Thanx Todd, I borrowed your explanation from the other thread. I wanted more guys to read this, maybe it will prevent some grief and educate.
Rc fuel pump pressure shutoff full#
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! Fuel was shut off, line burst and filled the interior of the plane with fuel as the owner scrambled to unhook the ECU pack. We have personally witnessed a runaway ECU with a fuel valve placed after the pump. If there is no fuel being fed into the gears, the fuel has no way of being pushed down stream. 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. the rest of the electronics then take care of themselves. If located before the pump, fuel flow stops IMMEDIATELY. The foolproof way is to interrupt one fuel pump wire ( positave or negative doesn't matter) fuel pump wire with a small micro switch, servo operated on a separate channel, therefore if it is all going pear shaped you can flick a switch and shut the pump down. Closing the valve abruptly can burst a line and make matters worse. BEFORE the pump! If an ECU malfunctions, the pump can still be running providing full pressure.
Rc fuel pump pressure shutoff install#
I ALWAYS install the shutoff valve after the pump.įrom experience. It is a ball valve so there is minimal pressure drop through the valve. The Tetra shutoff valve is included with most turbines so you don't have to buy the valve separately. You can buy a Festo 4mm ball valve ($14) and the mount ($15) which will not leak (since it's on the pressure side) and looks good but that's $29 total.Īdvantage: Turning off the valve immediately will stop any fuel delivery (since the pump is upstream) regardless of whether the pump is still running. Since it has barb fittings, you can't easily disconnect it. Also, as Jeremy said, if you shut the valve and the pump is still running, you can get cavitation which will allow a bit more fuel to flow.Īdvantage: The valve can be disconnected easily allowing easier removal of the fuel pump for maintenance if necessary.ĭisadvantage: The Tetra valve is a PITA to install and there are few ways to hard mount it to the model and safety wire it. Additionally, Festo valves are generally not designed to operate under a vacuum so the seals can potentially leak causing an air bubble and engine flame out. To reduce the pressure drop through the valve (which could cause cavitation), you need to use a Festo (or equivalent) 6mm 90 degree ball which is about $14. Installing the valve here (especially if you want to hard mount it somewhere) generally means a longer line. It can be installed before or after the pump but there are advantages and disadvantages of each as follows:ĭisadvantage: You need to have this line as short as possible.
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