The angle between the longitudinal axis of the airplane fuselage and the airfoil chord line is called the angle of incidence. It is positive when the leading edge of the the chord line is higher than the trailing edge.Ive been studying Ribletts book and right now Im stuck, can someone please help me?? Im trying to figure out the incidence angle on an airfoil. Im trying to follow the instructions in the “Aircraft Performance Prediction but I can not figure out how to read Ribletts chart Figure IV-13 for the .25 Cldes and I do not understand what he is calling dimensional effects. Any help would be appreciated!!

There is some general information here.

http://download.aopa.org/epilot/2007/8083-25-chap3.pdf

Figure IV-13, in my copy, plots the relationship of the coefficient of drag to the coefficient of lift for the given airfoil at two different Reynolds numbers. Google Reynolds numbers. At constant airspeed, Reynolds varies directly with wing chord length.

BJC

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