Linux Air Combat Frequently Asked Questions (FAQ)

LAC Standard Keyboard Layout LAC Standard joystick/numeric keypad controls
LAC's standard keyboard, numeric keypad, and joystick control layout. Consult these images as necessary when the discussion below references LAC commands. (Click images to see a larger version.)

Q01: Is LAC compatible with Microsoft Windows?

A:  No. With a lot of work, it ought to be possible to modify the source code and compile it on a Windows machine, but this will require a fair amount of skill, and we don't have the resources to help.
Commencing in late 2017 we began to hear reports from Microsoft that they were working on LINUX compatibility, including assertions that they may someday be able to run high-performance, graphically intense games. LAC ought to be among the easiest of these for Microsoft to get working and ought to make the ideal test case for this new development. We hope Microsoft's emerging attempt to run LINUX games is successful enough for them to support LAC. As of this writing in February 2018, we have heard no reports of success.

Q02: Do I really need to compile LAC?

A: Probably. At the time of this writing in October of 2017, we do all of our development work on Intel-based, PC-compatible desktop and laptop computers running current, 64-bit versions of PcLinuxOs. If that describes your environment, then you can use the binary file that's always distributed in the installation kit once you've downloaded the initial set of prerequisites. As of June 2017 we have confirmed that the binary version we are now publishing also works on 64-bit Ubuntu version 16.04.1 once all of the prerequisite components are installed. 

CLICK HERE to see our YouTube Playlist named "Linux Air Combat on Ubuntu Linux" showing exactly how we downloaded and installed Linux Air Combat on a brand new, 64-bit Ubuntu Linux desktop system in October 2017. Short clips within this playlist also show how we obtained all of the necessary prerequisites. Other short clips, also available in this playlist, even show exactly how we can compile LAC on these Ubuntu desktop machines.

If you are NOT running 64-bit PcLinuxOs or a recent 64-bit Ubuntu, you could give it a try, but success is unlikely.  The good news is that it is far easier to compile LAC than most other free, open-source projects, and many people without any prior compiling experience have reported success with it. Usually the entire process requires only half an hour or so, even for beginners, and all of the required tools and resources are available absolutely free of charge on most LINUX platforms. 32-bit systems are fully interoperable with 64-bit systems, so you can compile it for your preferred architecture and operating system.

Q03: How do I get the required prerequisites to run LAC on Ubuntu Linux?

LAC requires two additional libraries that do not come automatically on a generic installation of Ubuntu Linux. CLICK HERE for a brief YouTube video clip showing exactly how we installed LAC with those two libraries on a brand new, 64-bit Ubuntu Workstation installation in late October, 2017. For more Ubuntu-related information, CLICK HERE for our "Linux Air Combat on Ubuntu" YouTube playlist.

The commands to install those two libraries, issued into a bash command shell, are:

sudo apt-get install freeglut3
sudo apt-get install libsdl-mixer1.2


Q04: Do I really need a joystick?

A: No. It flies fairly well with just a mouse and a standard keyboard. However, flight with mouse controls is less precise. Furthermore, if you want to fly online, in competition with other players, you will be at a very serious disadvantage unless you have a joystick too, because it is measurably quicker and easier to maneuver with a joystick.

Q05: Do I really need the "Mumble" VOIP application?

A: No. The offline missions don't benefit from Mumble at all. You can even fly all of the online missions without Mumble, but you will be limited to the low-speed "Morse Code" (text) radio for communication with other players. Online LAC is a lot more fun when you can join in voice conversation with partners and opponents. Mumble is completely free, and even during our beta test period, our dedicated Mumble server is generally available at LinuxAirCombat.com, with preconfigured channels ready for your use in all of the missions and accessible by LAC's preconfigured "Hot Keys". Hundreds of thousands of people use Mumble, all over the world, with a wide variety of computers, headsets, microphones, speakers, and even through Android and IOS phones and tablets. You should have little trouble getting it to work, and its integration with LAC is better than any other comparable application. The intent is that people interested in a LAC session will just "hang out" on our Mumble server's "root" channel until other players show up, whereupon they can use Mumble to talk with one another and negotiate realms and missions of their liking.

