X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from nm25-vm0.access.bullet.mail.sp2.yahoo.com ([98.139.44.184] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with SMTP id 5091158 for flyrotary@lancaironline.net; Sat, 13 Aug 2011 15:10:00 -0400 Received-SPF: none receiver=logan.com; client-ip=98.139.44.184; envelope-from=keltro@att.net Received: from [98.139.44.104] by nm25.access.bullet.mail.sp2.yahoo.com with NNFMP; 13 Aug 2011 19:09:27 -0000 Received: from [98.139.44.88] by tm9.access.bullet.mail.sp2.yahoo.com with NNFMP; 13 Aug 2011 19:09:27 -0000 Received: from [127.0.0.1] by omp1025.access.mail.sp2.yahoo.com with NNFMP; 13 Aug 2011 19:09:27 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 367928.12425.bm@omp1025.access.mail.sp2.yahoo.com Received: (qmail 40666 invoked by uid 60001); 13 Aug 2011 19:09:27 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=att.net; s=s1024; t=1313262566; bh=yf/iSa21VoLpJSsIUYM/LidZYft1SMOeM0trOhoMg34=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=SgjmktGl8iz8gM/8pqpjd+AUXdZI+kX3t7omuT9MKFtlV7v+qs3dMQjV9IfcBYp5XZVaIgEYBnjilwhkEG+7rta2LprI3LVLMNpDtZVYrMfG1drxGJIkfL+g2luhE1QyYLM8dOGrvnlmAwesH9HRDaqEa/f5r324Z9Elcr587fM= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=att.net; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=F7wTOAtnJk5xH0ibO2F3Q5zIooXIs5J1rw1RXuhAPFfx7qLIurtiYR09+AVKcUMjWldLWsBplhAWY91z4QbawUdYOJMRWHcnyVMo/pDG/k/dz13sUv084BUIudoJH2qBiGXUHHyPIc2mOWEL1n4w1A3SzzrD8+ESdp8ODpcvOZU=; X-YMail-OSG: 4VbkQ7oVM1kwttbUhhsVBeEpMI7iCTfj8g7HZ_SERkZYHtv SX0YEQJL2Pmqmn13EolAoYNlYpb5mqRyx63Jh.f9biJ1h4yjvdqzo3DLohu6 tC_FEBu8H2BiIqHxSqe0pPKzqCreCno5kF3.fK9eejR6.W5TTtxQYQtR_n.l lNCSHB0s2UOMTyiqWo5HzuQiBlZwZhabRRd.AaP1bVqUsL6iIKGgUsGZIYsu aORXYVVobIUoolR2AYd.D47cCAYh1OCvkCr43gXnHoL7aQaexSMiKxaXPGLn Q44jtTDtyv3jtEHYrHo2q1BCHVjtk89ReqonuY43fu055gX0cPp67c5lpnLh s22Q0TQKyTzt0QAzBtsJ7wlYREcj9znBCJHodWFOywHxqZhPjVbzeIb1za8I H.GHvWdp9ZAoMXw-- Received: from [208.114.44.181] by web83913.mail.sp1.yahoo.com via HTTP; Sat, 13 Aug 2011 12:09:26 PDT X-Mailer: YahooMailWebService/0.8.113.313619 References: Message-ID: <1313262566.38955.YahooMailNeo@web83913.mail.sp1.yahoo.com> Date: Sat, 13 Aug 2011 12:09:26 -0700 (PDT) From: Kelly Troyer Reply-To: Kelly Troyer Subject: Re: vapor lock To: Rotary motors in aircraft In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-2096543680-1313262566=:38955" --0-2096543680-1313262566=:38955 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable William,=0A=A0=0A=A0=A0=A0 If it were not for the accessability problems in= some (not all) aircraft fuel tanks I would=0Aagree with you and Charlie...= .........When it comes time for me to replace=A0one or more=A0=0Aexternal h= igh pressure pumps (probably happen at a airport in the middle of nowhere)= =A0I =0Awould rather it be an hour job using a pump that I can carry in the= aircraft (like extra spark =0Aplugs) that requires no special gasket, seal= er=A0or tools beyond a screw or nutdriver, a=A0=0Acouple of wrenches and=A0= a pair of pliers...........<:)=A0=0A=0AKelly Troyer=0A"DYKE DELTA JD2" (Eve= ntually)=0A"13B ROTARY"_ Engine=0A"RWS"_RD1C/EC2/EM2=0A"MISTRAL"_Backplate/= Oil Manifold=0A"TURBONETICS"_TO4E50 Turbo=0A=0AFrom: William Wilson =0ATo: Rotary motors in aircraft =0ASent: Saturday, August 13, 2011 1:00 PM=0ASubject: [FlyRotary] Re: va= por lock=0A=0A=0AIt is not really the high pressure of the pumps that makes= a difference in modern cars, but the fact that the pumps are submersible i= n the tank.=A0 Even if there is negative pressure in the fuel tank the pump= can still do its job because the pressure at the bottom of the tank where = the pump inlet is is still positive because of the weight of the liquid fue= l.