Design Templates, with End Corrections, for Reynst Engines

[larry cottrill]

Well, if you believe what I was talking about in my 'Secrets of the Dead ...' thread on the Valveless Forum:
http://www.pulse-jets.com/phpbb2/viewtopic.php?t=1572
and if you care about designing such engines, and if you happen to use MS Paint, here's a little design aid for you: a set of Reynst Engine Design Templates.

The main one is the Engine Layout Template, which is just a to-scale layout of the total 1/4-wave path length, showing the critical points along the engine centerline. I have designed a straight-tube Reynst called the 'Henri' using this template alone, soon to be posted in the Valveless Forum.

The lower templates are for laying out a 'bent' [a la 'Chinese' valveless] intake. They are all to the same scale as the L/5 section of the main template, but carry a 'ruler' on the centerlines so you can easily divide the length up into the 'transition' [the "bent" part] and the 'straight' section [i.e. the part that's still parallel to the engine CL]. For example, if you want to try 35% as transition length and 65% as straight length, and you want the transition CL at 45 degrees, you would use Paint's Area tool to grab the right-hand 65% of the straight template and copy that onto your work file, then use the tool to grab the lower 35% of the 45-degree template and paste it on so its upper right CL end point just touches the left end point of the straight part -- and voila! You have the basic layout for your L/5 "bent" intake with transition. Templates are provided for 60-deg, 45-deg and 30-deg transitions. The bold marks on the rulers are at the 1/10 points along the CL length, with light tick marks at the intermediate [1/20] points - this means that each small increment represents L/100, incidentally. You can cut and paste the 'half angles' [up in the upper right quadrant] at the bend point to show the cut line between the two pipe sections.

The end corrections are shown as a pair of angles emanating from each critical point. You decide on the diameter [at the scale of the template] of the tube you want, and lay out lines above and below the CL ruler at the appropriate radii [there are short 'construction lines' above each of the lower templates precisely parallel to each template CL you can cut and paste for this]. Where these lines intersect the 'end correction lines' is where you would cut off the tube for the correct length.

Of course, if you have no idea what I'm talking about or wouldn't touch Paint with a long fork, none of this makes any meaningful sense. But, someone out there may find it useful.

What you probably want to do after downloading it to a working directory is to change the file permission to 'Read Only' so you can't accidentally screw it up, but can only copy and paste from it onto your Paint work file. You will also have to change it to a .gif or .bmp file for most versions of Paint to use.

L Cottrill

[Bruno Ogorelec]

I'm sure looking forward to seeing an engine designed on the basis of this template. Looks interesting. If this works, Larry, you have made a major contribution.

[larry cottrill]

I'm sure looking forward to seeing an engine designed on the basis of this template. Looks interesting. If this works, Larry, you have made a major contribution.

Thanks, Bruno!

The potential value might be more easily understood if I would work out a little step-by-step tutorial, using a simple design as an example; something like a straight pipe with a "Chinese" style intake.

The 'Henri' engine used the main template, but of course, none of the angle templates were needed, since it's an engine where everything lies on the axis. I just superimposed the 0-degree intake ruler onto the main template to get the position of the correction lines. These can still be seen in the 'Henri' drawing. Of course, there's some guesswork involved when you have smooth transitions rather than clean-cut ends, but that flat pinch should be pretty close to right. If you pick up the Henri top view as a whole and superimpose it directly on the template, you'll see the exact fit.

L Cottrill