.....as a "vague " but useful expression , in my opinion , can be defined in a more reliable and disposing text " manner " at :
http://www.peswiki.com/index.php/Direct ... ity_Motors
CLAIMS...Preface...
"For a rotary device to <work> , it has to achieve a full 360 rotation , with acceleration between each complete turn".
This is alike an inverted pendulum beginning his gravity fall with a starting velocity , each turn..
...so , we need a certain " behind push"/inertial thrust , each complete turn , if we intend a continuous motion due to gravity fall and inertia.
As a science "licence" , a liberty taken to deviate from the common scientific language , in order to produce a perceptive image , it's as an up-down increasing "gravity power wave" , on a cosmic "shore"...we are living.
I like to call the gravity motor , in a concise image , as a "lively pendulum".
Al_ex
Simplicity is the first step to knowledge.