Modern missiles use reduced-smoke solid-fuel rocket motors, as well as liquid-fuel motors. However, these cease to be “low-smoke” at altitude due to the drop in air temperature. The exhaust of solid-fuel missiles, such as the AMRAAM’s HTPB/AP fuel, contains Hydrogen Chloride HCl, which at low temperatures forms crystal hydrates that generate a dense contrail. The exhaust of liquid-fuel missiles contains water vapor, which also generates a dense contrail in cold air.
In winter, a contrail can appear even at low altitudes. At Arctic temperatures, the contrail may appear even at ground level.
In the screenshot, an F-15C aircraft launches a missile at a target high above it. As illustrated in the image, the first part of the missile's flight has a “low-smoke” trail where the air temperature is above -25°C. As the missile climbs, a dense contrail appears as the air temperature falls below -25°C.
On the Kola map, you can set the air temperature down to -30°C, and this results in “low-smoke” missiles having trails at surface level. This is an important tactical point, as the smoke trail reveals not only the missile launch but also its trajectory.
We have implemented two guidance modes for these missiles. By default, the improved proportional navigation mode is used, but if the target uses a jammer, or has a velocity of less than 100 meters per second, pure pursuit is used.
We recently added new and more realistic SAM missile proximity blast patterns for fuzes. The proximity blast pattern is now a more realistic, “wagon wheel” shape (blue shape on screenshot) rather than spherical.
This allows the SAM missile warhead to more effectively fuze when the target is in the lethal area of the expanding rod zone. This increases the SAM lethality. This new mechanism allows us to set unique shapes and sizes of patterns based on fuze and warhead types. It is an important step in the development of munitions for DCS. You can expect the first implementation of this feature for the AIM-120 air-to-air missile in the next update.
