Jetfan20

My Feedback: (21)

Hi All,

Where do you guys put your fuel shutoff valve? Before or after the Fuel pump? What is recommended?

Thanks in Advance!

FalconWings

My Feedback: (57)

I place all my manual shutoffs immediately before the engine feed fitting, as a back up for the solenoid valve.

Harley Condra

My Feedback: (4)

Locate the ball valve downstream of the fuel pump.

Boomerang1

I was advised to put the ball valve before the pump.

The reason given to me was with the pump pumping into a dead end
the pressure delivered by the pump could pop a fuel line fitting spraying
fuel everywhere. - John.

racer8297

My Feedback: (13)

After the fuel pump. It is the last fitting before the fuel line enters the motor.

mick15

Before the pump for the reasons John says.

m

smchale

My Feedback: (67)

If you develop a slight leak in the ball valve having it after the pump is better. This will then leak fluid out while still pumping fuel to your engine. If it leaks before the pump it will suck air in and cause a flame out.

proline8000

My Feedback: (12)

First of all you need to know why there is a requirement for a manual shut-off valve. The reason is for Emergency’s …. You need to be able to shut off fuel independently of the radio in case of a fire. If you place the shut off valve after the pump the fuel will be stopped from the turbine instantly and will shut off the turbine even if the pump is still running. If you put it before the pump the pump will still supply fuel to the turbine for a couple of seconds . The second reason is preventing fuel from filling up the turbine during re-fueling. Most fuel pumps that you use for re-fuelling will drive fuel thru the turbine pump and solenoid valves filling the turbine causing a hot start. As for the pressure of fuel from the turbine pump popping the fuel lines off, Never, the fuel line and barbs will hold 100 psi and the fuel pressure will never go that high, if you safety wire the fuel lines that should be good for a couple of hundred pounds of fuel pressure. The shut-off valve should be placed as far from the turbine as possible.

FalconWings

My Feedback: (57)

We really need to do a thread on proper fuel system etiquette. Things like vent sizing, optimal pump voltage, fuel supply to pump inlet transitions, vent spill protection.....
If I had the time I'd do it myself

lov2flyrc

My Feedback: (24)

From experience.... BEFORE the pump! If an ECU malfunctions, the pump can still be running providing full pressure. Closing the valve abruptly can burst a line and make matters worse. If located before the pump, fuel flow stops IMMEDIATELY. These are gear driven pumps; if there is no fuel entering the inlet, no fuel can exit the pump! Thinking fuel will still be delivered for "seconds" is incorrect. If there is no fuel being fed into the gears, the fuel has no way of being pushed down stream.
We have personally witnessed a runaway ECU with a fuel valve placed after the pump. Fuel was shut off, line burst and filled the interior of the plane with fuel as the owner scrambled to unhook the ECU pack.....
Personally, I see no logical reason to place the emergency shutoff valve AFTER a pump? It is no more prone to leaks than any other fitting in the system and in an emergency situation (the main reason the valve is required); far safer suffocating fuel from entering than blocking full pressure of the pump!
JMHO

Meesh

My Feedback: (135)

I agree with Todd.

In addition, if you put the valve after the pump, and you forget to open it while starting, you can blow the shaft seals in the pump. This happened to me on a Fliteworks pump.

Bob

FenderBean

from the looks of it where ever you like seems everyone has their own opinion. I put mine just before the turbine, because if I need to emergency shutdown trim low followed by the valve. I do this for the same reason the full size designs always cut off fuel as close to the turbine.

Kevin_W

My Feedback: (1)

I agree completely! [sm=thumbs_up.gif]

Gonzalo38

It's interesting to see that not even the manufacturers have an agreement on the placement of the Fuel Shutoff valve.

When looking at a Jetcentral manual, the installation drawing for a turbine with kerostart says that the valve goes before the fuel pump. For the same turbine but this time with gas start, the installation drawing shows the valve between the pump and the solenoid.

When looking at a Jetcat manual, the installation drawing shows the valve installed after the solenoid. In some other drawings (kerostart), they don't even show a shutoff valve in the drawing.

In the Wren manuals, no mention of a shutoff valve.

afterburner

My Feedback: (18)

I'm in the middle of installing a new JC Cheetah KS and the diagram shows the cutoff right after the pump.

Marty

Gonzalo38

Interesting..... so not even for different turbines of a same manufacturer instructions are the same. I was looking at the Mammoth

Gonzalo38

Afterburner:

I was checking the drawing of the Cheetah KS manual, and the shutoff valve is installed before the pump. I was checking the downloadable version of the manual. In the gas version is after the pump.

grbaker

My Feedback: (29)

I hope you can get to it when fire is coming out of both ends. []

lov2flyrc

My Feedback: (24)

Agreed! Probably the worst place to locate the valve!

afterburner

My Feedback: (18)

My diagram for kero install is dated Febrero 2012.

Marty

mick15

Here’s a thought for you, have you ever pressure tested a fully stalled Hausle pump, no I thought not, they can deliver well over 250psi!!

m

marc s

Kaaaaaabooooooooooooooooooom !!!!!!!

So my choice - before the pump.

marcs

ira d

I have never really seen the logic behind having a extra shut off valve seems to me it would be better to have a servo operated switch in line with fuel pump.

Boomerang1

In Oz you are required to have both a manual & radio controlled method of shutting down
the engine indepenent of the turbine electronics.

My bunch of jet buddies usually drive the ball valve with a mini servo but one of us uses
a micro servo driving a switch to interupt the power to the ECU as ira d mentions in a tiny
Lambert install where there's no spare room.

Either method may have helped the A-10 in the video with two engine fires at the same time.

- John.

FalconWings

My Feedback: (57)

I just don't buy the theory of a running pump generating enough pressure to either break a connection loose, or cause the manual SOV to leak. If any of these happen, only means the installation was probably not very robust to begin with.
The manual SOV is for engine kill, not pump kill.

If your engine throws out fire from the intake side, you already have a catastrophic event, and you should be reaching out for a fire extinguisher, not a SOV!!!!