Mailing List flyrotary@lancaironline.net Message #28587
From: Tracy Crook <lors01@msn.com>
Subject: Re: [FlyRotary] Re: Heat exchangers
Date: Mon, 19 Dec 2005 17:24:38 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Good point Rusty. 
 
 I used Bellville washers under the nuts on the 4 threaded rods which will allow the tanks to thermally expand.  Left about .040" of travel in the washer stack for this purpose.  The spring pressure on the tanks is about the same value as the oil pressure trying to split them apart, according to my rough calculations.   I'll still use the accumulator to damp out pressure pulses if I try this thing though.
 
Random thought:  Very strange that Lynn and other car racers have not had a problem with the cores but you busted 2 of them.   BTW, your aluminum welding looked fine to me!  My AL welding looks like hell so far.
 
Tracy 
----- Original Message -----
Sent: Monday, December 19, 2005 2:06 PM
Subject: [FlyRotary] Re: Heat exchangers

Here is a picture of the Ford fitting attach area. Note the strap to hold the stack together. Also not the 1/8 thick plate that the fitting is attached to. Looks like this may have been a fix for a design problem with the other cores.  
 
Hi Monty,
 
I wonder about the wisdom of trying to restrain the cores from being able to expand. I installed a radiator that came with dire warnings against rigidly mounting it.  They said it had to be allowed to expand and contract with temp changes, and if you mounted it rigidly, it would fail in short order.  
 
I realize the strap in the photo is stock, and perhaps if you keep the same type material (aluminum, steel, etc), and subject it to the same temps, then it will expand and contract along with the core.  I just don't think it would be wise to try to beef up a core, without knowing what new stresses it might cause. 
 
Cheers,
Rusty
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