-----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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