Mailing List flyrotary@lancaironline.net Message #4910
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: dual EWP plumbing?
Date: Tue, 23 Dec 2003 09:12:34 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
I am trying to understand this plumbing scheme. Where in the circuit are the water pumps? Are they after the "Y splitter", or on the line going from the core to the Meziere inlet? 
 
They will be in the return line from the cores, to the engine.  
 
   The pumps are likely to do better at 'pushing' the liquid rather than pulling it, so you want the outlet of the pump going into the evaporator core. 
 
Actually, this is why I figured they'd be better in the return line.  It's also nice to keep the coolant pressure in the engine as high as possible, so I figured it made sense to have the pumps feeding directly to the engine.    
 
One operational concern is if you are operating on one core, and the thermostat calls for the second pump, when it turns on, it is going to be delivering 'cold' fluid that has been stagnant in the core to the engine. you 'might' end up with oscillations in the cycling of the pump. Will this cause a problem?
Bill Schertz
KIS Cruiser # 4045 
 
Hmmm, good question.  I don't know if that will be a problem or not.  The one way valves require .5psi to flow, so even if the pump is off, there might still be some flow.  Unfortunately, I just don't have a feel for how much flow, if any there will be.  
 
BTW, I do appreciate the comments.  Fortunately, the difference between the two plumbing schemes is a simple modification.  I guess I'm just trying to decide if there's any good that can come from running one pump per core.  
 
Cheers,
Rusty
 
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