Today's Message Index:
----------------------
1. 02:32 AM - Re: Popham Sunday? (G-IANI)
2. 05:01 AM - Re: O2 needs at altitude (Karl Heindl)
3. 05:41 AM - Boiling fuel due to underpressure? (Frans Veldman)
4. 05:43 AM - Re: O2 systems (TELEDYNMCS@aol.com)
5. 06:40 AM - Re: Boiling fuel due to underpressure? (Gilles Thesee)
6. 07:18 AM - Re: Boiling fuel due to underpressure? (Frans Veldman)
7. 07:45 AM - Re: Re: Boiling fuel due to underpressure? (Gilles Thesee)
8. 07:59 AM - Re: O2 needs at altitude (Paul McAllister)
9. 08:07 AM - Re: Re: Boiling fuel due to underpressure? (G-IANI)
10. 10:56 AM - Re: Re: Boiling fuel due to underpressure? (pjeffers@talktalk.net)
11. 11:14 AM - Re: Re: Boiling fuel due to underpressure? (Frans Veldman)
12. 12:44 PM - =?ISO-8859-1?Q?Re=3A_Europa-List=3A_Popham_Sunday=3F? (Carl Pattinson)
13. 02:07 PM - Adhesive Question (Paul McAllister)
14. 04:25 PM - Re: O2 needs at altitude (craig bastin)
Message 1
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Yes to Popham, weather permitting.
Ian Rickard G-IANI XS Trigear
Message 2
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Subject: | O2 needs at altitude |
Craig=2C
I use an Aerox cylinder=2C 9 cft=2C which is supposed to last up to 16 hour
s. It fits neatly inside the port
'headrest'.
Karl<html><div></div>
From: craigb@onthenet.com.auTo: europa-list@matronics.comSubject: Europa-Li
st: O2 needs at altitudeDate: Sat=2C 11 Oct 2008 15:58:07 +1000
For those of you with completed AC or previous experience=2C I would like y
o know what you use for
supplimental O2 needs at say 15=2C000 ft. specifcally size of bottles=2C lo
cation=2C weight and how long they
last in flight. Some of the legs here in australia=2C like north america=2C
or UK across europe=2C could be 6+ hours duration and i want to make
sure i have enough capacity. I realise this will vary depending on age=2C h
ealth=2C fitness level etc. Secondly
has anyone used or considered the clip on O2 sensors (ear lobe/little finge
r) to monitor blood O2 levels accurately.
Craig
Message 3
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Subject: | Boiling fuel due to underpressure? |
I guess somebody here can tell me whether this is normal or not.
While testing my just finished fuel system on my 914, I noticed that quite some
air was passing through the filters. (I temporarily use the factory supplied
"glass" filters, to see what is going on and how much gunk will be collected during
the fuel flow tests). I of course expected some air in the system, and also
expected it to last some time before the last bubble would be gone.
Today I decided to let the fuel pump run while I was doing some other things, just
to see if there were no small leaks and to "flush" the fuel system. After
some time I noticed that the "air" still wasn't gone, actually it got worse. It
looks like massive amounts of air are sucked in, also regulary I hear the pumps
swallowing some air.
Although I have no fuel leaks if I leave the system alone, I suspected to have
an air leak upstream the suction side of the filters. Air can pass through smaller
holes than fuel I think. It doesn't matter whether I'm on Main or Reserve,
so it had to be after the fuel selection valve and before the filters. Happy
with that, because that is just one hose, and a Tee to both filters.
Now I'm not too happy anymore, because after spending a few hours chasing this
mystery air leak, I'm quite convinced there is no leak. Of course there could
be air leaks in both connections before the fuel selection valve, but this would
be a dual fault, and not too likely.
If I close the fuel selection valve while the pumps are still running, the fuel
in the filters is instantly gone. In fact, this is how I empty the filters before
disconnecting them. After test #687 and disconnecting once again one of the
filters, a few minutes after I got the filters sucked empty, I noticed how
the air got sucked in again when I pulled the hose of it. It indicates that the
vacuum is pretty good preserved during these few minutes, and this is in contradiction
with the assumption that I have an air leak. At the same time, the
amount of air I see through the fllters is increasing all the time, it looks at
the moment like the air/fuel ratio is 50%. Still though, the pumps humm happy
and don't seem to ingest much of this "air". Something is not right here. As
indicated by two fuel flow sensors, there is 130 liters per hour of flow, and
the fuel pressure is about 5 psi over the airbox pressure. (The engine is not
running, can't do that yet because I'm not finished
with the rest of the installation).
