X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from nm28.bullet.mail.sp2.yahoo.com ([98.139.91.98] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with SMTP id 5091213 for flyrotary@lancaironline.net; Sat, 13 Aug 2011 17:50:44 -0400 Received-SPF: none receiver=logan.com; client-ip=98.139.91.98; envelope-from=roundrocktom@yahoo.com Received: from [98.139.91.67] by nm28.bullet.mail.sp2.yahoo.com with NNFMP; 13 Aug 2011 21:50:09 -0000 Received: from [98.139.91.3] by tm7.bullet.mail.sp2.yahoo.com with NNFMP; 13 Aug 2011 21:50:09 -0000 Received: from [127.0.0.1] by omp1003.mail.sp2.yahoo.com with NNFMP; 13 Aug 2011 21:50:09 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 844905.79967.bm@omp1003.mail.sp2.yahoo.com Received: (qmail 31830 invoked by uid 60001); 13 Aug 2011 21:50:09 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1313272209; bh=hXxNHVqsHWH1QEWoZ+pXY90VZvEGHnKAfe47aaHIJIc=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=uCk96NVvLZe/GkUf0AvxlDkRXAboxsG4gm3aQF72EffXD0SXjibeQSKAw1ZRSKpn14FaiUdCob4dnkQJlTq70ded2Df5xVknQSo0CnIZxfX2YjdTmXkLyVuC76I+bw1aTSx31+yPpTG8HaW/jPPRGPh493841CmC4iHwSvEGV/Q= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=Nv04YxRljWqR/a3MCx+HkBLO+NDF6KoD5YhAvAYFnXfCdf/vv1kDS3J0PwspxYK1c3piaYTuxmgDwMukiJRVpksxcAiqsSqhEaNXdjYC2H5t/+9jsgEQ5QKvsCgPE/xnUTYFPsV1A0v0DyYokCudHTinZLg4JXnVWOmBxe3Rojk=; X-YMail-OSG: yZEk7kIVM1mqhi2opwVwWeJN1PFb.PDjbi4ASY2UHjdmYvT JawtsIsMNohNbSf5K3K40gFlv7gKLcroKTSPH3yBbUkAeRhy8t4km.KYJCoh whwOENzeLxnJDz_eN1u87rmfwcRmbg7ixnwdOque4T3BB7ngv4I__rpWGmdC 3sA.b.Uth81V17sce4IDd6DjqX08A2SZCIWf0hFBu8mvCzLhIn9pqsB3AO2_ wMNdtj2XVgO1rXXJ8ry0AJC960IqKeqkmwJvzbOQtHMn_T3q5_Mig8UEQitf VaL7CFYaMH6ZYyGu0rZuhCxvrB1jxiuhUuDh0IdlKZ3oJQi_t80ZXhV8yV5S NB9llTpVmCAUuKbzGQCWBW8IWwCGa4Tt13e5CCYfoSicKcDfxF_TCnutbXiV jO1wM41d.a4KC4ucel0IRbfXye6gNZfoRxNUoRiTqhjKrhgKyG5FduXZIZDx jYA-- Received: from [66.68.30.169] by web111512.mail.gq1.yahoo.com via HTTP; Sat, 13 Aug 2011 14:50:09 PDT X-Mailer: YahooMailWebService/0.8.113.313619 References: Message-ID: <1313272209.22374.YahooMailNeo@web111512.mail.gq1.yahoo.com> Date: Sat, 13 Aug 2011 14:50:09 -0700 (PDT) From: Tom Walter Reply-To: Tom Walter Subject: Re: [FlyRotary] Re: vapor lock To: Rotary motors in aircraft In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-672993426-163291085-1313272209=:22374" ---672993426-163291085-1313272209=:22374 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Dennis,=0A=0AThanks.=A0 Little different with a high wing (i.e. leave on bo= th).=0A=0AI'll have aux tanks (10 gallons each), those are plumped into the= 25 gallon main tanks,=0Avia the Facet Pumps.=A0 I don't recognize Faust=A0= (perhaps a sublime joke I missed?).=A0 =0A=0A=0AI might never need all 70 = gallons (65 useable), but nice to have the extra capacity.=0A=0ATom=0A=0A= =0A=0A=0A________________________________=0AFrom: Dennis Havarlah =0ATo: Rotary motors in aircraft =0ASent: Saturday, August 13, 2011 2:53 PM=0ASubject: [FlyRotary] Re: v= apor lock=0A=0A=0ATom,=0A=A0=0AI have no fuel valves.=A0 I copied Tracy's = =0Amethod - feed the high pressure fuel injection pumps from the left tank.= =A0 I =0Ause a Faust low pressure pump to transfer fuel from the right tank= to the left =0Atank.