Whats new?



Version 4.25 available (Download)

  • Updated solver with improved wake model (concerns only propellers)
  • New and improved quick-start models available through the Quick-Start menu in the app.
  • Updated license options and pricing. For more information, visit the Store.



Version 4.24 available (Download)

  • Span-efficiency factor (aka Oswald factor) included in results (and available as objective for optimizations)
  • Drag-and-Drop: Aeolus ASP model files (*.xml) and CAD files (*.stp, *.obj, *.x3d) can be easily loaded through drag and drop
  • New result charts of Center-of-pressure and Aerodynamic-center locations
  • New result chart Cmy(Cl)
  • Results include figures on the required power and thrust for level flight at different speeds
  • Airfoil drop-down list is now searchable
  • Lift distribution plot: added the elliptical reference curve
  • New line force distribution view in 3d shows the strip-wise force components
  • Optimization-, and Parameter-study progress panels are now equipped with chart controls to zoom in/out
  • Improved the force balance 3d view
  • CAD Model import transformations sequence improved and text fields aligned with this new sequence to make it more intuitive
  • Aircraft reference surface changed to the sum of the reference surfaces of all wings in the model. Same with MAC, taken as the surface-weighted average.
  • Fixed the sign of Cdi in the span-wise distribution charts. Now, local strip-wise thrust is shown as negative Cdi
  • Password reset feature available in the sign-in panel
  • As usual: bug fixes and performance improvements



Version 4.22 available (Download) - Give it a try!

  • Optimization feature now uses CMA-ES algorithm by default (instead of BOBYQA) to improve convergence
  • Fixed issue of multiple warning messages popping up on bad number format
  • Improved Nacelle modeling feature
  • Cl(AOA) chart has a trend line
  • C-Wing optimization example added to the Quickstart menu
  • Minor bug fixes and performance improvements



Propeller Test


For Freefly's AltaX aircraft, we have been optimizing their current blades using Aeolus ASP. The resulting blade shape proposed by the optimizer has been machined from Aluminum and tested a few days ago.


Efficiency improvements:

  • Simulation (Aeolus ASP): 4.2%
  • Test: 4.5%

With this good agreement between simulation and test we are now prototyping another blade that was found using Aeolus ASP promising approx. 19% efficiency gains.



Version 4.21 released (Download)

  • Command line/API: AeolusASP can be run from the command line. The User Manual provides more information.
  • Airfoil contour in Cp plots: 2D plots of chord-wise pressure coefficients are now normalized and show the airfoil contour at the current strip. Also, a data table was added to export the plot data to any other plotting tool (right-click in the table)
  • Froude model: Propeller results now also include the Froude model.
  • The Power-Speed-Coefficient is computed for Propellers and available for Optimization or Parameter studies
  • Minor bugfixes of the login and licence panel.



Aeroelasticity with Aeolus ASP

Next Generation Propeller Blades: +18% endurance for UAVs?

Compared to legacy UAV props in the 33 inch range, +18% more efficient prop shapes were found using the numerical shape optimization feature of Aeolus ASP. As we move torwards thinner airfoils and higher aspect ratio blades, aeroelasticity and manufacturing feasibility becomes increasingly challenging. We use FEM and numerical aeroelasticity analysis based on a week coupling of Aeolus ASP and NX Nastran, providing a feedback loop between aerodynamic loads and structural displacement.



Version 4.20 released (Download)

  • Performance improvements through increased parallelization providing 20% analysis speed-up
  • More robust and accurate results through improved wake model. Particularly on multi-wing models and propeller blades.
  • Propeller analysis in pure hover conditions (advance ratio J=0) now available.
  • Propeller model plots added: thrust distribution and Cfx
  • Quick start examples improved. Optimization examples converge much better now. 
  • Model scale factor added, allowing a quick scale as well as scaling during shape optimizations and parameter studies
  • Mach number: contour plots or all fixed-wing and propeller models available. Particularly useful when used as constraints in propeller shape optimization.
  • Airfoils can be inverted. This is useful for highly non-planar configurations, like boxwings. Inspect the new "Swept Boxwing" example accessible in one click through the Quick Start Menu.
  • Airfoil plots improved
  • Flow field vector size improved
  • The usual minor bugfixes



Reverse Engineering using Aeolus ASP


Check out our report on aerodynamic analysis of an existing propeller blade. Simulation results and OEM specs differ by less than 6% on thrust and shaft power.


