Today's Message Index:
----------------------
1. 12:37 AM - Re: 914 Fuel Pumps. (ivor.phillips)
2. 12:53 AM - Re: 914 Fuel System (Gilles Thesee)
3. 12:55 AM - Re: 914 Fuel System (Gilles Thesee)
4. 01:02 AM - Re: 914 Fuel Pumps. (Richard Holder)
5. 01:18 AM - Re: 914 Fuel Pumps. (BEBERRY@aol.com)
6. 02:22 AM - AW: 914 Fuel Pumps. (Ing. Gottfried Komaier)
7. 02:37 AM - Re: AW: 914 Fuel Pumps. (BEBERRY@aol.com)
8. 07:35 AM - Ignition Check (irampil@notes.cc.sunysb.edu)
9. 01:40 PM - Re: AW: 914 Fuel Pumps. (Gilles Thesee)
10. 03:00 PM - Re: 914 Fuel Pumps. (MICHAEL PARKIN)
11. 04:38 PM - AW: 914 Fuel Pumps. (Ing. Gottfried Komaier)
12. 08:05 PM - Re: Fuel pumps in series can get blocked (europa flugzeug fabrik)
13. 08:44 PM - Nav Lights using Luxeon LEDs (Andrew Sarangan)
Message 1
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| Subject: | Re: 914 Fuel Pumps. |
--> Europa-List message posted by: "ivor.phillips" <ivor.phillips@ntlworld.com>
Have just checked my 2005 engine and the fuel pump camshaft lobe is in
place,
No problem to fix mechanical back up pump, ( except for running fuel line
back and forth on top of a hot engine)
> all the 914 have the eccenter for the pump-drive installed.This is the
> status since around 2003. I can't say how the situation was before.
>
Ivor Phillips
Message 2
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| Subject: | Re: 914 Fuel System |
--> Europa-List message posted by: Gilles Thesee <Gilles.Thesee@ac-grenoble.fr>
Ing. Gottfried Komaier a crit :
..
> The dependence on electricity is
>the real and only problem of the 914 fuel system, not the PARALLEL -or
>SERIES- design.
>
>
>
Hi all,
Gotfried is right about the real issue on the 914.
The pumps must be fed from truly independant electrical sources. In this
respect, the architecture suggested by Rotax leaves much to be desired.
Concerning the installation of the pumps, Rotax first suggested a
correct parallel setup EXCEPT they forgot about the check valves.
They then suggested the "inline" configuration. It is not a real series,
as the fuel bypasses one of the pump in case of blockage (remember
Pierburg says the pumps are not really transparent). Nothing wrong with
this system. Just a bit tortuous.
Two years ago, we adopted the standard parallel system with check
valves, as suggested in the Pierburg information. The French importer
could not see any reason why we should not do it.
The airplane (not a Europa, I'm afraid ;-) has been flying for one year
now, and has been tested up to FL 145 without any problem, from -14C to
+37C.
I'm crafting a little web summary on this issue.
Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
Message 3
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| Subject: | Re: 914 Fuel System |
--> Europa-List message posted by: Gilles Thesee <Gilles.Thesee@ac-grenoble.fr>
Paul McAllister a crit :
>--> Europa-List message posted by: "Paul McAllister" <paul.mcallister@qia.net>
>
>Hi all,
>
>I am a curious to know if the 914 pump can be purchased from any one other
>than Rotax? Does anyone know ?
>
>
>
Hi Paul and all,
Yes, the "Rotax" pumps are just plain vanilla Pierburg EIF pumps. A well
proven and ubiquitous model in european cars.
Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
Message 4
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| Subject: | Re: 914 Fuel Pumps. |
--> Europa-List message posted by: Richard Holder <rholder@avnet.co.uk>
ivor.phillips wrote:
> Have just checked my 2005 engine and the fuel pump
> camshaft lobe is in place, No problem to fix mechanical
> back up pump, ( except for running fuel line back and
> forth on top of a hot engine)
Ivor,
The mechanical pump is the _primary_ pump as it can't be
switched off !
Of course I have 912S with a mechanical pump, and an
electric pump in series.
Use firesleeve to cover the fuel lines across the top of
the engine. They will be fine.
Richard
G-OWWW High Cross
Message 5
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| Subject: | Re: 914 Fuel Pumps. |
--> Europa-List message posted by: BEBERRY@aol.com
Why should the mechanical pump ( if you can fit one) be the 'back up pump?
It would seem sensible to adopt general G.A., practise and have a permanently
running mechanical pump and electrical back ups which are used only for take
off and when below 3000ft on the approach.?????
Patrick
Message 6
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--> Europa-List message posted by: "Ing. Gottfried Komaier" <gottfried.komaier@gmx.net>
Patrick,
The reason why the mechanical pump is the backup and not the other way round
is easy to explain:
The mechanical pump do not deliver as much pressure as the electrical one.
