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

through 10 hours of flight.  I then squeeze them down to 1/8"

slots and ran

it up on the ground and it did reduce the noise level.  However, I

came back

after a 45 minute flight and both were shredded.

 I have made dual  48" long 2" dia pipes with 260 1/8" holes and

have added

on a section of pipe to each end that I made into 1/8" fishtails.

At least

that way if the fishtails shred again I can just replace them

rather than

cutting the ends off the pipe.  I hung them on the aircraft today

and they

do make a considerable difference in the noise (still not likely

to fall

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

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