Mailing List flyrotary@lancaironline.net Message #67834
From: Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Fuel injection Diagram
Date: Mon, 24 Feb 2025 16:07:10 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
If you're returning all fuel to right tank you'll have an interesting time managing fuel.
When both tanks are full you'll have to select right tank.
Then, when you're sure the right tank won't overflow, switch to  left tank.
May have to switch back to right tank  to make room for more fuel.
Then left tank until empty. Then switch to right tank.

That's why you'd typically have one of these configurations:
1) Header tank you can return fuel to
2) Dual-port fuel selector so you can return fuel to same tank you're pumping from
3)  Pump only from one tank you also return fuel to, plus a transfer pump.

Finn

On 2/24/2025 1:17 PM, Le Roux Breytenbach breytenbachleroux@gmail.com wrote:
Thanks Steve got it ! 
After all the info and inputs, my thoughts still pussing for a left and right tank set up 

Faset pumps for each wing - then fuel selector then to high pressure pumps ( 2 in parallel) filters before each pump , fuel pressure regulator and return to one wing.

This is what i have in mind - don’t know if this is redundant enough left and right seperate from each other ?
image0.jpeg
Sent from my iPhone
Le Roux Breytenbach 

On 22 Feb 2025, at 10:55, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:

 Hi Le Roux

Your gut is correct, the Glasair has a single tip to tip main wing tank with flapper values to keep fuel somewhat balanced across the tank.
Yes, the facet pumps (two in series - main and backup) pump the main wing fuel into the header that then overflows back into the centre of the main tank.
So all fuel is continuously being circulated through the main filter into the header and back again.
There is no fuel tank selection. 
During my preflight walk around I always check the header tank is full.

I have a microcontroller I call my ‘CoPilot' managing a series of things onboard.
Two of those functions are:
1. Automatically sense a drop in Fuel Pressure at the engine fuel rail and switch on the backup engine fuel pump.
2. Automatically sense a drop in Fuel Transfer between wing and header and switch on backup transfer pump.
Both these Automatic Backups are checklist tested before flight.
a. Turn OFF main fuel pump, backup activates so engine continues to run, and CoPilot LED changes from Solid to Flashing indicating the backup has been triggered.
While IAS below ~60 Knots(as in we're not flying) by pressing the CoPilot BUTTON, the system is reset/rearmed.
b. Turn OFF main transfer pump…. Same processs as above.
These system tests take about 5 seconds to carry out and are done after startup along with testing computer B and Coils. (Tracy’s EC2)

There is also capacitive senders in the tanks with alarms. 
If the header tank level drop below near full, I get an audible voice alarm, and if the transfer flow drops I get an audible voice alarm which means I either have a transfer pump failure or the Wing tank just emptied leaving me on my header tank reserve of 28L

Steve








On 22 Feb 2025, at 4:17 pm, Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:

Thanks guys for all your inputs much appreciated. 
Stephen so there is no fuel selection from one tank to the other in your set up.? Or do you select left or right tank with faset pumps for each wingtank ?
152 L seems to me are both wings together as i have also a composite wing..
The header tank flow back to only one wingtank or both ? 

Regards Le Roux






On Sat, Feb 22, 2025 at 8:57 AM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
Hi LeRoux

Here is my setup

Steve Izett
Glasair Super IIRG



> On 22 Feb 2025, at 12:14 am, Le Roux Breytenbach breytenbachleroux@gmail.com <flyrotary@lancaironline.net> wrote:
>
> Hi : Do somebody have a schematic drawing ? Of a typical low wing experimental aircraft fuel system to the 13B.
> Can’t find good detail info.
> The feed from the wings to the high pressure fuelpumps.
> Where to place the low pressure fuel pumps and then to fuel injection pumps.
> Must i do a header tank ? or not.Must the high pressure pumps be inside or outside on the firewall?
>
> Regards Le Roux
>
> Sent from my iPhone
> Le Roux Breytenbach
>
> --
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