CLICK HERE for our YouTube playlist showing how to download, configure, and begin to use Mumble.
CLICK HERE for our YouTube clip showing how to create Mumble "Shortcuts" to perfect the interface between LAC and Mumble.

Q06: Will it run on a Raspberry Pi?

A: Not well enough to enjoy. It's easy to compile it on the Pi, but the Pi's hardware just doesn't have enough power for smooth flight. It's really, really, really cumbersome on the Pi. You won't like it.

Q07: Which is the best airplane for beginners?

A: The Spitfire is easy to fly and quick to turn. Most beginners love it. The F6F is similar. The P51 is a little faster, and still fairly easy to control. Avoid the P38 unless you are a Lightning fan, because you really need to understand use of flaps and dive brakes to fly it safely. 

Q08: Is it OK to "Vulch"

A: Yes. "Vulching" (the practice of diving on helpless, low-flying aircraft that have just entered a mission to shoot them down before they reach escaping or maneuovering speed) is allowed in all of our missions. If you can set up a "vulching" opportunity, you are encouraged to take full advantage of it. If you are being "vulched" a lot, you need to take off from different airfields, or change the way you fly! "Vulching" has been a real part of every air war. The mission named "MissionNetworkBattle01" is specifically designed to model the extensive use of "vulching" that characterized many World War II air battles. 

Moderation, however, is appropriate when "vulching", as it can be discouraging to get vulched. In particular, if your opponent is new to LAC, it would be a good idea to talk with them and teach them how to avoid being victimized in this way. It's good for our community to encourage new people!

Q09: Are jets allowed?

A: Yes, but in many situations it isn't polite to use the jet. If you see other jets participating in a mission, feel free to join them with another jet. However, it would be very rude to drive a jet into a well-organized group of WW2 aircraft that are trying to mimic historic flight. It's a good idea to use Mumble to ask about this.

Q10: How do I defend against missiles?

A: That's a good question. The missiles in LAC aren't very smart, and most of the time they don't lock on to their targets very well, so you may not need to worry about them unless your opponent has a lot of practice flying into optimal range before using them. However, LAC provides NO advanced warning of a missile shot in the online, multiplayer missions. You can't see or hear missiles in flight, and the RADAR doesn't see them either. Firing flares and chaff works offline, but in online missions, they aren't seen by opposing aircraft so they can't help you. It's considered "good form" and good etiquette to get on the radio, in the main mission channel, and broadcast a "Missile Away" message when you fire a missile. If you ever hear a message like that from a nearby, hostile player, you can often beat the missile with a sudden, violent maneuver.

Q11: How do I land my airplane?

A: Almost every mission has airfields. They are very simple, straight, flat, black strips on the terrain. They are fairly easy to spot from the air, and generally they are even easier to spot from "Map Mode". You will need to throttle back, slow down to about 170 MPH or lower (it will help to enter a shallow climb for awhile as you slow down), and drop flaps and undercarriage. Then, being careful to keep your speed low enough to keep your flaps and undercarriage from automatically retracting, turn toward one end of one of the runways and adjust throttle, elevator, and aileron so that your speed diminishes to the point of stalling as your aircraft flies over the near end of the runway, just a few feet up. If you time everything right, you will hear a satisfying "squeak" as your tires brush the pavement, and your cockpit status panel will show no damage. In strategic missions, if your aircraft has been damaged, it is automatically repaired a few seconds after you come to a complete stop on a runway. (Just wait awhile on the runway until your instruments settle down to indicate a "slow enough" speed.)  Your aircraft is also re-fueled and re-armed automatically while you are on the ground. 

After landing, you should pay attention to your elevators if you will want to take back off.  If left unattended, your elevator may drift off-center. If you try to take off while your elevators are stuck way too high or way too low, you will crash. 

Q12: How do I take off?

