Chainsaw Repair

I still need to wade through all the details of this paper.  However, I think it is important not to lose sight of what the authers were trying to accomplish.  They state this in the opening paragraphs:

By changing the crankcase volume and lengths of the exhaust and inlet pipes, the authors have experimentally investigated the effect of the crankcase volume on the delivery ratio, and the effect of exhaust and inlet systems to compensate for the drop in delivery ratio caused by increasing the crankcase volume.

So once again it is all about the pipes, which makes sense because that effect is so dominant.  But what if there is no pipe?  Here, the only real hint seems to be in the following graphs, if we look at both intake and exhaust as "shortest" (i.e. untuned).  However these graphs don't go any lower than a case to swept volume ratio of 2, so even here it may not be relevant:

Figure 6 shows that there is no rpm relationship to the delivery ratio - the delivery ratio peaked at some rpm, and it didn't matter what the case volume was. 

Figure 9 shows that even by 3000 rpm, with no tuned pipes increasing the case volume reduces delivery ratio. 

I don't know why the no pipe lower rpm plots in Figures 7 & 8 show larger case volume is better - perhaps because there is so much time that other effects dominate, or maybe because the no pipe situation was not really the focus of their efforts and some other effect was going on.   

Still, I think what little data there is in this paper about engines with no tuned intake or exhaust confirms that at reasonable rpms smaller case volume is always better.

sorry, i cannot post the screenshots.  best i can do.  EDIT <<<<<<hahaha fixed it. silly windows.

believe it is best to use the words from the paper in my reply.

imho:
the first one shows the graphs being similar.
the second one shows what i used to come up with the graphs i made.
the third one addresses, part of the intent of the paper.

i'm looking at the 'untuned' pipes as being the 'shortest-shortest' as well.