Comet 4 Panel Manual

Panel Manual VC extras Checklists Flying Tips Main Centre Autopilot Fuel Overhead Electrics & Ignition

Fuel Panel

The fuel panel is a separate window & is toggled on/off by the fuel button  The Comet has tanks in the wings and a central tank in the fuselage. I do not have the ability to produce a fully functioning fuel system for the Comet & so the model is simplified, with a basic left / centre / right control of fuel cocks and pumps. This panel also contains the pressurization, cabin heating and de-icing controls at the bottom.

Fuel Tank Levels The Comet has separate fuel tanks in the wings, plus a central tank in the fuselage.  All tanks can feed all engines depending on the state of the pumps, cocks & crossfeed valves. Each fuel level gauge displays in kilograms x 100. The centre tank gauge reads up to 7500kg, with each wing having tanks of 3100kg, 5300kg, 3300kg & a wing pod tank of 1800kg. A Comet 4B will always read zero in the wing pod tanks. Under the main tanks is a red light that is lit when the contents are low (unless the cock is closed).

Fuel Flow This shows the current rate of fuel to an engine in kilograms per hour x 100. It also has a fuel quantity counter (kg), which can be reset to zero by clicking the gauge. Due to limitations of FS variables, this gauge uses a simulated formula based on total fuel used, divided by four (four engines).  Because of this, the counter will continue for an engine that has been shut down, although the sum total across all four engines is always correct. The gauge pictured shows a fuel flow of just under 1700 kg/hr, with 4 kg having been used.

Fuel Temperature Fuel temperature entering engines in degrees centigrade. The switch below is for fuel heating. This should always be on if the fuel temperature is less than 5 deg C. A red warning light at the side of the switch comes on if the fuel filter becomes blocked (due to ice).

Oil Pressure & Temperature Oil pressure & temperature for each engine.  Temperature in Celsius, Pressure in pounds per square inch.

Fuel Pressure Fuel pressure for each engine in pounds per square inch.

Fuel Cocks & Pumps To keep things simple the fuel tanks are grouped as left, centre & right.  The centre tank is a single tank, while left & right wings have up to four tanks each. On the Comet all cocks (top switch) should remain open while there is fuel inside the tank. If any tank is empty the coresponding fuel cock should be closed. The pumps (bottom switches) are used to bring the tank into use or not. The 'gulls eyes' in between show if fuel is being pumped from the tanks or not. The schematic diagram shows how the tanks are linked to the engines. Certain tanks-to-engine combinations can only be achieved by opening crossfeed valves. Note that the centre tank is naturally routed to only feed the left two engines and it can only ever feed the right side if the crossfeed is opened. On the model, when fuel pumps are off, fuel can not be delivered from that tank.

Required Cabin Altitude Once airborne the air pressure must be allowed to reduce in order to keep the pressure inside the hull at a safe level. Required cabin altitude should be set depending on your expected cruise altitude. Max required cabin alt is 8000ft. A cabin alt of 2000ft is ok for flying at 10000ft, but you would need maximum cabin alt of 8000ft when cruising at 37000ft.

Cabin Alt & Pressure Differential The two readings on the Cabin Pressure Differential (left) & Cabin Altitude (right) gauges must remain outside the red sections. Setting a higher 'Required Cabin Alt' will raise the Cabin Alt and reduce the Cabin Pressure Differential. High Cabin Alt is uncomfortable for the passengers, but High Pressure Differential stresses the aircraft. Try to roughly balance them out.

Cabin Alt Rate Shows the rate of change to the cabin altitude, up to 2000 ft/min in either direction. The rate should normally change at 400 ft per minute until the cabin height has reached the set required level. This rate can be altered by the knob top left of the gauge.

Pressure Valve Manually open or close the pressure safety valve. This valve regulates air pressure, automatically opening to let excess pressure escape & closing to let pressure build. The normal flight setting is for the valve to be 'closed'. The valve can be manually opened at any time to let air escape (depressurize).

Cabin Mass Flow Indicates the amount of air flowing through the pressure & heating system. The air is fed from the engines & there is one gauge for Port & one for Starboard sides. Pressurization & heating will only operate if there is sufficient mass flow in the system. In the case of pressure, the needle of at least one cabin mass flow indicator should always be in the white 'NORMAL RANGE' section.

Cabin Temperature The indicator shows the current temperature inside the cabin in degrees farenheit, from 50 to 100. The switch selects to increase or decrease the temperature. For ease of use, the tooltip on the switch shows the selected temperature. Any change in cabin temperature is only noticable over some time.

Air Inlet Temperature The cabin temperature is governed by the air inlet temperature. Heating can only be provided if the inlet temperature is greater than the background temperature outside. Likewise, cooling can only be brought about by a cooler temperature. The indicator shows the current air inlet temperature in degrees celsius, from 0 to 150. The switch selects to increase or decrease the temperature. For ease of use, the tooltip on the switch shows the selected temperature.

Engine De-ice Down at the bottom of the engineers panel. Switches toggle on/off the de-ice valves for each engine. The windows show 'OPEN' when the valves are open, 'SHUT' when the valves are shut, and show a crosshatch when in transit or there is no power.

1 : Port De-ice Provides air from the port engines (1&2) into the structural de-ice system. Either de-ice lever ON is sufficient to de-ice the leading edges. Temperature gauges on the pressure panel show the temperature of the de-ice system. 2 : Air Pressure Supply Four levers provides air from each engine into the pressurization & heating system. The cabin mass flow indicators display the air flow provided here. 3 : Starboard De-ice Provides air from the starboard engines (3&4) into the structural de-ice system. Either de-ice lever ON is sufficient to de-ice the leading edges. Temperature gauges on the pressure panel show the temperature of the de-ice system. 4 : Crossfeed Valves The outer levers operate the common fuel valves between engines 1&2 & engines 3&4 respectively. The middle lever operates the central crossfeed valve. Each of these valves is represented by a 'gulls eye' indicator in between the fuel flow gauges on the fuel panel. The other levers here are currently dummy only & serve no purpose in FS. The red lever is for the red emergency hydraulic system should green fail. Move up for flap operation & move up again for gear opeartion. The green lever is for changing over the battery & the yellow lever to the right of that is for Bus Bar changeover. Both for electrical problems which you will not get in FS.

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