Alfonso Lebron-Berges wrote:

I found it very interesting but remembering the years when I was
hobby-building expansion chambers for racing motorcycles I think if
my memory isn't wrong, that for high rpm tuning the chambers were
long & of thin diameter and just the opposite for low rpm tuning
(i.e. trials motorcycles). Another thing that caught my attention was
that they postulate a slower transmission of the wave with increased
exhaust gases density. I thought that cooler and denser gases should
allow for better and faster transmission.

One final thought. How much water would be consumed (weight) in a
three to four hour flight? Maybe Ed has the numbers?

Corrections are welcomed.

Alfonso Lebron-Berges

Ken Powell wrote:

It's been 10 years since I last modified an expansion chamber, but I
think this post has it backwackwards.  A short / fat pipe is for high
RPM, and a long skinny pipe is for low RPM.  If you will remember, the
trials bikes did not appear to have an expansion chamber at all, 125CC
motocross pipes were short and fat, and Open class bikes had pipes
with a thin center section.  Could be wrong, but this is how I
remember it.

Ken Powell

Alfonso,
    Don't recall the amount of water, but clearly it would be a substantial
amount.  Jon Lauter (Marine Rotary) indicated that this is a common practice
with marine installations (of course unlimited water there).  He indicated
that water used in cooling is often ejected in the exhaust pipes.  Did not
indicate whether any performance gains.  Just thought for MSD to produce a
module to control such a function likely indicates someone believes power
gains are a result.

Ed  Anderson

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org