Fuel Flow sensors

28 Jul 2013 Fuel Flow sensors

The standard methods of installing fuel flow sensors is to use an inline fuel flow transducer that is moved by the fuel flowing to the engine.
The two most popular options (as of 2013) are the Flowscan and the EI FT-60 “Red Cube”.

My concern with this technology is that it causes pressure drops since it clearly provides some restriction and resistance to the fuel flow. To minimize the chance of vapor lock, these transducers need to be installed on the “high pressure” side of fuel system, between the last fuel pump and the carburetor or the fuel injection spider. The challenge is that this a rather high heat, high vibration environment with rather short hoses and not a lot of space. Of course it has been done in thousands of aircraft in that past, so it can be done reliably.

While I expect that I will need to do the same, I am holding off on installing a fuel flow transducer as I think new technology will be available in the coming years that uses ultrasonic sensing of the fuel flow, like this difficult to obtain model from Gill Sensors in the UK.

Time will tell – hopefully a small model which will work for our application and can be simply wrapped around one of the fuel lines in the cockpit will be available soon!