Before I go crazy completely, let me ask a question. Is it possible, that while
the pumps are pumping 130 liters per hour through the system, that the underpressure
on the suction side of the pumps just lowers the boiling point of the
fuel so much that the fuel starts "boiling"? Maybe it is just normal to see all
these bubbles dancing around in the fuel filters? If anyone has noticed this
as well, please let me know, it saves me a lot of time chasing "ghost" air leaks.
Temperature at the moment is a nice 20 Celcius and the airplane has been
standing in the sun for a while. (Yup, I know that sun isn't good for composite
airplanes, but messing with the fuel in a confined space isn't very good for
me).
It would explain why today it is much worse than yesterday evening: the temperature
is much higher today, It also explains why the amount of "air" apparently
sucked in is much more than the occasional burp I hear through the fuel pumps.
If this is not normal, I can only suspect to have air leaks on both tank connections.
Tiny enough not to let them drip overnight, but big enough to let massive
amounts of air in while the pumps start running...
Frans
Visit - www.EuropaOwners.org
Message 4
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In a message dated 10/11/2008 3:01:08 A.M. Eastern Daylight Time,
europa-list@matronics.com writes:
For those of you with completed AC or previous experience, I would like yo
know what you use for
supplimental O2 needs at say 15,000 ft. specifcally size of bottles,
location, weight and how long they
last in flight.
Hey Craig,
With the exception of the occasional wave day, we don't have much use for O2
here in the SE USA but a lot of our glider customers who fly in the
mountains out west like the Mountain High O2 systems. This is probably the most
common O2 system we see in gliders that come through our shop. The MH system uses
a pulsed, on-demand regulator and that, I'm told, saves a lot of O2. Fairly
important when you are flying out on the middle of nowhere when refills are
scarce. These folks also sell the finger type pulse oximeters that monitor
your O2 saturation.
Here's a link: _www.mhoxygen.com_ (http://www.mhoxygen.com)
Hope it helps!
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Back flying now that UL93 fuel is finally available again.....
**************New MapQuest Local shows what's happening at your destination.
Dining, Movies, Events, News & more. Try it out
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Message 5
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Subject: | Re: Boiling fuel due to underpressure? |
Frans Veldman a crit :
> Before I go crazy completely, let me ask a question. Is it possible, that while
the pumps are pumping 130 liters per hour through the system, that the underpressure
on the suction side of the pumps just lowers the boiling point of the
fuel so much that the fuel starts "boiling"? Maybe it is just normal to see
all these bubbles dancing around in the fuel filters? If anyone has noticed this
as well, please let me know, it saves me a lot of time chasing "ghost" air
leaks. Temperature at the moment is a nice 20 Celcius and the airplane has been
standing in the sun for a while. (Yup, I know that sun isn't good for composite
airplanes, but messing with the fuel in a confined space isn't very good for
me).
Frans,
You're spot on. And not crazy at all, by the way ;-)
We also noticed those bubbles in the transparent test lines when testing
our fuel system.
This is normal behaviour for fuel when "sucked" by pumps that are
*above* fuel level.
Aviation fuels, and to a greater extent autogas are a mix of many
hydrocarbon substances, several of which have a very low boiling point.
Autogas can even contain some butane and propane solved. So when sucked
out by the pumps, the most volatile hydrocarbons turn to vapour.
We have flown our airplane up to FL 135/145 with no problem, but I must
admit that a fuel system with pumps below fuel level would be far better.
FWIW,
Best regards,
--
Gilles
http://contrails.free.fr
Message 6
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Subject: | Re: Boiling fuel due to underpressure? |
Ok, once I started to suspect that I didn't have an air leak but just boiling fuel,
I decided to do a simple test (should have thought about that earlier): I
connected one of these glass filters to the fuel inlet of the engine, so I could
see what the engine was getting.
