Booster fuel pump question?

[escalantea]

In reviewing the KAI, Firewall FWD & Fuel System page 25/43 and 31/43 I notice the Sling TSi has a Posi-flow Electrical fuel pump!
I also found some mention of this booster pump in the POH v3 (not as many as I expected...)

Question for completed/flying builders or the Factory. If the Main and Aux Rotax Fuel pumps fail, will the booster pump cover the needs of fuel for the engine?

If someone with a completed plane, but not yet flying, can you try reading the fuel pressure on the G3X with both main/aux pumps off and only the Booster pump on?

Thanks!

[escalantea]

From Barry at TAF Torrance:

Yes, there is a 3rd boost pump that ensures fuel pressure even if the other two pumps should fail.
There were some fuel pump issues on the earlier Sling TSi however, the factory now provides updated fuel pumps in the Firewall Forward Kit.

Best Regards,
Barry Jay
North American Sales and Marketing Manager

[huzilulu]

The facet pumps only put put about 10-15psi (max) depending on the model you are using… so I doubt the booster pump would be enough for the engine needs - however, they are very useful in providing a good head pressure to the main/aux pump by pumping fuel from the tanks which are quite far away for those units…

Also - as far as I know the booster pump is wired with the main fuel pump switch, so there is no setup where just the booster pump is running to test fuel pressure on any actual built TSis…

[escalantea]

This is the response from Barry at The Airplane Factory USA, Torrance:

Yes, there is a 3rd boost pump that ensures fuel pressure even if the other two pumps should fail.
There were some fuel pump issues on the earlier Sling TSi however, the factory now provides updated fuel pumps in the Firewall Forward Kit.

Best Regards,

Barry Jay
North American Sales and Marketing Manager
The Airplane Factory USA
3401 Airport Drive
Torrance, CA 90505
www.airplanefactory.com

[Skepilot]

This is the response from Barry at The Airplane Factory USA, Torrance:

Yes, there is a 3rd boost pump that ensures fuel pressure even if the other two pumps should fail.
There were some fuel pump issues on the earlier Sling TSi however, the factory now provides updated fuel pumps in the Firewall Forward Kit.

Barry is incorrect.

[permagray]

So, what is the correct and complete answer regarding the fuel pumps? I am at the stage of fuel pumps and fuel lines. I also have the Rotax AD new fuel pumps. Question: Do the main fuel pumps cycle on and off with pressure, or do they just run all of the time? How about the Facet pump? I assume that fuel pressure is maintained in the fuel rail by a limiting orefice in the return side. If that is the case, the pump should cycle with fuel rail pressure. as there would be a steady return of fuel to the tank but a variable amount of fuel going to the fuel rail depending on the usage of the engine . Since I have the new AD Rotax Fuel Pumps, do I even need to install the Facet pump?
#slingsupport