Make them smaller and gradually larger as the wave travels down the
pipe?

Paul Lamar

        Perhaps the pressure wave cannot dissapate from the
first holes only. Must continue on until area of holes matches
the area of the pipe. Even then you have the speed of the
wave to allow for, cannot make a sharp turn to exit holes.
Virg

Finn,

    The holey mufflers I have seen have the holes turn into louvers of a
sort.  Taking a rod that will fit the hole and wiggle it back and forth
longitudinally and bend the metal surrounding the hole until the back edge
of the holes raises up approx 1/8" (maybe more) into the tube with the front
edge of the hole being bent down outside the surface of the tube.  Don't
know if this may help capture the sound wave that just a plain hole.
I have done mine that way and it looks like a metal porcupine inside the
tube for half the circumference.  Don't know if that might help or not but
sounds like it wouldn't hurt anything.

Ed Anderson

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

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