While the inlet filter looked like I was pumping foam, the filter at the inlet
of the engine showed that the engine was only getting liquid fuel, without a single
bubble of air...
Now I have determined that I have no air leak but simply that my fuel is boiling
due to underpressure at the suction side of the fuel system, I have some further
questions:
1) Is this nornal, or do I have bad fuel, or for some reason too much underpressure
that is causing this? With other words, do I have a problem?
2) At altitude, the pressure will be even lower, hence the fuel will boil earlier.
Today is a nice fall day, but the temperatures are nowhere as high as I'm
going to experience during my flights in the south of Europe. Isn't it likely
that some of the vapour bubbles will make it into the carbs once the conditions
go "worse"? Once you have vapour, the bubbles tend to grow rather than to dissolve.
It just doesn't look good that the fuel is already boiling at this comfortable
but not too high a temperature at 10 ft AMSL...
Frans
Visit - www.EuropaOwners.org
Message 7
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Subject: | Re: Boiling fuel due to underpressure? |
Franz
> Ok, once I started to suspect that I didn't have an air leak but just boiling
fuel, I decided to do a simple test (should have thought about that earlier):
I connected one of these glass filters to the fuel inlet of the engine, so I
could see what the engine was getting.
>
> While the inlet filter looked like I was pumping foam, the filter at the inlet
of the engine showed that the engine was only getting liquid fuel, without a
single bubble of air...
>
Congratulations for this example of practical engineering sense.
All 914 owners will benefit from such experiments.
> Now I have determined that I have no air leak but simply that my fuel is boiling
due to underpressure at the suction side of the fuel system, I have some further
questions:
>
> 1) Is this nornal, or do I have bad fuel, or for some reason too much underpressure
that is causing this? With other words, do I have a problem?
> 2) At altitude, the pressure will be even lower, hence the fuel will boil earlier.
Today is a nice fall day, but the temperatures are nowhere as high as I'm
going to experience during my flights in the south of Europe. Isn't it likely
that some of the vapour bubbles will make it into the carbs once the conditions
go "worse"? Once you have vapour, the bubbles tend to grow rather than to
dissolve. It just doesn't look good that the fuel is already boiling at this comfortable
but not too high a temperature at 10 ft AMSL...
>
>
We regularly fly over the French Alps at FL 130+ with no problem.
I imagine you won't have to climb that high to clear terrain every day
in the Netherlands ;-)
The point is, the fuel pressure at the carbs is higher than airbox
pressure, so the fuel won't be boiling and any vapour bubble will be
collapsed by positive pressure.
*But* there is always the risk that the pumps be starved should the
"boiling" become too intense at the tank pickup. As already said, the
only real cure is to *push* fuel and not *draw* it up to the pumps.
But this often implies a major redesign of the fuel tank and fuel system.
Best regards,
--
Gilles
http://contrails.free.fr
Message 8
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Subject: | Re: O2 needs at altitude |
Hi Craig,
I have a Mountain High pulse on demand system with a 22 cubic foot
Kevlar cylinder mounted on the back of the "D" bulk head. The pulse
demand unit sits between the two pilots and I am using the pneumatic
on off switch / valve that Mountain High supply. This is mounted in
the over head panel. It did require me running tubing around the
place and threading through my already full cable ducts was a bit of a
pain, but it is all out of sight and looks fairly neat.
So far I am delighted with the system. Most of my flying is two cross
country legs of 3 to 3.5 hours. Winds permitting I typically fly in
the 14,000 to 16,000 feet range. The cylinder seems to last a very
long time. To be honest apart from my initial fill, I haven't bought
oxygen since, I get it filled at airshows twice a year and Jim Butcher
gave me a fill once, so running out on a cross country trip is just
not a concern.
>From a physiological perspective I always use it from 10,000 feet and
above, and if I know I am climbing to that altitude I use it from the
commencement of the flight. The Mountain High unit can be set to turn
itself on automatically from 5000 feet. I am a non smoker, over 50
and I workout several times a week so I am in pretty good shape, but
with that said I find that using oxygen significantly improves my well
being and general cognitive performance. I can't imagine how a
sedentary smoker of my age or older would be performing at altitude.