A: All of the current missions spawn you in the air. Most of the online ones spawn you at low altitude, at low speed, almost out of fuel, fairly close to an airfield. Before you can ever take off, you must land as described above. While you are on the ground, your elevators may try to drift outside of the normal zone near their center point. Don't let that happen, or you may crash when you try to take off. Taxi into a corner at one end of the runway, and use your rudder to turn around. Use "short field" techniques to take off. Retract your flaps all the way to minimize air resistance as your speed builds up.  You will need all the power you can get in order to take off in a WW2 aircraft.  Throttle all the way up. Use "War Emergency Power" if your airplane allows it. After your airspeed builds up above about 70 MPH, extend your flaps all the way, and, if necessary to lift off, gently pull back on your joystick. Most of the runways are slightly elevated above adjacent terrain, so if you run out of runway before reaching sustainable flight speed, you may be able to dip down a bit as you fly off the end of the field to pick up enough speed. Your aircraft will take off safely if you get the timing right. Retract your undercarriage right away. Keep your climb angle very shallow until your speed exceeds about 130 MPH, and then begin retracting your flaps. Once your airspeed exceeds about 200 MPH, your aircraft should be able to maneuver nicely. 

Q13: How do I find other players?

A: Before you start flying, it's best to check in on our Mumble server at LinuxAirCombat.com. Just "hanging out" in the "Root" channel there will let you know when somebody else joins to do the same, and from there members of the LAC community can talk with one another to arrange missions, schedules, and team affiliations. Because our LAC community is just getting started, upon joining our Mumble server, you might find that you are the only one there. With patience, you can just wait for somebody else, and we usually have one or two people checking in for at least one or two hours daily, but you will definitely need to be patient until our community grows. (It is commonplace to see several "inactive" or nonresponsive players hanging out in the various channels of our Mumble Server. Those are computers used in our development laboratories, and they are unattended most of the time.) You will probably have a better experience if you encourage one of your own friends to join you on a mutually agreeable schedule.

At the time of this writing, we are using two different LAC servers. The development server is at BoseNet.no-ip.biz, and the main production server is at LacServer2.LinuxAirCombat.com. (Generally, you will want the production server.) Edit your LacConfig.txt file (in your ~home/.LAC folder) to specify one of those servers and give it a try. If you can't find any other players, try announcing your intentions on the "Root" channel of our Mumble server. If anybody in our development laboratories is within earshot, they will want to talk with you and they can let you know if the servers are up. They might even join you in flight!
 
Once you start flying within a multi-player mission, your "NETWORK ROUTER PANEL" is your best tool for finding other players. CLICK HERE for a YouTube Video clip showing what the newly introduced Router Panel looked like when three nearby players were participating in an old, six-player, test mission. That panel has two rows, each with room for as many as 10 little lights to flash. The top row (Labeled "P") indicates the arrival of a network packet from a networked player participating in the current mission and realm. You should see a rapidly flashing light representing your own aircraft on that row, and its left-right position will correspond with your numeric mission ID (typically between 1 and 10). If you see any OTHER lights flashing in that top row, you can know for sure that the corresponding player is participating in your mission. If their simulated location is near yours, then their little light will be flashing very rapidly. On the other hand, if they are flying far away from you, then their little light will flash much more slowly. (At extreme distances, you will only see a flash about once every 10 seconds.) If you see no lights flashing other than your own after 20 seconds of attentive observation, then you are all alone in the mission and realm. (You will still be able to shoot at your own "bots", but that's all...) 

Your RADAR is another important tool for finding other players. Make sure it is "ON". CLICK HERE for a brief YouTube video clip introducing LAC's RADAR. Zoom RADAR range out far enough to see little "dots" marking the positions of mission "bots", or big, bright dots representing online players. The RADAR screen is oriented so that your own position is at the center. Dots above that point are generally in front of you. Dots below that point are generally behind you. Dots to the left of that center point represent aircraft to your left, etc. The distance between your position in the center of the RADAR display and any dot is proportional to their distance from you in the simulated world. Zoom your RADAR range in and out as necessary to see dots representing aircraft. You can use the "Target Next" and "Target Previous" commands to select one of the target blips displayed on the RADAR. The selected blip will have a bright, white dot in its center. Each bot or network player is associated with a numeric player designator within the mission (typically between 1 and 10).  As you select a target, the corresponding player number is displayed in your cockpit's system message panel, and you will hear a vocalization of the associated number and team affiliation (like "Red Three") if LAC has determined that the selected player is a sentient, network-connected human instead of a bot. In online missions with human players, you should just ignore the "bots" and pay attention to the other human players. When your RADAR system is sure a blip represents a human player, it will make the corresponding RADAR blip much bigger and much brighter than the blips representing bots. After selecting a target, you can get additional help locating them by using the "TARGETVOCALIZE" command, which will speak to you with a sentence like "Target Six is at Three O'clock, Angel's five". This means that you have selected target six within this mission, which is located to your right, flying at about five thousand feet altitude.

