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Richard Wheelwright
Joined: 15 Sep 2008
Posts: 111
Location: Halifax, West Yorkshire, UK
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 Posted: Thu Jan 23, 2014 10:41 am Post subject: 912 ULS SB New Fuel Pump |
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912 uls Drivers
I have just fitted the new Rotax Fuel pump (912-063 (UL) R2 ) This pump is of higher pressure than the old AC pump.
The Questions are:- Has anyone had any problems with the higher pressurizer of the Rotax stated 5.8 psi and 7.2 psi MAX ?
Why do they give 2 high MAX pressures?
My pressure is indicating 5.8psi 2500 rpm and 5 psi at 5400 rpm static, this seems to be the new "normal range" for my aircraft.
Richard
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grahamhall123(at)gmail.co
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| Posted: Thu Jan 23, 2014 12:13 pm Post subject: 912 ULS SB New Fuel Pump |
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Have you seen this month and last month's safety spot in light aviation magazine?
Bit of info on the new pump.
Best wishes,
Graham.
On Jan 23, 2014, at 6:41 PM, "Richard Wheelwright" <rpwheelwright(at)yahoo.co.uk> wrote:
| Quote: |
912 uls Drivers
I have just fitted the new Rotax Fuel pump (912-063 (UL) R2 ) This pump is of higher pressure than the old AC pump.
The Questions are:- Has anyone had any problems with the higher pressurizer of the Rotax stated 5.8 psi and 7.2 psi MAX ?
Why do they give 2 high MAX pressures?
My pressure is indicating 5.8psi 2500 rpm and 5 psi at 5400 rpm static, this seems to be the new "normal range" for my aircraft.
Richard
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=417489#417489
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Remi Guerner
Joined: 14 Dec 2010
Posts: 284
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| Posted: Fri Jan 24, 2014 2:13 pm Post subject: Re: 912 ULS SB New Fuel Pump |
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Richard,
Obviously the max acceptable fuel pressure is determined by the design of the carburetor not the pump: a too high pressure may override the float valve and flood the carbs. Rotax received a lot of complaints about the new pump exceeding the 5.8 psi limit. It seems to me that instead of finding a technical solution and rework the pump, they just decided to extend the fuel pressure limits! Crazy!
One issue is the aging of the carbs. The float needle of the Bing carb is made of rubber and is subject to wear with engine hours due to vibrations, aging etc... new carbs may withstand 7.2 psi or more without leaking but what happens after 500, 1000 hours? Note there are several provisions designed by Rotax to deal with carburetor flooding: drip tray drains and airbox drains. This is an indication that flooding is likely. I think it is safer to stay with the original limit. Another thing is to calibrate your pressure gauge as most are grossly wrong.
Remi
<<<<<<Rotax>>>>>>
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Richard Wheelwright
Joined: 15 Sep 2008
Posts: 111
Location: Halifax, West Yorkshire, UK
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| Posted: Sat Jan 25, 2014 12:57 am Post subject: Re: 912 ULS SB New Fuel Pump |
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Remi
Thank you for your reply. Yes I agree with you totally and understand the issue.
I was just wanted to know if anyone had had any problems with the new replacement pumps? I'm satisfied with the pressure I have on my aircraft at a new 5.8 psi (4 bar) MAX, as this was the maximum limit with the old pump. the new max limit is 7.2 psi (5 bar) and can not reached, this dew to the return to the tank (unless it gets blocked)
I did read the info in the LAA Magazine which give the thoughts of LAA engineering very well explained.
I can see this subject coming up for discussion again, as eventual all engines will require the new pump, and it is included in the 5 year rubber replacement and will need to be completed eventual.
As my engine falls within the less than 5 years old and has just gone into service, I decided it was a good move to fit the FREE replacement.
Richard
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richard collings
Joined: 08 Jul 2011
Posts: 73
Location: warwickshire england
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| Posted: Sat Jan 25, 2014 3:32 am Post subject: 912 ULS SB New Fuel Pump |
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Hi Richard
I have been watching this problem for some time and for what its worth I
would fit a fuel pressure gauge if you haven't already and then adjust the
pressure by increasing the size/diameter of the metering hole in the return
line. The main problem [if you can call it that] is that the Rotax engine is
very efficient and uses very little fuel so the carburettor jetting is very
fine which in turn increases the danger of blockage. It sounds to me that
Rotax have sourced a pump that is capable of delivering a much greater
amount of fuel than its predecessor and is overwhelming the carburettor
float valve.