Propeller simulation validation using the R3390 blade
Adobe Acrobat Document 602.8 KB



Version 4.19 released

  • Multi-threading: Up to 32 CPU cores may now be used, enabling even faster optimizations on modern workstations. Also, we have just invested in a cluster ourselves for future development and engineering optimization services for our clients. An additional cloud-based HPC computing option is planned for the future.
  • An improved surrogate model feature is now available and can be fine-tuned through a number of custom settings accessible in the Screening Tree.
  • Major updates on the Users Guide: Synchronized with the latest GUI, containing more information, and describing modeling, results, and optimizations/parameter-study features in more detail.
  • Reynolds number analysis now also available for propeller blade analysis
  • Minor performance improvements
  • XML files for propeller blades only define the first blade, as all other blades on the hub are a copy of that blade. This simplifies scripting of XML files outside the GUI.
  • Update to the latest JavaFX version 17.
  • New example propeller APC 19x12" available through the quick start menu.


  • Preferences available again
  • Blade color selection applies to all blades on the hub
  • Surrogate model can handle optimization restarts and design space changes



Version 4.18 released

  • Improved aerodynamic solver for higher fidelity in propeller analysis based on wake model improvements, particularly for low advance ratios (e.g. hover). Check out the comparison with wind tunnel results below:
Propeller validation cases
CR-19-13-RevA_Comparison of Aerodynamic
Adobe Acrobat Document 688.5 KB
  • Surface smoothing option available in the Discretization panel. When enabled, wings and propeller blades are lofted through a spline instead of the piecewise linear interpolation resulting in a smoother surface. 
  • Surrogate model for optimizations: You can enable the training of a surrogate model during the optimization. When the fidelity of the surrogate is good enough, the optimizer will use the predictions from the surrogate instead of doing an exact analysis, which ultimately speeds up the optimization. Give it a try! A full documentation will come with the next release.
  • NACA4412 added to the default airfoil catalogue (often used on UAV propellers)
  • Boxwing propeller example added to the QuickStart Menu
  • Propeller pitch chart added
  • Removed constraints on propeller blade twist
  • Improved UX through various GUI enhancements
  • Licensing model: Aeolus ASP is now available with different licenses. Check out our store for more information 


  • Optimization constraints text fields parse correctly
  • ANSYS export fixed
  • Lift coefficient sign fixed for negative AOAs

KNOWN ISSUES to be resolved with the next release:

  • User preferences panel not available
  • Quick start guide and User manual show an outdated model tree structure



On propeller blade shape optimizations: Global vs. local optimum

Specifically for propeller shape optimizations, version V4.14 sometimes runs into local optima resulting in not-so-feasible (yet interesting) results, such as this one:


The main reason is, that propeller shape optimization problems have a very high modality (that is, there are many local optima) and the global optimum is more challenging to find. If you restart your optimization case multiple times and each time get a different result, then its a good indication that these are local optima and the optimizer struggles to find the global optimum.


To improve the optimization robustness, the algorithms in Aeolus ASP are getting tweaked at the moment. One example of improved robustness is shown below on a an eggholder test function. The left picture uses the current optimizer from Version 4.14 which exhibits limited design space exploration, whereas the right picture shows the new one to come in the next version. and which finds the global optimum

Here is a teaser for some more robust blade shape optimization in the upcoming version. Also, you can see that surface smoothing is now available :)



A place for discussions and suggestions:

We’re using GitHub Discussions as a place to connect with other members of our community. We hope that you:


  • Ask questions you’re wondering about.
  • Share ideas.
  • Engage with other community members.
  • Welcome others


Version 4.14 released (Download)


  • Various GUI improvements for modeling and postprocessing
  • Optimization shows current best value
  • Optimization can be paused and restarted
  • At the end of the optimization the best design gets loaded
  • Less strict requirements for the model's XML file
  • Additional unit system mm-t-s (for FEM users)
  • CSV export feature of sections, super sections and reference points
  • Improved rendering of large vehicles
  • Fixed wrong pressure values from propeller models when exported to FEM
  • The property panel has been fixed such that it does not get cleared anymore when making changes that invalidate the previous results

29.09.2020 - Version 4.8 released

  • Quick start optimization model added, accessible through the Quick start menu


  • Parameter study feature more stable
  • Step-wise constraints working again
  • Blender Dialog more stable now
  • Airfoil import dialog works now also multiple times
  • Unit systems table is showing conversion factors again

17.09.2020 - Version 4.5 released



  • DLL loading problems resolved
  • Flaps table bugs resolved
  • FEM Export to ANSYS and NASTRAN fixed

