 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
jimandlaura(at)peoplepc.c
Guest
|
 Posted: Thu Feb 01, 2007 6:43 am Post subject: Fuel Return?Fuel Return?Fuel Return? |
 |
|
Linn,
As far as I know, the return line is only needed if you have an injected engine with a high pressure electric fuel pump. The electric fuel pump will have an over-pressurization line that needs to be run somewhere, preferably back into one or more tanks. The way I’m setting mine up is to run an extra line from my right tank for this purpose. I’m not spending $500 bucks just to be able to select my return tank, come on! Anyway, putting a T in your main fuel line is a bad idea. You’re just asking to suck air into your line. Not a good thing!
v/r, Jim R
jimandlaura(at)peoplepc.com
40191, Finishing
________________________________________
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
|
|
|
| Back to top |
|
 |
apilot2(at)gmail.com
Guest
|
| Posted: Thu Feb 01, 2007 7:19 am Post subject: Fuel Return?Fuel Return?Fuel Return? |
|
|
I guess I am having difficulty seeing the need. Yes, Continental fuel
injection and some others operate with a return line, but Bendix fuel
injection systems, at least on the 4 cyl Lycomings do not have any
fuel return line, and they work just fine.
My Mooney fuel system consists of a Dukes electric high pressure pump
in the belly, feeding an AC mechanical high pressure pump on the
engine, then going to the Bendix fuel servo. It operates in the 24-28
psi range. From the fuel selector to the fuel distributor there is a
single line, with the pumps in series. I suspect that the certified
installs of six cylinder Lycomings is very similar.
On 2/1/07, jimandlaura <jimandlaura(at)peoplepc.com> wrote:
| Quote: |
Linn,
As far as I know, the return line is only needed if you have an injected engine with a high pressure electric fuel pump. The electric fuel pump will have an over-pressurization line that needs to be run somewhere, preferably back into one or more tanks. The way I'm setting mine up is to run an extra line from my right tank for this purpose. I'm not spending $500 bucks just to be able to select my return tank, come on! Anyway, putting a T in your main fuel line is a bad idea. You're just asking to suck air into your line. Not a good thing!
v/r, Jim R
jimandlaura(at)peoplepc.com
40191, Finishing
________________________________________
|
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
|
|
|
| Back to top |
|
|
LloydDR(at)wernerco.com
Guest
|
| Posted: Thu Feb 01, 2007 7:29 am Post subject: Fuel Return?Fuel Return?Fuel Return? |
|
|
Just be careful that all of that fuel from your full left tank is not
ported overboard from your full right tank when you first turn on the
engine. The flow rate on the pumps is quite high and can quickly
overfill the tank. Besides the Andair valve just looks cool, as
evidenced by people making the anodized handles for the Vans valves to
look like the Andair ones.
It just makes it easier to use a duplex valve. When you look at accident
reports and one of the highest incidents is still fuel starvation, I was
not willing to mess with fuel management. For $500 it was worth it to
not have to worry about which tank I am drawing fuel from and which tank
I am returning it to. With your setup you would always have to start out
on the right tank to make room for the fuel from the left tank, and if
you forget to switch from left to right, it is pretty likely you will
run it over and dump fuel.
Just my thoughts, the fuel system is not an area to be manipulated
without allot of analysis.
Dan
N289DT
--
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
|
|
|
| Back to top |
|
|
pitts_pilot(at)bellsouth.
Guest
|
| Posted: Thu Feb 01, 2007 8:54 am Post subject: Fuel Return?Fuel Return?Fuel Return? |
|
|
Let's work this through. Maybe I should have said to place the 'T'"
between the boost pump and mechanical pump. Now I have. Read on.
jimandlaura wrote:
| Quote: |
Linn,
As far as I know, the return line is only needed if you have an injected engine with a high pressure electric fuel pump.
All injected engines have a 'high pressure' mechanical fuel pump and
|
boost pump. Pressure carbs like the one on my Pitts need a high
pressure pump too. My PS-5A (pressure carb) also has a return line
..... but that's because it has diaphragms controlling the fuel flow
and no float. Standard carbs for our engines need around 5 Lbs max and
the PS-5A needs above 12 Lbs. I'm not sure what the pressure capability
is for an injected boost pump, but it's higher
| Quote: | The electric fuel pump will have an over-pressurization line that needs to be run somewhere, preferably back into one or more tanks.
I'm not positive (there may be some different systems out there) but I
|
think the return line is a function of the fuel controller. AFAIK, some
need a return and some do not. There is always that 'purge valve' that
I'm not familiar with. But that's only a small amount anyway.
| Quote: | The way I’m setting mine up is to run an extra line from my right tank for this purpose. I’m not spending $500 bucks just to be able to select my return tank, come on!
You just need to fly off some fuel from full .... on the right tank
|
..... to prevent overflowing ...... add that to your pre-start checklist.
| Quote: | Anyway, putting a T in your main fuel line is a bad idea. You’re just asking to suck air into your line. Not a good thing!
OK, tell me where the AIR comes from! I can see where there might be
|
fuel vapor in the return line from a heat soaked engine. Vapor lock
(fuel vapor in the fuel line) occurs when suction is applied to a line
with hot fuel in it, usually an engine driven pump. The pump cannot
compress the fuel vapor enough to expel it out the through the reed valve.
The solution is to turn on the boost pump and put pressure in the system
to force the fuel vapor back into it's liquid state and make the system
normal. There should be sufficient pressure from just about any pump to
accomplish this ..... even the little Facet pumps.
The boost pump will provide cooler fuel to the system as the vapor
condenses. You will not circulate hotter and hotter fuel (where does
the heat come from) no matter what. All you need is for the system to
build enough pressure to overcome the spider spring and the injectors
themselves.
This is as I understand it ..... if I'm wrong, please back up your
comments with data, not hearsay.
Linn
do not archive
| | - The Matronics RV10-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV10-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