Q14: How does it perform WITHOUT an nVidia or ATI accelerated graphics card?

A: It can run pretty well with a simple, very low-cost Intel graphics card and celeron CPU, especially if you are willing to diminish the video quality settings and/or run it in a smaller window. Here is a YouTube video clip by Stefano Peris, who decided to set up a torture test. Using a very low-cost computer with only Intel graphics, he ran LAC at the highest possible graphic detail and got "good enough" performance. CLICK HERE to see it on YouTube.

Q15: How are online teams and missions organized?

In the online, multiplayer missions, all players are automatically assigned to one of two teams, named "BLUE" and "RED", respectively. This assignment is based upon your player number within the mission. This, in turn, comes from the "MyNetworkId" parameter that you have configured within your ~home/.LAC/LacConfig.txt file. If you have an odd number there, you will be assigned to the "RED" team, and players with even numbers are assigned to the "BLUE" team. (If two players both try to use the same number, LAC will automatically change one of them within a few seconds.) You will see your player number displayed along the left edge of your cockpit instrument panel, and you will hear an audio message that will welcome you into the mission, referring to you by that number.

These missions ALWAYS show 10 aircraft, even if there are fewer than 10 human players participating. In that case, the other aircraft are "bots", flown automatically by your own computer. RADAR dots, HUD target frames, Mumble channel designators and messages are colored red or blue according to their team affiliation just as one might expect (Mumble "Broadcast" messages that are sent to both teams are colored purple). The blue and red colors used to represent bots are pale and subdued, but the colors used to represent network-connected  humans (also known as "Sentients") are bold and bright.  When flying with or against other sentient players in these missions, you really should just ignore the "bots", because the bot positions you see on your computer do NOT correspond with bot positions seen by the other players on their computers; only the positions and actions of Sentient players are transmitted on the network. 

In all three of the current online, multiplayer missions, BLUE team members will find their HQ at airfield 28, and RED team members will find their HQ at airfield 29. Defend your own HQ airfield from hostile aircraft while you and your team-mates attack the hostile HQ airfield. Airfield damage is retained between sorties, so long as at least one player remains active in the mission. The missions all end when the last player exits, or when one of the HQ airfields is destroyed. When either HQ airfield is destroyed, all players hear a declaration of victory for one of the teams, accompanied by a dramatic musical bulletin and 15-second countdown with a warning that the mission is about to end. Any players that are still flying when those 15 seconds expire are immediately destroyed and returned to LAC's menus.  Restart the mission to re-establish the expected competition.

Q16: How does the new Norden bombsight work?

In any of the current online, multiplayer missions, use the keyboard key configured within your ~home/.LAC/LacControls.txt file as "key_WEAPONSELECT" to cycle through your aircraft's available weapons (usually this is the asterisk key of your numeric keypad). If your aircraft is lugging any bombs, an indicator will illuminate near the extreme lower-right corner of your cockpit to indicate the number of available "BOMB 500 LB" weapons. If at least one bomb is available and selected, then you can activate your Norden Bombsight. Use the keyboard key configured within your ~home/.LAC/LacControls.txt file as "key_MapViewOnOff" to toggle your view system into "Map Mode" (usually this is "m"). An aerial map of the vicinity beneath your aircraft will appear. Unless you have "scrolled" your map away from its center point, your aircraft is in the exact center of that map. If you have armed at least one bomb, then helpful, white text will appear at the bottom of the map alerting you of the other conditions necessary to activate the Norden bombsight. That text will tell you that you must "zoom" the map all the way out (use the keyboard keys configured within your ~home/.LAC/LacControls.txt file as "key_MapZoomOut"  and "key_MapZoomIn" to do that), and you must make sure the map is centered (use the keyboard keys configured within your ~home/.LAC/LacControls.txt file as "key_MapScrollEast", "key_MapScrollWest", "key_MapScrollNorth", and "key_MapScrollSouth" to do that). Under those conditions, a new set of helpful, green text will appear that will instruct you in the use of the two "pippers" that will also appear. That text will inform you that the small white circle pipper, always located at the center of the Norden bombsight map, represents your aircraft as the map scrolls beneath you according to the direction of your travel. The small round green pipper, known as a "CCIP" or "Continuously Computed Impact Point", marks the approximate place on the map where an immediately dropped bomb is likely to strike the ground. Fly your aircraft so that the green pipper is centered over your target, and then release your bomb with the joystick button or keyboard key configured within your ~home/.LAC/LacControls.txt file as "joystick_FIRESECONDARY" or "key_SECONDARY". If your aircraft is stable and your hand steady, a hit on or near the target is fairly likely, and damage will accumulate after the bomb has had enough time to fall all the way to the ground.

