Study relative wind and angle-of-attack: http://www.faa.gov/regulations_polic...lane_handbook/
It is also possible for a helicopter to experience effective-translational-lift (ETL) in a hover: http://www.faa.gov/regulations_polic...ying_handbook/

As for RC models, if you have a simulator try slope soaring, or dynamic soaring. Hot-liners actually prefer more wind....

CRRCsim is a great soaring program if you already have a USB Tx: http://sourceforge.net/apps/mediawik...itle=Main_Page