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This small Java applet uses design rules according to [22], [23], and [24], to size a tuned pipe for a 2 stroke piston engine. The calculations are assuming a speed of sound in the exhaust gas, which is not known exactly; also, it depends on the temperature and thus on fuel/air mixture and external conditions. In this applet, the gas conditions for methyl alcohol (methanol) and gasoline have been implemented. The results of the calculations can be used as a good starting point for experiments and fine tuning, deviations of +/-10% are surely possible.

Usage

• Measure the timing of your engines exhaust and transfer ports in degrees (see below).
• Measure the dimensions and calculate the area of the exhaust port opening in the sleeve.
• Assume the velocity of rotation of your engine in rpm (dreaming doesn't help much though).
• Either:
  • use the sliders to adjust the values according to your engine, or
  • enter the corresponding values into the text fields and press [enter] to update the graph.
• Printing and Exporting only works, after you have adjusted the appropriate Java security settings of your browser.
  You could create a hardcopy of the program window, though, using your systems suitable tools.
• You can manually plot the cones to build a paper model or to transfer the shape onto sheet metal by using the values of R and phi noted below each cone. Plot two concentric circles (having the same center) using the two radii R. The flattened cone spans a segment with an opening angle of phi degrees between the two circles.
• The Print... command will print a scaled version of the cones. The Export... command will create two AutoCad compatible DXF files for the two cones.

Background

Used Formulas (a mixture from [22], [23], and [24]):

(metric units)

The opening angles of the cones should be 4° to 10° for the opening cone and approximately twice this value for the closing cone.

Cut view of a tuned pipe with silencer.

Enlarged view of the muffler section.

see also:
F3D Pylon Racing Engines with some engines optimized for tuned pipes,
Peter Soule's documentation to learn more about the history of tuned pipes for model engines,
my Silencer Application software, including a similar tuned pipe designer.

How to download JavaPipe to use as a standalone Application

Remark:  to use JavaPipe in the standard way in your browser, over the internet, it is not necessary to perform the procedures described in this section. I cannot give much support to solve any problems occurring while running your local copy based on your local Java installation. If you have not already a working Java system on your machine, you might want to consult a computer guru.

If you want to run your local copy of JavaPipe , you can download a copy of the JavaPipe archive to your disk. You can also save the applet page to a local file, depending on the method you want to use for running you local copy.

Step by Step Instructions to download the required files

• Check, whether you have a Java virtual machine (VM) installed on your system.
  • Windows: open a command window and execute the commands jview and wjview. Usually a Java VM can be installed during the installation or when upgrading the Microsoft Internet Explorer.
  • Unix: open a shell or xterm window and execute the command java.
• If these commands can be found, your system probably has a working Java installation. If not, you will have to get the appropriate Java Runtime Environment (JRE) for your system from Suns web site http://java.sun.com/.
• Download this html file from
• Download the ZIP archive with the class tree from the following web address:
• Create a subdirectory "java" below the directory, where you have copied this html file and move the tunedpipearchive.zip file into this directory.
  
  
• Now you have both files to run JavaPipe either as an applet or a standalone application. You can run the applet by loading this html page into your browser or by using the AppletViewer.
  [More details can be found here].
  
  
• To make life for Windows users easier, you can download the following VBScript file to start JavaPipe as a stand alone application:
  Using this script and the archive, you can run JavaPipe by merely clicking onto the .vbs file.
  
  
• To make life for Windows users even easier, you can also download the following Windows Installer file which contains all you need and installs it correctly:
  To re-install or de-install use the "Software" applet inside the System Control Program of Windows.
  

last modification of this page: 21.08.01

[Back to Home Page] [Index of all Pages] Suggestions? Corrections? Remarks? e- Martin Hepperle.
As I get quite a number of messages, it might take some time until you receive an answer and in some cases I get lost in the flood and you may even receive no answer at all. I apologize for this, and if you have not lost patience, you might want to send me a copy of your e-mail after a month or so.
Copyright 1986-2001 Martin Hepperle
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