1. MAE 3241: AERODYNAMICS AND FLIGHT MECHANICS
AIRFOIL DATA
FROM: INTRODUCTION TO FLIGHT, APPENDIX D
BY: JOHN D. ANDERSON, JR.
Mechanical and Aerospace Engineering Department
Florida Institute of Technology
D. R. Kirk

2. DATA COMMENTS
Data is from low-speed wind tunnel measurements made by NACA
Airfoils spanned across the test section, hence the data applies for infinite wings
The first page (left side) of Appendix D gives data for cl and cm,c/4 versus angle of attack
The second page (right side) of Appendix D gives cd and cm,ac versus cl for the same airfoil
Since cl is a known function of a from the first page, the data from both pages can be cross-plotted to obtain the variation of cd and cm,ac versus a
Points to note:
Reynolds number is abbreviated by R, and values are located on right side panel
There are two scales on the left side panel
Lift coefficient, cl
Moment coefficient about quarter-chord point, cm,c/4
There is only one scale on the right side panel for cd and cm,ac
An upper set of cl versus a curves correspond to the flap down position shown for some airfoils as depicted in the airfoil picture in the upper right side panel
Note that the moment coefficient data for all airfoils about the aerodynamic center is very nearly independent of cl, and hence a

3. EXAMPLE: NACA FOUR-DIGIT SERIES
First digit specifies maximum camber in percentage of chord
Second digit indicates position of maximum camber in tenths of chord
Last two digits provide maximum thickness of airfoil in percentage of chord
Example: NACA 2415
Airfoil has maximum thickness of 15%
of chord (0.15c)
Camber of 2% (0.02c) located 40%
back from airfoil leading edge (0.4c)
NACA 2415