So, in conclusion, I really like the Mountain High Pulse demand
system, 22 cubic feet will last you a very long time, and lastly, from
what I know now, if your poking around at 10,000 feet or more, you
probably should be using oxygen.
What don't I like about the system ?. It cost a lot !
Paul
Message 9
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Subject: | Re: Boiling fuel due to underpressure? |
Frans
The pumps behave as Gilles described. I have seen bubbles in the pumps at
any temperature from 0C to 35C on a hot day and with various fuels. From
experience this is nothing to worry about. The engine gets only what it
needs from the pumps and continues to run very sweetly.
Ian Rickard G-IANI XS Trigear, 200 hours
Europa Club Mods Rep (Trigear)
e-mail mods@europaclub.org.uk
or direct g-iani@ntlworld.com
Message 10
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Subject: | Re: Boiling fuel due to underpressure? |
Hi guys,
I now have 1250 hours and since new there have always been lots of bubbles in the
filters.when the pump is running.? All i can do is reassure anyone that this
is completely normal.? Don't know why but is OK.
Pete Jeffers
-----Original Message-----
From: G-IANI <g-iani@ntlworld.com>
Sent: Sat, 11 Oct 2008 16:06
Subject: RE: Europa-List: Re: Boiling fuel due to underpressure?
Frans
The pumps behave as Gilles described. I have seen bubbles in the pumps at
any temperature from 0C to 35C on a hot day and with various fuels. From
experience this is nothing to worry about. The engine gets only what it
needs from the pumps and continues to run very sweetly.
Ian Rickard G-IANI XS Trigear, 200 hours
Europa Club Mods Rep (Trigear)
e-mail mods@europaclub.org.uk
or direct g-iani@ntlworld.com
Message 11
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Subject: | Re: Boiling fuel due to underpressure? |
Gilles Thesee wrote:
> We regularly fly over the French Alps at FL 130+ with no problem.
> I imagine you won't have to climb that high to clear terrain every day
> in the Netherlands ;-)
We won't stay with the Europa in the Netherlands. Quite a substantial
amount of flying will be done in the French Alps, as my wifes parents
live close to Barcelonnette, and we love to fly over there (she has a
PPL also). We have been there twice this year, with a Cessna with
Thielert conversion. The bad news with a Cessna is its poor climb rate,
but the good news with this Cessna is that it is turbo-charged, and it
always climbs with 500 ft per minute, on sea level, but also on 12.500
feet. It is one of the reasons we wanted to have a 914 (turbo) in the
Europa as well. We are looking forward to start flying over there with
our Europa once it is finished. These plans are one of the reasons I
want to make sure the fuel system is working correctly, also at
altitude, in the mountains where you won't find acceptable emergency
landing spots everywhere.
Frans
Message 12
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Subject: | =?ISO-8859-1?Q?Re=3A_Europa-List=3A_Popham_Sunday=3F? |
X-mailer: iAVMailScanner 1.5.5.5
We are planning to be there for lunch 12 - 1 ish hopefully..
Carl & Dot
G-LABS
----- Original Message -----
From: Richard Iddon
To: europa-list@matronics.com
Sent: Friday, October 10, 2008 4:30 PM
Subject: Europa-List: Popham Sunday?
Anyone heading for Popham this Sunday for their end of season fly-in?
Richard Iddon G-RIXS
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Message 13
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Subject: | Adhesive Question |
Hi All,
I have an engine heater which is made up of a band that heats the oil
tank and a stick on pad on the engine block. I noticed today that the
the heating pad on the engine block came unstuck. When I installed it,
it came with some adhesive that looked like gray silicon.
Does anyone happen to know what type of adhesive is used for this ?
Thanks, Paul
Message 14
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Subject: | O2 needs at altitude |
Thanks for all the replies on and off list, the MH systems look quite good,
with the on demand pulse system
unless the law has been changed I am required to carry O2 at 10000 ft and
required to use it at 12000ft. The auto
on system at 5000ft is a nice feature too
thanks
craig
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