Brian, just to follow along with Tennessee's thoughts, I have access to several full size hit and miss engines and, while running one a couple of days ago, I made the following observations.
They all have two flywheels, so a very large rotating mass.
Using the term "throttle response" which is wrong for these engines I know, but everyone understands what I mean, the engine I was running could not even be described as "sluggish". I held the governor off and casually counted to ten. A rough estimate would put the increase in speed at somewhere between 50 and 100rpm in an engine which was running at 300rpm. This is of course a product of rotational mass and cylinder torque.
However, killing the ignition and allowing the engine to coast to a stop, took about 1 minute. This is purely rotational mass at work along with friction and pumping losses.
The other aspect of operation surrounded the governor which is very sensitive. Whilst running normally, there was almost no discernable change in rpm between hitting and missing, although the governor was obviously doing it's job. This engine would typically fire once and spin maybe 6 revolutions on miss.
So to sum up, I wonder if perhaps you know how big a speed variation your engine requires in order for the governor to do its thing? Is there any friction in the governor mechanism?
One final thought. Do our model engines actually produce too much torque per firing stroke and should we try to make them a bit more "sluggish"?
Just my two cents worth.
Ian.
