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Rotax fuel flow detection

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graeme bird

Joined: 15 Jul 2010
Posts: 434

Posted: Thu Oct 21, 2010 12:36 am Post subject: Rotax fuel flow detection

Just sorting the fuel system on my new build. I am considering including an RS type flow sensor for future use but what confuses me on the 912 install is that some of the fuel comes back which would make the reading useless unless a return sensor was also fitted. This is the reason my fuel calculator in my C42 is worse than useless. Any advice appreciated.

_________________
Graeme Bird
kit4 (Wagstaff) TBD
Kit3 G-CLXU (Gregory) mono 914 xs Woodcomp
Kit2 G-PATS - (kesterton) Mono Classic 912 warpdrive
Kit 1 G-UMPY - Mono Classic/XS 912S, Woodcomp G(@)gdbmk.co.uk

peter.rees01(at)tiscali.c
Guest

Posted: Thu Oct 21, 2010 1:23 am Post subject: Rotax fuel flow detection

Could be wrong but I don't think that the LAA allow the RS fuel flow 

sensor to be used because of the danger of blockage. I think that the 

Flowscan units are the suggested route (I think that Parts for Aircraft 

is a good UK source - cheaper in the US if you can be bothered to save 

a few quid) - quite a bit more money than the RS unit but not as much 

as putting the aeroplane down in a field.



----Original Message----



From: graeme(at)gdbmk.co.uk



Date: 21/10/2010 9:36 



To: <europa-list(at)matronics.com>



Subj: Rotax fuel flow detection






Just sorting the fuel system on my new build. I am considering 

including an RS type flow sensor for future use but what confuses me on 

the 912 install is that some of the fuel comes back which would make 

the reading useless unless a return sensor was also fitted. This is the 

reason my fuel calculator in my C42 is worse than useless. Any advice 

appreciated.



--------



Graeme Bird



Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=316546#316546





_-

============================================================

grahamsingleton(at)btinte
Guest

Posted: Thu Oct 21, 2010 1:51 am Post subject: Rotax fuel flow detection

Floscan is the best transducer, it uses an infra red sensor so is not susceptible to magnetic interference. Unlikely to block, the hole is larger than anything that would get throuhg your filter. Look for it on marine or automotive markets. Non certified units are the same but cheaper. My Grand Rapids monitor uses the Floscan and the do sell them separately.

Graham

From: "peter.rees01(at)tiscali.co.uk" <peter.rees01(at)tiscali.co.uk>

To: europa-list(at)matronics.com

Sent: Thursday, 21 October, 2010 10:14:43

Subject: Re: Rotax fuel flow detection

--> Europa-List message posted by: "peter.rees01(at)tiscali.co.uk (peter.rees01(at)tiscali.co.uk)" <peter.rees01(at)tiscali.co.uk (peter.rees01(at)tiscali.co.uk)>

Could be wrong but I don't think that the LAA allow the RS fuel flow 

sensor to be used because of the danger of blockage. I think that the 

Flowscan units are the suggested route (I think that Parts for Aircraft 

is a good UK source - cheaper in the US if you can be bothered to save 

a few quid) - quite a bit more money than the RS unit but not as much 

as putting the aeroplane down in a field.

----Original Message----

From: graeme(at)gdbmk.co.uk (graeme(at)gdbmk.co.uk)

Date: 21/10/2010 9:36 

To: <europa-list(at)matronics.com (europa-list(at)matronics.com)>

Subj: Rotax fuel flow detection

--> Europa-List message posted by: "graeme bird" <graeme(at)gdbmk.co.uk (graeme(at)gdbmk.co.uk)>

Just sorting the fuel system on my new build. I am considering 

including an RS type flow sensor for future use but what confuses me on 

the 912 install is that some of the fuel comes back which would make 

the reading useless unless a return sensor was also fitted. This is the 

reason my fuel calculator in my C42 is worse than useless. Any advice 

appreciated.

