GUIPEP - Graphical User Interface to PEP

GUIPEP has now been officially abandoned (Aug-1-2012). There have been no published updates to it for a really-really long time. Although some effort was made over the years in testing GUIPEP under various versions of Windoze and trying to get it to run in 64 bits, it's now way past its time. Besides... someone has done an awesome job of porting the PROPEP source code!

PROPEP 3 has recently been introduced and is now recommended by me over GUIPEP. Look for the PROPEP 3 link on the NASSA DATA AQUISITION SYSTEM web site. Dave Cooper has done a fantastic job of porting the PROPEP Fortran source to .NET, which now allows it to run on any Windoze OS version that is XP SP2 or beyond. Both 32 and 64 bit. Thanks again, Dave!

This web page will remain here for historical purposes and to provide a destination for all the many pages that currently link to it.


PROPEP is a program for those interested in determining the characteristics of different propellant formulations. A copy of it can be obtained here:

Although this program works well, its user interface is downright barbaric! To solve this problem, I wrote a GUI in Microsoft Visual Basick 3.0 that makes using it almost trivial.

GUIPEP is known to run on all 32 bit Microsoft Windows operating systems from 3.1 and above. This includes Win3.1, Win3.11, Win95, Win98, WinME, WinNT3.1 through WinNT4.0, Win2000, WinXP, Vista, Win7, and Win8 desktop mode (only 32 bit).



The latest version of GUIPEP can be located on my WWW site at the following address: This is the official distribution point, anything else is just a cheap copy ;-)

To install it on your Microsoft Windoze based system, do the following:

  1. Download it from here (544K).
  2. Uncompress on the hard disk of your machine using PKUNZIP, or something similar.
  3. Execute the setup program (named GUIPEP.EXE)
  4. Install GUIPEP to the same subdirectory that you have previously installed PROPEP (193K). This directory name should contain **NO SPACES** in it.
  5. You may need to modify the 'setup.pep' file that came with your version of PROPEP (you will if you got it from the previous step). I have one that should work on any machine here.


GUIPEP is in an alpha phase. It is being made available to those that are willing to put up with the usual sorts of problems that always seem to show up during an alpha.

When complete, GUIPEP will be available for no charge for anyone to use. It may be freely distributed as long as there is no charge made for doing so.

The author maintains all rights to the software and can not be held responsible for the results of its use.


What platforms will GUIPEP run on?
It is known to run on all 32 bit Microsoft Windows operating systems from 3.1 and above. This includes Win3.1, Win3.11, Win95, Win98, WinME, WinNT3.1 through WinNT4.0, Win2000, WinXP, Win7, and Win8 (32 bit).

I just installed it, why doesn't it work?
There are many possible reasons for this, but I will enumerate some common issues:

  1. Make sure the PROPEP works first. It comes with a sample input file. The next item contains a common reason for it to not work.
  2. The standard distribution of PROPEP usually comes with a 'setup.pep' configuration file that has hard-coded paths for that particular users machine. No idea why that is. Try this one instead. Just copy in place of the existing one in whatever directory you installed it, mine uses relative paths.
  3. The installer likes to make a subdirectory named GuiPep under the directory you named to install into, even if that directory is named GuiPep. Thus accidentally installing into C:\Programs\GuiPep\GuiPep, when you meant C:\Programs\GuiPep, is all too easy. Sorry, keep an eye open for this.
  4. GuiPep may not work right if installed into a path that has spaces in the name, or names over eight characters in length. It also doesn't like paths that contain non-ASCII characters. Thus C:\Program Files\GuiPep and C:\MyAeroSpaceSoftware\GuiPep are bad. If in doubt, install to C:\Programs\GuiPep.
  5. The files setup.pep and pepcoded.daf had accidentally been re-formatted to Unix style ASCII (line feeds only) while being transferred to their new home on LEKSTUTIS.COM, and although they looked right, were not compatible with GuiPep or ProPep. This happened around September 2003 and was corrected October 14th 2003. Sorry for any inconveniences this may have caused.

Why doesn't my favorite/secret ingredient 'unobtainium 2000' show up on the list?
There are many possible ingredients that one could put into rocket fuel, and the authors of PROPEP aperently didn't think that one was useful at the time. There are several things you can do:

  1. Find an alternative on the list that is similar enough. In many cases, if the quantity is small enough, it will make no real difference anyway.
  2. I am constantly updating my own with entries that I have made, and others contributed. Take a look here.
  3. You can add it yourself. Let me know if you do so I can share it with others. What you need to know is: You can then edit the pepcoded.daf file and add this to the list with a plain text editor like Windoze Notepad (don't use Word!!!). The file is very sensitive to format, but just look at the others and it should be obvious what you need to do. Make sure you have a backup BEFORE you play with it!

What will the burn rate be?
PROPEP is unable to determine the burn rate. There really is only one way to determine this, and that is to burn some under the actually conditions that it will be used. Sorry, even the pros need to do this.

