
AVL Overview
Summary Description
AVL is a program for the aerodynamic and flight-dynamic analysis of rigid aircraft
of arbitrary configuration. It employs an extended vortex lattice model for
the lifting surfaces, together with a slender-body model for fuselages and nacelles.
General nonlinear flight states can be specified. The flight dynamic analysis
combines a full linearization of the aerodynamic model about any flight state,
together with specified mass properties.
Extended Vortex-Lattice Model
- Aerodynamic Components
- Lifting surfaces
- Slender bodies
- Configuration definition
- Keyword-driven geometry input file
- Defined sections with linear interpolation
- Section properties
- camberline is NACA xxxx, or from airfoil file
- control deflections
- parabolic profile drag polar, Re-scaling
- Scaling, translation, rotation of entire surface or body
- Duplication of entire surface or body
- Singularities
- Horseshoe vortices (surfaces)
- Source+doublet lines (bodies)
- Finite-core option
- Discretization
- Uniform
- Sine
- Cosine
- Blend
- Control deflections
- Via normal-vector tilting
- Leading edge or trailing edge flaps
- Flaps independent of discretization
- General freestream description
- alpha,beta flow angles
- p,q,r aircraft rotation components
- Subsonic Prandtl-Glauert compressibility treatment
- Aerodynamic outputs
- Aerodynamic forces and moments, in body or stability axes
- Trefftz-plane induced drag analysis
- Force and moment derivatives w.r.t. angles, rotations, controls
Trim Calculation
- Operating variables
- alpha,beta
- p,q,r
- control deflections
- Constraints
- direct constraints on variables
- indirect constraints via specified CL, moments
- Multiple trim run cases can be defined, saved, recalled
Mass Properties
- Optional mass definition file (for trim setup, eigenmode analysis)
- User-chosen units
- Itemized component location, mass, inertias
- Trim setup of constraints
- level or banked horizontal flight
- steady pitch rate (looping) flight
Eigenmode analysis
- Predicts flight stability characteristics
- Rigid-body, quasi-steady aero model
- Eigenvalue root progression with a parameter
- Display of eigenmode motion in real time
- Output of dynamic system matrices

Release Conditions
The most important conditions are:
- You may copy, modify and redistribute AVL or its modifications freely.
- Any such redistributions must be done under the terms of the GPL,
else the permission is withdrawn.

Software
Latest Versions
- avl3.32.tgz (496506 bytes)
AVL 3.32 for Unix and Win32. Gzipped directory tar image.
All source code, User Guide, sample AVL session inputs.
Requires Fortran 77, C compilers, windowing support.
- avl332.zip (678020 bytes)
AVL 3.32
executable for Windows.
- AVL3.27_MacOSX_10_4.zip (269506 bytes)
AVL 3.27
executable for MacOSX.
Older Versions
- avl3.27.tar.gz (453338 bytes)
AVL 3.27 for Unix and Win32. Gzipped directory tar image.
- avl327.zip (319170 bytes)
AVL 3.27
executable for Windows.

Documents
Sample Input Files

Number of unique visitors since 4 November 2007
Authors:
- Mark Drela, drela (AT) mit (DOT) edu
- Harold Youngren, guppy (AT) maine (DOT) rr (DOT) com

Page Revisions
1 Sept 2004
- Page created. AVL 3.14
2 Sept 2004
- A few links fixed.
- Comments added to AVL's Makefile (in new avl3.14.tar.gz)
13 Oct 2004
- Fixed compilation problems occurring on some compilers. AVL 3.15
- Windows executable provided (courtesy Hal Youngren).
18 Oct 2004
- Fixed bug in handling of runtime-loaded input file. AVL 3.16
28 Aug 2005
- Fixed bug in the design-variable implementation. AVL 3.18
- Added CY (sideforce) constraint to the available list.
24 Oct 2005
- Fixed printing error in stability-axis yaw rate r'b/2V. AVL 3.20
25 Oct 2005
- Fixed small error in axis transformations in Cl,Cn moment calculations. AVL 3.21
12 Nov 2005
- Fixed and clarified stability derivative output.
Added strip cl to surface listing output. AVL 3.22
17 Mar 2006
- Added a non-existent airfoil file check and warning.
Added Pan and Expand hot keys to Keystroke Viewer. AVL 3.24
29 Apr 2006
- Set default printnames for run-case parameter units.
- Added freestream-referenced cl to Trefftz-Plane plot.
- Fixed hinge-moment calculation for leading-edge flaps.
- AVL 3.26
11 Aug 06
- Windows executable of AVL 3.26 (courtesy of Doug Greenwell)
28 Feb 07
- Modified the GPL summary above.
Previously this wasn't a correct GPL interpretation, as discussed
here .
23 May 08
- Removed the small influence of CLAF on the zero-lift angle.
- Added file output options to listing commands (FT,FN,FS,etc)
- Made a bunch of other minor tweaks (see version_notes.txt)
- AVL 3.27
21 Jul 08
- Windows executable of AVL 3.27 (courtesy of Ralph Paul)
4 Aug 08
- Reorganized and updated the AVL description above
26 Jan 11
- MacOSX executable of AVL 3.27 (courtesy of Emanuele Rizzo)
6 Apr 11
- Added runs/ directory links
- AVL 3.31 for Linux. Lots of new goodies since 3.27.
See version_notes.txt and avl_doc.txt
16 Dec 12
- Fixed post-processing calculation of the strip center of pressure (FS command in OPER).
It was not correct for sections with significant sweep or dihedral.
- AVL 3.32 for Linux.
- Windows executable of AVL 3.32 (courtesy of Harold Youngren)