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Autofeather
Autofeather is a feature of the engines on some turboprop or piston engine aircraft. When the power being produced by the engine drops to the point where it is not contributing to thrust, the propeller will go into a feathered mode to reduce drag. The auto feather system also allows pilots to reduce the drag of the propellers during an engine failure, therefore, allowing the plane to glide for a longer period of time. An automatic feathering system was first introduced on the Martin 4-0-4 The Martin 4-0-4 was an American pressurized passenger airliner built by the Glenn L. Martin Company. In addition to airline use initially in the United States, it was used by the United States Coast Guard and United States Navy as the RM-1G ... aircraft, a piston engine airplane. The system was designed to automatically feather an engine that failed during takeoff or initial climb. It is not used during cruise. Aircraft engines {{engine-aircraft-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turboprop
A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts. The hot combustion gases expand through the turbine stages, generating power at the point of exhaust. Some of the power generated by the turbine is used to drive the compressor and electric generator. The gases are then exhausted from the turbine. In contrast to a turbojet or turbofan, the engine's exhaust gases do not provide enough energy to create significant thrust, since almost all of the engine's power is used to drive the propeller. Technological aspects Exhaust thrust in a turboprop is sacrificed in favor of shaft power, which is obtained by extracting additional power (beyond that necessary to drive the compressor) from turb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feathering (propeller)
An aircraft propeller, also called an airscrew,Beaumont, R.A.; ''Aeronautical Engineering'', Odhams, 1942, Chapter 13, "Airscrews". converts rotary motion from an engine or other power source into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil-section blades such that the whole assembly rotates about a longitudinal axis. The blade pitch may be fixed, manually variable to a few set positions, or of the automatically variable "constant-speed" type. The propeller attaches to the power source's driveshaft either directly or through reduction gearing. Propellers can be made from wood, metal or composite materials. Propellers are most suitable for use at subsonic airspeeds generally below about , although supersonic speeds were achieved in the McDonnell XF-88B experimental propeller-equipped aircraft. Supersonic tip-speeds are used in some aircraft like the Tupolev Tu-95, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martin 4-0-4
The Martin 4-0-4 was an American pressurized passenger airliner built by the Glenn L. Martin Company. In addition to airline use initially in the United States, it was used by the United States Coast Guard and United States Navy as the RM-1G (later as the VC-3A). Design and development When production of the earlier Martin 2-0-2 was stopped due to problems with wing structural failure the company decided to re-wing an improved version (which had already flown as the Martin 3-0-3). The new aircraft was the Martin 4-0-4. It had structural changes to the wings, pressurization and was lengthened slightly to take 40 passengers. Like the earlier 2-0-2, the 4-0-4 was a cantilever monoplane with a standard tail unit (cantilever tailplane and single vertical stabilizer). It had an airstair in the lower tail section for passenger boarding and disembarkation, retractable tricycle landing gear and was powered by two Pratt & Whitney R-2800-CB16 radial piston engines. Operational history ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
