ORIGINAL: marc s
There seems to be a mixed view as to where to instal the fuel shut off valve when installing a turbine, hence the poll, just a simple 'before' or 'after' should do it.
marcs
After the pump is my preference (for a quick, clean shut-down), but the BMFA COP doesn't agree...
Quote:
B. Gas Turbine Protection and Control
B.1 Start up and static running
Where engines are being run statically, on a test bench or during start up procedures in a model aircraft, boat or vehicle, a manual fuel shutoff mechanism must be provided. This mechanism may take any suitable form such as a fuel valve or electrical switch to cut power to the pump, but must be independent of the normal throttle control.
Where a fuel valve is used in a liquid fuel system it should be located in the low-pressure part of the fuel line, between the tank and the pump. In a self-pressurised (gaseous fuelled engine) system it should be located as close as possible to the engine to ensure a rapid shutdown.
B.2 Operation under remote control,
The following paragraphs apply only to engines that are operated remotely, such that the manual control referred to in B.1 above is inaccessible.
B.2.1 Shutdown mechanisms.
The engine control function must include an independent fuel shut off device in addition to the valve (gaseous fuelled engines) or pump speed controller (liquid fuelled engines), as used by the throttle control.
The fuel shut off device could be a solenoid valve or a servo operated valve in the fuel line, in which case the considerations in regard of positioning given in B.1 above should apply.
Alternatively a relay, servo operated switch or additional transistor in the pump circuit may be used. Engine control units (ECUs) driving fuel solenoid valves should meet this requirement.
End quote:
Cheers,
Dick