NACA-TN-1874nAn analysis of aircraft-carburetor design with emphasis on air-flow equations, and altitude- or density-compensation sys¬tems is presented. Several theoretically perfect methods of com¬pensating carburetors for density are developed and the resulting compensation equations are set up for air density sensed as a single variable and for air density sensed by separate indica¬tions of pressure and temperature.nAn approximation of the theoretical air-flow equation has been presented for carburetor use that has a maximum deviation of ±1.5 per¬cent from the theoretical equation. It has been found that the simplest means of compensating for the variation in air density is that of varying the area of the venturi as a function of air density; this method also offers the advantage of increased air-flow capacity at altitude. Air-side compensation, or variation of the effective venturi pressure drop, as used in present carburetors was found to be one of the more complicated methods.
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