In Hearts of Iron 4, there are many factors besides land armies that will decide if you are going to win World War 2 or not. You can’t just invest everything in land divisions and forget completely about air and naval forces.
If your main priority is conquering land, as it is for most HOI4 players, then the most important part of your air force will always be the CAS (Close Air Support) planes. These bad boys will deal a lot of damage to enemy land troops, allowing your men to easily push into their territories.
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Unfortunately, it can be relatively hard to make a good CAS design since it isn’t clear what you should invest in. It is obvious that you need a lot of Ground Attack, but what other stats are important for this vital plane?
In this guide, we will give you a list of the best CAS designs that you can use in HOI4 throughout the years, with the best design for every important technological year for planes.
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Best CAS Designs in HOI4
All of the CAS plane designs that we will show you for HOI4 will be based on the technology you can get at each point in the game.
Since players have access to new plane technology almost every 2 years, we have come up with a few designs for each airframe and upgrade you get throughout a normal playthrough.
Since the CAS can only use the Small Airframe, there aren’t a lot of ways to improvise with these designs. The main focuses are two stats: Ground Attack and Agility.
Many players will tell you that you should just pump the Ground Attack stat to the skies and ignore everything else, however this will just end up with many of your CAS getting destroyed needlessly in some of the more intense air zones where you don’t necessarily have 100% Superiority.
If you also had to choose, Air Defense would also be important since it would make your plane withstand more damage before going down.
Here are the best CAS plane designs in HOI4, based on each year you can get their parts:
Best CAS Design for 1936
Unfortunately, in 1936, all plane designs are really bad. All of the parts that you can place on a CAS for 1936 will give you a below-average plane that will try to do its best until it eventually gets surpasses in 2 years.
Agility will be incredibly low, so you will likely lose a lot of them if you don’t have a few good Fighters to support them. However, we made sure Ground Support and Air Defense are as high as possible without losing all Agility.
Here is the best CAS design for the start of HOI4 in 1936, to have at least a few if you want to do some early conquest:
- Basic Small Airframe
- CAS Weapons – Small Bomb Bay
- CAS Weapons – Small Bomb Bay
- 1x Engine II
- Defense Turrets – Light MG Defense Turret
- Special Modules – Dive Brakes
You will need to have researched Basic Small Airframe, Bombs, Light MG, Engines II, and Range Improvements to get this build ready for pre-WW2 battles.
The reason we go for 1x Engine instead of 2x Engine is that it will significantly reduce the cost of the CAS, allowing you to mass produce them for most countries.
However, if you can afford the 2x Engine II, then go for it since it will make the plane 100 times better.
We are again going to remind you that this CAS is relatively weak against other planes, but it can deal a lot of damage on the ground with the right Fighters around it.
Best CAS Design for 1938-39
In 1939, players will have the ability to research three important new air techs: Survivability Studies, Heavy MG, and Cannons I.
Though we don’t really have anything to do with Cannons here, we have two new pieces that we can add to the previous CAS design.
The reason we have a different build for this is because you can usually start researching this from 1938, and it will be useful for the Sino-Japanese War and the first steps of German expansion.
Here is the best CAS design in HOI4 for 1938/39:
- Basic Small Airframe
- CAS Weapons – Small Bomb Bay
- CAS Weapons – Small Bomb Bay
- 1x Engine II
- Defense Turrets – Heavy MG Defense Turret
- Special Modules – Self-Sealing Fuel Tanks
The Heavy MG Turret is better since it will increase Air Defense and Attack a bit while keeping Agility at the same level while on CAS missions.
The only problem is that Maximum Speed goes down a bit, but not enough to make a huge negative difference.
The Self-Sealing Fuel Tanks are also better than the Dive Breaks since you will get +2 Air Defense and -1 Weight, which will increase your Agility. The only problem here is that you will need to use +1 extra Rubber during Production.
Best CAS Design for 1940
We’ve now reached the main CAS design you will use for most of your HOI4 playthrough since there aren’t really any new parts you can get until 1943/44.
Here is the best CAS design in HOI4 for 1940:
- Improved Small Airframe
- CAS Weapons – Anti-Tank Cannon II
- CAS Weapons – Rocket Rails
- Fighter Weapons – 4x Heavy Machine Gun
- 1x Engine III
- Defense Turrets – Heavy MG Defense Turret
- Special Modules – Self-Sealing Fuel Tanks
- Special Modules – Extra Fuel Tanks
As you can tell, there are quite a few changes here. The main improvement is the airframe, which will make the plane a lot more powerful.
The Anti-Tank Cannon II is an amazing improvement over its predecessor and will make your CAS powerful while also keeping its Agility above 20. With this stat, the CAS will have a chance against the enemy’s AA.
We have also added Heavy Machine Guns to the weapons arsenal since it will significantly improve the CAS’ Air Attack, making it much harder to destroy in air battles.
However, if you don’t care that much about keeping the CAS alive and more about Ground Support, then you can go for the Anti-Tank Cannon.
This will likely result in almost 99% casualties for your CAS, and you will have to pump a lot of them out to keep up, but you will feel the effect on the ground.
The Extra Fuel Tanks are also a great addition since they will increase the range close to 1k km, allowing you to generally support the troops in most regions that aren’t extremely large.
Best CAS Design for 1943-44
By 1944, the Second World War should be close to an end, and your CAS should be ready to show its final form:
- Advanced Small Airframe
- CAS Weapons – Anti-Tank Cannon II
- CAS Weapons – Rocket Rails
- Fighter Weapons – 4x Heavy Machine Gun
- CAS Weapons – Rocket Rails
- 1x Engine IV
- Defense Turrets – Cannon Defense Turret
- Special Modules – Self-Sealing Fuel Tanks
- Special Modules – Extra Fuel Tanks
- Electronics – Radio Navigation II
At the final level, your CAS shouldn’t deal extreme levels of Ground Attack, since that would mean 1 Agility, which would result in instant destruction in most fights.
Otherwise, besides the extra Rocket Rails, which improve Ground Attack for free, and the new airframe, the 1944 CAS isn’t very different from the 1940 one.
The Radio Navigation II is also a nice addition since night penalties can really ruin your planes’ stats.
The only other improvement you can get now is the Modern Small Airframe, which will significantly increase Air Defense, Agility, and Range.
That’s everything you need to know about the best CAS design in Hearts of Iron 4!
Have any input or suggestions for this guide? Let us know in the comment section below.
