Airfoil

Airfoil Resources

Friday, 20 November 2009 22:26 |

Written by Aleksey Matyushev |

Airfoils are in a lot of ways considered the heart of the aircraft. A good airfoil is critical in attaining the desired aircraft performance. On the other hand, a designer cannot spend a lot of time selecting and optimizing a given airfoil for an aircraft because there is no right or wrong answer.

If an airfoil meets the design requirements and exemplifies performance data at cruise resulting in the total desired aircraft performance data, the airfoil should be used.

Custom airfoil design is wonderful for large companies to utilize because they have the resource pool to validate the designed airfoil in a wind tunnel. For small companies on a limited budget or with no access to a wind tunnel, there is no sense in putting forth the time and financial resources in developing a custom airfoil when available data for an airfoil meeting the requirements already exists.

Last Updated (Monday, 15 February 2010 16:48)

XFOIL Tutorial Part 1

Saturday, 31 October 2009 21:34 |

Written by Aleksey Matyushev |

Launching and navigating XFOIL

To launch XFOIL in Windows, execute the executable file after downloading it from the MIT or openAE website. In Linux, simply type “xfoil” in the terminal.

XFOIL has a wonderful help system which can called upon at any time by typing “?” in the prompt and hitting “ENTER”. It is also important to note that XFOIL is not case-sensitive, meaning that it does not matter if the commands you type are in capital letters or lower-case.

It is also imperative to describe the structure of XFOIL. Although XFOIL is a command based program, it has different operating modes or menus. Each operating mode/menu has a different set of commands which can be given. The diagram below depicts the mode/menu structure of XFOIL.

Last Updated (Tuesday, 16 February 2010 00:38)

UIUC Airfoil Database

Tuesday, 06 October 2009 01:38 |

Written by Aleksey Matyushev |

The University of Illinois at Urbana-Champaign (UIUC) Airfoil database is a growing list of airfoil coordinate files and their images. Before 1995, the database had a total collection of about 160 low Reynold's number airfoils. In 1995 David Lednicer contributed his personal collection of over 800 airfoils and the total number of airfoils grew to over 1000. Since then, the UIUC aerospace department has been constantly contributing more and more airfoils.

Last Updated (Sunday, 28 March 2010 17:05)

XFOIL Tutorial Part 2

Friday, 20 November 2009 20:48 |

Written by Aleksey Matyushev |

Loading an airfoil for analysis

First of all, the airfoil which is going to be analyzed needs to be loaded into XFOIL. NACA four digit airfoils can be loaded straight from the program, but ALL other airfoils need to be loaded into XFOIL through an input file usually having a “.dat” extension.

To load in a four digit series NACA airfoil straight from XFOIL's database, use the following command: NACA XXXX (where XXXX is NACA's airfoil designation). In this tutorial we will analyze a NACA 2432 airfoil, so input the following command into the prompt and hit “ENTER”:

XFOIL c>naca 2432

XFOIL will now load the airfoil NACA 2432. To load a custom airfoil you need to use the “LOAD” command and give XFOIL the location of the input file. Using Linux (the directory format is different in UNIX based systems), and having an input file located on the desktop the following command can be given to load an airfoil input file (Test_Airfoil.dat):

Last Updated (Tuesday, 16 February 2010 00:39)

XFOIL Tutorial Part 3

Wednesday, 02 December 2009 03:41 |

Written by Aleksey Matyushev |

Analyzing the airfoil

To analyze the airfoil you must enter the operational mode of XFOIL. This operational mode can be entered by the following command from the main XFOIL menu:

XFOIL c>oper

After entering the operational mode of XFOIL, the flow conditions and angle of attack for analysis needs to be given. The angle of attack can be varied by using the following command:

Last Updated (Friday, 12 February 2010 20:17)

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XFOIL Tutorial