The measurement of the smoking characteristics of jet engines and jet engine components is necessary to evaluate the relative merits of proposed methods of smoke reduction, identify sources, and estimate the visibility of the exhaust plume. Several techniques have been employed by the General Electric Co. to collect data over a wide range of environment.
Techniques evaluated included optical systems, quantitative gravimetric system, and soiled tape methods. Many of the soiled tape methods of measuring smoke are compared, and a calculation procedure is described for making a direct comparison of any two soiled tape methods.
The soiled tape method used by General Electric to measure jet engine smoke is described in detail. The measurement system utilizes a GE spot meter which filters the smoke through Whatman paper and produces a smoke number that is based upon the diffuse reflection from the filtrate produced by filtering 0.3 cu ft of smoke through a square inch of filter paper.