This is the maximum load factor authorized during flight. This is an indicator of aerodynamic efficiency. The ratio of the lifting force to drag force produced by an aircraft. The lift slope is constant over a range of angle of attack away from stall. In incompressible flow, the dynamic pressure is defined as \(q = \frac$$ĭefines the change in lift coefficient with angle of attack. Pressure in a fluid as a result of the motion of that fluid.
A tangent line drawn from the origin to the polar plot gives the point of maximum aerodynamic efficiency (highest lift-to-drag ratio). An aircraft produces a drag force as it moves through the air, which is counter-acted by the thrust produced by the aircraft engine.Ī graphical plot showing the relationship between an aircraft’s lift and drag by plotting the dependence of lift (Y-axis) on drag (x-axis). The downward deflection of air caused as a by-product of the aerodynamic process of producing lift by an airfoil, blade or rotor.Īn aerodynamic force opposing the direction of motion as a result of a body’s motion through a fluid. It is named for its similarity to the Greek uppercase letter Delta (Δ). This refers to a wing planform shaped like a triangle. On an airfoil, the chord is defined as a straight line joining the leading and trailing edge. This is a point on a body where the total pressure distribution on that body can be collapsed into a single resultant vector acting at the center of pressure. It can also be defined as the balance point of an object. This is a geometric property of weight defined as the average location of the weight of an object. Airfoils are designed with camber to increase the maximum lift coefficient.
A camber line is drawn by a spline connecting a series of points along an airfoil chord equidistant between the upper and lower surface. This is a fluid mechanics term that refers to the region of fluid (air) in the immediate vicinity of a body where the viscous effects of the body causes the fluid in this region to attain a velocity less than that of the free-stream.Ĭamber refers to the asymmetry between the top and bottom surface of an airfoil. The angle between the wing and the horizontal is termed the “bank angle”. When completing a turn, an aircraft will rotate its wings about the longitudinal axis to an angle relative to the horizontal. It is a term used in both the FAR 25 and CS-25 regulations where an aircraft must be shown to demonstrate that the accelerate-stop distance and take-off distance is less than or equal to a given available runway length both with all engines operating and one engine inoperable. This refers to a runway condition where the aircraft accelerate-stop distance is equal to the take-off distance required for a given aircraft weight, configuration, and thrust setting. In cases where the wing is tapered, it is convenient to define the aspect ratio as the square of the wing span divided by the total planform wing area. It is calculated as the ratio of wing span to chord.
This is a measure of the spanwise area distribution of a wing. This is a design technique used to reduce the total aircraft drag particularly at transonic and supersonic speeds by a narrowing or ‘waisting’ of the fuselage in the region of the wings. It is most often used in an aeronautical context to describe the angle between the chordline of an airfoil and the relative wind or resultant direction of airflow. The airfoil section refers to the cross-sectional shape of a wing, blade (propeller/rotor) or sail.Īngle of attack refers to the angle between a reference line on a body and the vector representing the relative motion between the body and the fluid through which it is moving. The point (fraction of chord) at which the pitching moment coefficient of an airfoil is constant with a changing lift coefficient (angle of attack). This occurs when static pressure increases in the direction of flow. The ratio of the freestream fluid (air) velocity to the propeller (rotor) tip speed. Use the links provided to see additional information on a particular term, or posts and calculators associated with the term. Below is a glossary of aeronautical and aerospace related terms used throughout this website.