=A0 I use the EM-2 with it's=A07 minute timer to remin= d me to turn =0Aoff the transfer pump.=A0 I use=A0one GM auto filter on the= outlet of each =0Afuel injection pump.=A0 The pumps are in parallel.=A0 To= change the fuel =0Afilters I first run the left tank low and than drain mo= st of the remaining =0Afuel.=0A=A0=0AMy .020 orifice discharge and the =0Ap= ressure=A0regulator return flow both go to a -4 return line that is "T" ed = =0Ainto the Faust discharge line to the left tank.=0A=A0=0ADennis H.=0A----= - Original Message ----- =0A>From: Tom Walter =0A>To: Rotary motors in air= craft =0A>Sent: Saturday, August 13, 2011 1:51 PM=0A>Subject: [FlyRotary] = Re: vapor lock=0A>=0A>=0A>Dennis,=0A>=0A>=0A>What fuel valve are you using?= =0A>=0A>=0A>My plans on the Bearhawk (high wing taildragger):=0A>=0A>=0A>Le= ft and Right fuel lines flow into a "R-Both-L-off" single Andair valve.=0A= >=0A>=0A>Then to the gascolator (low point at rest)=0A>=0A>=0A>Gascolator f= eeds header tank, then into two pumps (only one in flight).=0A>=0A>=0A>Eve= rything is under the floor of the planer, under a 0.032" 2024 floor board.= =0A>=0A>=0A>Fuel return though a small "T" (0.020" orifice) to header tank= .=0A>=0A>=0A>Where does the regulator return fuel to?=A0 =0A>=0A>=0A>=0A>Wi= th the high wing, any air bubble from the header tank should work it's way= =0A>back up the line into the tank.=A0 -6 aluminum tubing (note tanks have = for and=0A>aft pickups, that meet up under the door.=A0 Allow for flow at = high angles of=0A>attack.=0A>=0A>Tom=0A>=0A>=0A>=0A>=0A>=0A>=0A>=0A>=0A>= =0A>=0A>=0A>=0A>=0A>=0A>________________________________=0A> From: Dennis H= avarlah =0A>To: Rotary motors in aircraft =0A>Sent: Saturday, August 13, 2011 12:41 PM=0A>Su= bject: [FlyRotary] Re: vapor lock=0A>=0A>=0A> =0A>Right On Kelly!!=0A>=A0= =0A>I have the fuel system=A0Kelly described in my RV-7A.=A0 I've used Mog= as with and without ethanol with outdoor temperatures up to 105 ' F.=0A>= =A0=0A>I have never had a vapor lock problem.=A0 After stopping for fuel a= nd the engine compartment=A0 heat soaks I hear the vapors being pushed out= of the fuel rails and thru the bypass orifice =A0when I turn on the pumps= .=A0 No Hot Start Problems!!=A0 It takes less than 5 seconds for the vapor= s to be removed and returned to the tank.=A0 That means that all the injec= tors see is cool fuel when I start the engine.=A0 =0A>=A0=0A>My fuel pumps= are located on the floor between the pilot and passenger.=A0 Because the = pumps are very low fuel from the left tank will flow into the pumps by gra= vity.=A0 =A0One -6 aluminum fuel line from the pumps runs to the firewall.= =A0 If any fuel leaks during flight I will smell it and turn off the pumps= and start gliding.=A0 If I have a leak in the engine compartment I may no= t detect it before it ignites.=0A>=A0=0A>Just my two cents worth.=A0 It do= es work for me.=0A>=A0=0A>Dennis H.