From Gordon Jennings in 'The Two-Stroke Tuner's Handbook' page 70:
More recently, I have been able to perform a series of tests using a dynamometer,
to see if my inside-stinger idea (which, I had learned, was an idea also advanced by an
obscure German researcher some several years earlier) had any real merit. An expansion
chamber was constructed with its baffle-cone terminating in a clamp, to allow rapid
changes in outlet pipes. and we tried pipes of different diameters and lengths, and moved
them back and forth in the clamp to find the change in output as the outlet's forward end
was advanced up the baffle-cone. The results were most interesting: There was
absolutely no difference in power output with the outlet pipe in full-forward and full-back
positions, but we did find a quite noticeable drop in power with the pipe's forward end
pushed up to the approximately-halfway point in the baffle-cone. We also found that the
same outlet pipe diameter produced optimum results no matter what the location, but that
the system was rather less sensitive to outlet pipe length when the pipe's forward end was
located an inch or so ahead of the baffle-cone's forward end. Finally, we found that the
noise output with the forward-located outlet pipe was very much reduced: to about the
same level as a conventional expansion chamber fitted with a bolt-on, fiberglass-packed
muffler. I was, of course, a bit disappointed that my inside-stinger pipe did not show a
big advantage in power over the conventional variety (there may be a slight broadening
of the power curve, but the differences observed were too small to offer conclusive
proof). Still, by that time, the sound-damping properties of the inside-stinger
arrangement had become extremely important, as they could be used in conjunction with
a low-resistance muffler ...
Crazy
