History of Ice Protection System Design at Bell Helicopter 2003-01-2093

At the 1972 International Helicopter Ice Protection Conference it was noted that “New York Airways is shut down an average of one day/month in the winter due to forecast icing,” that “The Canadian Navy finds its operations restricted by 25 percent of the time off the coast of Nova Scotia in the winter,” and “approximately 7 percent of the helicopter training flights in the United Kingdom are curtailed due to forecast icing,”. This is quite significant, especially for low altitude rotorcrafts. Bell Helicopter manufactures and offers a wide range of helicopter models and Tiltrotors. Bell Helicopter has accumulated a large database of experience in research, design and development of ice protection systems for rotorcraft. All Bell Helicopter commercial models propulsion systems and most of the military models are certified/qualified for operation in icing. The model 412 and 214ST have also been tested at the NRC spray rig, behind the Helicopter Icing Spray System (HISS) and in natural conditions. The V-22 Tiltrotor has been tested behind the HISS, the NKC-135 icing spray tanker and natural conditions. The Bell/Agusta BA609 is following the tradition of rigorous testing set by the previous programs in its process of full FAA icing certification. This paper summarizes the many Bell Helicopter icing projects conducted throughout the years through flight test on helicopters as well as analytical and model testing research.