I've finally joined the modern age. You can follow me on Twitter, to be alerted to updates (or if you have a penchant for nature retweets). You should see a follow button below:

    • 04/20/19 (Most recent update):
      • Made some corrections to the modern turbofan example. The archived files, in the B787-10 folder, weren't properly saved. I made the appropriate corrections and updated the performance comparison. No significant changes occurred however

There is no change log. I started developing PROP_DESIGN in 2008. I tried making a change log a couple of different times. However, it quickly became so long that there didn't seem to be value in it. Who is going to read through pages and pages of cryptic change notes. The important thing is to use the current version of PROP_DESIGN.


The download does not contain any viruses, spyware, or malware. However, it is a good idea to scan all files you download, to ensure they haven't been tampered with.


See the support page and the concepts page for many applications of PROP_DESIGN. This includes; hovercraft, VTOLs, turbofans, adjustable thrust vectoring nozzles, stators, and more.


I have been trying to complete the project for many years. At this point, I believe the program is as close to perfect as I can make it. Therefore, no further updates are planned. Any further improvements are left to others. If you do release your own version of PROP_DESIGN, please call it something else, to avoid confusion between my version and yours.


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. It also contains several additional examples. These examples cover; counter-rotation, hovercraft, VTOLs, turbofans, and stators

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 for 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. In the past, I also tested PROP_DESIGN on a 32-bit ARM processor and it worked perfectly.

Operating Systems:

If you want to run PROP_DESIGN on an operating system other than 64-bit Windows, you will have to re-compile the source code using a Fortran compiler that supports the Fortran 77 standard. As far as I know, all Fortran compilers support that standard. If available for your OS of choice, 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. However, the executable files that gfortran creates run about 4x slower than those created by Intel Fortran.

Mobile Computing:

The Microsoft Surface Pro line of tablets run 64-bit Windows. Therefore, you would not have to modify PROP_DESIGN for mobile computing, on these devices. This would allow you to design a propeller for a prospective customer without having to return to your office. So if you were in a meeting or at a trade show, with a few inputs from the prospective customer, you could generate a design right there.