Originally Posted by
flybyjohn
To tell you the truth, I don't really know much about the porting on the engines. I got the basic concept but don't understand how improvements in performance are achieved by doing different modifications. Does blocking a boost port increase fuel efficiecy? I don't really want to do anything permenant because I am planing to convert back to glow. I have had no problems with the glow setup on this plane, I just thought I could get better power and more speed out of this engine as a diesel to begin with and now have found out other wise. The cost of diesel makes it cost prohibited for an everyday plane and although some may disagree, there is a bit more hassle with the diesel for me than with the glow since I am already set up for glow.
Since most modern R/C glows come out of the box with the compression set low very low, there is considerable power (~ 10% at least) gain to be had free just by setting the squish height somewhere near optimum. It probably means shaving the underside of the head a bit. Further power can be unleashed by going to a Turbo or Nelson style bottom sealing glowplug. I don't know what this does to the idle but it's a lot cheaper than having to use premium priced diesel fuel.
There is a place and role for model diesels (I own at least a 100 of 'em), but cheaper flying isn't an attainable goal.