X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.123] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5110417 for flyrotary@lancaironline.net; Thu, 01 Sep 2011 08:34:16 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.123; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=4MSDN839FDsgJpwQlr+eLEnlTy8eaQTddc4+Fk+GTfI= c=1 sm=0 a=wUz_2pd9at4A:10 a=SC71y0a/4S6V9vjVxUojGA==:17 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=3oc9M9_CAAAA:8 a=V0sYiUSkAAAA:8 a=o9KuFcxMAAAA:8 a=J8SDXSTdg5YyUG9GhXUA:9 a=RsXbWGDYDTZxQFNjOiAA:7 a=wPNLvfGTeEIA:10 a=XptUGg1y60QA:10 a=U8Ie8EnqySEA:10 a=GhIjh3UBWcwA:10 a=j0ivVUoOkfVcJh0s:21 a=9aeOX9xtEQHxKhV_:21 a=pedpZTtsAAAA:8 a=Ia-xEzejAAAA:8 a=4PR2P7QzAAAA:8 a=mmYX7hXNGF3GbQbqlPUA:9 a=UZ9hsOLYZ2bBKXDagWsA:7 a=eJojReuL3h0A:10 a=EzXvWhQp4_cA:10 a=djSSOgbfo6cA:10 a=SC71y0a/4S6V9vjVxUojGA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.175.135 Received: from [174.110.175.135] ([174.110.175.135:59368] helo=EdPC) by cdptpa-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 1E/E5-28959-5AB7F5E4; Thu, 01 Sep 2011 12:33:41 +0000 Message-ID: <0336395369FE479DB6650D1AF74EB1CC@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Pump Suck Lock?: [FlyRotary] Re: CG Products Intake Manifold Date: Thu, 1 Sep 2011 08:33:37 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0047_01CC6881.D852D9C0" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_0047_01CC6881.D852D9C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I don't see any problem with the term "vapor lock" itself - because when = the pressure on the pump inlet gets low enough, that is exactly what = happens - sufficient fuel enters a gaseous state to interfere with the = pumping of liquid fuel to the high pressure side. So the term is not = that bad a description so long as we all realize it happens on the Low = pressure (inlet) side of the pump and NOT the high pressure side. =20 My experience with "vapor lock" showed that by turning my boost pump on = (adding pressure to the "suction " side of the EFI high pressure pump) = eliminated the condition - which again indicates the problem is low = pressure on the inlet side of the EFI pump. If there were liquid there, = it would be pumped, so must be vapor - so the pump is "vapor locked" = but, - not on the high pressure side. =20 Perhaps we should refer to a more technical accurate descriptive name , = how about "Pump Suck Lock" {:>) - just kidding. Ed=20 Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com From: Charlie England=20 Sent: Wednesday, August 31, 2011 3:07 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: CG Products Intake Manifold Data point: One of the big aviation engine/fuel injection suppliers = installs -4 lines everywhere in front of the firewall up to the = 'spider', on all 4 cyl Lycs (up to 200+ hp) and if memory serves, even = on the 6cyl engines (230+ hp). The individual lines from the 'spider' to = the cylinders are so small you'd be hard pressed to get safety wire = through them. This is on a Bendix style injection system using a = diaphragm type fuel pump and no return line after the pump. These = systems run at between 15 & 30 psi. Logic is that minimum diameter line = minimizes quantity of fuel that can boil on the engine side of the = firewall.=20 With minimum diameter lines, as long as the pump can provide pressure it = won't take long to clear any vapor as soon as cranking begins, or you = hit Tracy's 'cold start' button a couple of times. (Vapor in the = combustion chamber is a good thing anyway, right?) :-) As Al Wick pointed out, the only place vapor should be a problem is at = the inlet to the pump itself. Charlie On 08/31/2011 07:35 AM, CozyGirrrl@aol.com wrote:=20 Interesting Chad. The people flying Subes and using autogas were also guessing that = altitude was a factor in vaporlock. We won't be using autogas due to = variable formulation eating up epoxy tanks. We were thinking that if the regulator was the last item in the chain = and that the rails were hooked up serially that it would minimize = vaporlock and also a few seconds of the pump running before a hot = restart would cool and clear the rail. Chrissi & Randi www.CozyGirrrl.com CG Products, Custom Aircraft Hardware Chairwomen, Sun-N-Fun Engine Workshop In a message dated 8/30/2011 11:36:05 P.M. Central Daylight Time, = crobinson@medialantern.com writes: I recently researched EFI regulation a bit and found something = interesting. Many modern (post-1995) vehicles have "returnless" EDI = systems where the regulator is in or near the tank, not the engine = compartment. It turns out this isn't for complexity reasons, though it does save = a bit. It's for emissions. The heating of the fuel in the engine = compartment transfers heat back to the tank. The tank's emissions do = count even though they're not huge. It's also one less part, hose, and = set of fittings to fail- and get warranty calls on. To deal with vapor lock they just crank up the pressure to 65 or = more psi. Very effective. Not at all saying we should do the same, but the purpose is = interesting, no? As well as the vapor lock" solution"... Regards, Chad ------=_NextPart_000_0047_01CC6881.D852D9C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I don't see any problem with the term "vapor = lock" itself=20 - because when the pressure on the pump inlet gets low enough, that is = exactly=20 what happens - sufficient fuel enters a gaseous state to = interfere=20 with the pumping of liquid fuel to the high pressure side.  So the = term is=20 not that bad a description so long as we all realize it happens on the = Low=20 pressure (inlet)  side of the pump and NOT the high pressure = side. =20
 
