Rubber Deicer Boot System

 Airline flying was hindered in the early days of aviation because of aircraft ice accumulation. Pilots did not dare fly into clouds where ice could exist. But with improved instruments and radio, and with the introduction of newer models of aircraft, flight into icing conditions did occur. And to remove the ice, the B.F. Goodrich Company developed a rubber deicer boot that was installed on the leading edges of the wings and the empen­nage. An example of just such an aircraft..

Principle Of Operation: A rubber boot containing several longitudinal tubes is fastened to the leading edge of the surface, and air from the discharge of the engine driven vacuum pump is passed through an oil separator to remove the oil that has been used to lubricate and seal the pump. Newer types of vacuum pumps do not need to use oil separators. This air is now passed through a timer-operated distributor valve into the tubes in a sequential manner. As can be seen  , the boot is installed on the leading edge of a wing with all of the tubes deflated. When they are deflated, suction from the suction side of the pump or from an ejector around the pump discharge line holds the tubes evacuated, so air flowing over the boot will not cause the tube to distort the shape of the leading edge of the wing. , the center tube is inflated and any ice that has formed over it will crack.

The center tube now deflates, , and the outer tubes inflate and push up the crack­ed ice so air flowing over the wing will get under it and blow it off of the surface. All of the tubes now deflate and are held tight against the boot by suction until the ice reforms, and then the cycle repeats itself. 

The cycle of operation causes the tubes to inflate in a symmetrical manner so the disruption of lift during the inflation will be uniform and will not

cause any flight control problems. The manufac­turer of the aircraft has determined by flight tests the proper cycle time for the operation.

The larger aircraft that use this type of deicing system have an electric motor-driven timer to operate solenoid valves that, when the system is turned on, will continually cycle the system through all of the tubes, and then provide the proper duration of rest time to allow the ice to form over the boots; then the cycle is repeated. Any time the tubes are not inflated, suction is applied to them as mentioned earlier.

A smaller aircraft deicing system , does not use the elaborate timer, but is turned on by the pilot when they detect an accu­mulation of ice on the leading edges that should be removed. When the deicing switch is turned on, the boots will cycle through one, two, or three operating cycles, depending upon the design of the system, and then the tubes will be connected to the vacuum side of the air pump to hold them tight against the leading edge.