Hi,
so I just did a proper cold Start Procedure on the Dr.400, which has a Carburetted Engine, and just noticed for the first time that when I turn on the Booster Pump the Fuel Pressure doesn’t come up.
As with all of these old Engines, to avoid flooding, you slowly feed in the Mixture after about two Rotations of the Propeller.
Once I started feeding in the Mixture, the Pressure also came up.
Now, that really confused me. Fuel Pressure is controlled by Needle and Seat, not by the Jetting.
The only answer to this I can imagine is that the Game models some sort of Fuel Injection. But a Dr.400 is not Injected. It’s from the 70s.
Moved to #self-service:aircraft-systems
At zero mixture, depending on where the sensor is, there will be no pressure, as fuel feed is closed. This is common for aircraft, but is aircraft dependent. It all depends on where the sensor is placed.
Sensibly it is placed in the line between pump and Carburettor. But Mixture doesn’t Control the Inlet into the Float Chamber or does it?
And even if, wouldn’t less Fuel with still running Pump mean higher Fuel Pressure/more Restriction?
I mean, the Mixture controls the Main Jet, not the Needle and Seat.
As far as I know they remain constant and Fuel Pressure should also be Constant with Boost Pump running.
It’s a simple On/Off Clickedy-Clack Electric Pump.
Sensibly doesn’t matter.
Various airplanes are configured in one or the other configuration, before the cutoff and after. IOW, if we’re going to simulate actual aircraft, the pressure sensor needs to be placed where it is in the plane being simulated.
Yes, but in a Float Type Carburettor the Fuel Pressure in the Feed Line doesn’t change based on the Mixture. The Needle and Seat are fully separate from the Jetting.
They just keep the Fuel Level in the Float Chamber constant, no matter what.
The Carburettor is an unpressurized Design, a very elaborate bowl which has fuel pulled out of it via Bernoulli Principle.
(unless going negative G when the Gas flows to the Top and the Fuel Pressure pushes the Valve open and terminally floods the whole affair, ending in a massive plume of smoke once going level again)
And if you have ever worked on a Carburettor, reducing Fuel Flow to it results in nothing but a badly running Engine.