Since the first airplane flight in 1903, flying during the winter has been a problem. Ice formations on aircraft components such as wings, tails, and propellers can create dangerous situations in flight. During the 1920's and 1930's, when regular commercial aviation was in its infancy, the limitations of winter flying conditions were becoming more apparent. For example, attempts to establish transatlantic routes were hampered because the most direct routes were too dangerous to fly.
Icing became more apparent in the early years of America's involvement in World War II. Over 100 cargo planes were lost due to icing while flying over The Hump of the Himalaya Mountains between India and China.

Responding to a need expressed by the Army, Air Force and aircraft manufacturers, the National Advisory Committee for Aeronautics (NACA) instructed that an Icing Research Tunnel (IRT) be added to the Altitude Wind Tunnel (AWT) then under construction. The IRT was designed and constructed from 1942 to 1944 for 670 thousand dollars. The first icing test was performed on June 9, 1944. The airspeed in the test section can be varied from about 25 to over 400 mph at essentially a sea-level pressure.

Correspondent Jennifer Pulley took Destination Tomorrow Behind the Scenes to see how NASA Glenn's Icing Research Tunnel is helping engineers combat icing conditions on aircraft.

Additional Information
Icing Research Tunnel
http://www.grc.nasa.gov/WWW/IRT/index.html