eVader 6D
grgress you know the rest  ..............research
info@gressaero.com  .........all other inquiries
eVader 750
Educational video: Propellers as
CMGs and 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 (OAT) paper AHS - Gress
Gyroscopically Controlled Air Vehicle - Thorne
Multirotor UAV with Tilting Rotors - Segui-Gasco
UAV having Two Tilting Rotors - Kendoul et al
Discovery Channel (Daily Planet) segment on Gary's aircraft and their control (2007)
Nymbus 650
Only two rigid, non-cyclic propellers are
required for hovering an aircraft if they are
treated as
CMGs (control moment
gyroscopes) and momentum wheels
The inertial control moments produced do
not depend on distance from the aircraft
center of mass and, of course, are
independent of the atmosphere.  These
aircraft are even fully controllable about all
three axes in outer space,
Related theses and papers:
Enhanced Aircraft Hover Control
using Propeller Dynamics
Gary's artwork at Fine Art America
Nymbus composite, 2011 (5 min)
Gary's artwork on Facebook
Gary Gress
University of Calgary
Passively Stabilized VTOL Aircraft - Gress  MSc
Nymbus at U of C  2013 (1 min)
Nymbus over lake, 2011 (2 min)
Machined aluminum rings attached to commercial propellers to increase their moment
of inertia and
allow self-stabilization of the aircraft in pitch and roll, i.e., no electronics.
(April 2015).  Inset shows preliminary proof-of-concept test rig with plastic rings.
The team of fourth-year Mechanical Engineering students at the University of
Calgary responsible for the design, analysis, construction and testing of the
inertial rings.  From left to right: Austin Mireault, Derek Chen, Brendyn Stone,  
David Dyck, Jovana Cuzovic, Jeff Woolsey.  (April 2015)
Rigid-Propeller Bicopter VTOLs
bicopters in production:
Ringed-propeller research: