X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao03.cox.net ([68.230.241.36] verified) by logan.com (CommuniGate Pro SMTP 4.3.4) with ESMTP id 1008890 for flyrotary@lancaironline.net; Tue, 21 Jun 2005 11:12:53 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.36; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao03.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050621151202.PIVW17043.fed1rmmtao03.cox.net@BigAl> for ; Tue, 21 Jun 2005 11:12:02 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] EFI return fuel testing Date: Tue, 21 Jun 2005 08:12:15 -0700 Message-ID: <000001c57673$9c2a9480$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C57638.EFCBBC80" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C57638.EFCBBC80 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit One of the Velocity builders with a Soob (Wayne - something) said he had so much foam returning to the sump tank from the pressure regulator that the foam would come out of the fuel system vent. He added a small reservoir of some kind in the vent line as a foam/liquid separator. That apparently solved his problem. In the 4-5 hours of running time I have on my 20B I have not observed any foam from the stock venting; nor have I heard of anyone else observing this phenomenon. Why in one case, I have no idea. But the potential for foam buildup is there, and it is something to keep in mind when designing your fuel system. Al While running my ground testing, during the winters using auto fuel. I used clear 3/8" tubing for fuel line, from my Facet pump up to my carburetor. While the engine was producing power, I noticed bubbles in the line, on the pressure side. Baffeled by how air could be leaking into a six psi line, I looked it over, and discovered that there was a slight kink in the tubing. The bubbles were from the small restriction in the pressure line (come to think of it, it may have been a three psi pump, not six). Anyway, the bubbles really don't bother the Carter carb, with a float, but, I wonder how much vapor bubbles are returned from the EFI pressure regulator. It seems likely, that with a 35 psi pressure drop, the vapor may be very significant. Certainly, someone on this list must have a setup capable of testing the theory. All one would need would be a clear vessel to return the fuel to, and perhaps suck fuel out of, with the remaining system intact. Pump on, engine off would seem the worst case. Cold weather auto fuel would be the most likely to vaporize. Test results could contribute to safe fuel system design. George Graham Mazda Rx7ez N4449E Homepage __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0001_01C57638.EFCBBC80 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

One of the Velocity builders with a Soob (Wayne = – something) said he had so much foam returning to the sump tank from the pressure regulator that the foam would come out of the fuel system = vent.  He added a small reservoir of some kind in the vent line as a = foam/liquid separator.  That apparently solved his problem.

 <= /font>

In the 4-5 = hours of running time I have on my 20B I have not observed any foam from the = stock venting; nor have I heard of anyone else observing this phenomenon.  Why in = one case, I have no idea.  But the potential for foam buildup is there, = and it is something to keep in mind when designing your fuel = system.

 <= /font>

Al

 <= /font>

While running my ground testing, during the winters using = auto

fuel.  I used clear 3/8" tubing for fuel line, from my = Facet

pump up to my carburetor.

 

While the engine was producing power, I noticed bubbles in = the

line, on the pressure side.  Baffeled by how air could = be

leaking

into a six psi line, I looked it over, and discovered that = there

was a slight kink in the tubing.  The bubbles were from = the

small restriction in the pressure line (come to think of it, = it

may have been a three psi pump, not six).

 

Anyway, the bubbles really don't bother the Carter carb, with

a float, but, I wonder how much vapor bubbles are returned =

from the EFI pressure regulator.  It seems likely, that = with

a 35 psi pressure drop, the vapor may be very = significant.

 

Certainly, someone on this list must have a setup capable of

testing the theory.  All one would need would be a clear = vessel

to return the fuel to, and perhaps suck fuel out of, with = the

remaining system intact.  Pump on, engine off would seem = the

worst case.  Cold weather auto fuel would be the most = likely

to vaporize.

 

Test results could contribute to safe fuel system design.

 

 

 

George Graham

Mazda Rx7ez N4449E

Homepage <http://bfn.org/~ca266>

 

______________________________________________= ____

Do You Yahoo!?

Tired of spam?  Yahoo! Mail has the best spam protection around =

http://mail.yahoo.com

 

>>  Homepage:  http://www.flyrotary.com/

>>  Archive:   = http://lancaironline.net/lists/flyrotary/List.html

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