=0A>=A0=0A>=A0=0A>=A0=0A>=A0=0A>----- O= riginal Message ----- =0A>>From: Kelly Troyer =0A>>To: Rotary motors in air= craft =0A>>Sent: Saturday, August 13, 2011 9:22 AM=0A>>Subject: [FlyRotary= ] Re: vapor lock=0A>>=0A>>=0A>>Guys,=0A>>=A0=0A>>I vote for keeping high p= ressure pumps as close to the tanks and as low =0A>>as possible to fuel le= vel...............I would not locate pumps and/or suppy=0A>>hoses=A0firewa= ll forward unless totally encapulated,=A0insulated and cooled=0A>>by ram a= ir...........And by all means use the bypass oriface...........Besides=0A>= >helping to reprime pumps (as Mark says) it will relieve pressure on leaky= =0A>>injectors to prevent flooding (if you have experienced this with the = 13B=0A>>you know what I mean and the Renesis is even worse to clear) and t= o=0A>>allow a vapor lock to clear the high pressure supply lines=A0from=A0= pump to =0A>>the regulator............One more thing I would install the r= egulator after the =0A>>fuel rails/injectors to allow any vapor to pass thr= ough the rails on their way =0A>>to the bypass oriface...........I have se= en some fuel regulator=A0installations =0A>>with the fuel rails "Dead Ende= d" after the regulator leaving vapor trapped=0A>>in the rail..............= ...When flying vapor might clear with only an apparent =0A>>misfire to the= pilot but=A0after shutdown and after heat soak it could cause =0A>>"Hot S= tart" problems (has anyone tryed to hot-start an fuel=A0injected=A0 "Lyc"= =0A>>lately............IMHO=A0=0A>>=A0=0A>>Kelly Troyer=0A>>"DYKE DELTA JD2= " (Eventually)=0A>>"13B ROTARY"_ Engine=0A>>"RWS"_RD1C/EC2/EM2=0A>>"MISTRAL= "_Backplate/Oil =0A Manifold=0A>>"TURBONETICS"_TO4E50 Turbo=0A>>=0A>>=0A= >>From: Ed Anderson =0A>>To: Rotary motors in a= ircraft =0A>>Sent: Saturday, August 13, 2011 = 8:16 AM=0A>>Subject: [FlyRotary] Re: vapor lock=0A>>=0A>>=0A>>No question= , Charlie=A0-=A0the more of your fuel line kept under EFI pump level press= ures , the less chance for vapor lock.=A0 In tank pumps certainly do that = - but, as you point out there are other considerations.=A0 Wing root sound= s like a pretty good compromise in luie=A0 of in-tank pumps.=A0 I consider= ed that but in the end decided against it as it would have high pressure f= uel lines inside my cockpit - which I personally do not favor {:>)=0A>>=A0= =0A>>Don't know for certain (and may never) the cause of the latest sputte= ring engine event - but, in absence of in-tank pumps and/or return to tank= - I still believe that pressure applied by a boost pump can prevent vapor= lock (based on my own personal experience with my unique installation)=0A= >>=A0=0A>>Ed=0A>>=0A>>=0A>>From: Charlie England =0A>>Sent: Saturday, Augus= t 13, 2011 9:06 AM=0A>>To: Rotary motors in aircraft =0A>>Subject: [FlyRota= ry] Re: vapor lock=0A>>=0A>>The really frustrating thing about all this is = that every installation is different (not to mention that it's only specul= ation as to what caused this particular power loss).=0A>>=0A>>Sixties-era = cars (carb, =0A engine mounted fuel pump) had vapor lock problems all th= e time in hot =0A weather. Modern cars, almost never (in-tank high press= ure pump). Keeping the =0A pumps as low & as close to the tank(s) as pra= ctical would seem to be the =0A best path. Van recommends mounting pumps= on the floor in the cabin. That =0A means that the max lift would be ma= ybe 3-4 inches, through a -6 line, and =0A nowhere near the high under-c= owl temps. There's a guy flying an injected Lyc =0A on ethanol-laced mog= as who never has a problem with vapor lock. He removed =0A the mech pump= and uses wingroot mounted electric pumps.