You may wish to consider tilt-rotor patents; at
http://www.uspto.gov/patft/index.html

A few are;

Sikorsky's Variable diameter rotor blade actuation system ~ 6,019,578

VTOL airplane with only one tiltable prop-rotor ~ US 6,382,556

Optimum speed tilt rotor ~ US 6,641,365





wrote in message
Hey guys, I am thinking on giving a seminar on Tilt-Rotor Aircrafts as
a part of my Mechanical Engineering Final Year Syllabus. However all
the info i found on the net (read Google) deals with the BA-609 and the
Osprey specifically and not with the concept of Tilt Rotors. Can anyone
help me out? The seminar has to be about 20 pages long.