The 673-hour private pilot, who reported having accumulated 120 hours in the same make and model helicopter reported that while departing on his third flight of the day, into the wind, when approximately 40-feet above ground level (AGL) the helicopter suddenly "veered" to the right. As the pilot responded by applying full left anti-torque pedal, the low rotor RPM warning horn sounded. The pilot then lowered the collective control and applied aft cyclic control. With the helicopter quickly settling, the pilot pulled-up on the collective control; however, he was not able to arrest the high rate of descent. The helicopter landed hard and managed to remain in the upright position. The pilot and two passengers were uninjured. The pilot reported that at the time of the accident, the temperature was 60 degrees Fahrenheit and the winds were from 300 degrees at 10 knots.