I mixed up a batch, and the stuff didn't even burn! What gives?
A lot of things could have gone wrong. Try a simulated run with water and aluminum, for example, and PROPEP will report the combustion properties. Actually, this combination does burn, but it is not a trivial matter (if possible at all) to make it burn in a way useful as a rocket fuel.

The point is: PROPEP only reports the potential combustion results **IF** you get the stuff to burn completly, it doesn't have any way to know if it will.

I mixed up a batch, and the stuff detonated! What gives?
That can possibly happen. PROPEP makes no predictions as to the burn rate or detonation sensitivity of the mixture: it can't, it doesn't have enough information to do this.

The moral: be prepared for anything, this is potentially a very hazerdous hobby.

How come Zn/S doesn't work?
Actually, there are many combinations of fuels that will burn well but PROPEP can't figure out. In the case of Zn/S, PROPEP doesn't have the built in knowledge of the various Zn compounds that are formed, and thus doesn't realize that it will 'burn'.

But you don't really want to use this stuff anyway, do you? Damned dangerous with very poor performance. Join the RRS before you kill someone: these guys have a lot of practical experience with the stuff. Seriously.

Why was it written in VB3?
Several reasons actually:

  1. VB3 generates 16 bit code, which will work on most any Microsoft Windows platform (Win3.1 or greater).
  2. VB3 generates less junk then later versions of VB that will need to be downloaded over the network to install an application.
  3. I was using it for a commercial application at the time and was quite fluent in it.
  4. It's easy to quickly bang out code in it.

Do you plan to make any changes to it?
Nope. It's done Jim.


PROPEP and GUIPEP uses a configuration file named 'pepcoded.daf' to identify all of the ingredients that you can use in your recipe. I'm trying to set up a clearing house for everyone to submit changes and get the latest version.

The latest copy of my 'pepcoded.daf' file is located here. Just download it and copy it in place of your old one. You will not want to do this IF your copy has changes as they will be lost forever.

If you have any new ingredients, or corrections to old ones, please let me know so that I can share it with others.

The following are the current additions that I have:

C   1093 HYDROGEN PEROXIDE (85 PC)Liq  500H 435O   0    0    0    0  -1690 .0495]
C   1094 HYDROGEN PEROXIDE?(85 PC)Gas  500H 435O   0    0    0    0  -1296 .0000]
C   1095 HYDROGEN PEROXIDE?(70 PC)Gas  746H 579O   0    0    0    0  -1633 .0000]
    1096 ETHANE                          2C   6H   0    0    0    0   -666 .0120]
    1097 FURFURYL ALCOHOL                5C   8H   2O   0    0    0   -673 .0463]
C   1098 HYDROGEN PEROXIDE (35 PC)     234H 143O   0    0    0    0  -2926 .0400]
    1099 CHLORINE DIOXIDE                1CL  2O   0    0    0    0    371 .0361]
    1100 POTASSIUM PERMANGANATE          1K   1MN  4O   0    0    0  -1230 .0975]
    1101 NEON                            1NE  0    0    0    0    0      0 .0060]
    1102 DEXTROSE (GLUCOSE)              6C  12H   6O   0    0    0  -1689 .0567]
    1103 SORBITOL                        6C  14H   6O   0    0    0  -1776 .0531]
    1104 BITUMEN (ASPHALT)              84C  11H   3O   1N   1S   0   -351 .0400]
    1105 CHARCOAL (OAK)                 71C   3H  13O   1N   0    0   -396 .0206]
    1106 CHARCOAL (MAPLE)               79C   3H  14O   0    0    0   -222 .0206]
    1107 EICOSANE (PARAFFIN)            20C  42H   0    0    0    0   -469 .0000]
    1108 STRONTIUM NITRATE               1SR  2N   6O   0    0    0   -234 .1019]
    1109 CALCIUM HYPOCHLORITE            1CA  2CL  2O   0    0    0   -180 .0848]
    1110 ACETONE                         3C   6H   1O   0    0    0  -1026 .0285]
    1111 ACETIC ACID                     2C   4H   2O   0    0    0  -1924 .0379]
    1112 LITHIUM HYPOCHLORITE            1CL  1LI  1O   0    0    0    -58 .0342]
    1113 TOLUENE                         7C   8H   0    0    0    0    130 .0313]
    1114 MANGANESE ACETATE               4C   6H   1MG  4O   0    0  -1577 .0570]
Last updated: 3/14/01


Current version: 0.04, alpha

Fixes in this release:

  1. The distribution set now includes to previously missing files: GSWDLL.DLL and GSW.EXE
  2. All fields visible at 640x400 resolution
  3. Decimal places are always generated in file driving PROPEP, even when international settings specify otherwise (PROPEP needs this).

Current known anomalies (bugs):

  1. You can not yet generate charts
  2. There is no help file

Take me
Updated: August 1 2012