Chainsaw Repair

Graphs and charts are fine Joe, but I tend to approach problems from concepts first, and since I do not know what you are trying to show they may not be meaningful to me. 

To that end, V_C and V_S are fixed for a given engine design.  The authors devised a way to vary V_C and look at how that effected delivery ratio at various rpm.  Still, for each value of V_C, both V_C and V_S are fixed and not a function of rpm, so equating different combinations of them (V_C/V_S vs. CCR) tells you nothing about delivery ratio. 

It is delivery ratio that is a function of rpm and V_C and V_S.  If you could come up with a way to model Figure 5 for an un-piped engine that might be useful, but it would be very complex - and it appears that if you tune the engine for typical saw rpms, then the simple model of smaller-case-volume-is-better will suffice in most cases anyway.  In my opinion that is what Figure 5 shows, and I think if you look at what the manufacturers are doing it confirms this.  It might technically be possible to make the case volume so tight that the rpm of max delivery ratio moves higher than the port timing can be set up for, but I think in practice this would be very difficult to do.