--------

Graeme Bird

Read this  topic online here:

http://forums.matronics.com/viewtopic.php?p=316546#316546

_-

===================================

ref="http://www.matronics.com/Navigator?Europa-List" target="_blank">ht  - sp;               -Matt Dralle, List Adm========

 [quote][b]

milneab(at)btinternet.com
Guest

Posted: Thu Oct 21, 2010 2:41 am Post subject: Rotax fuel flow detection

The Europa Club have a standard LAA approved mod for the addition of a fuel 

flow transducer that allows for the return flow including type of 

transducer, schematic and installation requirements.  See the Club website.



Alasdair Milne   (Secy Europa Club)

---

air.guerner(at)orange.fr
Guest

Posted: Fri Oct 22, 2010 3:27 am Post subject: Rotax fuel flow detection

Hi Alasdair,



I cannot find this Mod on the Club website. Could you help please?



Remi Guerner



<<<<<<The Europa Club have a standard LAA approved mod for the  

addition of a fuel

flow transducer that allows for the return flow including type of

transducer, schematic and installation requirements.  See the Club  

website.

Alasdair Milne   (Secy Europa Club)>>>>>>>>

g-iani(at)ntlworld.com
Guest

Posted: Fri Oct 22, 2010 4:51 am Post subject: Rotax fuel flow detection

Remi



The mod is an LAA Standard Mod 12209 (on the LAA site).  I have attached a

copy for you



It will be on the Europa Club site when we get it sorted out



Ian Rickard G-IANI XS Trigear, 300hours

Europa Club Mods Specialist

e-mail g-iani(at)ntlworld.com

12209_Fuel_Flow.pdf

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air.guerner(at)orange.fr
Guest

Posted: Fri Oct 22, 2010 9:56 am Post subject: Rotax fuel flow detection

Thank you Ian for posting the LAA mod.



I have not installed a fuel flow in my aircraft but if I had to, I  

would use the attached schematic which allows measuring the flow to  

the carbs with a single sensor, therefore improving accuracy and  

reliability and reducing cost.



The same principle can be used for the 914. In that case the single  

flow sensor would be installed between the pressure regulator and the  

carbs.



Remi Guerner

F-PGKL

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kheindl(at)msn.com
Guest

Posted: Fri Oct 22, 2010 12:09 pm Post subject: Rotax fuel flow detection

Remi,



I tried just that. It does not work. The fuel flow at that point is not smooth and you get very erratic readings. Only John Wigney managed to get it to work with a pulsation damper.

I tried that too, but with little improvement. So I will also have to buy another Floscan transducer. The price at ACS is as good or as bad as any.

Karl

 	  Quote: 	
		   From: air.guerner(at)orange.fr

 Subject: Rotax fuel flow detection

 Date: Fri, 22 Oct 2010 19:53:24 +0200

 To: europa-list(at)matronics.com

 

 

 Thank you Ian for posting the LAA mod.

 

 I have not installed a fuel flow in my aircraft but if I had to, I  

 would use the attached schematic which allows measuring the flow to  

 the carbs with a single sensor, therefore improving accuracy and  

 reliability and reducing cost.

 

 The same principle can be used for the 914. In that case the single  

 flow sensor would be installed between the pressure regulator and the  

 carbs.

 

 Remi Guerner

 F-PGKL


	


 		 	   		    [quote][b]

jan_de_jong(at)casema.nl
Guest

Posted: Fri Oct 22, 2010 4:53 pm Post subject: Rotax fuel flow detection

There is information in the total flow from the pump(s).

Jos O. once mentioned that one of his pre-flight checks was a total 

forward flow of 120 l/h or so (Rotax 914). Anything less would be an 

early sign of trouble.

Jan de Jong



Guerner Remi wrote:

 	  Quote: 	
		  

 Thank you Ian for posting the LAA mod.



 I have not installed a fuel flow in my aircraft but if I had to, I 

 would use the attached schematic which allows measuring the flow to 

 the carbs with a single sensor, therefore improving accuracy and 

 reliability and reducing cost.



 The same principle can be used for the 914. In that case the single 

 flow sensor would be installed between the pressure regulator and the 

 carbs.