My experience with "vapor lock" showed that by = turning my=20 boost pump on (adding pressure to the "suction " side of the EFI high = pressure=20 pump) eliminated the condition - which again indicates the problem is = low=20 pressure on the inlet side of the EFI pump.  If there were = liquid=20 there, it would be pumped, so must be vapor - so the pump is "vapor = locked" but,=20 - not on the high pressure side.  
 
Perhaps we should refer to a more technical = accurate=20 descriptive name , how about  "Pump Suck Lock" {:>) - just kidding.
 
 
Ed 
 
 Edward L.=20 Anderson
Anderson Electronic Enterprises LLC
305 Reefton=20 Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com
 
 
 
 

 
From: Charlie England
Sent: Wednesday, August 31, 2011 3:07 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: CG Products Intake=20 Manifold

Data point: One of the big aviation engine/fuel injection = suppliers installs -4 lines everywhere in front of the firewall up to = the=20 'spider', on all 4 cyl Lycs (up to 200+ hp) and if memory serves, even = on the=20 6cyl engines (230+ hp). The individual lines from the 'spider' to the = cylinders=20 are so small you'd be hard pressed to get safety wire through them. This = is on a=20 Bendix style injection system using a diaphragm type fuel pump and no = return=20 line after the pump. These systems run at between 15 & 30 psi. Logic = is that=20 minimum diameter line minimizes quantity of fuel that can boil on the = engine=20 side of the firewall.

With minimum diameter lines, as long as = the pump=20 can provide pressure it won't take long to clear any vapor as soon as = cranking=20 begins, or you hit Tracy's 'cold start' button a couple of times. (Vapor = in the=20 combustion chamber is a good thing anyway, right?) :-)

As Al Wick = pointed=20 out, the only place vapor should be a problem is at the inlet to the = pump=20 itself.

Charlie

On 08/31/2011 07:35 AM, CozyGirrrl@aol.com wrote:=20
Interesting Chad.
The people flying Subes and using autogas were also guessing that = altitude was a factor in vaporlock. We won't be using autogas due to = variable=20 formulation eating up epoxy tanks.
We were thinking that if the regulator was the last item in the = chain and=20 that the rails were hooked up serially that it would minimize = vaporlock and=20 also a few seconds of the pump running before a hot restart would cool = and=20 clear the rail.
 
Chrissi=20 & Randi
www.CozyGirrrl.com
CG Products, Custom = Aircraft=20 Hardware
Chairwomen, Sun-N-Fun Engine Workshop
 
In a message dated 8/30/2011 11:36:05 P.M. Central Daylight Time, = crobinson@medialantern.com= =20 writes:

I recently researched EFI regulation a bit and found something=20 interesting. Many modern (post-1995) vehicles have "returnless" EDI = systems=20 where the regulator is in or near the tank, not the engine = compartment.

It turns out this isn't for complexity reasons, though it does = save a=20 bit. It's for emissions. The heating of the fuel in the engine = compartment=20 transfers heat back to the tank. The tank's emissions do count even = though=20 they're not huge. It's also one less part, hose, and set of fittings = to=20 fail-  and get warranty calls on.

To deal with vapor lock they just crank up the pressure to 65 or = more=20 psi. Very effective.

Not at all saying we should do the same, but the purpose is = interesting,=20 no? As well as the vapor lock" solution"...

=

Regards,
Chad


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