Project Status; I am currently looking into adding stators to PROP_DESIGN. I started working on the math. I think I may be able to add a new code that would compute stator geometry without too much trouble. Four variables would get re-defined after PROP_DESIGN_ANALYSIS runs the rotor design, then the code would re-run to compute the stator performance etc... The only reason for a new code is to keep the amount of output files down inside the folder. It would also make for less coding work. So it may be called something like PROP_DESIGN_STATORS. I will add some notes to describe the math, which I already created. I would also have to add something to the user manual to explain how to use PROP_DESIGN_STATORS. Right now, my thought is just to keep PROP_DESIGN the same. So that would be for the rotor. Then you would run PROP_DESIGN_STATORS to get the stator info. Finally, you could use the output of PROP_DESIGN_ANALYSIS and PROP_DESIGN_STATORS to compute the total performance in a spreadsheet. Those calculations are very simple. PROP_DESIGN_STATORS would just be a slightly modified version of PROP_DESIGN_ANALYSIS. One additional DO loop would be needed. So the code would run twice, once for the rotor and again for the stator. Only the stator info would remain as the output information. So you would basically run; PROP_DESIGN_OPT to find the optimum rotor design, then run PROP_DESIGN_ANALYSIS to get more info on that design, then run PROP_DESIGN_STATORS to get the stator info. Lastly, if you wanted overall performance metrics, simply compute them in a spreadsheet. I will probably provide one which you could use.


PROP_DESIGN was first released on March 12, 2010. Please use the current version of PROP_DESIGN, as it contains many bug fixes and new features. The current version of PROP_DESIGN can be downloaded from my Google Drive account:

All files I have uploaded are virus, spyware, and malware free. However, it is a good idea to scan all files you download, to ensure they haven't been tampered with.


Unfortunately, there is no change log. I started developing PROP_DESIGN in 2008. There have been so many changes over that time, that the change log would be huge. I always recommend using the latest version of PROP_DESIGN. Below are some of the most recent changes:

  • 07/18/18 - Noticed there was a missing letter l in one word of the notes. After hours of trying to correct this, I finally just had to give up. I added the missing letter to the pdf file. However, the tools I used to make one nice pdf file with headers, footers, and bookmarks no longer function correctly. So I am now simply providing the pdf files that I used to generate the former 'PROP_DESIGN Notes.pdf' file. So in the 'Reference Information' folder, there is a new folder called 'PROP_DESIGN Notes'. Unfortunately, since Windows 10 came out, most of the old freeware has vanished. Some just died out, most went to online only, others were trashed with adds, etc... So the ecosystem of freeware has really dwindled. In any event, you get a missing letter l from one word, woo hoo. I'm switching to Google Drive to host the downloads. Microsoft OneDrive sucks in comparison. My upload speed is dreadfully slow (how does 1 Mbps grab you), so constantly having to upload to two locations takes forever. Hopefully, everyone will be able to download the files without issue. Like before, you may have to use a VPN service, if your country has firewalls up to cock block you.
  • 07/17/18 - Added a new concept / example to the reference information folder and website. This is for a traditional aircraft propeller combined with a stator. No ducting or sweep is needed to achieve excellent performance at a Mach .7 cruise speed. The new concept doubles as an example, since I include performance details. Pictures and animations are near the bottom of the about page. Details are found in the folder entitled 'Propeller with Stator Concept and Example'. The new concept / example is a follow-up to the modern turbofan example. I also made updates to the modern turbofan example documentation.
  • 07/11/18 - Made changes to any reference of single threaded. For some reason, PROP_DESIGN now uses multiple threads but a single core. There seems to have been a change to the compilers since I first wrote the documentation. Previously, PROP_DESIGN utilized only one thread.
  • 06/04/18 - Made a few very minor edits to the Fortran Compiler Comparison. Updated several website images.
  • 06/02/18 - Updated my hovercar concept renderings.
  • 05/30/18 - Re-compiled all executable files using Intel Fortran 2018 Update 3. Updated the Intel Fortran Prompts to work with Intel Fortran 2018 Update 3. Changed the c1, c2, and c3 *.bat files from march=silvermont to march=bdver4. This matches my current system, however, you may need to make changes to match your system. This only applies if you are compiling the source code with gfortran. Updated my Fortran Compiler Comparison, now compares Intel Fortran 2018 Update 3 to gfortran 8.1. Also made a small change to the user manual wrt to the benchmarking information. This reduced redundant documentation, which I try hard to avoid for my sake and yours.
  • 05/29/18 - Updated the portion of the user manual related to gnuplot installation. Updated some of the images in the user manual. Updated all of the website renderings, this includes the webpage backgrounds. Added new images specifically for use as desktop wallpaper. These are for the modern turbofan example and my hovercar concept.
  • 02/04/18 - Updated the website. Based on years of web traffic data, I realized that people only visit an average of five pages. So a lot of useful and important content often went unseen. Given this knowledge, I rearranged the content to exist on only five pages. Nothing was added or taken away, simple moved.
  • 12/22/17 - Added mass flow rate in units of lbm/s to the output of AIRFOIL_MESH_TEST_TWO, so the output file should once again match that of PROP_DESIGN_ANALYSIS (as it was always intended to do).
  • 12/21/17 - Fixed a few minor bugs; PROP_DESIGN_ANALYSIS_MESH_TEST_TWO.f had some WRITE statement issues. At some unknown point, the MAPS_AIRFOIL_COMPARE folder was moved into the MAPS_CS folder by accident.
  • 11/11/17 - Updated the areas used for the drag hand calcs in the modern turbofan example. Previously, I used cross-sectional area. I believe I was supposed to use the planform area, like the way wing drag is calculated, but not really sure. The reference information I have for the drag coefficients, isn't really clear. This doesn't change anything about the example. The only document updated was 'Opt 1 Duct Drag Calculations.pdf'.
  • 10-26-17 - I added a new example called the modern turbofan example. This contains a lot of useful information for PROP_DESIGN users. Slight update to the user manual. Added mass flow rate in lbm/s to ANALYSIS output.
  • 09-26-17 - I created a very cool flying wing concept. It utilizes a novel adjustable thrust vectoring nozzle. This concept and others can be found on the about page of this website. All of the concepts shown are of my own design. Description:

