How To...Design An Electrical Panel

By Dai Griffiths

ne of the major problems with a lot of flightsim aircraft is the lack of any form of coherent systems: hydraulic system, electrical system, avionics system etc. You jump into your FS aircraft, hit Ctrl+E (or CTRL+J!) and away you go - no checklists, no real start-up sequence, no nothing. Unless you are designing a complete system from scratch for a single aircraft (as in my SD3-60) and are a competent gauge programmer, there seems to be nothing you can do about this.

Some time ago I set out to try and address this problem for the "average" panel builder and decided that at the very least, it was possible to design a "plug'n'pray" electrical system that could be used across all panels and would service up to four engines. All this required on the part of the panel builder was a willingness to repaint the gauges I released to match the panel they were building and a little time to study the documentation on which gauges worked together, and how. Although I have seen a few panels exploiting the capability of these gauges, it seemed as if somehow the original idea had gotten lost amongst the massive archives here and so the intention of this How To is simply to bring these ideas to a wider set of panel builders and hopefully to increase the realism of more panels. These gauges were originally designed for FS98 and although the majority of them do work with FS2000, the "Dragonflight Design" document in each archive details which ones have definitely been tested with it.

The Electrical Panel concept has been designed for extreme flexibility in creating more realistic panels and each gauge has its own set of sounds depending on the job it does. It works via the concept of "shared variables" in the FS SDK, whereby one gauge will broadcast some information and other gauges will/will not react depending on what that information is. It is a true "plug-in" system and you can have as few or as many EP gauges on a panel as you require; the "master gauges" will recognise a new gauge as soon as you add it to the panel.cfg file. You have to do no more work than that to get them to function!

There are very few "master gauges" and these depend on the aircraft type you are creating. All of the others are completely optional and usage depends entirely on the look of your panel. For a greater description of the gauge functions and the gauge archives, please read "DragonFlight Design". I will not repeat that information here as this is simply a guide to planning an electrically controlled panel and showing you what is currently available.

As to why I have chosen to release most switches in both rocker-style and toggle-style instead of just allowing one set to be repainted, the answer is simple. The active mouse area for a rocker switch is always larger than the corresponding area for a toggle switch. If the toggle switch had a rocker-sized active mouse area then placing a whole row of toggle switches close together would mean overlapping mouse areas and some switches would become unusable.

To save continually repeating the same information (i.e. both gauge names and the descriptions "rocker-style" or "toggle-style) I have added an asterisk (*) to the gauge name which represents either the letter "t" or the letter "r", where t = toggle style and r = rocker style switches and I will be using this convention throughout the rest of the document.

Power

These "master gauges" all supply power to the aircraft systems.

1. For a jet use dfd_apu.
2. For an FS98 turboprop based on the jet model use dfd_jetmaster. For an FS98 turboprop based on the prop model use dfd_*master.
3. For a prop aircraft use dfd_mastercombo (combined battery and generator switch common to most modern singles and twins) or dfd_*master.

Due to the number of requests to add gauge types that are common across many different aircraft, I have used all of the spare future-use variables I had coded into the various master power switches. To get round this rather embarrassing problem, I have taken the last two spare variables to power a pair of gauges that are nothing but "power" broadcasters. The first of these two gauges - dfd_mbcast1 - is included in every archive released from May 2000 onwards; it would be a good idea to treat it as a "must-have" gauge and include it in every panel you create. The gauge is completely invisible but it must be included somewhere on the same panel as you put the master power switch (whether APU or battery switch) e.g.

gaugeXX=dfd_mbcast,0,0,1 As I have now given myself a further sixty spare "power" variables, I don't anticipate this happening again...

Starting The Aircraft

For a prop aircraft you must fit a magneto switch for each engine you have. These are designed such that the engine will not start until the magneto switch is in the "Start" position.

1. For aircraft with gravity-fed fuel tanks use dfd_magneto1 to dfd_magneto4. ⁽¹⁾
2. For aircraft fitted with fuel pumps use dfd_fpmagneto1 to dfd_fpmagneto4; if you use these then you must also use dfd_*propfuelpump1 to dfd_*propfuelpump4. ⁽²⁾

The fuel pump switches have optional indicators (dfd_proppumpind1 to dfd_proppumpind4) and there is also an optional gauge for each mag switch (dfd_startlight1 to dfd_startlight4) that indicates the starter motor is engaged. The starter light can be used with either type of mag switch.

