Mothland

Rather than artificial stacking limits, Air Combat is limited to 1v1 or 2v1 fights within larger battles. Overall numbers still matter, but only so many planes can effectively engage another at one time. We felt this reflected real historical battles much more closely.

No more Interceptors or Multirole Aircraft. Instead, we have Fighters and Heavy Fighters, the latter being twin engine planes which are faster and more heavily armed but less agile. Historically, not many planes perfectly fit a specific role, so it will be up to the player to decide in what direction to steer plane development. In general, Heavy Fighters are good at shooting down Bombers, but have trouble against more agile Fighters. Fighters can shoot down Bombers too, of course, but being less heavily armed they take longer to do so.

Speed now affects targeting order in combat. Faster planes get to pick their targets first. Because of this, speed and firepower will be the most important attributes for planes you intend to intercept bombers.

Agility is a new stat. When two planes meet in combat, the more agile plane will be able to use a greater percentage of its Air Attack value.

Coverage is more a concept than a stat, and is based on a plane's Range stat compared to the distance to the center of the Strategic Region it is operating in. Planes which can just barely reach the target have a poor Coverage value compared to a plane that can fly laps around the area.

While individual planes do not gain experience, combat/missions have the possibility of generating Aces. Aces can be assigned to Air wings and improve the efficiency the planes. We'll talk more about them in a later dev diary.

Once again it is time for a Hearts of Iron Dev Diary! This time I'm going to talk about how Air Combat has changed, and boy, it sure has changed! In earlier HoI games, air units were all "wings", a grouping of a non-specific amount (but notionally around 100) planes which you could order to carry out missions in an area or targeting a specific province. In HoI4 we no longer use only wings; each plane is an individual piece of equipment, and rather than give each one orders, you give orders to your air bases to send a certain number of planes on missions to a given Strategic Region.I'll go into more detail in a moment, but in previous diaries there have been questions about how our design and development process works, so I thought I'd share a little info about that first. Before working on HoI4, both Podcat and myself worked on the For TheMotherland and Their Finest Hour expansions for HoI3, so we already had a lot of ideas about what we wanted to be different in the next game. One of our main ambitions was reducing the micromanagement needed for Air units and making the Air game more about your overall campaign goals. You shouldn't have to manage every sortie. So after seeking inspiration and doing some research, we held a brain-storming session which resulted in these concrete details being nailed down:Now, to those of you without years of game development experience, that may look like a jumbled mess of nonsense scribbles, but rest assured that Podcat, as he says, "doesn't even see the code" at this point and can make perfect sense of it (perhaps one day I will develop this skill too!). After that we write up a proper design based on our notes from the meeting and start turning that design into code and actual bits of a game. For example, here is an early debug screenshot showing a stream of German fighters and bombers attacking Britain:We often do visual aids like the above when developing new graphical systems. The red lines show possible generated attack paths for planes as they attack, while the blue lines show their return paths. Which attack/return path they take varies so not all missions follow the same path and things look nice. Of course, we do not show every dogfight in real time on the map. The planes on-screen represent the average goings-on in an area, so if there are fighter battles going on in a region you will see a dogfight happening, with whoever is getting the worst of the battle being shot down.And here is how air combat currently looks, although it is still in development:We've made various other changes to how planes work in HoI4:Now, getting back to how air missions work: HoI4's map is divided into large areas which we call Strategic Regions. These are the targets for Air Missions. To give you an idea of the size, mainland France is divided into just two Strategic Regions. You can give orders to any air base within range of the region to send however many planes you want, set mission priorities, and can then largely leave the planes alone to fight it out until you want to change orders or just monitor their progress. The balance of forces in a given Strategic Region affects the Air Superiority value within it, and when Air Superiority is lopsided it will affect how often the weaker side can carry out missions. This will also, of course, negatively affect the operation of ground forces in the Region.Actual missions (and let's assume a Strategic Bombing mission for this example), barring bad weather or enemy air dominance, are flown twice a day - a daytime and nighttime flight - and will either follow priorities set by the player or be split up logically if the player has set no priorities. When a mission flies, it has a chance of being detected by the enemy based on weather, Day/Night, RADAR coverage, enemy Air Superiority, etc. If it is detected, the enemy's defending planes may intercept it. Enemy planes will prioritize attacking bombers, but the mission's escorts have a chance to catch intercepting aircraft. After the air battle is concluded, the mission continues with available aircraft. The damage done will be affected by not just the number of planes sent, but also a Disruption Penalty, calculated based on the proportion of bombers sent that were engaged or destroyed while on the way to their target.Overall we hope the Air War in HoI4 will be more a matter of Planning and Production than micromanaging Air Wings. It is intended to be something that will require you to wear down an enemy's air force with campaigns of attrition before your own air force can really cause major damage to their country with strategic bombing. As you can guess, many of these changes also affect how Carriers work, but that's another subject of a future DD.