Documentation Folder:

  • The PROP_DESIGN User Manual folder - Contains the PROP_DESIGN User Manual, applicable to the 64-bit Windows version of PROP_DESIGN (as the other versions of PROP_DESIGN did not exist at the time the document was written). I recommend reading the PROP_DESIGN User Manual, even if you are not going to use the 64-bit Windows version of PROP_DESIGN. This is due to the fact that all versions of PROP_DESIGN are very similar. Moreover, once you understand how the 64-bit Windows version of PROP_DESIGN works, you can easily figure out how the other versions function.
  • The Reference Information folder - Contains information which, among other things, aids the understanding of the PROP_DESIGN source code, derives some important equations, and answers some common questions.

Fortran Compiler Comparison Folder:

  • BENCHMARKS folder - Based on PROP_DESIGN_MAPS. The only difference is the addition of numerous *.bat files. The *.bat files are what is responsible for actually running the benchmarks.

Optional Documentation Folder:

  • The Airfoil Model folder - Contains information regarding the airfoil model utilized by PROP_DESIGN.
  • The Atmospheric Model folder - Contains information regarding the atmospheric model utilized by PROP_DESIGN.
  • The Stall Model folder - Contains information regarding the stall model utilized by PROP_DESIGN.

Optional Programs for 64-bit Windows Folder:

  • The AIRFOIL_CFD_INPUTS folder - Contains a Fortran 77 program that helps correlate airfoil wind tunnel data to CFD inputs. You input airfoil chord, Reynolds number, and Mach number. Geopotential altitude, density, speed of sound, kinematic viscosity, pressure, and temperature are output. This is useful when the chord analyzed by CFD is different than what was tested in the wind tunnel. This causes the atmospheric properties to change.
  • The ATMOSPHERIC_PROPERTIES folder - Contains a Fortran 77 program that will output various atmospheric properties. It uses the same atmospheric model as PROP_DESIGN. You input geopotential altitude in units of feet. Density, speed of sound, and kinematic viscosity are output.
  • The ATMOSPHERIC_PROPERTIES_ALT folder - Contains a Fortran 77 program that will output various atmospheric properties. It extends the atmospheric model used by PROP_DESIGN. You input geopotential altitude in units of feet. Density, speed of sound, kinematic viscosity, pressure, and temperature are output.
  • The VELOCITY_CONVERSION folder - Contains a Fortran 77 program that will convert true airspeed to Mach number. Moreover; true airspeed (TAS) in units of mph, combined with geopotential altitude in units of feet, are used to determine aircraft velocity in units of Mach (which is an input to PROP_DESIGN).

