Flares in COADE are sticks of pyrotechnic mixture that burn slowly from one end to the other, producing heat that attracts missiles.

Choosing a Pyrotechnic Mixture
The best pyrotechnic for use in flares (in vanilla) is Nitrocellulose because of its inherently slow burn rate. This means you don't have to dilute it terribly much to slow it down to reasonable levels. The stock flares are decently good examples of this.

Adjusting your Burn Rate
The game allows adding delay composition to your pyrotechnic so you can tailor the burn rate of your flare to the specific application. The more mass fraction of your flare is made of inert material, the slower it will burn.

Generally the best delay comp for your pyrotechnic mixture is one with the lowest possible density. In vanilla, this is lithium. It seems that the effect on the pyrotechnic burn rate is more directly related to the volume ratio of pyrotechnic to delay comp than the mass ratio, as denser materials require much higher mass ratios to achieve the same burn rate as low-density ones.

Designing the Flare Module
To design a flare of the desired heat output and burn time, I typically start with a mixture of about 10% (0.1 mass fraction) of lithium and 90% nitrocellulose. I also set the armor material to something low density like Polyethylene and minimum thickness (1mm).

• Increase or decrease the radius of the flare to achieve the desired power output. Larger end surface area means higher heat output.
  
• Increase or decrease the height of the flare to achieve the desired burn time. Longer flares burn for longer.
  
• Now that the correct power output and duration are achieved, review the design requirements (e.g. the required diameter, length, and mass). If those requirements are too wildly different from the actual flare, you may have to rethink your deployment method.
  
• If the flare is too long, you'll have to decrease the burn rate (add more delay comp) and increase the radius. Once you bring it back to the original power & duration, it should be roughly the same mass as before.
  
• If the flare is too wide, you'll have to increase the burn rate (reduce delay comp) and increase the length.

Blast Launchers
Blast launchers are the vanilla way to deploy flares.
Pros:

• Don't require crew or power
  
• Able to launch flares at medium velocity (100-500 m/s easily)
  
• Well understood by COADE AI (wont spam them)
  
• Very easy to design

Cons:

• Fixed firing direction, which can occasionally render them ineffective
  
• Cannot add delay fuses without AI spamming them mercilessly
  
• Explode violently when hit by enemy fire

Good flare blast launchers should have:

• Good muzzle velocity (300-500 m/s)
  
• Long flare burn duration (7-15 seconds)
  
• Heat output more than twice that of the launching ship's peak heat
  
• Relatively short flares (<4-5 meters) for easy fit into ship. Small diameter flares are easier to launch faster, but require more launch tube mass & depth into the ship.
  
• Best vanilla tube material is Boron Filament for mass & cost balance
  
• Best vanilla propellant is Nitrocellulose for its slower burn rate & high energy
  
• Do NOT set an engagement range or set it to target shots. This will cause AI to spam it! The AI already knows to launch limited numbers of flares against enemy missiles, if and only if it's setup just like the stock decoy launchers
  
• Decoy payload with ONLY a flare module and nothing else. Otherwise AI will spam it.

Flare Guns
This section will apply to chemical guns mostly. Railguns and coilguns main downsides, high cost, high power draw, and design difficulty, are much more tolerable in point defense guns than in launching flares.
Pros:

• Flares are fired towards incoming missiles, disrupting their flight path more at medium range
  
• Closer flares are weighted higher than farther flares, so gun-launched flares can be more effective
  
• Able to launch flares at high velocity (>1 km/s)
  
• Able to put delay fuses on flares without worry of AI spam (this prevents friendly missiles from targeting flares, enabling simultaneous use of interceptor missiles)
  
• Able to pre-detonate missiles at longer ranges even if they don't normally explode on shots

Cons:

• Flare guns will not fire unless they can actually track the missiles they're shooting at
  
• Flare gun turrets must swing around quite fast to be practical (large power draw)
  
• Fire rate is limited by autoloader power draw & barrel heat
  
• Large capital ships need large diameter flares to ward off missiles, ballooning gun size
  
