THREE types of systems are used to give protection against the formation of ice on airplanes: mechanical, chemical, and thermal; the thermal systems being the most successful and the most widely used.
The most satisfactory method of ice prevention, for instance, in that most essential accessory, the carburetor, is by heating the carburetor walls and throttle.
Similarly, surface heating appears to be the best way of protecting the propellers, wings, and empennage from the formation of ice.
Heated air flowing in the passage between the panes of a double windshield is also most successful for keeping the pilot's windshield clear.
Despite the use of such improved methods of ice prevention, however, full benefit cannot be realized from their use until radio facilities and blind landings have been developed further, for flights must now be cancelled because of limited visibility even if icing conditions do not prevent flight.