PROP_DESIGN 64-bit Windows Folder:

  • The PROP_DESIGN folder - Contains various versions of PROP_DESIGN. Each version of PROP_DESIGN contains examples. The best way to get started with PROP_DESIGN is to review the PROP_DESIGN User Manual and run the examples. If you are interested in aircraft propeller theory, study the PROP_DESIGN source code files and reference information.
  • The PROP_DESIGN_UNDOCUMENTED folder - Contains undocumented versions of PROP_DESIGN. They were created to study different aspects of PROP_DESIGN and aircraft propeller design in general. One particularly useful version, creates performance maps for constant speed propellers. Although these versions are undocumented, if you are familiar with PROP_DESIGN, you will have no trouble figuring out how to utilize them. Since I am finished developing PROP_DESIGN, I decided to share them with you, rather than just delete them.

Compatibility Notes:

All versions of PROP_DESIGN have been tested on AMD and Intel x86 processors. However, they should work on any processor capable of performing 64-bit floating-point arithmetic. You would have to re-compile the source code files to experiment with other processor types.

32-bit Windows:

If you need to run PROP_DESIGN on 32-bit Windows, you will have to re-compile the Fortran 77 source code files. I recommend using the Intel Fortran compiler, in order to achieve the highest performance. If you would rather use gfortran, mingw-builds is a good option.


In November of 2012, I tested PROP_DESIGN on Linux. PROP_DESIGN works fine on Linux, as expected. For use with Linux, place the 64-bit Windows versions of PROP_DESIGN in your Documents folder. Delete all *.bat and *.exe files. You will need to install gfortran and gnuplot. Make sure the wxt terminal is the default for gnuplot. Lastly, re-compile all source code files, using gfortran.


In January of 2014, I tested PROP_DESIGN on an Android tablet using three free apps. I was able to compile and run PROP_DESIGN using the CCTools and 920 Text Editor apps. I was able to view all *.plt files using the Mobile Gnuplot Viewer (free) app. These apps require a fair amount of free storage space to install.


You may have to edit all of the *.plt files. Moreover, the paths to the *.dat files need to match the locations of the files on your particular device. This seems to be a limitation of the Mobile Gnuplot Viewer (free) app.


The Android tablet used a 32-bit ARMv7 processor. There were no issues compiling or running PROP_DESIGN. Comparing results, obtained with the 32-bit ARMv7 processor against those from a 64-bit x86 processor, showed agreement down to the last significant digit.


During Android testing, I did have one issue. CCTools froze, while installing the Fortran add-on. I rebooted the tablet and re-opened CCTools. The Fortran add-on showed as installed. However, once I went to use it, it wasn't actually installed. So I uninstalled the Fortran add-on and re-installed it. There were no issues during or after the second install.


Screencasts and all files used in the screencasts are available from my Google Drive account:

All files I have uploaded are virus, spyware, and malware free. However, it is a good idea to scan all files you download, to ensure they haven't been tampered with.


The PROP_DESIGN Screencasts folder contains the following tutorials:


     1) Using PROP_DESIGN_XYZ data with Rhino - Part 1.mp4

     2) Using PROP_DESIGN_XYZ data with Rhino - Part 2.mp4

     3) Meshing using Netgen.mp4

     4) Finding the Cold Shape using Mecway.mp4 

     5) Static Stress Analysis using Mecway.mp4 

     6) Checking for Blade and Duct Interference using Mecway.mp4 

     7) Pre-Stressed Modal Analysis with Spin Softening using Mecway.mp4


'PROP_DESIGN Screencast' contains all the files discussed in the screencasts.

Screencast Notes:

The screencasts were recorded with Screencast-O-Matic and can be viewed with the VLC media player. It's best to watch the screencasts in the order they were recorded (1-7). The following software was used in the screencasts:

  • Rhino v5
  • Netgen v6.1 Experimental
  • Mecway v5
  • LibreOffice