FLIGHT MECHANICS

1.1. Understanding
Flight mechanics is a study about the forces act on the aircraft or spacecraft, that cause the motion. This study is application of Newton’s Law to the aircraft or spacecraft. The motion of aircraft have two kind of references. First is a point outside the aircraft or spacecraft, and second is center of gravity on the aircraft or spacecraft. This references are basic for the classification in the branch of flight mechanics.

(a) Outer reference point

(b) Reference point attach to the center of gravity

Figure 1. Different kind of Motion Reference

1.2. Classification
As we know before, different reference points of motion will result in different treatment to analize. This causing flight machanics have four main brances of study.

Figure 2. Study brunches of Flight Mechanics

a. Flight performance (dreaming time)
Flight performance is a branch of flight mechanics that study about flight vehicle performance along the path, due to all force acting on it. The vehicle is representated by its center of gravity
Input: major or dominant force
Output: distance, endurance, speed, etc
Common issue: speed, economics flight, distance, fuel, etc



b. Flight Guidance / Navigation (start point)
Flight Guidance is a study about how to guidance the flight vehicle through its cours or path that has been planned.
Input: Flight plan, course, destination,
Output: Flight path
Common issue: optimal course/path, Minimal fuel for space travel, etc.

c. Flight Dynamics
Flight Dynamics is a study that learn about the attitude of flight vehicle and the respon to the inner force or disturbance acting on it.
Input: inner force, disturbance, dumping character, vehicle configuration, etc.
Output: vehicle stability character
Common issue: stability of the aircraft when there are disturbance acting on it.


d. Flight Control and Stability
Flight Control is a branch of flight mechanics that study about how to reach or to keep the attitude of the flight vehicle.
Input: aerodynamic force, thrust, etc
Output: optimal respons, stability, etc
Common issue: how to stabilize the vehicle, maneuverability, control system loop,



1.3. For a better understanding
For a better understanding, I suggest you to learning or familiar with some of the list below:
- Coordinat
- Fligth configuration
- Flight attitude
- Shape parameter of flight vehicle
- Some aerodynamics and astrodynamics important terms



REFERENCE


Jenie, S. D. (1985). DINAMIKA TERBANG (a lecture note MS 455). Bandung.