Mitch, I've never seen such a thing on a Coupe's pitot/static tube. I think it should be removed.
The airflow across the static holes is supposed to be pretty straight and linear, not turbulent. That donut thingy would make a mess of the airflow over the static holes and the results would be, I'd guess, undefined and variable. Mitch uploaded a copy of the photo (also included as an attachment in his second message) to the tech photo page for those who'd like to view it. Look for N99325. Ed Ed Burkhead http://edburkhead.com/Ercoupe/index.htm East Peoria, Illinois ed -at- edbur???khead.??com (remove the ? marks and change -at- to @)