=0A=0AI would not worry about running high pressure fuel through the plan= e unless there is a part that is not rated for the pressure.=A0 Modern cars= all do this and none of them leak fuel.=A0 The pumps are not positive-disp= lacement pumps and so once they build up their maximum pressure, that's all= you get, even if you have the fuel selector turned off.=A0 You can easily = check the system any time you like by by doing exactly that and sniffing ar= ound.=0A=0AIf you really don't want high pressure fuel (or can't install a = submersible pump) your best bet is to mount a low-pressure fuel pump as low= and close to the tank as possible, and then have a header tank somewhere e= lse with a high pressure submersible pump in it.=A0 This system can still v= apor lock, depending on how far the first stage pump has to suck fuel.=A0 I= f the header tank is below the regular tank gravity will keep the fuel flow= ing to it even without the first-stage pump and this system will also be re= sistant to vapor lock (but you would need to make sure the gravity feed is = able to supply enough fuel flow).=A0 Because of the extra risks and complex= ity of these types of systems I think the in-tank high pressure pump is the= best way to go but it will still work.=0A=0A=0AOn Sat, Aug 13, 2011 at 8:2= 2 AM, Kelly Troyer wrote:=0A=0AGuys,=0A>=A0=0A>I vote for = keeping high pressure pumps as close to the tanks and as low =0A>as possibl= e to fuel level...............I would not locate pumps and/or suppy=0A>hose= s=A0firewall forward unless totally encapulated,=A0insulated and cooled=0A>= by ram air...........And by all means use the bypass oriface...........Besi= des=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 t= he 13B=0A>you know what I mean and the Renesis is even worse to clear) and = to=0A>allow a vapor lock to clear the high pressure supply lines=A0from=A0p= ump to =0A>the regulator............One more thing I would install the regu= lator after the =0A>fuel rails/injectors to allow any vapor to pass through= the rails on their way =0A>to the bypass oriface...........I have seen som= e fuel regulator=A0installations =0A>with the fuel rails "Dead Ended" after= the regulator leaving vapor trapped=0A>in the rail.................When fl= ying vapor might clear with only an apparent =0A>misfire to the pilot but= =A0after shutdown and after heat soak it could cause =0A>"Hot Start" proble= ms (has anyone tryed to hot-start an fuel=A0injected=A0 "Lyc"=0A>lately....= ........IMHO=A0=0A>=0A>Kelly Troyer=0A>"DYKE DELTA JD2" (Eventually)=0A>"13= B ROTARY"_ Engine=0A>"RWS"_RD1C/EC2/EM2=0A>"MISTRAL"_Backplate/Oil Manifold= =0A>"TURBONETICS"_TO4E50 Turbo=0A>=0A>=0A>From: Ed Anderson =0A>To: Rotary motors in aircraft = =0A>Sent: Saturday, August 13, 2011 8:16 AM =0A>=0A>Subject: [FlyRotary] Re= : vapor lock=0A>=0A>=0A>=0A>No question, Charlie=A0-=A0the more of your fue= l line kept under EFI pump level pressures , the less chance for vapor lock= .=A0 In tank pumps certainly do that - but, as you point out there are othe= r considerations.=A0 Wing root sounds like a pretty good compromise in luie= =A0 of in-tank pumps.=A0 I considered that but in the end decided against i= t as it would have high pressure fuel lines inside my cockpit - which I per= sonally do not favor {:>)=0A>=A0=0A>Don't know for certain (and may never) = the cause of the latest sputtering engine event - but, in absence of in-tan= k 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>=0A>Ed=0A>=0A>=0A>From: Charlie England =0A>Sen= t: Saturday, August 13, 2011 9:06 AM=0A>To: Rotary motors in aircraft =0A>S= ubject: [FlyRotary] Re: vapor lock=0A>=0A>The really frustrating thing abou= t all this is that every installation is different (not to mention that it'= s only speculation as to what caused this particular power loss).