REFLECTOR: Plenum-Runner-firewall connections

[Jeffrey Clough]

I am beginning the fabrication of my plenum to NACA runners....I looked 
at the online construction pics......it looks like the plenum is screwed 
into the firewall via a flange at the NACA ducts and at the other end it 
is screwed into the plenum via a flange......in the MIDDLE of the 
runners is a joint of what appears to be engine baffle wrapped around 
and pop riveted to the lower runner section.....does the upper runner 
section just 'fit like a glove' into this baffle wrap?  Is this the best 
way to do this?  Is it easy to disassemble...to remove the plenum...with 
this method?  Does this isolate the engine vibrations from the 
runner-NACA junction?  Does the upper runner section still insert into 
the lower section an inch or two or do they approximately 'butt' inside 
the baffle wrap??   Thanx for your help!
Jeff Clough    173 RG Clamshell Franklin