----- Original Message -----
From: keltro@att.net
Date: Friday, October 24, 2003 0:30 am
Subject: [FlyRotary] Re: EWP check valves

>    Ernest,
>      I am still planning on remote radiators but not as far to
> the rear of
> the Delta as you have indicated. I plan on mounting a GM
> evaporator on each
> side of the a/c to the rear of the firewall between the second and
> third rib
> inboard of the Delta centersection. the large 9.5"x13" evaporators
> fit very
> well here. I am using a NACA report on radiators buried in wings
> from the
> 1940's to size, shape and position the inlets and outlets. I will
> use alum.
> tubing and short hose connectors. Not sure of what size yet but
> will be
> larger than 5/8" but smaller than 2". I am leaning toward 1.25" or
> 1.5".
>     I am considering running the alum tube inside a duct that I
> can put
> cooling air through.
>
>    Kelly Troyer  
>

I think I'm going to have to follow your lead.  I found some engineering data on how to calculate the backpressure caused by tubing, and then worked up a spreadsheet.  Inputs are tube diameter and length.  Useful outputs are weight and head pressure.
Off the top of my head, the 5/8 tube would only add about 4lbs but require over 2000psi of pressure.  the 1.25 tube will add almost 30lbs, but only need 3psi.