=0A>=0A>Si= xties-era cars (carb, engine mounted fuel pump) had vapor lock problems all= the time in hot weather. Modern cars, almost never (in-tank high pressure = pump). Keeping the pumps as low & as close to the tank(s) as practical woul= d seem to be the best path. Van recommends mounting pumps on the floor in t= he cabin. That means that the max lift would be maybe 3-4 inches, through a= -6 line, and nowhere near the high under-cowl temps. There's a guy flying = an injected Lyc on ethanol-laced mogas who never has a problem with vapor l= ock. He removed the mech pump and uses wingroot mounted electric pumps.=0A>= =0A>If it weren't for the maintenance related inconveniences, I'd seriously= consider in-tank pumps, as others have done.=0A>=0A>But we still don't kno= w whether this is what caused the recent power loss....=0A>=0A>Charlie=0A>= =A0=0A>On 08/13/2011 06:20 AM, Ed Anderson wrote: =0A>I should have added -= the best overall approach - returning hot fuel to the heat-sink tanks and = drawing new cooler fuel into the lines.=0A>>=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 lock=0A>>=0A>>=0A>>Ok, Fin= n, =A0that was my guess as well.=A0=0A>>=0A>>=A0That then brings up a quest= ion - my understanding of "vapor lock" is that it is caused by a low pressu= re area/combined with hot fuel on the EFI pump intake which cause the gasol= ine to flash to vapor - naturally the EFI pumps can not pump vapor - theref= ore as fuel is injected from the high pressure side of the pump (reducing p= ressure on that side), vapor can form there as well.=A0 In any case, insuff= icient fuel is injected into the engine.=0A>>=0A>>Since the injectors are s= till clicking open, it would seem that any vapor on that side of the pump a= lready has a chance to vacate the line (through the injector)=A0- so my ass= essment is that it is not the relief of vapor/gas from the high pressure si= de that remedies the problem, it's removing the gas from the low pressure s= ide (pump inlet) and thereby permitting liquid fuel to be pumped that "cure= s" a vapor lock situation.=A0 =0A>>=0A>>So I am puzzled why a gas vent on t= he high pressure side 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 pressure - and even if it were, the injector opening would pro= vide 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 side prevents vapor lock.=0A>>=0A>>In my opinion, there are t= wo ways to reduce/eliminate the vapor in the low pressure side - either coo= l the fuel sufficiently (somewhat difficult to do) or to increase the press= ure in the low pressure line forcing the vapor back into the liquid - ergo = - use=A0 a boost pump.=0A>>=0A>>FWIW=0A>>=0A>>Ed=0A>>=0A>>=0A>>=0A>>From: F= inn Lassen =0A>>Sent: Saturday, August 13, 2011 2:53 AM=0A>>To: Rotary moto= rs in aircraft =0A>>Subject: [FlyRotary] Re: vapor lock=0A>>=0A>>Hi Ed,=0A>= >=0A>>I believe it's simply a return to the tank from the high-pressure sid= e via a very small orifice. How small I do not know.=0A>>=0A>>Finn=0A>>=0A>= >On 8/10/2011 9:28 AM, Ed Anderson wrote: =0A>>=0A>>=0A>>>=0A>>>The one I p= otential preventive measure/fix I have not looked into is the vapor by-pass= /dump that I know a few folks are using.=A0 I search the archive but could = not find a description of this method - anyone care to provide one?=0A>>=0A= >=0A>=0A> --0-2096543680-1313262566=:38955 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
William,
 