=0A>>=0A>>If it weren't =0A fo= r the maintenance related inconveniences, I'd seriously consider in-tank = =0A pumps, as others have done.=0A>>=0A>>But we still don't know whether= this is =0A what caused the recent power loss....=0A>>=0A>>Charlie=0A>>= =A0=0A>>On =0A 08/13/2011 06:20 AM, Ed Anderson wrote: =0A>>I should hav= e added - the best overall approach - returning hot fuel to the heat-sink = tanks and drawing new cooler fuel into the lines.=0A>>>=A0=0A>>>Ed=0A>>>= =0A>>>=0A>>>From: Ed Anderson =0A>>>Sent: Saturday, August 13, 2011 6:47 AM= =0A>>>To: Rotary motors in aircraft =0A>>>Subject: [FlyRotary] Re: vapor lo= ck=0A>>>=0A>>>=0A>>>Ok, Finn, =A0that was my guess as well.=A0=0A>>>=A0=0A= >>>=A0That then brings up a question - my understanding of "vapor lock" is= that it is caused by a low pressure area/combined with hot fuel on the EF= I pump intake which cause the gasoline to flash to vapor - naturally the E= FI pumps can not pump vapor - therefore as fuel is injected from the high = pressure side of the pump (reducing pressure on that side), vapor can form= there as well.=A0 In any case, insufficient fuel is injected into the eng= ine.=0A>>>=A0=0A>>>Since the injectors are still clicking open, it would s= eem that any vapor on that side of the pump already has a chance to vacate= the line (through the injector)=A0- so my assessment is that it is not th= e relief of vapor/gas from the high pressure side that remedies the proble= m, it's removing the gas from the low pressure side (pump inlet) and there= by permitting liquid fuel to be pumped that "cures" a vapor lock situation= .=A0 =0A>>>=A0=0A>>>So I am puzzled why a gas vent on the high pressure si= de would have much (if any) effect on vapor lock.=A0 IF there is pressure = on the injector side - I question whether it would be as high as pump pres= sure - and even if it were, the injector opening would provide a path for = it to be release - not to mention the pressure regulator.=A0 So as I said = -I'm a bit puzzled as to the mechanism that a vent in the high pressure si= de prevents vapor lock.=0A>>>=A0=0A>>>In my opinion, there are two ways to = reduce/eliminate the vapor in the low pressure side - either cool the fuel= sufficiently (somewhat difficult to do) or to increase the pressure in th= e low pressure line forcing the vapor back into the liquid - ergo - use= =A0 a boost pump.=0A>>>=A0=0A>>>FWIW=0A>>>=A0=0A>>>Ed=0A>>>=A0=0A>>>=0A>>>= =0A>>>From: Finn Lassen =0A>>>Sent: Saturday, August 13, 2011 2:53 AM=0A>>>= To: Rotary motors in aircraft =0A>>>Subject: [FlyRotary] Re: vapor lock=0A>= >>=0A>>>Hi Ed,=0A>>>=0A>>>I believe it's simply a return to the tank =0A = from the high-pressure side via a very small orifice. How small I do not= =0A know.=0A>>>=0A>>>Finn=0A>>>=0A>>>On 8/10/2011 9:28 AM, Ed Anderso= n wrote: =0A>>>=0A>>>=A0=0A>>>>The one I potential preventive measure/fix I= have not looked into is the vapor by-pass/dump that I know a few folks ar= e using.=A0 I search the archive but could not find a description of this= method - anyone care to provide one?=0A>>>=0A>>=0A>>=0A>>=0A>=0A> ---672993426-163291085-1313272209=:22374 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Dennis,