• Flare gun ammunition storage is extremely explosive
  
• Will not disrupt missile flight path very much until flare passes through missile formation
  
• Cannot set engagement range unlike blast launchers
  
• Suffer against high-velocity (>4-6 km/s) missiles compared to blast launchers due to firing directly forwards
  
• Much more expensive than blast launchers for the same amount of ammo

Good flare guns should have:

• High muzzle velocity (>800 m/s)
  
• Good turret rotation speed (6-10 RPM) to track missiles
  
• Low fire rate (500-1000ms reload) to conserve flares for future missile salvos
  
• Medium flare duration (3-6 seconds) depending on muzzle velocity and desired effective range
  
• Flare heat output greater than launching ship, but doesn't need to be 2x more
  
• Medium ammunition reserves (100-300 rounds)
  
• Heavy armor on turret and ammunition to help prevent magazine detonation
  
• Best vanilla propellant is Nitrocellulose
  
• Best vanilla sabot & gun barrel material is Vanadium Chromium Steel
  
• Often helpful to oversize the cannon bore to achieve higher velocities
  
• Small spread not required, go with lightweight barrel to reduce actuator power
  
• See other guides on making good turrets, but generally use electric actuators only with small turrets, and low density momentum wheels otherwise

This section refers to guided missiles equipped with flares. Due to the low fire rate required, these can quite easily be either electromagnetically- or blast-launched.

It is also possible to equip flares with a rocket booster without guidance. However, this provides only the advantage of higher terminal velocity, without the particular benefits of guidance, and as such I will not discuss unguided decoy rockets in detail here.

Pros:

• Able to achieve high velocity (2+ km/s)
  
• Able to set engagement range appropriately for the time of flight
  
• Able to put flare much closer to incoming missiles, similar to flare guns. Smaller heat output (diameter) is acceptable, meaning more burn time for the same mass
  
• No need for aiming prior to firing
  
• No electrical power requirement
  
• Able to be used as kinetic kill vehicles in a pinch (if within designed flaring range)
  
• Will not interfere with other friendly missiles due to onboard remote control

Cons:

• Much heavier and more expensive per round than blast or gun flares
  
• Effectiveness can only be either long or short range, not both, due to opposing requirements of flare heat output and burn duration
  
• Short range decoy missiles need very high TWR & maneuverability, which costs mass & volume
  
• Long range decoy missiles need long-burning flare modules, which lowers mass efficiency
  
• Requires several crew members to fly and maintain, unlike blast flares
  
• Rarely beats blast launched flares at close range due to initial velocity disadvantage
  
• Tuning effective range band requires trial and error,

A good long range decoy missile will have:

• Lower heat output than peak heat of launching ship. As low as 1/2 to 1/3 depending on targeted range band.
  
• High TWR of 6-12 G and delta-V greater than 2 km/s. Aim for thruster burn shorter than 6-8 seconds to get out in front before high speed missiles get too close.
  
• Aggressive or hyper-aggressive missile guidance law expending 90-95% of propellant in the boost phase
  
• Delay fuse activation timed to end of thruster burn, +/- a couple seconds. This is a compromise between effective maximum range and resistance to hypervelocity missiles that might blow past the decoy missiles before the flare starts burning.
  
• Flare burn duration sized for decently long effective range band at final velocity (3 second burn at 3 km/s = 9 km range band)
  
• High performance chemical rocket propellant (e.g. LOX/RP-1, NTO/UDMH, F2/H2)
  
• Fast turnaround time (<2 seconds for RCS, <1 second for gimballed engine)

A good short range decoy missile will have:

• Higher heat output than launching ship's peak. More than 1.5x is a good place to start
  
• Extreme TWR of 15-30 G and delta-V greater than 1.5 km/s. Aim for thruster burn shorter than 3-4 seconds to catch high speed missiles
  
• Delay fuse activation set to 0.25-1 seconds after launch, to catch high speed missiles
  
• Flare burn time for long effective range band (say 5 second burn at 2km/s = 10 km range band)
  
• Hyper aggressive guidance law & high performance rocket propellant
  
• Very fast turnaround time