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Trim Drag
Trim drag, denoted as Dm in the diagram, is the component of aerodynamic drag on an aircraft created by the flight control surfaces, mainly elevators and trimable horizontal stabilizers, when they are used to offset changes in pitching moment and centre of gravity during flight. For longitudinal stability in pitch and in speed, aircraft are designed in such a way that the centre of mass (centre of gravity) is forward of the neutral point. The nose-down pitching moment is compensated by the downward aerodynamic force on the elevator and the trimable horizontal stabilizer. This downwards force on the tailplane (horizontal stabilizer and elevator combination) produces lift–induced drag in a similar way as the lift on the wing produces lift–induced drag. The changes (shifts) of the position of the centre of mass are often caused by fuel being burned off over the period of the flight, and require the aerodynamic trim force to be adjusted. Systems that actively pump fuel between sep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerodynamic Drag
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or between a fluid and a solid surface. Drag forces tend to decrease fluid velocity relative to the solid object in the fluid's path. Unlike other resistive forces, drag force depends on velocity. Drag force is proportional to the relative velocity for low-speed flow and is proportional to the velocity squared for high-speed flow. This distinction between low and high-speed flow is measured by the Reynolds number. Drag is instantaneously related to vorticity dynamics through the Josephson-Anderson relation. Examples Examples of drag include: * Net force, Net Aerodynamic force, aerodynamic or Fluid dynamics, hydrodynamic force: Drag acting opposite to the direction of movement of a solid object such as cars, aircraft, and boat hulls. * Viscou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight Control Surfaces
Flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude. The primary function of these is to control the aircraft's movement along the three axes of rotation. Flight control surfaces are generally operated by dedicated aircraft flight control systems. Development of an effective set of flight control surfaces was a critical advance in the history of development of aircraft. Early efforts at fixed-wing aircraft design succeeded in generating sufficient lift to get the aircraft off the ground, however with limited control. The development of effective flight controls allowed stable flight. A conventional fixed-wing aircraft uses three primary flight control surfaces– aileron, rudder and elevator to control the roll, yaw, and pitch respectively. Secondary flight control surfaces might include spoiler, flaps, and slats on the wings. The main control surfaces of a fixed-wing aircraft are attached to the airfram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centre Of Gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the barycenter or balance point) is the unique point at any given time where the weighted relative position of the distributed mass sums to zero. For a rigid body containing its center of mass, this is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion. In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Stability
In flight dynamics, longitudinal stability is the Flight dynamics (fixed-wing aircraft), stability of an aircraft in the longitudinal, or Aircraft principal axes, pitching, plane. This characteristic is important in determining whether an aircraft pilot will be able to control the aircraft in the pitching plane without requiring excessive attention or excessive strength. The longitudinal stability of an aircraft, also called pitch stability, refers to the aircraft's stability in its plane of symmetry about the lateral axis (the axis along the wingspan). It is an important aspect of the handling qualities of the aircraft, and one of the main factors determining the ease with which the pilot is able to maintain level flight. Longitudinal static stability refers to the aircraft's initial tendency on pitching. Dynamic stability refers to whether oscillations tend to increase, decrease or stay constant. Static stability If an aircraft is longitudinally statically stable, a small i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutral Point (aeronautics)
In flight dynamics, longitudinal stability is the stability of an aircraft in the longitudinal, or pitching, plane. This characteristic is important in determining whether an aircraft pilot will be able to control the aircraft in the pitching plane without requiring excessive attention or excessive strength. The longitudinal stability of an aircraft, also called pitch stability, refers to the aircraft's stability in its plane of symmetry about the lateral axis (the axis along the wingspan). It is an important aspect of the handling qualities of the aircraft, and one of the main factors determining the ease with which the pilot is able to maintain level flight. Longitudinal static stability refers to the aircraft's initial tendency on pitching. Dynamic stability refers to whether oscillations tend to increase, decrease or stay constant. Static stability If an aircraft is longitudinally statically stable, a small increase in angle of attack will create a nose-down pitching mom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel Tank
A fuel tank (also called a petrol tank or gas tank) is a safe container for Flammability, flammable fluids, often gasoline or diesel fuel. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled (Fuel pump (engine), fuel pump) or released (pressurized gas) into an engine. Fuel tanks range in size and complexity from the small plastic tank of a butane lighter (fire starter), lighter to the multi-chambered Cryogenics, cryogenic Space Shuttle external tank. Uses Typically, a fuel tank must allow or provide the following: * Storage of fuel: the system must contain a given quantity of fuel and must avoid leakage and limit evaporative emissions. * Filling: the fuel tank must be filled in a secure way, without sparks. * Provide a method for determining level of fuel in tank, fuel gauge, gauging (the remaining quantity of fuel in the tank must be measured or evaluated). * Venting (if ove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
