Aerodynamics
Physics of Aerodynamic Flight
Pioneer simulates aerodynamic drag and lift in a relatively simple manner. All non-ship dynamic objects (missiles, cargo etc.) are considered to be perfect spheres in the drag equation.
drag_force = 0,5 * atmospheric_pressure * velocity^2 * drag_constant
Drag constant for sphere is 0,1.
The drag values for ships are calculated separately for each axis (local to the ship), by getting the ship's cross section for each axis. Each ship has it's cross section area values in their respective .json files, in meters squared.
Sum of all forces in three axises allow ships to generate lift and/or manuever by increasing their angle of attack. Pioneer simulates non-cambered wings, with equal air displacement on either side of AoA.
Pioneer also simulates stall. If the angle of attack is too high, the airflow will get disrupted, resulting in loss of lift force. With the current simulation (wiki updated at 22 September 2019), generated lift peaks at around 20 degrees, and falls off fully at 35-ish. However, this is relatively poorly simulated and probably needs to be swapped with a curve-based implementation in the future.
Most spacecraft in Pioneer are passively stable in atmosphere, forcing a nose-first orientation by generating torque while travelling in atmosphere. The strenght of this force is highly ship-specific, and better aerodynamic designs (like Wave and Deneb) are more stable compared to non-aerodynamic ships (like DSMiner). However, just like the case of AoA simulation, this is rather poorly simulated and probably needs some change in the future.
Aerodynamic Manuevers
(Could be moved to it's own tutorial page?)
If the atmospheric pressure is good enough, the current simulation model allows aerodynamic spacecraft to move like airplanes (go where you are pointing at.)
By carefully increasing and decreasing the perpendicular area to the velocity vector, pilots can perform very precise aerobraking manuevers. This also makes managing the atmospheric entry heat much easier.
The current aerodynamic flight simulation could, in theory, allow pilots to perform an aerogravity assist. (https://en.wikipedia.org/wiki/Aerogravity_assist)
