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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.
 
  
  
    
      
        
        Determining the Timing
          
         | 
        The animation shows, how to measure the timing angles of exhaust and 
        transfer port. These angles define how long the ports are open, 
        expressed in crankshaft angle. You can attach a disk with divisions in 
        degrees to the crankcase and a pointer to the crankshaft (or vice 
        versa). 
        Then you adjust disk and pointer so that the it indicates 180° when the 
        piston is at its bottom dead center. Now you turn the crankshaft until 
        the port of interest closes (when the piston crown arrives at the upper 
        edge of the port). It is helpful to point a flashlight or a halogen lamp 
        through the plug hole or to remove the cylinder head. 
        Reading the angles in both directions must be symmetrical to the bottom 
        dead center, e.g. a port opening at at 100° must be closing again at 
        360°-100° = 260°, as shown in the animation. The port timing angle 
        (shown in blue) is then 260° - 100° = 160°. This means, that port is 
        open while the the crankshaft turns 160°. 
        Usually the transfer port will have a shorter timing than the exhaust 
        port. | 
      
    
   
  
  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 javapipe.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:
21.05.18

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