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The main purpose of this research is to investigate distortion and duct total pressure loss at the duct exit (engine face) of a special S-shaped air intake at different simulated flight regimes with and without lip-screen installation. This air intake is supposed to be equipped with a micro jet engine.

Experimental investigations were performed by using a low subsonic close loop wind tunnel to simulate different flight regimes such as negative stall, cruise, shallow angle climb, steep angle climb and positive stall. In order to investigate flow behaviour along the duct length, static pressure changes were also measured. Test results were plotted in terms of total pressure contours and reduced results were tabulated. Static pressure results were also illustrated in different figures.

Results indicated that duct total pressure loss is within the acceptable range and is less than the 2 percent (allowable value) at various flight regimes, but installation of lip-screen has approximately reduced duct pressure recovery between 5 and 15 percent. Results also showed that mean distortion coefficient at duct exit is between 0.22 and 0.3, which is greater than the amount recommended by many jet engine producers.

It would be desirable to investigate the effects of flow control devices installed on this air intake in future researches.

It is highly recommended to practically examine any designed air intake to make sure it is geometrically optimized.

Current research developed an initial test bed for evaluation of the overall aerodynamic behavior of a previously designed special purpose S-shaped duct air intake. Obtained experimental results will help to analyze the internal flow characteristics of the current model as well as preparing data to compare with the future test results for improving its performance.