Gary Gress
Gyroscopic Birotor Research
University of Calgary
Video: Nymbus test flight, July 2013
eVader 6D
email:  .........research/academic/institutional  ..........all other inquiries
eVader 750
Propellers as CMGs & momentum wheels
for 3D attitude control in air and outer space
Nymbus and eVader 6D on display at Ottawa's Aviation and Space Museum, 2012
Oblique Active Tilting paper AHS - Gress
Gyroscopically Controlled Air Vehicle - Thorne
Multirotor UAV with Tilting Rotors - Segui-Gasco
UAV having Two Tilting Rotors - Kendoul et al
Some of the aircraft designed by
Discovery Channel (Daily Planet) segment on Gary's aircraft and their control (2007)
(CMGs = control moment gyroscopes)
Nymbus 650
Nymbus at Lake of Two rivers, Ontario, Oct 2011

Only two rigid propellers are required for hover if they are
treated as CMGs (control moment gyroscopes) and momentum
wheels.  Gyroscopic moments arising from the propellers'
forced precession are an order of magnitude larger and faster
than the conventional thrust vectoring moments they

These new, dynamic moments are independent of distances to
the aircraft center of mass, and, of course, are independent of
the atmosphere.  Yes, they can fully control an aircraft about
the three axes in outer space, which translates to exceptional
maneuverability and gust resistance here on earth.
Related papers:
Dynamic Control with Propeller Gyroscopics
Gary Gress's Art