From: keltro@att.net
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: overflow connections
Date: Thu, 04 Mar 2004 02:29:19 +0000
Message-Id: <030420040229.20639.36bf@att.net>


> To continue to beat up on this "air vent line from top of engine" - its been
> made clear that the line should not be large.  I'd treat it like I would a
> "direct oil pressure gage":  If the oil line to gage breaks, you don't want
> to dump all your engine oil out a big broken line, so folks use very small
> lines and even put in restrictors.
> 
> Well, in this air/steam vent line, the issue is not breaking and dumping -
> rather, it is "bypassing the radiator".  So, to minimize coolant that
> doesn't get cooled, then either use the smallest possible line, or, as in
> the oil pressure tubing, put in a restrictor.  Air doesn't need much of a
> hole to flow up to your vent tank.
> 
> For my education, Kelly, how big is a -3 hose?  3/16 ID?
> 
> David

        Yes David. AN hose ID is expressed in 1/16 inch increments. Dash 3 is 
  3/16", dash 4 is 4/16"(1/4'),dash 6 is 6/16"(3/8"), etc,etc.
        You are right,smaller is better but even  dash 6 will not cause a
  major problem. The vent fitting at the rear of the engine block (front in a 
  tractor A/C) picks up air and water from the hot side of the engine before
  it flows through the cool (relatively) side and sends it directly to the
  expansion tank where the air stays in the tank and the water goes directly
  to the suction side of the pump and to the radiator. IMHO 
        Sorry if I got carried away!

  Kelly Troyer