Ed Anderson wrote:

Jerry, I had the same experience with my fishtails.  My pipes were

15" long

with 30 5/16" dia holes in each pipe and the ends squeezed to

first 1/2"

slots and then 1/8" slots.  With the 1/2" fishtail slots the

fishtails lived....

SNIP....

asleep, but certainly quieter) and they did not appear to affect

static rpm

which was 5600 rpm.

 I plan on flying again later this week and will see if they

survive.

Best Regards

Ed Anderson

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
 
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