With enough holes you could just close the end of the

pipes,Virg

 I agree Virg,
    Right now trying to find the right combination of hole

diameter and

number of holes that will adequately reduce the intensity of the

exhaust

sound and yet not provide so much back pressure as to serious

degrade

performance.
    Squeezing down from 1/2" slot on the fishtail to 1/8" slot

appeared to

make a lot of difference in the force the exhaust pulse was

exerting on the

fishtail lips.

    I know have 260 1/8" dia holes in a 36" length of 4' tubing.

One for

each exhaust.  The fishtail is squeezed down to 1/4" slot.  So we

will see if it lives when next I fly.

Ed

Are you beefing up your fish tails Ed?
Paul Lamar

If the area of the holes is greater that the area of the exaust pipe,
you should be in great shape, Virg

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

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