Clear Ice Research Paper

The two types of ice that are encountered during flight are clear and rime. Clear ice is formed when the remaining liquid fragments of the water drop flows over the aircraft surface, constantly freezing as a smooth layer of solid ice. Forming occurs when droplets are bigger, such as in heavy rain or in thunderstorm clouds. Clear ice is solid, hard, heavy, and cohesive. Removing it by deicing equipment is very challenging.

Rime ice is formed when water droplets are microscopic, such as those in atmospheric clouds or light shower. The liquid portion remaining after initial impact freezes swiftly before the water drop has time to expand over the surface of an aircraft. The small frozen water droplets traps air which gives the ice a white color. Rime ice is lighter than clear ice. However, aerodynamic efficiency of airfoils, reducing lift and increasing drag due to its irregular shape and rough surface. Rime ice is breakable and is easier to remove than clear ice.
Ice particles becomes mixed in clear ice, building a very rough amassing sometimes on leading edges. Whenever there is visible moisture in the air and temperature is near the freezing point ice may be expected to form. Carburetor icing is an exception icing, which may occur during warm weather without any visible moisture