    I= f it were not for the accessability problems in some (not all) aircraft fue= l tanks I would
agree with you and C= harlie............When it comes time for me to replace one or more&nbs= p;
external high pressure pumps (probably happen at a airport i= n the middle of nowhere) I
would rather it be an hour job using a pump that I can carry= in the aircraft (like extra spark
plugs) that requires no special gasket, sealer or tools= beyond a screw or nutdriver, a 
couple of wrenches a= nd a pair of pliers...........<:) 
 
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil = Manifold
"TURBONETICS"_TO4E50 Turbo

From:= William Wilson <fluffysheap@gmail.com>
To: Rotary motors in aircraft <flyrota= ry@lancaironline.net>
Sent: Saturday, August 13, 2011 1:00 PM
Subject: [FlyRotary] Re: vapor lock

It is not really the high pressure of the pumps that= makes a difference in modern cars, but the fact that the pumps are submers= ible in the tank.  Even if there is negative pressure in the fuel tank= the pump can still do its job because the pressure at the bottom of the ta= nk where the pump inlet is is still positive because of the weight of the l= iquid fuel.

I would not worry about running high pressure fuel throu= gh the plane unless there is a part that is not rated for the pressure.&nbs= p; Modern cars all do this and none of them leak fuel.  The pumps are = not positive-displacement pumps and so once they build up their maximum pre= ssure, that's all you get, even if you have the fuel selector turned off.&n= bsp; You can easily check the system any time you like by by doing exactly = that and sniffing around.

If you really don't want high pressure fue= l (or can't install a submersible pump) your best bet is to mount a low-pressure fuel pump as low and close to the tank as possible, and then = have a header tank somewhere else with a high pressure submersible pump in = it.  This system can still vapor lock, depending on how far the first = stage pump has to suck fuel.  If the header tank is below the regular = tank gravity will keep the fuel flowing to it even without the first-stage = pump and this system will also be resistant to vapor lock (but you would ne= ed to make sure the gravity feed is able to supply enough fuel flow). = Because of the extra risks and complexity of these types of systems I thin= k the in-tank high pressure pump is the best way to go but it will still wo= rk.

On Sat, Aug 13, 2011 at 8:22 AM, Kelly= Troyer <keltro@att.net><= /SPAN> wrote:
Guys,
 
I vote for keeping high pressure pumps as close to the tanks and= as low
as possible to fuel level...............I would not locate pumps= and/or suppy
hoses firewall forward unless totally encapula= ted, insulated and cooled
by ram air...........And by all means use the bypass oriface....= .......Besides
helping to reprime pumps (as Mark says) it will relieve pressure= on leaky
injectors to prevent flooding (if you have experienced this with= the 13B
you know what I mean and the Renesis is even worse to clear) and= to
allow a vapor lock to clear the high pressure supply lines = from pump to
the regulator............One more thing I would install the regu= lator after the
fuel rails/injectors to allow any vapor to pass through the rail= s on their way
to the bypass oriface...........I have seen some fuel regulator&= nbsp;installations
with the fuel rails "Dead Ended" after the regulator leaving vap= or trapped
in the rail.................When flying vapor might clear with o= nly an apparent
misfire to the pilot but after shutdown and after heat soak= it could cause
"Hot Start" problems (has anyone tryed to hot-start an fuel=  injected  "Lyc"
lately............IMHO 
 