Thanks.  = Little different with a high wing (i.e. leave on both).
I'll have aux tanks (10 gallons each), thos= e are plumped into the 25 gallon main tanks,
via the= Facet Pumps.  I don't recognize Faust  (perhaps a sublime joke I= missed?). 

I = might never need all 70 gallons (65 useable), but nice to have the extra ca= pacity.

Tom
=


From: Dennis Havarla= h <clouduster@austin.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net&g= t;
Sent: Saturday, Augu= st 13, 2011 2:53 PM
Subject: [FlyRotary] Re: vapor lock

=0A= =0A =0A =0A =0A
Tom,
=0A 
=0A
I have no fuel valves.  I copied Tracy's =0Amethod -= feed the high pressure fuel injection pumps from the left tank.  I = =0Ause a Faust low pressure pump to transfer fuel from the right tank to th= e left =0Atank.  I use the EM-2 with it's 7 minute timer to remin= d me to turn =0Aoff the transfer pump.  I use one GM auto filter = on the outlet of each =0Afuel injection pump.  The pumps are in parall= el.  To change the fuel =0Afilters I first run the left tank low and t= han drain most of the remaining =0Afuel.
=0A
 
=0A
My .020 orifice discharge and the =0Apressure regulator return flow = both go to a -4 return line that is "T" ed =0Ainto the Faust discharge line= to the left tank.
=0A
 
=0A
Dennis H.=0A
=0A
----- Original Message -----
=0A
From: =0A Tom =0A Walte= r
=0A =0A
= Sent: Saturday, August 13, 2011 1:51 =0A PM
=0A
Subject: [FlyRotary] Re: vapor lock
=0A
=0A
=0A =
Dennis,
=0A

=0A
<= span>What fuel valve are you using?
=0A

=
=0A
My plans on the Bearhawk (high wing taildragger):
=0A

=0A
Left and Right fu= el lines flow into a "R-Both-L-off" single Andair =0A valve.
= =0A

=0A
Then to the gascolator (lo= w point at rest)
=0A

=0A
Gascolator feeds header tank, then into two pumps (only one in =0A flig= ht).
=0A

=0A
Everythin= g is under the floor of the planer, under a 0.032" 2024 =0A floor board.
=0A

=0A
Fuel return tho= ugh a small "T" (0.020" orifice) to header =0A tank.
=0A
=0A
Where does the regulator return fuel to? 
=0A

=0A
With the high wing, any air bubble from th= e header tank should work it's =0A way
=0A
back up the line int= o the tank.  -6 aluminum tubing (note tanks have =0A for and
=0A=
aft pickups, that meet up under the door.  Allow for flow at hi= gh =0A angles of
=0A
attack.
=0A

Tom
= =0A

=0A

=0A

=0A

=0A

=0A
=0A

=0A
=0A
=0A
=0A <= span style=3D"FONT-WEIGHT:bold;">From: Dennis Havarlah =0A <= clouduster@austin.rr.com>
To: Rotary motors in aircraft =0A <flyrotary@lancaironline.net>=
Sent: Saturday, August = 13, 2011 12:41 =0A PM
Subject: [FlyRotary] Re: =0A vapor lock

=0A
=0A =0A=0A
R= ight On Kelly!!
=0A
 
=0A
I have the fuel sys= tem Kelly described in my =0A RV-7A.  I've used Mogas with and w= ithout ethanol with outdoor =0A temperatures up to 105 ' F.
= =0A
 
=0A
I have never had a vapor lock problem.  = =0A After stopping for fuel and the engine compartment  heat soaks I = hear the =0A vapors being pushed out of the fuel rails and thru the bypass= orifice =0A  when I turn on the pumps.  No Hot Start Problems!!=   It takes =0A less than 5 seconds for the vapors to be removed and r= eturned to the =0A tank.  That means that all the injectors see is co= ol fuel when I start =0A the engine. 
=0A
 
