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"It is possible that enough cloth or cloths somewhere in or at the entrance of the carburetor air system could have been present during take-off to restrict the carburetor air flow sufficiently to cause the engine to lose power."
Careful consideration was given by the Board to the possibility suggested by this report, i.e., that enough cloth or cloths could have been present in or at the entrance to the air induction system during take-off to restrict the carburetor airflow and cause the engine to lose power.
The air induction system to the carburetor of NC 13359 consisted of two air ducts, one for cold air and one for hot air. The opening to the air stream of the cold air duct was located between the No. 7 and No. 8 cylinders on the upper side of the engine, and faced forward. It was about 7 inches x 3 inches and was covered with a wire screen of ½ inch mesh to prevent foreign materials from being drawn into the duct and carburetor. The cold air duct extended backwards from this opening. The opening of the hot air duct was located inside the nacelle near the exhaust manifold and was covered with a wire screen of ⅛ inch mesh to prevent foreign materials from entering the duct and carburetor. These two ducts converged in a common tube a short distance below the carburetor at a point where a mixing valve was installed. This mixing valve was adjustable from the cockpit so that hot or cold air might be used to provide the proper temperature of the mixture and to safeguard against possible carburetor icing. The common tube extended upwards from the mixing valve to a grid directly beneath the carburetor. This carburetor grid was made of steel with apertures ½ inch x ½ inch.
