Return-Path: Received: from [206.46.170.133] (HELO out010.verizon.net) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 740951 for flyrotary@lancaironline.net; Tue, 15 Feb 2005 22:20:31 -0500 Received: from verizon.net ([4.12.145.173]) by out010.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20050216032023.RWQK25879.out010.verizon.net@verizon.net> for ; Tue, 15 Feb 2005 21:20:23 -0600 Message-ID: <4212BBE4.3080900@verizon.net> Date: Tue, 15 Feb 2005 22:20:04 -0500 From: Finn Lassen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax; PROMO) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Bad day at the airport References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------000307040100020504000707" X-Authentication-Info: Submitted using SMTP AUTH at out010.verizon.net from [4.12.145.173] at Tue, 15 Feb 2005 21:20:23 -0600 This is a multi-part message in MIME format. --------------000307040100020504000707 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Ed uses 100LL after a fuelling fire. Tracy and I continue to use 87 auto gas. Finn Paul wrote: > Hi, Jim....yes, I use the same gasoline as I use in my car. (Regular > unleaded). I think Tracy and Ed Anderson also use it, as they > mentioned that their spark plug life is greatly deteriorated when they > are forced to use 100LL. Guys, please step in here and correct me if > I am wrong. > Regarding alcohol, I am not overly concerned with it. I coated > my fuel tanks with 3 coats of the fuel tank sealant that comes with > the kit. (Smells like dead fish). It is supposed to be imperviant to > auto fuel and alcohol. Time will tell. Paul Conner > > > ----- Original Message ----- > From: Jim Sower > To: Rotary motors in aircraft > Sent: Tuesday, February 15, 2005 12:28 AM > Subject: [FlyRotary] Re: Bad day at the airport > > <... I was using auto fuel (regular). I have a fuel return line > and it goes ...> > > DAMN. I hadn't heard about that. Paul, that's a really important > factor. Maybe I lost it in all the chatter going on. Auto fuel > can be pretty close to avgas in volatility (Vapor Pressure) but > for the most part it's anyone's guess. Avgas is regulated at max~ > 6 psi Vapor Pressure. Mogas used to get as high as 16-20 psi VP. > That high a pressure can petty much guarantee vapor lock under > high under hood / cowl conditions. As time went on and more and > more cars got MPFI and environmental regulations progressed, Mogas > vapor pressures came down some. IIRC Calif has a 7-8 psi max > vapor pressure, and places with strict environmental regulations > (like cities who aren't making their air quality numbers) are more > likely to require lower VPs. Trouble is, VP can vary widely > across various sources of Mogas. > > I would guess that anywhere that requires gas pump nozzles that > capture vapor as you fill your tank will have lower VPs, but > sadly, they are also most likely to have alcohol added to mogas. > Alcohol is a major NO NO for aircraft. Mogas fuel systems should > be very carefully designed to prevent vapor lock or you are apt to > get into some VERY SERIOUS SHIT!!. Like there have been maybe > 80,000 Mogas STCs issued to Lycs and Conts. NONE to ANY > certified engine that's injected. > > Which is not to say that you can't make a system that runs > reliably with higher VP Mogas, but you need to be very VERY > attentive to the issue, both in design and operation. You also > have to figure out a way to find out what local VPs are. Alcohol > is easy to detect and distributors know how much they're adding to > the fuel. Good info on VP is more difficult to come by and it > might vary some from one distributor to another. > > I've been researching Mogas and recently gave a little > presentation to my EAA chapter and a couple of flying clubs. It's > wonderful stuff for your engine (lead is really terrible) but you > need to be very careful to not allow ANY alcohol into your > airplane and be very careful about checking and monitoring VP. > > Unleaded Avgas is coming, but VP will be an issue with it ... Jim S. > > > Mark R Steitle wrote: > >> Paul, >> >> It looks like the group has focused in on the fuel system, or >> more specifically the sump tank as the likely culprit. I >> suspected you might have been running mogas. Its my >> understanding that auto fuel has a much lower vapor pressure than >> avgas and is therefore more likely to vapor lock. >> >> Just a SWAG, but I think the engine and related systems got hot >> enough to heat the fuel in the fuel rails so that once it passed >> the pressure regulator (pressure drop) it started to boil, >> similar to when you open a hot soda. With the return fuel going >> to an unvented tank, the boiling fuel expanded enough to cause >> pressure in the header tank so as to prevent fresh fuel from >> flowing into the tank. Eventually, the header tank ran dry and >> the engine quit. You sure handled the situation like a pro. >> Hope I never have to face that scenario. >> >> Mark S. >> >> >> >> Hi, Mark...my humblest appologies for taking so long to respond. >> I am whittling down the 200 plus messages in my inbox. I was >> using auto fuel (regular). I have a fuel return line and it goes >> to the top of my aluminum sump tank that is located on the cool >> side of the firewall (inside the cabin, behind the rear seat). >> The return line is -8 in size. Hope this helps. Paul Conner >> > ------------------------------------------------------------------------ > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.300 / Virus Database: 265.8.7 - Release Date: 2/10/2005 > >------------------------------------------------------------------------ > >No virus found in this outgoing message. >Checked by AVG Anti-Virus. >Version: 7.0.300 / Virus Database: 265.8.8 - Release Date: 2/14/2005 > > >------------------------------------------------------------------------ > > > >>> Homepage: http://www.flyrotary.com/ >>> Archive: http://lancaironline.net/lists/flyrotary/List.html >>> >>> --------------000307040100020504000707 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Ed uses 100LL after a fuelling fire. Tracy and I continue to use 87 auto gas.

