Mailing List flyrotary@lancaironline.net Message #43483
From: Al Gietzen <ALVentures@cox.net>
Subject: Re: pre-mix
Date: Sat, 19 Jul 2008 07:45:03 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

About the fuel comming out of the fuel vent.   I have a 4 gal header tank like you.  Sometimes when I started the fuel pump it would spit some fuel out the vent, not every times.   I built a small tank, about 2 ounces and connected the vents from the two lower wing fuel tanks to it and the header tank vent to the bottom of this small tank.  The top of this tank is vented.  No more spit out, when the header tank spit it drains back to the lower wing tanks.

Rino;

 

My vent system has a manifold block where the lines from the sump and the 2 strake tanks join up to the single vent line going out.  I’m going to make a small accumulator as you did and install in place of the manifold block.  This should allow any foam coming up from the sump to separate out, and the fuel drain back to the tanks.

How did you make your small tank?  Since I don’t have welding ability so I’m thinking of making it out of fiberglass.

 

Al G

 

Rino Lacombe

Renesis Glass Goose

----- Original Message -----

From: Mark Steitle

Sent: Sunday, July 13, 2008 12:47 PM

Subject: [FlyRotary] Re: pre-mix; great trip

 

Beautiful picture Al.  Good observations on performance.  Glad to hear that everything is working well. 

Mark S.

On Sun, Jul 13, 2008 at 10:48 AM, Al Gietzen <ALVentures@cox.net> wrote:

Another thing I notice is a small amount of fuel is coming out of the fuel vent.  The only explanation I can come up with is foaming/bubbles forming in the return line after the pressure regulator.  This goes into the 3-gallon sump tank and up the ¼" vent line.  This may have been occurring previously, and the fuel evaporated as it went back along the surface; but now the blue 2-cycle oil is left behind to be quite visible at the back of the cowl; but I suspect the pre-mix is exacerbating the foaming.

 

I notice the plugs have less carbon than before, and the inside of the exhaust exit is now very light grey.

 

Al


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