Recently, we announced that combat helicopters will be coming to War Thunder in update 1.81 "The Valkyries".
In this devblog, we’d like to talk about the flight models and physics of these helicopters. You will learn how the helicopters will fly and what forces act upon them whilst doing so, and we will also show you how to control your heli in different game modes.
Gaijin Entertainment already has experience in developing games with combat helicopters - back in 2010, we released Apache: Air Assault (A:AA), undoubtedly some of you are familiar with that game. During the April Fools event of 2017, we used the flight models from A:AA. It was good enough for that ‘one time’ event, but to implement helicopters on a large scale in War Thunder, it didn’t really suit, since it did not allow us to reproduce the level of detail we already have for aerodynamics and damage models that we use for the planes in the game. Additionally, we had planned to introduce many more rotary-wing machines than we did in A:AA.
So, in order to introduce helicopters that meet the requirements of our current physics engine we had to implement some new simulation elements: a rotor with moving blades and a swashplate, turboshaft engines with detailed transmissions, and other important flight control systems besides what we have already implemented for the planes.
How does a helicopter fly? Flight physics in War Thunder:
A helicopter, just like a fixed-wing aircraft, has wings, a tail (even with a rudder sometimes) and a fuselage, and they all produce specific aerodynamic forces. However, both lift and thrust are created by a main rotor. Unlike the thrust provided by an aircraft propeller, main rotor thrust is: directed mostly upward; can be deflected a little bit left-right and forward-backward; depending on the point of the main rotor circle, it may vary thus creating a momentum and “tilting” of the rotor.
This allows it to create the horizontal component of the main rotor lift and to move forward/backward and left/right.
Here is some more technical talk on the topic as a bonus. If you just want to hear how the controls will work in War Thunder, skip ahead to the next section (after the end of the block quote).
Rotor disc tilt is created by a swashplate that controls the cyclic pitch of the main rotor. It is controlled by a cyclic-pitch lever that is placed in front of the pilot. When a cyclic-pitch lever is pointed in the given direction, it increases the angle of the rotor blades in one direction and reduces it in the opposite direction. Taking gyro precession into account, this means that in directions angled at 90 degrees from the directions with maximum and minimum cyclic pitch maximal and minimal lift is created as well as maximal and minimal rotor blades fly (up and down). The first one creates the momentum which tilts the helicopter, while the second tilts the rotor’s cone itself. Both of these factors create horizontal component of main rotor lift which allows a helicopter to move horizontally. The rotor cone tilt is possible because of the hinges that allow the blades to flap both horizontally and vertically, and rotate around their axes.
Just like with fixed-wing aircraft, a helicopter is controlled by 4 main control axes, but different terms are used to describe them: cyclic (roll and pitch), collective pitch, and pedals. Helicopters don’t have flaps or air brakes. A helicopter elevator and rudder behaviour is controlled by the axis of cyclic pitch and pedals(yaw).
In the “full controls” mode, a player will gain complete, manual control of the machine. Helicopters that in real life had auto-trimmers or stability augmentation systems (SAS) are implemented in War Thunder and make the controls easier. Most helicopters have a pedal trimmer which helps control yawing when collective pitch is changed.
In “Realistic” mode, the cyclic and pedals set the intended rotational speed through respective axes and the instructor performs the required manipulations, while the collective is controlled manually.
“Simplified mode” is identical to Realistic with only one difference - it has a “hovering” function, when a respective key is pushed (“H” by default) the helicopter hovers in one place but is able to move in all axes forward/backward, up/down/ and left/right - horizontal maneuvers are controlled by the cyclic, and vertical by collective pitch. Near the ground’s surface the vertical descent speed will be automatically limited in order to perform a soft landing.
Pedals set the rotation speed. To hover without moving, all axes should be at a neutral position.
In “Mouse aim” mode, a player sets the intended direction where the helicopter should turn and the instructor controls the cyclic and pedals in order to make it fly there. Keys that control cyclic pitch and pedals can be used for manual control - similar to Realistic and Simplified mode. The collective is controlled manually. A “hover” function is also available.
Quick reminder: As per usual when it comes to the introduction of something major to War Thunder (i.e. a new nation or vehicle type), participants of the closed beta test (CBT) will be the first to try these wonderful machines. Any purchase of a pack with a premium helicopter grants access to the CBT.
Source: War Thunder News Portal
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