⁽¹⁾ There is a second option for aircraft with gravity-fed fuel tanks and that is to add engine-powered mechanical fuel pumps. Strictly speaking, this particular archive (oldfp.zip) is not part of the Electrical Panel series because it will work on any panel but it increases the flexibility of the engine systems if used here as well.

⁽²⁾ If you use oldfp.zip with the electric fuel pumps then they will work as fuel on/off stopcocks.

Fig. 1. Frankenpanel! My Cessna R182RG prop test bed with no power applied.

For a jet aircraft it gets slightly more complex as the starting sequence is based on the common "three switch" set-up. Each engine requires a fuel pump, an ignition switch and a starter switch.

1. For engine 1 use dfd_fuelpump1, dfd_jetignitor1 and dfd_jetstarter1.
2. For engine 2 use dfd_fuelpump2, dfd_jetignitor2 and dfd_jetstarter2.
3. Etc.

Each of these engine switches has an optional indicator to show it is active:

1. The fuel pumps have dfd_fuel1_ind to dfd_fuel4_ind.
2. The starter switches have dfd_start1_ind to dfd_start4_ind
3. The ignition switches have dfd_ign1_ind to dfd_ign4_ind

I suggest that at a very minimum you use the fuel pump indicators that will remain on at all times. The ignition switch can be turned off after engine start-up is complete and the start light will turn out automatically when the engine fires up. Turning off the fuel pump will shut that engine down.

Fig. 2. Boeing 737 jet engine gauge test panel with the APU online, one engine started and DC power applied to the starboard bus.

Generating Power

Most aircraft also have some form of generator warning system. This may take the form of a simple warning light or may also have voltmeters and ammeters. The generator warning systems may require the use of additional gauges and those additional gauges again will depend on the panel you are creating. In all cases I have suffixed the gauge name with the engine number but if, say, you have a four-engine aircraft that only carries generators on two engines, then you only need to add the generator warning systems for those two engines. In the case of a jet panel, you must have at least one generator system otherwise the aircraft will shut down when the APU or GPU is disconnected. You don't get this problem with a prop engine as the magneto is completely self-contained and the engine will continue to run until either it is starved of fuel or the magneto is grounded via the "off" switch.

1. For a jet you must use dfd_rjetgenswitch1 to dfd_rjetgenswitch4 depending on which engines you want to equip with generators.
2. For a turboprop using either the jet or prop flight model and a prop aircraft not using dfd_mastercombo.gau, use dfd_*genswitch1 to dfd_*genswitch4. Again, the switches you use depend on which engines you want to equip with generators.
3. A prop aircraft using dfd_mastercombo is already equipped with the generator switching code and does not need any further switches.

At this point you have the main power bus and generator busses in place but really you need to add some form of indication that the generators really are online. You can have just the warning light that goes out when the generator spins up or you can also have an AC ammeter that displays the generator output and finally, you can also add a DC voltmeter to monitor your DC bus. All these are optional and all of them again are selected by engine number.

So if I had an older four-engine aircraft (say a Lockheed Constellation) that has generators on engines 1 and 2 and also has ammeters and voltmeters on the flight engineer's panel, I would use the following gauges:

1. Generator light for engine 1 - dfd_genlight1.
2. Generator light for engine 2 - dfd_genlight2.
3. Ammeter for engine 1 - dfd_acamps_cws1.
4. Ammeter for engine 2 - dfd_acamps_cws2.
5. Voltmeter for engine 1 - dfd_dcvolts1.
6. Voltmeter for engine 2 - dfd_dcvolts2.

On a newer aircraft (say a small twinjet) that has no analog gauges I would only use only dfd_genlight1 and dfd_genlight2. At this juncture I must also point out that the scales on the analog gauges almost certainly will not be right for your aircraft; so export them, repaint and re-import them!

There is also an under voltage test lamp available (dfd_lowvolts_light) similar to those fitted to the Cessna 152. Normally you'd only use this on a prop aircraft - see Fig. 1.

Other Engine Health Indicators

On all engine types you may also wish to add the optional oil pressure lights. These too have an engine number suffix and are dfd_oil_light1 to dfd_oil_light4. Each one is coded to come on as the engines register about 2% N1, so you will almost certainly find that when cranking over an engine, the oil pressure light will go out before the engine fires. This is correct! Please note that the oil pressure lights will not work without dfd_mbcast1 being present.

