Author Topic: Port areas  (Read 3657 times)

Offline Dan Rowe

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Re: Port areas
« Reply #15 on: April 28, 2016, 06:48:40 PM »
I located the textbook used by Frank J. Burris to write the article. It is Audels Engineers and Mechanics Guide: Volume 1, see pages 210-217. This book can be found on the web as it is out of copyright. The example in the book is nearly identical to the text by Mr. Burris he simply changed the bore and stroke of the example.

If you get stuck with this let me know.

Cheers Dan
ShaylocoDan

Offline Zephyrin

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Re: Port areas
« Reply #16 on: April 29, 2016, 11:53:32 AM »
You will find the fig 2 & 3 of the F Burris paper upon a click on the slideshow button !

Offline Dan Rowe

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Re: Port areas
« Reply #17 on: April 29, 2016, 02:46:56 PM »
Thanks Zephyrin,
Figure 2 is the Bilgram diagram and figure 3 is the slide valve. Just what i was expecting to see. I tried the slideshow button but I did not spot the arrows on the sides of figure 1.

Cheers Dan
ShaylocoDan

Offline Dan Rowe

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Re: Port areas
« Reply #18 on: April 29, 2016, 04:05:02 PM »
BikerBob,

The Bilgram diagram is a very handy tool to lay out the port face and valve face. I can walk you through the design of this engine. The thing I need to know is the length of the connecting rod and the design cutoff as a percent of the stroke.

If you are using Jason's suggestion of 3/32" holes then we know the port opening to get the ball rolling. Most of the model designs I have looked at have 0 lead so we can ignore that. The full size Shays I study have a 1/16" lead and when that is scaled down to the scale I work in it is very tiny so I use 0 for the lead.

If you want inside lap for compression and release then we will need the design point for that which is usually 0.9 x stroke.

The steps for doing this are in the article, but to be honest, I did not understand it the first 20 or so times I read it the first time I came across it.

Cheers Dan
ShaylocoDan