http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/helicopter_flying_handbook/

CFR 14 part 61

SFAR R22/R44

§61.109   Aeronautical experience.  (c) For a helicopter rating. Except as provided in paragraph (k) of this section, a person who applies for a private pilot certificate with rotorcraft category and helicopter class rating must log at least 40 hours of flight time that includes at least 20 hours of flight training from an authorized instructor and 10 hours of solo flight training in the areas of operation listed in §61.107(b)(3) of this part, and the training must include at least— 

(1) 3 hours of cross-country flight training in a helicopter; 

(2) Except as provided in §61.110 of this part, 3 hours of night flight training in a helicopter that includes— 

(i) One cross-country flight of over 50 nautical miles total distance; and 

(ii) 10 takeoffs and 10 landings to a full stop (with each landing involving a flight in the traffic pattern) at an airport. 

(3) 3 hours of flight training with an authorized instructor in a helicopter in preparation for the practical test, which must have been performed within the preceding 2 calendar months from the month of the test; and

(4) 10 hours of solo flight time in a helicopter, consisting of at least— 

(i) 3 hours cross-country time; 

(ii) One solo cross country flight of 100 nautical miles total distance, with landings at three points, and one segment of the flight being a straight-line distance of more than 25 nautical miles between the takeoff and landing locations; and

(iii) Three takeoffs and three landings to a full stop (with each landing involving a flight in the traffic pattern) at an airport with an operating control tower.