Aerodynamics

The atmosphere provides the medium in which aircraft operate. Its properties, including pressure, density, temperature, and humidity, directly affect aircraft performance, engine operation, and aerodynamic forces. Understanding the characteristics of the atmosphere is therefore essential to understanding the principles of flight. Before examining the fundamental laws of flight, several basic facts must be considered, namely … Read more

Helicopter flight is governed by several aerodynamic and mechanical forces that influence stability, control, and performance. Understanding how lift, thrust, drag, weight, torque, and gyroscopic forces interact provides the foundation for understanding helicopter flight characteristics and pilot control inputs. One of the primary differences between a helicopter and a fixed-wing aircraft is the source of … Read more

Aircraft operating at high speeds encounter aerodynamic effects that differ significantly from those experienced at lower speeds. As an aircraft approaches the speed of sound, air compressibility, shockwaves, and aerodynamic heating become increasingly important factors affecting performance, stability, and design. Understanding these high-speed aerodynamic principles is essential for the development and operation of modern transonic, … Read more

The center of gravity (CG) is one of the most important factors affecting aircraft stability and control. It represents the point through which the total weight of the aircraft acts and serves as the aircraft’s balance point. Understanding the location of the CG and the three axes of rotation is essential for understanding how an … Read more

Aerodynamics is the study of how air interacts with objects in motion, particularly aircraft. The principles of flight are governed by fundamental laws of physics that explain how forces are generated and how aircraft move through the atmosphere. Concepts such as motion, velocity, acceleration, relative wind, Newton’s Laws of Motion, and Bernoulli’s Principle provide the … Read more

An aircraft must possess sufficient stability to maintain a desired flight path and to recover naturally from various disturbing forces such as gusts, turbulence, or control inputs. At the same time, to achieve optimum performance and safe handling qualities, the aircraft must respond properly and predictably to pilot control inputs. Control refers to the pilot’s … Read more

Helicopter flight in forward motion introduces aerodynamic effects that do not exist in a hover. Dissymmetry of lift, blade flapping, cyclic feathering, and autorotation are fundamental rotor-system characteristics that allow helicopters to remain controllable throughout a wide range of flight conditions. Understanding these principles is essential for safe helicopter operation and performance. Hovering Flight During … Read more

An airfoil is a surface designed to obtain lift from the air through which it moves. Thus, it can be stated that any aircraft surface designed to produce lift from airflow is an airfoil. The profile of a conventional wing is an excellent example of an airfoil. [Figure 1] Notice that the top surface of … Read more

An aircraft in flight is constantly influenced by four fundamental aerodynamic forces that determine its performance and motion. Actually, this conflict is not as violent as it sounds, but it is the key to all maneuvers performed in the air. There is nothing mysterious about these forces; they are definite and known. The directions in … Read more