Originally posted by purge98
Can Coanda effect be created by sucking air into the wing or is it only for exiting air?
Also can coanda effect give lift if there is no passing airflow for the exiting airflow to "Adhere to"? (Ie. in the hover with no downwash)
No and sort of yes respectively.
To the first, you can keep flow attached over a wing at radical angles of attack using upper-surface suction - acheiveing CLs in excess of 4.5, but this isn't Coanda effect.
To the second - there can't be hover without downwash. Sorry, but good ol' Isaac prevents this. However, if you have an aircraft with jet engines on the top of the wing and a reall big honkin' flap in the back cranked down to 60 degrees or so, the Coanda effect will be active even with zero flight speed, since the jet is still blowing over the curved top. However, I don't think you could ever achieve hover with a system like this. Many russian STOL transports used it, though. Big plane go up FAST!