Thanks, for reply, this is in a Pegasus HP powered Cermark Viper II, that has flown for 10+ years and has even taken a Best Civilian Jet at Route66 as well as IRON MAN at Kentucky Jets so it has many flights proven on tailpipe at Eagle Tree Pitot speeds routine of 199.99MPH

As an engineer I am well versed on heat expansion/contraction, thus my question/confusion with tailpipes "BY DESIGN". So my take away is the corrugated standoff ring that "is" spot welded to "inner pipe" is just an "OD" dimensional friction fit to outer wall cooling pipe and mine has now lost some of its friction fit tolerance between the two.

The inner Pipe has two straps holding it to the kevlar full bypass, so I was thinking a security strap attached on the front end in like manner attached to wooden bulkead would not inhibit any dimensional expand/contract in diameter/length only acting a as piece of mind since it now will freely fall off if stood on end on the bench out of the model. This is something in never did before and no other pipe I own exhibit.