=0A
My fuel pumps are located on the floor between =0A the pilot an= d passenger.  Because the pumps are very low fuel from the =0A left t= ank will flow into the pumps by gravity.   One -6 aluminum =0A f= uel line from the pumps runs to the firewall.  If any fuel leaks durin= g =0A flight I will smell it and turn off the pumps and start gliding.&nbs= p; If I =0A have a leak in the engine compartment I may not detect it befo= re it =0A ignites.
=0A
<= /font> 
=0A
Just my two cen= ts worth.  It does work for =0A me.
=0A
 
=0A
Dennis H.
=0A
 
=0A
 =0A
 
=0A
 
=0A
=0A
----- Original Message -----
=0A =0A =0A =
Sent: Saturday, August 13, 2011 9:= 22 =0A AM
=0A
Subject: [F= lyRotary] Re: vapor =0A lock
=0A

=0A
=0A
Guys,
=0A
=  
=0A
I vote for keeping high pressure pumps= as close to the tanks and =0A as low
=0A
as = possible to fuel level...............I would not locate pumps =0A and/or= suppy
=0A
hoses firewall forward unless totally =0A encapulated, insulated and cooled=0A
by ram air...........And by all means use the bypass =0A= oriface...........Besides
=0A
helping to repr= ime pumps (as Mark says) it will relieve pressure =0A on leaky=0A
injectors to prevent flooding (if you have experienced= this with =0A the 13B
=0A
you know what I mea= n and the Renesis is even worse to clear) and =0A to
=0A =
allow a vapor lock to clear the high pressure supply =0A line= s from pump to
=0A
the regulator......= ......One more thing I would install the =0A regulator after the
=0A
fuel rails/injectors to allow any vapo= r to pass through the rails =0A on their way
= =0A
to the bypass oriface...........I have seen some fuel =0A= regulator installations
=0A
with the fu= el rails "Dead Ended" after the regulator leaving =0A vapor trapped
=0A
in the rail.................When flying vapor mig= ht clear with =0A only an apparent
=0A misfire to the pilot but after shutdown and after heat soak =0A= it could cause
=0A
"Hot Start" = problems (has anyone tryed to hot-start an fuel injected  "Lyc"
=0A
la= tely............IMHO 
=0A
=0A =
 
=0A
Kelly Troyer
"DYKE DE= LTA JD2" (Eventually)
=0A
"= 13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil =0A = Manifold
=0A
"TURBONETICS"_TO4E50 Turbo
=0A

=
=0A
=0A
=0A
From: Ed Anderson =0A <eanderson@carolina.rr.com&g= t;
To: Rotary motors in = aircraft =0A <flyrotary@lancaironline.net>
Sent: Saturday, August 13, 2011 8:16 =0A AM<= br>Subject: [FlyRotary] Re:= =0A vapor lock

=0A
=0A No question, Charlie - the more of your fu= el =0A line kept under EFI pump level pressures , the less chance for va= por =0A lock.  In tank pumps certainly do that - but, as you point = out there =0A are other considerations.  Wing root sounds like a pr= etty good =0A compromise in luie  of in-tank pumps.  I conside= red that but in =0A the end decided against it as it would have high pre= ssure fuel lines inside =0A my cockpit - which I personally do not favor= {:>)
=0A
 
= =0A
Don't know for certain (and may never) the= cause of =0A the latest sputtering engine event - but, in absence of in= -tank pumps and/or =0A return to tank - I still believe that pressure ap= plied by a boost pump can =0A prevent vapor lock (based on my own person= al experience with my unique =0A installation)
=0A
&= nbsp;
=0A
Ed
=0A
=0A

=0A
=0A =0A
Sent: Saturday, August 13= , 2011 9:06 AM
=0A =0A Subject: [FlyRotary] Re: vapor lock
=0A
<= br>
The really frustrating thing about all this is that every =0A i= nstallation is different (not to mention that it's only speculation as to = =0A what caused this particular power loss).

