Mailing List flyrotary@lancaironline.net Message #17860
From: Herb Sanders <hsanders@bellsouth.net>
Subject: RE: [FlyRotary] Re: Vapor Lock
Date: Thu, 24 Feb 2005 11:29:18 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Paul, I'm confused. Your post on 2/23 says you did not run with the vent
installed and the Facet in line - but this post says you ran it and it quit
from what appeared to be vapor lock.?????
Maybe I am misreading something.
Herb

> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
> Behalf Of Paul
> Sent: Wednesday, February 16, 2005 7:26 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Vapor Lock
>
> I ran my engine today with all the firesleeve installed and the new sump
> tank vent.  After 3 engine runs at WOT, the water temp hit 230 (and
> climbing), and the engine started acting just like it did the day of my
> forced landing.  Sputtering, erratic and finally just it quit, and would
> not
> restart. I turned on my inline Facet fuel pump.  It took 3 or 4 seconds,
> then the engine came back to life. I was able to taxi back to the hangar
> (I
> used about 1/2 throttle to get the aircraft rolling, then throttled back a
> bit to taxi).  My Facet pump is between the main tanks and the sump
> tank.(after the fuel selector valve). The EFI pumps are after the sump
> tank
> and before the fuel rail/regulator. The unused fuel from the regulator
> returns to the sump tank.  There is no way the engine would run without
> the
> Facet pump to push fresh gasoline into the sump tank, which was obviously
> filled with gas and bubbles after the thorough heat soaking it received.
> With the Facet pump still on, and taxiing under reduced power, the temps
> came down from 240 to 210 by the time I reached the hangar, and shut it
> down. My sump tank is vented with a 3/16" OD line on the top, which goes
> into the top of my left fuel tank. The line is opaque, and I can see fuel
> movement going through the new vent line when the Facet pump is turned on.
> Unfortunately, I can't tell if it is clear fuel or bubbles, or a mixture,
> as
> the line is opaque rather than clear, but I can definately see motion and
> tell it's direction of flow. Hope this more helpful than confusing.  Paul
> Conner
>
> ----- Original Message -----
> From: "Jim Sower" <canarder@frontiernet.net>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Wednesday, February 16, 2005 10:41 AM
> Subject: [FlyRotary] Re: Vapor Lock
>
>
> > <... HP pumps are capable of moving LOTS more fuel than a Facet pump ...
> > HP pumps would be drawing fuel through the Facet pump ... because the
> > Facet can't keep up ...>
> >
> > You're right.  I hadn't thought of that.  Facet pumps deliver 30 gph.
> > I'll check how much my HP pumps are putting out.  Wonder if Facet
> delivers
> > more at lower head pressure, objective being to push fuel through filter
> > and plumbing so there's less chance of pressure drop that could cause
> the
> > fuel to vaporize.
> >
> > Back to the drawing board ... maybe ... Jim S.
> >
> > Marvin Kaye wrote:
> >
> >> Jim Sower <canarder@frontiernet.net> wrote:
> >>
> >> """
> >>  I have a canard, but I will have a Facet pump near (and below) the
> wing
> >> tanks
> >> to PUSH the fuel through the filter and fuel flow transducer.  I don't
> >> want
> >> the HP pumps to SUCK through the filters and etc. for fear of
> vaporizing
> >> the
> >> fuel.
> >> """
> >>
> >> This doesn't make any sense to me, but perhaps I'm missing something.
> >> The HP pumps are capable of moving LOTS more fuel than a Facet pump.
> >> Consequently, it seems to me that the HP pumps would actually be
> drawing
> >> fuel through the Facet pump when they're switched on, simply because
> the
> >> Facet can't keep up with what's being drawn out of the sump tank by
> them.
> >> Additionally, a return system needs 2 flow transducers, one for the
> feed
> >> line and one for the return... then the display instrument's
> electronics
> >> deduct the return flow from the feed flow to properly calculate actual
> >> through-the-injectors instantaneous flow data.  (The EI fuel flow
> >> instrument uses an FFDM-1 (fuel flow differential module) to do the
> job,
> >> GRT EIS does it itself, as do other flow instruments with both feed and
> >> return inputs.)
> >>
> >> As long as the filters are rated to flow as much fuel as the HP pumps
> are
> >> capable of pushing I don't see that (vapoization) as an issue.  The
> >> filter elements do need to be kept clean, and are a replace-at-annual
> >> item.
> >>
> >>    <Marv>
> >>
> >>>>  Homepage:  http://www.flyrotary.com/
> >>>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
> >>>
> >>
> >>
> >
> >>>  Homepage:  http://www.flyrotary.com/
> >>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
> >
> >
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> >>  Homepage:  http://www.flyrotary.com/
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