06.09.2020 - Version 4.3 released

  • Graphics performance improvements through a new wireframe speed up the rendering and therefore also the wing shape optimizations
  • BOBYQA and CMAES Optimizer settings adapted to recent literature recommendations
  • Negative design lift force is now supported
  • Additional results in the output summary tables
  • Reduced Installer file size due to removed libraries
  • Increased app stability


  • Freezing Flight condition panel resolved
  • Optimization/Parameter study panel maintains constraint settings also after restart

20.01.2020 - Version 4.2 released



  • in the Geometry tab: The Table is now editable again
  • The NASTRAN Export method works again

12.01.2020 - Version 4.1 released


Happy new year - Aeolus ASP is now free and does not require any licence :)


NEW FEATURE: Propeller blade analysis

  • It is now possible to review the flow characteristics on a rotating propeller. It can have any number of blades and can be operating as compressor or turbine (eg for wind energy). Validation has been done against wind tunnel data. To access the feature, just load the default propeller from the Quick-Start menu and modify as needed.



  • Switched to JavaFX to improve graphics on 4k monitors and to resolve reported graphic issues with some graphic cards.

05.03.2019 - Version 4.0 released


NEW FEATURE: Propellers

  • Arbitrary number of propellers can be added to the model. Each propeller has a thrust vector which adds to the aircraft force balance and enables to study different propeller configurations, such as positions, mount angles, and thrust.
  • Additional result parameters related to propulsion, such as rate of climb, and pitch angle. 
  • Additional 3d plot entities: Center of gravity location, force balance, flight path angle, and horizontal reference

NEW FEATURE: Unit system

  • The systems of units can now be selected. Available systems are SI and Foot-pound-second (FPS). The system of units is saved with the model.


  • New formulation of penalties delivers much better results and helps the user to identify which constraints are violated. Also, the standard penalties have been changed and allow for a more straightforward application.
  • Improved optimization history plot showing the objective function including all penalties
  • Additional constraints are now available:  Pressure coefficient, geometry change rates, pitch angle, flight path angle, rate of climb, center of gravity location



  • Improved labels in 3d view
  • Bugfix in C_l_wet constraint. The lift coefficient of a strip does now take into account the full component of the force perpendicular to the onset flow, not only the part projected into the x-z-plane. Optimizations using this constraint now run much more robust and deliver better results.
  • Update of third-party libraries and the runtime environment for improved performance.
  • Improved exception handling

28.01.2019 - Version 3.11 released


NEW FEATURE: First propulsion parameters (Engines and Propeller feature to come soon)

  • Additional plots for required thrust and performance as function of airspeed at a given altitude for steady horizontal flight.
  • Thrust and performance parameters are accessible as objective functions, and constraints for optimization and parameter studies



  • Default penalty factors improved for different optimization constraints.

  • Increased resolution of carpet plots.

  • Default viscous drag coefficient changed to a more typical value, which can be used for most cases (at Reynolds numbers greater than 200 000)

04.01.2019 - Version 3.10 released


NEW FEATURE: Model export to CAD

  • Allows easy geometry export to all major CAD systems, including CATIA, SolidWorks, NX and many more using the STL format.


  • Undo/Redo bug fixed



  • Additional constraints are available in the optimization. In particular, structural constraints on the root bending now enable the analysis of bell-shaped lift distributions and new configurations with proverse yaw.
  • Notification when updates are available
  • Updated libraries increase performance

18.11.2018 - Version 3.9 released



  • Additional licence types are available, now also including a Free licence.
  • Updated in-app links to tutorials, store, and downloads due to a new website structure
  • Bugfix in airfoil import dialog


  • Values of design variables are shown as real values, not normalized


09.11.2018 - Version 3.8 released


  • Additional User hints in case of inconsistent bounds of design variables
  • 2D pressure distribution plots include the y position of the current strip

03.11.2018 - Version 3.7 released


NEW FEATURE: Parameter studies feature

  • Enables automatic screening of parameters and the impact on specific results. For example,  this feature can be used to understand the change of the static margin due to a change of the sweep angle.
  • Parameters include real and integer values, including geometry, discretization, computation settings etc.
  • Internal checks make sure that the setup is consistent
  • An additional results node provides access to the screening results. This is also true for optimizations.
  • Multiple parameters can be screened at the same time


  • More objective functions available
  • Design variables now also include flap angles


  • Number of panels per strip need not be even but may also be odd.
  • Strip-wise refinement option BOTH added. This increases the panel density at both extremities of a strip.


  • Different options for the definition of a section's chord length.


