. Hanson, who had previously worked at Convertawings on the quadrotor's rotor design and control system.<ref>{{cite web|url=http://www.google.com/patents/US3261407|title=Patent US3261407 - Helicopter rotor system|work=google.com|access-date=13 March 2015}}</ref><ref>{{cite book|url=https://books.google.com/books?id=GgntoJiYek4C&q=Hanson+Elastic+Articulated+Rotor&pg=PA157|title=The Seventh International Conference on Vibration Problems ICOVP 2005|access-date=13 March 2015|isbn=9781402054013|last1=Inan|first1=Esin|last2=Kiris|first2=Ahmet|date=2007-01-20|publisher=Springer }}</ref>