In the Aerofly FS 2 an airbrake represents a controllable area that creates drag.

aerowing, airfoil, aerofuselage, propeller, aerodrag

The airbrake is probably using something similar to this formula:

F_d = 0.5 * rho * v^2 * Cd * Area * Control

Where

• v is the velocity
• Cd is the drag coefficient for the maximum Area
• Area is the surface size in square meters perpendicular to X0.
• Control is the dynamic input values between 0.0 and 1.0 that scales the Area linearly
• X0 is the direction of the airbrake where it is acting (usually this is the x-axis but it could also be pointing upwards.
• rho is the air density at the Body.R position in the world (+R0 properly rotated with the Body orientation as far as the author of this text wants to believe)

Then the calculated drag is acted upon the Body at the R0 location along the X0 axis. The real formula used may be a lot more complex to account for the rotation speed of the Body.

Caution: Requires a rigidbody with the name Fuselage

            <[airbrake][Airbrake][]
                <[string8][Body][Fuselage]>
                <[tmvector3d][R0][ 0.0 0.0 0.0 ]>
                <[tmvector3d][X0][ 1.0 0.0 0.0 ]>
                <[float64][Cd][1.5]>
                <[float64][Area][1.0]>
                <[string8][Control][ServoAirbrake.Output]>
            >