what are the basic differences between the proportional flow control FCU and pressure control FCU? ( FCU : fuel control unit )
1 Answer
The pressure control system is a typical system as fitted to a turbo-propeller engine where the rate of engine acceleration is restricted by a propeller speed controller
The proportional flow control is a typical system where H.P. compressor shaft r.p.m. is governed by a hydro-mechanical governor which uses hydraulic pressure proportional to engine speed as its controlling parameter
Therefore the pressure control system is one step ahead as it looks at the tendance of speed, of course the pressure control system alone is not sufficient because even if the rate of speed increase is not excessive, the final speed could become excessive, that’s why also a speed limiter is included in the system
Today’s FADECs directly protect the engines for excessive speed and for excessive speed rate
Please refer to to the following Website
http://aeromodelbasic.blogspot.com/2012/01/fuel-control-system.html
Also please refer to the following website
http://aeromodelbasic.blogspot.com/2012/02/proportional-flow-control-system.html