by RCModelReviews » Tue Sep 14, 2010 1:08 am
The problem is that it's not just the carby. The .52 is an overbored .46 which is in turn, an overbored .40.
What this means is that these engines have very shallow transfer ports to carry the air/fuel charge from the crankcase to the combustion chamber during the transfer-cycle.
When you get a spray of *very* fine fuel droplets and squeeze them through a narrow channel, many of the tiny droplets bang into each other so as to create much larger droplets -- and those larger droplets take longer to vaporize and burn when ignited.
The poor mid-range and transition exhibited by the ASP52 is typical of almost all "overbored" glow engines on the market today and comes from the way the fine spray of fuel droplets is forced to become a spray of much larger droplets when directed through very shallow transfer ports.
However, there is some good news -- the use of a very hot plug (such as the OS#7 or Enya#3 does significantly improve the midrange of the ASP52.
It's still not what I'd call a "good" 3D engine but with such a plug it has much better mid-range than when using a normal OS#8 or other medium/medium-hot plug.
It also depends a little on your 3D style. If you don't spend too much time with the engine at idle, it's far less likely to load-up and hesitate when you open the throttle.
I'm going to be throwing one of my 52s in a 3D profile so I'll post a video sometime in the next month.
RCModelReviews.com, just the facts.