Boost Pumps

[skippydiesel]

Hi All,

For a 912ULS - please advise which 12V boost pump? you are using and why?

I note that:

Rotax recommend a boost pump Max pressure of 4.5 psi.

It would seem that all Facet pumps, with a Max pressure of up to 4.5 psi, have a 1/8 27NPT In/Out port - this is significantly reduced when an AN fitting is attached - does anyone have a problem with this restriction? and if so what is your solution?

Edited July 3, 2023 by skippydiesel

[skippydiesel]

Common guys & girls, almost all small aircraft pilots (particularly Rotax motivated) will be using a Facet or Facet style boost pump (mainly "Cubes") - what model do you have?

[RFguy]

Take a look at the pressure versus flow curves for the pump you have in mind  to determine suitability. Bit of pressure is useful to reducd chance of vapourization bubbles in hot weather  / high altitude  (high DA) ULP ops. 

You don't need much pressure to drive the Bings, as long as you get the flow

 

[RossK]

Evektor were using a Pierburg 12V pump, part number 7.21440.51, but since 2021 have been using a Facet 478360 pump.

 

 

[kgwilson]

The Facet pumps I installed came with their own nipples which fitted the 1/4" automotive fuel line so there were no AN fittings required. The main boost pump is 1.5-4 PSI & has heaps of flow to a Jab 3.3 engine so will have no issue with feeding a rotax. The wing tanks have a 4-6  PSI pump to transfer fuel to the main fuselage tank

[skippydiesel]

25 minutes ago, RossK said:

Evektor were using a Pierburg 12V pump, part number 7.21440.51, but since 2021 have been using a Facet 478360 pump.

 

 

Now that's what I would call a first class response/information - thanks Ross

[skippydiesel]

8 minutes ago, kgwilson said:

The Facet pumps I installed came with their own nipples which fitted the 1/4" automotive fuel line so there were no AN fittings required. The main boost pump is 1.5-4 PSI & has heaps of flow to a Jab 3.3 engine so will have no issue with feeding a rotax. The wing tanks have a 4-6  PSI pump to transfer fuel to the main fuselage tank

Good effort KG , especially the photos (love seeing other peoples aircraft/fit out) but lacks pump detail - if its a genuine Facet it will have model numbers stamped on to body, in/outlet flange or mounting bracket .

 

FYI - Facet pumps can be ordered as just the pump or a kit. The kit may have additional fittings, such as a filter, possibly push on tube adapters. In my case I will just be getting the pump as my system is all AN aluminium tubing.

[skippydiesel]

KG,

 

Good looking pump. 

One psi higher pressure than Rotax recommended at Max  4.5 psi

The integrated/serviceable filter is (for some) a handy feature

Not sure how this pump (Gold -Flo) compares with the Facet Cube style of the same/similar pressure/flow rate.etc

 

Facet 478360 pump.

PN	OEM PN	Volts	PSI Max-Min	GPH	Fitting Size	Lift Min. Dr

478360

478360E

12

5.5-4.0

36

1/8"-27 Int.

24"

 

[skippydiesel]

Apologies the above response should have been to RossK

[rgmwa]

The RV-12 ULS originally used a Facet 40105 but Vans upgraded it in 2018 to a Facet 40135.

[skippydiesel]

RGMWA - Interesting.

 

Thanks for your thought provoking information.

 

The only significant defence would seem to be Max pressure.

 

RV obviously feel that the Rotax recommended Max 4.5 psi, is not up to the job - I wonder why?

 

My fuel system runs at about 5.2 psi, so 7 psi would seem to be a tad over the top.

 

OLD

Part Number: 40105
Kit Number:
Type: Cube
Volts: 12
Max/Min: 4.5 - 3.0
GPH: 30
Fuel Filter Fitting: 1/8 - 27 NPTF
Lift Min: 36"
Check Valve: N
Positive Shut Off Valve: N
Internal Fuel Filter: n/a
Stainless Steel: N

NEW

Part Number: 40135
Kit Number:
Type: Cube
Volts: 12
Max/Min: 7.0 - 4.0
GPH: 32
Fuel Filter Fitting: 1/8 - 27 NPTF
Lift Min: 36"
Check Valve: N
Positive Shut Off Valve: N
Internal Fuel Filter: n/a
Stainless Steel: N

[rgmwa]

Here's the story: https://www.vansaircraft.com/wp-content/uploads/2018/12/Notification-2018-07-12.pdf

 

[facthunter]

I'm a bit surprised there's no RATE of flow check. It's specifed in other places referencing fuel system performance requirements.   I'd want to  see a flow above 150% of maximum  fuel   required at full power PLUS what is fed back to remove vapour.. Something around 40 Litres /hour.   minimum.  Nev

[rgmwa]

Here's a link to the Production Acceptance Procedures for the RV-12.  Although it's RV-12 specific, it's probably a pretty good guide for any homebuilder.

https://www.vansaircraft.com/wp-content/uploads/2020/10/RV-12-Production-Acceptance-Procedures-R14.pdf

There is a fuel system flow test on page G4-1. Under the system in the USA Vans is the registered builder of an ELSA RV-12, not the actual builder, so they need evidence that all the tests have been completed.

