Theory of Wing Sections
Including a Summary of Airfoil Data
Ira H. Abbott, A. E. von Doenhoff
- 704 pages
- English
- ePUB (mobile friendly)
- Available on iOS & Android
Theory of Wing Sections
Including a Summary of Airfoil Data
Ira H. Abbott, A. E. von Doenhoff
About This Book
`Most useful in working with wing sections and methods for using section data to predict wing characteristics . . . much detailed geometric and aerodynamic data.` — Mechanical Engineering
The first edition of this work has been corrected and republished in answer to the continuing demand for a concise compilation of the subsonic aerodynamics characteristics of modern NASA wing sections together with a description of their geometry and associated theory. These wing sections, or their derivatives, continue to be the ones most commonly used for airplanes designed for both subsonic and supersonic speeds, and for helicopter rotor blades, propeller blades, and high performance fans.
Intended to be primarily a reference work for engineers and students, the book devotes over 300 pages to theoretical and experimental considerations. The theoretical treatment progresses from elementary considerations to methods used for the design of NACA low-drag airfoils. Methods and data are presented for using wingsection data to predict wing characteristics, and judiciously selected plots and cross-plots of experimental data are presented for readily useful correlation of certain simplifying assumptions made in the analyses. The chapters on theory of thin wings and airfoils are particularly valuable, as is the complete summary of the NACA's experimental observations and system of constructing families of airfoils. Mathematics has been kept to a minimum, but it is assumed that the reader has a knowledge of differential and integral calculus, and elementary mechanics.
The appendix of over 350 pages contains these tables: Basic Thickness Forms, Mean Lines, Airfoil Ordinates, and Aerodynamic Characteristics of Wing Sections.
Frequently asked questions
Information
CHAPTER 1
THE SIGNIFICANCE OF WING-SECTION CHARACTERISTICS
1.1. Symbols.
| A | aspect ratio |
| An | coefficients of the Fourier series for the span-load distribution |
| CD | drag coefficient |
| CDi | induced drag coefficient |
| CL | lift coefficient |
| CLmax | maximum lift coefficient |
| CM | pitching-moment coefficient |
| CM | pitching-moment coefficient about the aerodynamic center |
| D | drag |
| E | Jones50 edge-velocity factor, equals ratio of the semiperimeter of the plan form of the wing under consideration to the span of the wing |
| E | a factor (see Fig. 13) |
| G | a factor (see Fig. 14) |
| H | a factor (see Fig. 15) |
| J | a factor (see Fig. 9) |
| L | lift |
| La | “additional” loading coefficient |
| Lb | “basic” loading coefficient |
| M | pitching moment |
| S | wing area |
| V | speed |
| Xac | longitudinal distance between the aerodynamic center of the root section and the aerodynamic center of the wing, positive to the rear |
| a | wing lift-curve slope |
| ae | effective section lift-curve slope, a0/E |
| a0 | section lift-curve slope |
| ac | aerodynamic center |
| b | wing span |
| c | wing chord |
| mean geometric chord, S/b | |
| c‘ | mean aerodynamic chord |
| Cd | section drag coefficient |
| section induced-drag coefficient | |
| Cl | section lift coefficient |
| Cla1 | local “additional” section lift coefficient for a wing lift coefficient equal to unity |
| Clb | local “basic” section lift coefficient |
| Clmax | section maximum lift coefficient |
| Cm | section-moment coefficient |
| Cmac | section-moment coefficient about the aerodynamic center |
| cs | root chord |
| ct | tip chord |
| d | section drag |
| f | a factor (see Fig. 8) |
| k | a spanwise station |
| l | section lift |
| la | “additional” section lift |
| lb | “basic” section lift |
| m | section moment |
| r | an even number of stations used in the Fourier analysis of the span-load distribution |
| u | a factor (see Fig. 10) |
| v | a factor (see Fig. 11) |
| w | a factor (see Fig. 12) |
| x | projected distance in the plane of symmetry from the wing reference point to the aerodynamic center of the wing section, measured parallel to the chord of the root section, positive to the rear |
| y | distance along the span |
| z | projected distance in the plane of symmetry from the wing reference point to the aerodynamic center of the wing section measured perpendicular to the root chord, positive upward |
| α | angle of attack |
| αo | section angle of attack |
| αe | effective angle of attack |
| αi | angle of downwash |
| α lo | section angle of attack for zero lift |
| α l0s | angle of zero lift of the root section |
| αs | wing angle of attack measured from the chord of the root section |
| αs(L=0) | angle of attack of the root section for zero lift of the wing |
| β | angle of sweepback |
| ε | aerodynamic twist from root to tip |
| ηm1 | multiplier for obtaining the wing characteristics |
| ηmn | multiplier for obtaining the span-load distribution |
| θ | |
| λmk | multiplier for obtaining the induced-angle distribution |
| π | ratio of the circumference of a circle to its diameter |
| ρ | mass density of air |