  • Coordinates do not need to be normalized anymore.
  • The model can also be loaded when the required airfoil is not available in the airfoil catalog. In this case a dummy airfoil will be used (NACA0012)
  • The airfoil name is not case-sensitive in the xml file
  • Names may contain dots

User Settings:

  • Preferences dialog enables the definition of colors, sizes, arrow types etc.
  • User Settings are saved when closing the application and restored at the next start.


  • Freshwater and Seawater models load properly



  • Improved Error Handling allows to save the model before potential crash
  • Multi-threading accelerates start-up
  • White canvas background and larger font size
  • Improved result plots of strictly vertical wings (such as VTPs)
  • xml suffix removed from model name
  • Automatic logging of results in a text file
  • New aileron example accessible through the QuickStart menu
  • Additional checks and error messages when loading an xml file improve  debugging of manually created xml files

23.09.2018 - Version 3.6 released



  • Each airfoil provides an optional flap to easily model ailerons, elevons etc.


  • More robust error handling at start-up
  • Open File- dialog working properly when invoked multiple times
  • Anonymous bug reports can be sent



  • Improved modelling of vertical wings (such as VTPs)
  • New performance plot Lift/Drag as a function of speed and altitude

15.09.2018 - Version 3.5 released


Airfoil catalog:


  • Added over 1000 airfoils to the built-in airfoil catalog
  • Airfoil import feature allows easy import of multiple airfoil files at the same time.
  • All airfoils in the catalog are accessible for inspection through a node in the Model Tree

02.09.2018 - Version 3.4 released


Flight condition:

  • new Fluids available (Seawater and Freshwater)
  • definition of additional fluid parameters
  • 2D plot of the lift coefficient and Mach number as a function of speed and altitude

Airfoil import:

  • Less strict format requirements allow different number formats, comment sections and different separators. As result, it is more compatible  with the traditional online database formats and enable direct import without a  need to tweak the airfoil files by hand.


  • Improved control of panel density through strip-wise definition of density and distribution.



  • Minor bug fixes and other improvements

21.08.2018 - Version 3.3.1 released


Third-party libraries updated for stability and performance


Improved Windows Installer

12.08.2018 - Version 3.3 released


Easy access to the Quick-Start and User Guide, tutorials, and examples


through a Welcome Dialog at start-up, and a new QuickStart menu item

08.07.18 - Version 3.2 released



Licence check shows warning message when there is no internet connection.

03.06.2018 - Version 3.1 released 




  • Nacelle feature stable
  • Toolbar icons path repaired

02.06.2018 - Version 3.0 released


NEW FEATURE: Multiple wings

  • Additional wings can be added to the model, such as tail planes, split flaps, biplanes, etc.
  • Unlimited number of additional, generic wings
  • All parameters of all wings are also accessible in the optimization
  • Individual wing designations and colors easy modelling

NEW FEATURE: Additional 3D plots

  • Surface velocity vectors
  • Center of pressure location
  • Aerodynamic center location
  • Global angle of attack
  • Reynolds number (strip-wise)


  • Easy modelling of circular wings, such as engine nacelles or ring wings


  • Polar plot and aerodynamic coefficients of all wings, and of the entire aircraft, respectively.
  • Oswald factor added
  • Parameter designations improved


  • Tapered blends for twist and chord using different options (Const.,Linear,Sin,1-Cos)


  • Panel includes estimated memory requirement
  • Large models do not throw warnings anymore


  • Constraint violation penalty sign corresponds to goal type
  • Sweep variation in blends
  • And some more minor improvements



  • Geometry panel shows the Wing's dependent parameters, such as wing area and mean aerodynamic chord
  • Model tree structure improved
  • Additional model checks including penetration of symmetry plane
  • New optimization algorithm CMA-ES implemented
  • Reference system node removed. The default reference area is the projected wing area and the reference length is the mean aerodynamic chord
  • Kernel update for improved stability and performance

25.03.2018 - Version 2.5 released



  • Blending dihedral changes (e.g. for smooth transitions to winglets)
  • Undo and Redo buttons available in the toolbar



  • Solver selects Kernel according to Windows version
  • Numbered sections improve modelling

12.02.2018 - Version 2.4 released


NEW FEATURE: Constrained optimization

  • Constraints can be defined to avoid unfeasible designs. Available constraints include stability measures and the local lift coefficient.



  • Optimization algorithm BOBYQA improved
  • Minor bugfixes




 31.01.2018 - Version 2.3 released


This is the initial release of Aeolus Aero Sketch Pad.