In the mid 1980’s, the US Army launched a competition for a new primary training helicopter to replace the TH 55. The specification called for a light single engine turbine powered machine. Schweizer responded by taking their proven Model 300C, installing a de-rated version of the Rolls Royce 250-C20 turbine engine, upgrading the transmission, increasing the size of the cabin and increasing the maximum take off gross weight. This and some other changes resulted in the Model 330. Bell Helicopter won the competition
with a version of the Bell 206B3 and Schweizer focused its marketing efforts on the civilian market. In 1994, increasing the main rotor size and increasing the take off gross weight upgraded the helicopter further. This model is referred to as the 300SP. In 2000, the Model 333 was introduced. This model takes the 330SP, increases both the diameter and chord of the rotor blades and provides a significant increase in take off gross weight. Many of the upgrades made with the 330SP can be installed on the 330 and similarly 333
upgrades can be installed on the 330SP.
The Schweizer 333 is a light single-engine turbine helicopter with a three-bladed, fully articulated rotor. It uses a de-rated Rolls Royce 250-C20W engine. Power is transferred from the engine to the transmission through a multiple V-belt and pulley arrangement. A two bladed tail rotor provides directional control. Compared to the Schweizer 300C, the cabin and tail boom have been made much more aerodynamic. The cabin has room for a pilot plus two or three passengers.
Development of the 330 was launched in 1987, first flight occurred in 1988 and certification was obtained in 1992 with first deliveries taking place the next year. The 333 were certificated in 2000 and deliveries commenced the same year.
Sikorsky Helicopter bought Schweizer Aircraft in 2004. In 2009, the helicopter line dropped the Schweizer name, and is now known only as Sikorsky.