Aerodynamic forces estimated from the quasi-steady analysis.

<p>A) Lift forces. B) Horizontal (thrust) forces. Red and blue colors denote the left (internal) and right wing, respectively. Both forces are normalized with the beetles’ body weight. Thrust/drag is defined as positive and negative when directed forwards and backwards, respectively. The insert above B shows the yaw torque due to asymmetric flapping that should lead to exiting the circular flight trajectory in free-flying beetles.