Q17 How does the new "Morse Code Radio" work?

In any of the current online, multiplayer missions, use the keyboard's "Caps Lock" key to toggle your keyboard's main alphanumeric keys between "Morse Radio" mode and "Flight" mode. When in "Flight Mode", your keyboard continues to work exactly as at has in all prior versions of LAC, with your keys mapped to flight functions as shown in the illustration above. When in "Morse Radio" mode, pressing any of the alphabetic, numeric, and unshifted punctuation keys of your main keyboard causes transmission of the associated character to all nearby players participating in the same mission and realm. Characters transmitted or received through this "Morse Radio" scroll horizontally, one at a time, through a small window on your cockpit (just below the "Mumble Panel") so everybody can see them. Immediately above this new "Morse Code" text window, a single character identifies the transmitting player with a number between "1" and "10". That identifying number will be colored Red or Blue as appropriate to the transmitting player's team affiliation. (It always represents the identity of the player associated with the most recent character.)

When transmitting a message on the Morse Code radio, don't type too fast. Morse Code is a rather slow communication mode. Watch the Morse Radio's horizontally scrolling text indicator. If your outgoing characters are skipped, you need to slow your typing down.

When receiving characters on the Morse Code radio, close range is very helpful. Aircraft within 10 miles will reliably see all of the transmitted characters. However, at 20 miles, only about 80% of the characters get through. At 50 miles, only about 40% of the characters are received. Accordingly, if you are trying to transmit a long-range message with the Morse Code Radio, you are advised to repeat it several times. This is consistent with the primitive Morse Code radios that were used at the beginning of World War II. For more reliable communication, use "Mumble", which emulates the much better and much more reliable voice radios that were used at the end of World War II.


Q18 How do I destroy the enemy RADAR?

Drop a bomb directly on the RADAR tower's base, or hit it with 2 rockets, or strafe it agressively, for several passes, with heavy cannons or multiple machine guns. (Rockets seem to work best.)  The enemy RADAR antenna will either stop spinning, or explode and fall to the ground. At that point, all of the RADAR indicators in all of that team's aircraft will go dark. Instead of the usual RADAR dots marking the relative locations of objects within RADAR range, they will see text announcing "NO SIGNAL". They will be unable to use RADAR until their surviving ground personnel can make repairs. While their RADAR is inoperative, they won't be able to use any of the "Target Selection" functions either, which  denies them access to any kind of target location or altitude information.

Note that RADAR can also fail if other airfield damage is so extensive that no surviving equipment can transmit RADAR information to the team's aircraft. In that case, although the RADAR antenna continues to spin as usual, RADAR functions are unavailable to the team's players.

Surviving maintenance personnel will immediately try to repair the RADAR and other airfield facilities. If accumulated damage was extensive, those repairs will take more time. Attacking aircraft can interfere with this maintenance activity by dropping additional ordnance on the RADAR rubble, or simply by flying around in close proximity to the damaged airfield (which will intimidate the maintenance personnel). Defending aircraft can accelerate repairs by clearing the area of hostile aircraft and establishing a friendly "Combat Air Patrol" over their damaged airfields. This will give the maintenance personnel the confidence they need in order to use their mechanized tools, resulting in much faster repairs