rc_cessna: increase drag and reduce motor torque

[StefanoColli]

Improved rc_cessna model simulation behaviour:

• increased wings drag for faster deceleration when there is no throttle
• increased vertical stabilizer area for a more realistic air resistance during banking manouvers
• decreased motor power to reduce the plane top speed at full throttle (from over 100m/s to a more reasonable 40-50m/s)

[Jaeyoung-Lim]

@StefanoColli Can you share flight logs that compares the previous and fixed behavior for reference?

[StefanoColli]

Do you mean some graphs showing the different behavior (e.g., for the speed at max throttle and deceleration at 0 throttle) or complete ulg logs? Because the latter also depends on the tuning on PX4 side and not only on the Gazebo models.

[Jaeyoung-Lim]

@StefanoColli Both. The description of the PR only discusses changes in the code without explaining the effects on the behavior of the model

[StefanoColli]

Top speed at full throttle and deceleration at min throttle

• With the previous model the plane was reaching 110m/s airspeed in a few seconds and the deceleration at throttle=0 was very slow
  
• With the new model the top speed is around 56m/s and the deceleration due to air drag is much more effective
  

[StefanoColli]

Vertical stabilizer area increased for banking maneuvers

• In the old model a banking maneuver would induce some oscillations in pitch and yaw
  
• Increasing the vertical stabilizer area (and thus its effects) smoothed those oscillations
  

[StefanoColli]

Tracking performance

• Old model with default tuning parameters from rc_cessna airframe
  
• New model with new tuning parameters from GZ RC Cessna: Improve rate tuning PX4-Autopilot#23758
  

Old model tracking log
New model tracking log

[Jaeyoung-Lim]

@StefanoColli Sorry for the late review. Thanks!