The controls below the instrument panel have been completed. These consist of the Main Fuel Cock, the KI-GASS Engine Fuel Priming Pump and the Fuel Tank Pressure Valve.
Main Fuel Cock
The Mk.IX had two tanks fitted in front of the instrument panel, an upper tank containing 48 gallons and a lower tank containing 37 gallons of 100 octane fuel. Fuel could run freely from the top to the bottom tank. The fuel flow from the lower tank to the engine fuel pump was controlled by the Main Fuel Cock located below the instrument panel to the right of the compass. In our case it provides interface to the simulation program by means of a simple toggle switch.
KI-GASS Engine Fuel Priming Pump
The purpose of the priming pump is to inject a fine spray of fuel into the air-intake of the engine for easier starting. The KI-GASS system was used on everything from the 1926 Vauxhall Tourer to diesel engined tractors.
It’s wonderful that the company still exists as Kigass Aero Components Ltd. in the UK and has been run by four generations of the Wardman family.
This interesting bit of equipment posed a few challenges to send the correct signals to the simulation software. The latter needs to be informed when the primer knob is unscrewed and then again when it is pumped. We solved this with some clever design and a simple toggle and micro switch.
Fuel Tank Pressure Valve
The Fuel Tank Pressure Valve is used to reduce fuel vapourisation at high altitudes or temperatures which would result in an engine out.
Pressurizing, however, impairs the self-sealing of the tanks and should be turned on only when the fuel pressure warning lamp lights up. In very warm weather at very high altitudes a rich cut may occur with the tanks pressurized, and pressure must then be turned off.
The default position of the pressurizer system is OFF, and must be turned ON only when a red warning light signals that the fuel pressure has dropped below 10lb/in2.
Again operation is through a simple toggle switch.
It is worth noting that DCS World and many other simulators are not able to assess the initial start-up value of the switches, hence following a pre-startup checklist to normalise all switch positions is important to ensure correct function.