Lighting, Heating And Avionics Systems

The Electrical Panel also has separate switches for the multiple switch gauges that FS98 supplies as default on the Cessnas and the Learjet. Again, these are completely optional.

1. Navigation and panel lighting - dfd_*navswitch.
2. Pitot heat - dfd_*pitotswitch.
3. Strobes - dfd_*strobeswitch.
4. Landing lights - dfd_*landswitch.
5. Open/close radio stack - dfd_*avswitch.

There is also an optional OMI navigational system. This is a bit of an oddity, as you require the (omisnd.zip archive that is not part of the Electrical Panel series. However, dfd_omitest switch is coded in such a way that it makes the three separate lamps part of the electrical system. The OMI is visible in Fig. 1 and all of the other switches show up on both panels.

Common Systems

This is a bit of a miscellaneous heading, as some aircraft will not need any of these at all! Otherwise these apply to both jet and prop aircraft.

The most obvious one is for a retractable undercarriage. You may choose to have just the gear handle (dfd_epgearhandle) or you can have the three warning lights as well (dfd_gearleft, dfd_gearright and dfd_gearnose). Allied to the basic gear handle is the "gear unsafe" warning horn but here the number suffix on the gauge means something completely different to the gauges above. It refers to the number of throttles that the gauge is monitoring, not the engine number.

1. For a single-engine aircraft use dfd_*gearhorn1.
2. For a twin-engine aircraft use dfd_*gearhorn2 only.
3. For a three-engine aircraft use dfd_*gearhorn3 only.
4. For a four-engine aircraft use dfd_*gearhorn4 only.

You may also have electrically-operated flaps. The use of this gauge (dfd_eflaps.gau) is a little restricted as it can only deal with four flap positions. You will need to repaint it as the background comes from the Shorts SD3-60 but when you do so, keep the handle track the same as the handle does follow the detents (unlike the flap handle in the default Learjet!). Again, if you look at Fig. 1 you will see the flap handle, gear handle, gear lights and warning horn switch.

Specialist Systems

Suitable aircraft can also be equipped with an automatic spoiler deployment system (dfd_pelarmspoiler). This can be added to any aircraft and throws out the spoilers on touchdown. The newer version of this gauge (dfd_*eparmspoiler) will also dump the spoilers if you pull back the throttles before you reach V1. Very useful if running an adventure that can fail an engine on you! This version will also automatically retract the spoilers at 40 knots. These gauges have their own optional indicator (dfd_autospind) which lights when the system is armed and when it is active.

There is a companion gauge to the auto-spoiler set and that is the auto-brake (dfd_*epautobrake) that also has its own optional indicator (dfd_autobrind) that lights when the system is armed. The auto-brakes will only work on a panel that is also equipped with the auto-spoilers - see Fig. 2.

There is also the smoke-generating system for aerobatic aircraft. You need to use dfd_elsmoke_* to turn the system on and off and the optional indicator dfd_elsmokelamp reads FS to ensure the smoke system really is running. If you use both of these gauges and the lamp does not light then it is almost certain that the .air file is not equipped with a smoke generator.

Anything Else?

Just the one at the moment - dfd_antemp. This is an analog temperature gauge that reads from -60 to +60 centigrade and can be fitted to any aircraft.

What's For The Future?

Currently unknown! The intention was simply to create the common electrical systems but I may add some navigational instruments and avionics at some stage in the future.

Where To Start With The Gauges?

The moment you read this How To it will most likely be out of date - I am continually updating and adding to the Electrical Panel series. I suggest that to find the most up-to-date information on what is available, you do a search on Dragonflight across the file libraries and download the latest file to mention Electrical Panel in the description. This How To will be in that archive (in a much rougher state!) as a document called "Electrical Panel Listing". The other document mentioned at the top ("Dragonflight Design") will also be in the archive. Each archive also contains a detailed readme.doc explaining how the gauges function.

Acknowledgements

I am very much in the debt of Bryan Kostick for giving me the sound routines incorporated in the gauges. The routines are proprietary to Bryan so please don't ask me for them.

Dai Griffiths
DragonflightDesign@compuserve.com

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