 Remi Guerner

 F-PGKL

air.guerner(at)orange.fr
Guest

Posted: Sat Oct 23, 2010 12:48 am Post subject: Rotax fuel flow detection

Svein,



I basically agree with what you wrote. However  my proposed schematic  

is very close to the one recommanded (and optionally  supplied) by   

Rotax in the 912 Install Manual (see attached). This arrangement works  

on most LSAs so I do not see why it would not work with the addition  

of the fuel flow sensor as propsed.



Regards

Remi Guerner



<<<<<<At first sight, your proposal may look like the obvious  

solution.  With

respect, however, I think it is not to be recommended for 912ULS

installations (I do not know enough about 914 to comment on that  

engine).



Contrary to what seems to be a common assumption, the return flow  

through

the restrictor is not insignificant - it is roughly 10 litres per hour  

(i.e.

roughly half of the net cruise consumption, or roughly 1/3 of the fuel  

going

to the engine is flowing back to the tank).  The reason for this  

relatively

high surplus circulation is of course to reduce the time the fuel is  

exposed

to heat before it reaches the carbs, by increasing the flow velocity  

through

the fuel line.  According to the build manual, the return line  

branches off

at the point farthest from the pump, just before the left side carb

(assuming the fuel line goes from the pump to the right side of the  

engine

with a short branch off to the right carb, and from there across the  

back of

the engine to the left carb).



Moving the return line branch-off upstream (closer to the pump)  

increases

the risk of vapour forming in the fuel lines downstream from this  

branch-off

point.  By how much, I do not know, but maybe it is critical under

unfavourable circumstances.  "Maybe's" under the cowling are not nice  

- - -

- - .>>>>>>>>>

912_fuel_system_-_Rotax_IM.pdf

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europapa

Joined: 30 Aug 2010
Posts: 63

Posted: Wed Oct 27, 2010 12:21 pm Post subject: Rotax fuel flow detection

I will too install a fuel computer this winter to my 912s.

     In the manual of my FC1 Flybox is a schematic I will post here

     and I can´t see why it shoud not work.

     Even measuring the fow of only one carb it should be no problem to     find the right k-faktor setting.

     [img]cid:part1.07050804.01050908(at)onlinehome.de[/img]

     

     Am 23.10.2010 10:44, schrieb Guerner Remi:      	  Quote: 	
		  Svein,       

       

       I basically agree with what you wrote. However  my proposed       schematic is very close to the one recommanded (and optionally        supplied) by  Rotax in the 912 Install Manual (see attached). This       arrangement works on most LSAs so I do not see why it would not       work with the addition of the fuel flow sensor as propsed.       

       

       Regards       

       Remi Guerner       

       

       

       

       

       

       

       

       <<<<<<At first sight, your proposal may look       like the obvious solution.  With       

       respect, however, I think it is not to be recommended for 912ULS       

       installations (I do not know enough about 914 to comment on that       engine).       

       

       Contrary to what seems to be a common assumption, the return flow       through       

       the restrictor is not insignificant - it is roughly 10 litres per       hour (i.e.       

       roughly half of the net cruise consumption, or roughly 1/3 of the       fuel going       

       to the engine is flowing back to the tank).  The reason for this       relatively       

       high surplus circulation is of course to reduce the time the fuel       is exposed       

       to heat before it reaches the carbs, by increasing the flow       velocity through       

       the fuel line.  According to the build manual, the return line       branches off       

       at the point farthest from the pump, just before the left side       carb       

       (assuming the fuel line goes from the pump to the right side of       the engine       

       with a short branch off to the right carb, and from there across       the back of       

       the engine to the left carb).       

       

       Moving the return line branch-off upstream (closer to the pump)       increases       

       the risk of vapour forming in the fuel lines downstream from this       branch-off       

       point.  By how much, I do not know, but maybe it is critical under       

       unfavourable circumstances.  "Maybe's" under the cowling are not       nice - - -       

       - - .>>>>>>>>>

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