Sixties-era cars (ca= rb, =0A engine mounted fuel pump) had vapor lock problems all the time i= n hot =0A weather. Modern cars, almost never (in-tank high pressure pump= ). Keeping the =0A pumps as low & as close to the tank(s) as practic= al would seem to be the =0A best path. Van recommends mounting pumps on = the floor in the cabin. That =0A means that the max lift would be maybe = 3-4 inches, through a -6 line, and =0A nowhere near the high under-cowl = temps. There's a guy flying an injected Lyc =0A on ethanol-laced mogas w= ho never has a problem with vapor lock. He removed =0A the mech pump and= uses wingroot mounted electric pumps.

If it weren't =0A for the = maintenance related inconveniences, I'd seriously consider in-tank =0A p= umps, as others have done.

But we still don't know whether this is = =0A what caused the recent power loss....

Charlie
 
On= =0A 08/13/2011 06:20 AM, Ed Anderson wrote: =0A
=0A
I should have added - the best ove= rall approach - =0A returning hot fuel to the heat-sink tanks and draw= ing new cooler fuel into =0A the lines.
=0A
&nbs= p;
=0A
Ed
=0A
=0A

=0A
=0A =0A
Sent: Saturday, August 13, 2011 6:= 47 AM
=0A =0A
Subject: [FlyRotary] Re: vapor = lock
=0A

=0A
Ok, Finn,  that was my guess as =0A well. =0A
 
=0A
 That th= en brings up a question - my =0A understanding of "vapor lock" is that= it is caused by a low pressure =0A area/combined with hot fuel on the= EFI pump intake which cause the =0A gasoline to flash to vapor - natu= rally the EFI pumps can not pump vapor - =0A therefore as fuel is inje= cted from the high pressure side of the pump =0A (reducing pressure on= that side), vapor can form there as well.  In =0A any case, insu= fficient fuel is injected into the engine.
=0A
 =
=0A
Since the injectors are still clic= king open, it =0A would seem that any vapor on that side of the pump a= lready has a chance to =0A vacate the line (through the injector) = ;- so my assessment is that it =0A is not the relief of vapor/gas from= the high pressure side that remedies =0A the problem, it's removing t= he gas from the low pressure side (pump inlet) =0A and thereby permitt= ing liquid fuel to be pumped that "cures" a vapor lock =0A situation.&= nbsp;
=0A
 
=0A
So I am puzzled why a gas vent on the high pressure =0A side woul= d have much (if any) effect on vapor lock.  IF there is =0A press= ure on the injector side - I question whether it would be as high as =0A = pump pressure - and even if it were, the injector opening would provide = a =0A path for it to be release - not to mention the pressure regulato= r.  =0A So as I said -I'm a bit puzzled as to the mechanism that = a vent in the =0A high pressure side prevents vapor lock.
= =0A
 
=0A
In my opinion,= there are two ways to =0A reduce/eliminate the vapor in the low press= ure side - either cool the fuel =0A sufficiently (somewhat difficult t= o do) or to increase the pressure in the =0A low pressure line forcing= the vapor back into the liquid - ergo - =0A use  a boost pump.
=0A
 
=0A
FWI= W
=0A
 
=0A
= Ed
=0A
 
=0A
=0A

=0A
=0A =0A
Sent: Saturday, August 13, 2011 2:53 A= M
=0A =0A
Subject: [FlyRotary] Re: vapor lock
=0A

Hi Ed= ,

I believe it's simply a return to the tank =0A from the high-= pressure side via a very small orifice. How small I do not =0A know.
Finn

On 8/10/2011 9:28 AM, Ed Anderson wrote:
=0A =0A
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=0A =
The one I potential preventive measure/fix I h= ave =0A not looked into is the vapor by-pass/dump that I know a few = folks are =0A using.  I search the archive but could not find a= description of =0A this method - anyone care to provide =0A on= e?




=


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