Finn

Paul wrote:
Hi, Jim....yes, I use the same gasoline as I use in my car. (Regular unleaded).  I think Tracy and Ed Anderson also use it, as they mentioned that their spark plug life is greatly deteriorated when they are forced to use 100LL.  Guys, please step in here and correct me if I am wrong.
      Regarding alcohol, I am not overly concerned with it. I coated my fuel tanks with 3 coats of the fuel tank sealant that comes with the kit. (Smells like dead fish). It is supposed to be imperviant to auto fuel and alcohol.  Time will tell.  Paul Conner
 
----- Original Message -----
From: Jim Sower
Sent: Tuesday, February 15, 2005 12:28 AM
Subject: [FlyRotary] Re: Bad day at the airport

<... I was using auto fuel (regular). I have a fuel return line and it goes ...>

DAMN.  I hadn't heard about that.  Paul, that's a really important factor.  Maybe I lost it in all the chatter going on.  Auto fuel can be pretty close to avgas in volatility (Vapor Pressure) but for the most part it's anyone's guess.  Avgas is regulated at max~ 6 psi Vapor Pressure.  Mogas used to get as high as 16-20 psi VP.  That high a pressure can petty much guarantee vapor lock under high under hood / cowl conditions.  As time went on and more and more cars got MPFI and environmental regulations progressed, Mogas vapor pressures came down some.  IIRC Calif has a 7-8 psi max vapor pressure, and places with strict environmental regulations (like cities who aren't making their air quality numbers) are more likely to require lower VPs.  Trouble is, VP can vary widely across various sources of Mogas.

I would guess that anywhere that requires gas pump nozzles that capture vapor as you fill your tank will have lower VPs, but sadly, they are also most likely to have alcohol added to mogas.  Alcohol is a major NO NO for aircraft.  Mogas fuel systems should be very carefully designed to prevent vapor lock or you are apt to get into some VERY SERIOUS SHIT!!.  Like there have been maybe 80,000 Mogas STCs  issued to Lycs and Conts.  NONE to ANY certified engine that's injected.

Which is not to say that you can't make a system that runs reliably with higher VP Mogas, but you need to be very VERY attentive to the issue, both in design and operation.  You also have to figure out a way to find out what local VPs are.  Alcohol is easy to detect and distributors know how much they're adding to the fuel.  Good info on VP is more difficult to come by and it might vary some from one distributor to another.

I've been researching Mogas and recently gave a little presentation to my EAA chapter and a couple of flying clubs.  It's wonderful stuff for your engine (lead is really terrible) but you need to be very careful to not allow ANY alcohol into your airplane and be very careful about checking and monitoring VP.

Unleaded Avgas is coming, but VP will be an issue with it ... Jim S.


Mark R Steitle wrote:

Paul,

It looks like the group has focused in on the fuel system, or more specifically the sump tank as the likely culprit.  I suspected you might have been running mogas.  Its my understanding that auto fuel has a much lower vapor pressure than avgas and is therefore more likely to vapor lock. 

Just a SWAG, but I think the engine and related systems got hot enough to heat the fuel in the fuel rails so that once it passed the pressure regulator (pressure drop) it started to boil, similar to when you open a hot soda.  With the return fuel going to an unvented tank, the boiling fuel expanded enough to cause pressure in the header tank so as to prevent fresh fuel from flowing into the tank.  Eventually, the header tank ran dry and the engine quit.  You sure handled the situation like a pro.  Hope I never have to face that scenario.

Mark S.

 

Hi, Mark...my humblest appologies for taking so long to respond.  I am whittling down the 200 plus messages in my inbox.  I was using auto fuel (regular). I have a fuel return line and it goes to the top of my aluminum sump tank that is located on the cool side of the firewall (inside the cabin, behind the rear seat). The return line is -8 in size.  Hope this helps.  Paul Conner

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