Lynn,

Some speculation going on here.  When you run the exhaust thru a turbo, will it break up the pulses enough for a fishtail to work? I'm hoping to use a fishtail to create an augmentor out the back of my plane. Should I reinforce the fishtail to insure rigidity?

Bob Tilley
Albany, Ga
temporarly on loan to Baton Rouge
 
I would just based on what I did to myself trying to put a form of fishtail on my Fiat racer. Not to form a muffler but to get the exhaust pipe under the Fender seam. So I decided that if I maintain the cross sectional area the same as the main pipe, I should loose nothing, flow wise.
 
So I cut a length of pipe down the centerline and add triangular pieces top and bottom, in .062" mild steel the same as the pipe. Then I squished the opening down to 1" tall in the vise. Then three weekends later the bottom triangle is split in the center. The top would have failed as well but it had a bracket welded on at 90 degrees to bolt it to the car.
 
So I started to notice how others had done the same thing, and guess what? each installation had  a few virtical walls between the top and bottom flat areas, and no cracks. Now I am smart too............
 
I would add these to you fish/mouth/tail..........
 
Lynn E. Hanover