What does Fuel Tank Pressure Valve do?

[SharpeXB]

According to the manual p 121

“Normal position is "OFF". Tank pressure must be turned on when the fuel low pressure alarm is active.”

From what I can tell the wobble pump will pressurize the fuel tank (alarm turns off) regardless of how this is set. Does this pressurize the tank once the engine is running? From the description it seems like you’d turn it on if the low pressure light came on in flight. 

Edited May 27, 2023 by SharpeXB

[grafspee]

Low pressure light is for fuel pressure inside main line which feeds carb, not for fuel tank. 

Fuel tank is unpressurized all the time during normal operation, and pressurize handle when switched On  will pressurize fuel tank which in older Spitfires was way to prevent vapor lock in fuel system at high alt, but since our spitfire has electric fuel pump this handle is never to be used. 

Same with wobble pump it is just relic from older models, you can pressurize fuel system by turning fuel pump for couple seconds which i do because wobbling this pump is so annoying for me  

After startup turn fuel pump ON and all problems with fuel pressure will be gone.

Edited May 27, 2023 by grafspee

[SharpeXB]

7 hours ago, grafspee said:

After startup turn fuel pump ON and all problems with fuel pressure will be gone.

Yeah it seems you need to switch the fuel pump on at high altitudes. 

[Art-J]

Not only for high altitudes, but on the ground right after engine start, if you want to follow real Pilot's Notes fir Mk IX and XVI that is. Then you can pretty much forget about it.

DCS manual misses this step for some reason.

Edited May 27, 2023 by Art-J