On the 914 you will need an fuel pressure of
Airboxpressure + 0,25 bar , 3,63
psi(normal)
Airboxpressure + 0,15 bar , 2,18
psi(minimum)
Airboxpressure + 0,35 bar , 5,08
psi(maximum)
At Take Off the engine produce an manifold pressure of 1350 hPa = 39,9 in.Hg
= 19,6 psi
That means, you need a max. Fuel pressure at the carburetor of 24,7
psi!!!!!!
The mechanical pump delivers 0,15 bar up to 0,4 bar(5,8 psi). Do you see
that difference?!
That's the reason why the mechanical pump can feed the engine only up to
~2000m with ~55% power and can works in this situation only as an EMERGENCY
equipment to bring you with reduced power to an airfield. . (Better than
nothing!!!)
You have a fine explanation of the Fuel pressure system in the Maintenance
Manual on pages 34&35
I hope this helps and bring a little light in the complicated 914 fuel
system. This is one of the reason, why the 914 is
so much expansive vs.the 912S
All the best,
Gottfried
-----Ursprngliche Nachricht-----
Von: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] Im Auftrag von
BEBERRY@aol.com
Gesendet: Donnerstag, 23. Februar 2006 10:16
An: europa-list@matronics.com
Betreff: Re: Europa-List: 914 Fuel Pumps.
--> Europa-List message posted by: BEBERRY@aol.com
Why should the mechanical pump ( if you can fit one) be the 'back up pump?
It would seem sensible to adopt general G.A., practise and have a
permanently running mechanical pump and electrical back ups which are used
only for take off and when below 3000ft on the approach.?????
Patrick
Message 7
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| Subject: | Re: 914 Fuel Pumps. |
--> Europa-List message posted by: BEBERRY@aol.com
Thanks Gottfried for your explanation - very useful for a non techie ( at
least on fuel systems, pressures etc)..
Patrick
Message 8
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--> Europa-List message posted by: irampil@notes.cc.sunysb.edu
Ron Asks:
Where should prop setting be when checking ignition system?
Remember that you should have first set your prop stops to 5800 for TO,
5500 for climb
and about 5000 for cruise. These are approximate and you may alter them
after appropriate
flight test.
Ignition test is done at 4000 rpm, therefore neither fine or coarsest
setting will latch up
and control the prop speed and either should allow a change with bad
plugs. I use fine setting
for ignition test, then flip the Airmaster to manual and depress the
coarse switch to test that
the prop pitch is changable
Ira 224XS
Message 9
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| Subject: | Re: 914 Fuel Pumps. |
--> Europa-List message posted by: Gilles Thesee <Gilles.Thesee@ac-grenoble.fr>
>That's the reason why the mechanical pump can feed the engine only up to
>~2000m with ~55% power and can works in this situation only as an EMERGENCY
>equipment to bring you with reduced power to an airfield. . (Better than
>nothing!!!)
>
>
>
Gottfried and all,
Not sure I clearly understand your setup : are you intending to add a
mechanical pump to the two electrical pumps ?
So that is 3 fuel pumps, correct ?
Have you already run your engine with the mechanical pump ? If I recall
correctly, no one mentioned the possibility of upsetting the delicate
enrichment algorithm that protects the engine against detonation. The
need for the wastegate servo "disconnect switch" might come from
instabilities when the TCU little brain loses control.
I tried not to modifiy the Rotax 914, but designed the electrical
architecture so that each pump has a truly independent source of power.
This way I can insure redundant fuel delivery.
Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
Message 10
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| Subject: | Re: 914 Fuel Pumps. |
--> Europa-List message posted by: "MICHAEL PARKIN" <mikenjulie.parkin@btopenworld.com>
> At Take Off the engine produce an manifold pressure of 1350 hPa = 39,9
> in.Hg
> = 19,6 psi
>
> That means, you need a max. Fuel pressure at the carburetor of 24,7
> psi!!!!!!
> The mechanical pump delivers 0,15 bar up to 0,4 bar(5,8 psi). Do you see
> that difference?!
>
Gottfried,
But that 24,7 psi includes the local atmospheric pressure. Consider
pressure at sea level on an ISA day. If the atmospheric pressure was 1013
hpa, then the fuel pump pressure required would be (1350+250)-1013 = 587 hpa
(8.5psi) this as you correctly say is beyond the capability of the
mechanical fuel pump. (Ref - Maintenance Manual p34). However, that is a
max power calculation.
If one considers the max continuous condition as quoted in the operating
manual - 5000 rpm, 31 in/hg, the situation with just the mechanical pump
would be considerably better and certainly sufficient to continue to a
diversion without a problem - all be it at a fairly low altitude.
