Cyclic, if you have looked at the web page Dave Jackson points you to you will probably now understand that your 1/3 and 2/3 concept and Nick's blowing air downwards are in fact the same. the 1/3 underneath the aerofoil produces pressure upwards and in doing so is deflected downwards by the blade - the 2/3 above the aerofoil is accelerated over the top (thus reducing it's pressure and sucking the blade upward) but continues to follow the shape of the blade and is spat off the trailing edge which is pointing downward. The overall effect is to deflect all the air downwards (giving the downwash) whilst producing a force (lift) upwards. When the next blade comes round a fraction of a second later the air it meets is already going downwards, and by the time the blades of your rotor have passed round a few times the air will be going straight down through the rotor which has induced the airflow through it (the big green Induced Flow arrow on the vector diagram).
Or think of it another way - a cubic metre of air weighs 1.225Kg (according to ICAO) so a 5000kg helicopter will have to move 6125 cubic metres of air constantly through it's rotor disc to hover! As Nick said, the bigger the rotorarea, the easier it is to achieve and a smaller rotor will have to work harder (using more power) and produce a more concentrated and powerful downwash.