[facthunter]

1 US gallon in 3 minutes. Sounds fine.  Nev

[skippydiesel]

7 hours ago, rgmwa said:

Here's the story: https://www.vansaircraft.com/wp-content/uploads/2018/12/Notification-2018-07-12.pdf

 

I was sure I answered this but the.........????

 

I have had an on going, intermittent low fuel pressure warning during climb out - sounds much like the RV 12 story.

Fuel pressures all as expected, on the ground & in air (strait & level) - after much debate, decided to change fuel return line restrictor jet, reducing by pass fuel down from 7 to 5 L/hr - certainly helped but did not completely cure.

The gold coloured, cube style, boost pump, I have, has no markings -definably not a Facet, could be a Goss, Syntex or some other copy. 

Will now review Facet offerings with a view to installing a pump of a known Max pressure/volume output.

Edited July 4, 2023 by skippydiesel

[skippydiesel]

6 hours ago, facthunter said:

1 US gallon in 3 minutes. Sounds fine.  Nev

If my maths is correct  - Rotax 192ULS consumes less than 6.4 US Galls/hr (.32 Gals/3 min 1.2L/3mins) at Max power - 1US Gallon/3 minutes is a tad over the safety need.

[facthunter]

It is but what's the problem?   You have to add the amount returned too. It should also be checked periodically to see if any restrictions are happening. Nev

[skippydiesel]

22 hours ago, rgmwa said:

Here's the story: https://www.vansaircraft.com/wp-content/uploads/2018/12/Notification-2018-07-12.pdf

 

Do any Rotax 9 series experts out there have any comment on the Vans RV- 12/Rotax 912ULS advice??

 

It would seem that this Facet Cube 40135 is readily available in Australia, in the kit offering, Part Number FEP12SV

 

 

Part Number: 40135
Kit Number:
Type: Cube
Volts: 12
Max/Min: 7.0 - 4.0
GPH: 32
Fuel Filter Fitting: 1/8 - 27 NPTF
Lift Min: 36"
Check Valve: N
Positive Shut Off Valve: N
Internal Fuel Filter: n/a
Stainless Steel: N

 

[danny_galaga]

No idea what model mine is, came with the Bushcat kit. Facet 'cube'. If anyone is using facet, as far as I know they don't make 'aircraft' grade pumps, so just get it from Repco etc...

[kgwilson]

Facet do make soild state and other types of aviation fuel pumps. They are just the same as automtive except have lots of paperwork and cost 4 times as much.

[danny_galaga]

15 hours ago, kgwilson said:

Facet do make soild state and other types of aviation fuel pumps. They are just the same as automtive except have lots of paperwork and cost 4 times as much.

When I used to work at an auto electrical wholesaler, we used to say that if it's marine grade, double the price. If it's aviation grade, add a zero 😄

[danny_galaga]

On 04/07/2023 at 11:31 AM, skippydiesel said:

RGMWA - Interesting.

 

Thanks for your thought provoking information.

 

The only significant defence would seem to be Max pressure.

 

RV obviously feel that the Rotax recommended Max 4.5 psi, is not up to the job - I wonder why?

 

My fuel system runs at about 5.2 psi, so 7 psi would seem to be a tad over the top.

 

OLD

Part Number: 40105
Kit Number:
Type: Cube
Volts: 12
Max/Min: 4.5 - 3.0
GPH: 30
Fuel Filter Fitting: 1/8 - 27 NPTF
Lift Min: 36"
Check Valve: N
Positive Shut Off Valve: N
Internal Fuel Filter: n/a
Stainless Steel: N

NEW

Part Number: 40135
Kit Number:
Type: Cube
Volts: 12
Max/Min: 7.0 - 4.0
GPH: 32
Fuel Filter Fitting: 1/8 - 27 NPTF
Lift Min: 36"
Check Valve: N
Positive Shut Off Valve: N
Internal Fuel Filter: n/a
Stainless Steel: N

How far does the pump have to move fuel? Maybe it's a bit longer than other setups so they want a bit extra. It would seem to me a bit extra is fine since it just gets returned to the tank if not needed 

[skippydiesel]

".............it just gets returned to the tank ..............."

 

One of the fixes I implemented , when trying to address  low fuel pressure  on climb out was to put a small aperture restrictor jet in the return line, reducing fuel return flow from 7+L/hr down to 5L/hr  - helped but not 100%.

 

The RV-12 advise pretty much mirrors my concerns, so I will try the higher capacity pump AND re install the larger aperture restricted jet in the return line.

[kgwilson]

What is the purpose of a return line to the tank? With a Facet electronic cube pump it continues to run to its maximum pressure when the carb bowl is full and the shutoff valve closes. Pressure does not build up past its maximum. Mine is 1.5psi to 4 psi so when the carb bowl is full it just keeps running at 4 psi with no fuel flow.