Example:
Condition - 75% power, 5000 rpm, 31 in/hg. Air box pressure = 1049 hpa.
therefore fuel pump pressure required at 1000 ft (ISA day) - (ambient
pressure = 976 hpa)
(1049+250)-976 = 324 hpa which is 4.7 psi.
Using the minimum pressure required of 0,15 bar a calculated fuel pressure
required from the mechanical pump would be 3.2 psi.
Plainly, pressure altitude is the driving factor here.
kind regards,
Mike (G-JULZ)
Message 11
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--> Europa-List message posted by: "Ing. Gottfried Komaier" <gottfried.komaier@gmx.net>
Mike,
thank you for your discussion-input. As we see, the mechanical fuel pump
helps only in an electrical total failure (which will be on an 914-driven
aircraft an "EMERGENCY") and can bring you in this situation - and only in
that - safely to the ground.
To see the fuel pressure of the mechanical pump more exactly, we have to
consider that the pressure would be higher as laid down in the manual,
because there is no open return line back to the tank. This means, the
available power-situation would be better in an emergency.
Regards,
Gottfried
-----Ursprngliche Nachricht-----
Von: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] Im Auftrag von MICHAEL
PARKIN
Gesendet: Donnerstag, 23. Februar 2006 23:57
An: europa-list@matronics.com
Betreff: Re: Europa-List: 914 Fuel Pumps.
--> Europa-List message posted by: "MICHAEL PARKIN"
--> <mikenjulie.parkin@btopenworld.com>
> At Take Off the engine produce an manifold pressure of 1350 hPa = 39,9
> in.Hg = 19,6 psi
>
> That means, you need a max. Fuel pressure at the carburetor of 24,7
> psi!!!!!!
> The mechanical pump delivers 0,15 bar up to 0,4 bar(5,8 psi). Do you
> see that difference?!
>
Gottfried,
But that 24,7 psi includes the local atmospheric pressure. Consider
pressure at sea level on an ISA day. If the atmospheric pressure was 1013
hpa, then the fuel pump pressure required would be (1350+250)-1013 = 587 hpa
(8.5psi) this as you correctly say is beyond the capability of the
mechanical fuel pump. (Ref - Maintenance Manual p34). However, that is a
max power calculation.
If one considers the max continuous condition as quoted in the operating
manual - 5000 rpm, 31 in/hg, the situation with just the mechanical pump
would be considerably better and certainly sufficient to continue to a
diversion without a problem - all be it at a fairly low altitude.
Example:
Condition - 75% power, 5000 rpm, 31 in/hg. Air box pressure = 1049 hpa.
therefore fuel pump pressure required at 1000 ft (ISA day) - (ambient
pressure = 976 hpa)
(1049+250)-976 = 324 hpa which is 4.7 psi.
Using the minimum pressure required of 0,15 bar a calculated fuel pressure
required from the mechanical pump would be 3.2 psi.
Plainly, pressure altitude is the driving factor here.
kind regards,
Mike (G-JULZ)
Message 12
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| Subject: | Re: Fuel pumps in series can get blocked |
--> Europa-List message posted by: "europa flugzeug fabrik" <n3eu@comcast.net>
tonyk(at)kaon.co.nz wrote:
> The reason for the change to series based pumps is to bring the fuel pressure
down to that specified by Rotax. If you measure the differential fuel pressure
to airbox pressure as recommended then you'll find that the pressure delivered
by parallel pumps is too high.
I have them in parallel, and it would be a rather "Rube Goldberg" arrangement to
make them series. That's because I have (all in the trigear console tunnel)
a sump I made. It's attached to the front of the floor-mounted fuel valve and
has 2 outlets.
In a parallel setup, do you think cutting back the volts on the boost/emergency
pump will relieve the pressure? I was thinking a 3.9V 10W Zener diode (if I
can find 'em), parallel pair (reasonably matched in Vz) for redundancy. I know
I can test it for flow rate etc., but do you see a reason not to do this?
> Unless you intend retrofitting the UMA pressure sensor there is no need to change.
I think that don't come out quite right. [Wink] The 914 carbs may indeed tolerate
excess pressure, but to restate what a famous football coach here once said,
"On any given Sunday....a carb may flood!"
Reg,
Fred F.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=14556#14556
Message 13
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| Subject: | Nav Lights using Luxeon LEDs |
--> Europa-List message posted by: Andrew Sarangan <asarangan@yahoo.com>
Folks
I designed and built a nav light system using the Luxeon LEDs
(brightest LEDs in the industry). The performance was quite stunning;
about 300-500% higher than the FAA specs at only 2 Amps current draw.
It is bright enough to almost function as landing lights. It weighs a
little over 3oz for each side.
See complete details of the installation at:
http://www.sarangan.org/aviation/europa/wing/Wing-tip-Lights.pdf
Let me know what you think.
Andrew Sarangan
http://www.sarangan.org
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