--
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Richard Wheelwright
Joined: 15 Sep 2008
Posts: 111
Location: Halifax, West Yorkshire, UK
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| Posted: Sat Jan 25, 2014 6:58 am Post subject: Re: 912 ULS SB New Fuel Pump |
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Richard,
I fitted a UMA fuel pressure gauge from the start, calibration results are good (Advice given by Andy Draper) I agree the fuel pressure gauge is a must fit item. It has already proved it reason it should be in an aircraft panel.
OK, one problem with making the return restricter an increased hole size from the 0.35, (Printed in the LAA Magazine) is that it will not allow the electric pump to deliver the 125% of fuel required by the LAA. This then makes the aircraft unfit for flight !!! OK a larger electric pump to deliver the correct amount of fuel could be fitted, this would then increase the pressure.... so it goes on etc... etc...
Another point is that all new engines now have the new pump and pressure is standard now at MAX 7.2 psi (5 bar) Aircraft kit suppler will have to alter there biuld manuals to cover this also advising LAA of there intentions. It is going to be interesting to see how different Aircraft kit suppliers cover this in there manuals
Richard
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max8992
Joined: 28 Jul 2011
Posts: 142
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| Posted: Sat Jan 25, 2014 8:30 am Post subject: 912 ULS SB New Fuel Pump |
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Hi there,
To make it even simpler I fitted a fuel pressure regulator which cost is 45€....
Max Cointe
mcointe(at)free.fr
F-PMLH Europa XS_TriGear
Kit #560-2003 912ULS/AirmasterAP332 490 hours
F-PLDJ Dyn’Aéro MCR 4S
Kit #27-2002 912ULSFR/MTProp MTV7A 1600 heures
-----Message d'origine-----
De : owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] De la part de richard
Envoyé : samedi 25 janvier 2014 12:32
À : europa-list(at)matronics.com
Objet : Re: Re: 912 ULS SB New Fuel Pump
Hi Richard
I have been watching this problem for some time and for what its worth I would fit a fuel pressure gauge if you haven't already and then adjust the pressure by increasing the size/diameter of the metering hole in the return line. The main problem [if you can call it that] is that the Rotax engine is very efficient and uses very little fuel so the carburettor jetting is very fine which in turn increases the danger of blockage. It sounds to me that Rotax have sourced a pump that is capable of delivering a much greater amount of fuel than its predecessor and is overwhelming the carburettor float valve.
--
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_________________
Max8992
Europa XS #560 F-PMLH |
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Richard Wheelwright
Joined: 15 Sep 2008
Posts: 111
Location: Halifax, West Yorkshire, UK
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| Posted: Sat Jan 25, 2014 9:15 am Post subject: Re: 912 ULS SB New Fuel Pump |
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Max,
Yes the fuel regulator may be a the way to go, or a variable return restriction, something spring loaded in the return line? This would probably give correct fuel pressure through out the different RPM range and stay constant. Something like a check valve set at the correct tension load for the pressure (simple solutions are always the best)
Going back to the original question, Has any one had a problem with the New Fuel Pump? The answer seems to be, NON Reported.
After all, Rotax will have tested the fuel pump to extreme levels in all situation before the great expense in re-calling and exchanging them.... wont they????
Richard
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Richard Wheelwright
G-IRPW
First Flight 24th July 2013 |
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clivesutton
Joined: 23 Jan 2013
Posts: 187
Location: KENILWORTH
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| Posted: Sat Jan 25, 2014 9:38 am Post subject: 912 ULS SB New Fuel Pump |
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Hi Richard, ive fitted one and had to modify my lower cowling as the pump flange takes up more space. I used a cut-out after discussing with Andy Draper. Clive Sutton
Sent from Clives mobile
On 25 Jan 2014, at 17:15, "Richard Wheelwright" <rpwheelwright(at)yahoo.co.uk> wrote:
| Quote: |
Max,
Yes the fuel regulator may be a the way to go, or a variable return restriction, something spring loaded in the return line? This would probably give correct fuel pressure through out the different RPM range and stay constant. Something like a check valve set at the correct tension load for the pressure (simple solutions are always the best)
Going back to the original question, Has any one had a problem with the New Fuel Pump? The answer seems to be, NON Reported.
After all, Rotax will have tested the fuel pump to extreme levels in all situation before the great expense in re-calling and exchanging them.... wont they????
Richard
--------
Richard Wheelwright
G-IRPW
First Flight 24th July 2013
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=417573#417573
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