Kelly Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil = Manifold
"TURBONETICS"_TO4E50 Turbo

From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net&= gt;
Sent: Saturday, Augu= st 13, 2011 8:16 AM

Subjec= t: [FlyRotary] Re: vapor lock

No question, Charlie - the more of your f= uel line kept under EFI pump level pressures , the less chance for vapor lo= ck.  In tank pumps certainly do that - but, as you point out there are= other considerations.  Wing root sounds like a pretty good compromise= in luie  of in-tank pumps.  I considered that but in the end dec= ided against it as it would have high pressure fuel lines inside my cockpit= - which I personally do not favor {:>)
 
Don't know for certain (and may never) the cause of= the latest sputtering engine event - but, in absence of in-tank pumps and/= or return to tank - I still believe that pressure applied by a boost pump c= an prevent vapor lock (based on my own personal experience with my unique i= nstallation)
 
Ed

The really frustrating thing about all this is that every in= stallation is different (not to mention that it's only speculation as to wh= at caused this particular power loss).

Sixties-era cars (carb, engin= e mounted fuel pump) had vapor lock problems all the time in hot weather. M= odern cars, almost never (in-tank high pressure pump). Keeping the pumps as= low & as close to the tank(s) as practical would seem to be the best p= ath. Van recommends mounting pumps on the floor in the cabin. That means th= at the max lift would be maybe 3-4 inches, through a -6 line, and nowhere n= ear the high under-cowl temps. There's a guy flying an injected Lyc on etha= nol-laced mogas who never has a problem with vapor lock. He removed the mec= h pump and uses wingroot mounted electric pumps.

If it weren't for t= he maintenance related inconveniences, I'd seriously consider in-tank pumps= , as others have done.

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

Charlie
 
On 08= /13/2011 06:20 AM, Ed Anderson wrote:=20
I should have added - the best overall approach - r= eturning hot fuel to the heat-sink tanks and drawing new cooler fuel into t= he lines.
 
Ed

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

Ok, Finn,  that was my guess as well. 
 
 That then brings up a question - my understan= ding of "vapor lock" is that it is caused by a low pressure area/combined w= ith hot fuel on the EFI pump intake which cause the gasoline to flash to va= por - naturally the EFI pumps can not pump vapor - therefore as fuel is inj= ected from the high pressure side of the pump (reducing pressure on that si= de), vapor can form there as well.  In any case, insufficient fuel is = injected into the engine.
 
Since the injectors are still clicking open, it wou= ld seem that any vapor on that side of the pump already has a chance to vac= ate the line (through the injector) - so my assessment is that it is n= ot the relief of vapor/gas from the high pressure side that remedies the pr= oblem, it's removing the gas from the low pressure side (pump inlet) and th= ereby permitting liquid fuel to be pumped that "cures" a vapor lock situati= on. 
 
So I am puzzled why a gas vent on the high pressure= side would have much (if any) effect on vapor lock.  IF there is pres= sure on the injector side - I question whether it would be as high as pump = pressure - and even if it were, the injector opening would provide a path f= or it to be release - not to mention the pressure regulator.  So as I = said -I'm a bit puzzled as to the mechanism that a vent in the high pressur= e side prevents vapor lock.
 
In my opinion, there are two ways to reduce/elimina= te the vapor in the low pressure side - either cool the fuel sufficiently (= somewhat difficult to do) or to increase the pressure in the low pressure l= ine forcing the vapor back into the liquid - ergo - use  a boost pump.=
 
FWIW
 
Ed
 

Sent: Saturday, August 13, 2011 2:53 AM
Subject: [FlyRotary] Re: vapor lock

Hi Ed,

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

Finn

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







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