Accession Number : ADA298155

Title :   Effect of NACA Injection Impeller on Mixture Distribution of Double-Row Radial Aircraft Engine,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC

Personal Author(s) : Marble, Frank E. ; Ritter, William K. ; Miller, Mahlon A.

PDF Url : ADA298155

Report Date : 1945

Pagination or Media Count : 16

Abstract : Because the NACA injection impeller attacks the problem of fuel distribution in a fundamental manner, some success in all installations can be expected. The results of the present investigation apply, however, only to the injection impeller installed on a particular radial aircraft engine. Observations indicated that the engine using the injection impeller had better starting characteristics and a reduced frequency of backfire as compared with the engine using the standard spray bar. The injection impeller provides a simple and effective means of water injection and, because of the location of the fuel injection, reduces the probability of ice formation in the induction system. The significant results of the investigation may be summarized as follows: (1) Use of the NACA injection impeller markedly improved the fuel-air-ratio distribution for all engine powers and speeds investigated. Except for rich operation at rated power, the difference between the fuel-air ratios of the richest and leanest cylinders was reduced to approximately one-third (2) As a direct result of the improved mixture distribution, the maximum cylinder temperatures were reduced about 30 deg F and the temperature differences between the hottest and coldest cylinders were reduced to two-thirds their value with the standard spray bar. (3) No severe decrease in supercharger pressure ratio resulted from fuel injection near the impeller outlet; a reduction from 1.71 to 1.60 was the greatest encountered during the investigations. (KAR) P. 15

Descriptors :   *AIRCRAFT ENGINES, *FUEL INJECTION, *IMPELLERS, IONS, INJECTION, TEMPERATURE, PROBABILITY, ICE FORMATION, CENTRIFUGES, MIXTURES, CYLINDRICAL BODIES, INSTALLATION, FUEL AIR RATIO, RATINGS, POWER, STARTING, SPRAYS, SPRAYERS.

Subject Categories : Aircraft
      Reciprocating and Rotating Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE