ac "airfoil converter"

1. ac

This small program converts any airfoil file in the standard ".dat" format, to special ".txt" file format for use with LEparagliding. It also creates a .dxf file.

It is important to remember that special LEparagliding airfoil .txt format is similar to .dat format, but adding a header that indicates the total number of points in the profile, the number of points on the top surface, the number of points in the area of  the air intakes, and the number of points in the soffit. This points also serve to define the start and end point of the air intakes in %. The way to choose the points is indicated in the manual: http://www.laboratoridenvol.com/leparagliding/manual.en.html#05 . But it is necessary to understand well what is being done, and calculate new interpolated points in the profile. Program "ac" helps make this. Soon, it will be integrated into leparagliding.

2. Use:

- Put your standard
airfoil.dat file in working directory (you must use exactly these name airfoil.dat), with acdata.txt and the ac.exe (and cygwing1.dll) or ac.out.
- Edit acdata.txt to select inlets position, and airfoil thickness
- Run ./a.out executable in Linux (or a.exe in Windows)
- Read output file airfoil.txt and verify result matches your objective
- rename airfoil.txt file acording these especified in leparagliding.txt data file.
- Verify inlets positions in leparagliding.txt file (SECTION 2, columns 3 and 4) matches exactly with the defined airfoil(s).
- Open airfoil.dxf file generated (extrados-inlet-intrados in different colors)

File acdata.txt structure:

real    integer
real    integer


1.6    -1
6.3    -1


Line 1 column 1: real (0 to 100 is % of chord inlet in)
Line 1 column 2: boolean (-1,0,+1) -1 denotes point below chord, 0 point in chord, and +1 point over chord

Line 2 column 1: real (0 to 100 is % of chord inlet out)
Line 2 column 2: boolean (-1,0,+1) -1 denotes point below chord, 0 point in chord, and +1 point over chord

Line 3: real thickness amplification (1.0 is most habitual; use 0.0 for wing tip)

3. List of files included with the program

Source code: ac.f (GNU Fortran, compile with f95)

Manual: ac-man.txt

Input file:  airfoil.dat  will be any standard .dat file, but renamed exactly to "airfoil.dat"

Data file: acdata.txt

Executable program:

In GNU/Linux:   In a console type ./a.out

In Windows: Simply double click in a.exe (but may) be also necessary a file cygwin1.dll specific 32-bit or 64-bit in the same folder.

Output files:

airfoil.txt airfoil in leparagliding format, and scaled in thickness
airfoil.dxf  the .dxf version of the airfoil. New chord is 100 units.

All files, input, executables, and output will be in the same folder, named for example "ac".

4. Download

Download "ac" folder with source code, executables, and all example files.