Spoiler
After the MiG-29 was added to War Thunder, we received many questions, why the static thrust of the aircraft in the game is lower than that declared by the manufacturer. There are many reasons for this, let us list the main ones.
Static thrust in full afterburner mode and no afterburner max speed are 8,300 kgf and 5,040 kgf. This thrust is given by the manufacturer for conditions of 0 m and 0 km/h, without taking into account the loss of thrust in the air intake ducts, power supply of onboard equipment and other factors that rise when the engine is mounted in the aircraft.
According to the main source about the aircraft (“Аэродинамика самолёта МиГ-29”) ", the static thrust of the installed engine in the full afterburner mode (see “ПОЛНЫЙ ФОРСАЖ”) is about 8,000 kgf, and in the maximum speed mode (see “МАКСИМАЛ”) about 4,900 kgf, which are 300 kgf and 100 kgf, respectively, lower than declared. The graphs below do not reflect the influence of the MiG-29 inlet devices, which are represented by the blow-in door of the critical section of the air intake duct at the inlet, as well as the upper air intakes. In the take-off mode, the blow-in doors completely block the axial inlet of the air intake to prevent solid objects from entering it and damaging the engine, and all air supply to the engine goes through small slots in the lower part of the door, as well as through the upper inlet. The engine in this mode operates with a lack of air and is not able to gain the thrust indicated in graphs 3.16 and 3.17.
At lower speeds the listed performance can not be achieved either. Due to the uneven mixing of flows from the upper and axial inlets, the air flow at the air intake is unstable, which results in the engine not having sufficient air supply. This phenomenon is described in the same source.
Furthermore, the engine is controlled and adjusted by a number of automatic systems, which may also cut thrust and engine speed.
As a result, the listed factors reduce the available thrust, affecting it most at lower speeds. The graph of the available thrust displays the full afterburner and full speed modes. Since our flight model operates the available thrust, this static available thrust is presented in the engine performance in the game.
The estimated available thrust also coincides with the estimates indirectly calculated from the graphs of the available longitudinal acceleration Nx (Fig. 5.3, 5.4), which, in fact, display the aircraft’s thrust-to-weight ratio minus the required thrust. The amount of available thrust is also confirmed by the graphs of maximum speeds, graphs of rate of climb, graphs of turn rates, as well as the take-off rate from the moment the brakes are released and the available acceleration at the start (paragraph 8.3.2 of the source). At the moment, the aircraft in the game shows all these characteristics quite close to the declared ones or even slightly exceeds them.
