Fuel Flow Guage / Totaliser

[nomorecatering]

Can anyone explain how a fuel flow/Totaliser guage workes as applicabe to say the Cirus.

How does it determine the flow rate going to the engine, and also how does it know how much fuel has been used. Something to do with psi in the fuel line??.

What about the big jets.

[Intruder]

In "the big jets," a flowmeter is installed at each engine, and measures the fuel as it is used.

In fuel injected piston engines the concept is similar. The flowmeter(s) must be installed downstream of the return line. In the presurized system, some fuel is returned to the tank, so that fuel must not be measured by the flowmeter(s). I don't know if there is any installation that has a flowmeter for each cylinder, though it is possible.

[IFixPlanes]

Some Info out of my Training Letter B737:
The fuel flow transmitter uses the angular momentum of a rotor to measure the mass flow rate. It is made to minimize the drop in fuel pressure across the transmitter. External power is not necessary. Fuel goes in the transmitter and flows to a swirl generator. The swirl generator causes the fuel to swirl around or turn as the fuel goes through the angled fins. The swirling fuel causes the rotor to turn. The rotor has two magnets attached to its surface. One magnet on the rotor induces a start pulse in a coil each time the magnet passes the coil. Fuel then flows to a spring restrained turbine. The turbine moves radially as the fuel passes through it. The turbine has a signal blade which protrudes back to the rotor. A stop pulse is induced each time the second magnet on the spinning rotor passes the signal blade. The time interval between the start and stop pulses is measured by the fuel flow indicator and converted to a fuel flow rate.
http://img183.imageshack.us/img183/1803/fuelflowtransmitterb7377nh.th.jpg (http://img183.imageshack.us/my.php?image=fuelflowtransmitterb7377nh.jpg)