Helicopter

hHelicopter Definition A helicopter (or chopper, helo or whirlybird) is a type of rotorcraft in which lift and thrust atomic number 18 supplied by rotors. This allows the helicopter to take finish up-key and land vertically, to hover, and to fly forwards, backwards, and laterally. These attributes allow helicopters to be utilize in congested or isolated aras where fixed-wing aircraft would usually not be able to take off or land.The cap mightiness to hover efficiently for extended periods of time allows a helicopter to accomplish tasks that fixed-wing aircraft and other forms of vertical takeoff and landing aircraft cannot perform. The word helicopter is adapted from the French helicoptere, coined by Gustave de Ponton dAmecourt in 1861, which originates from the Greek helix/helik- ( ) = twisted, curved and pteron ( ) = wing. Helicopters were developed and built during the first half-century of flight, with the Focke-Wulf Fw 61 being the first in operation(p) helicopter in 1936 .Some helicopters reached limited production, but it was not until 1942 that a helicopter designed by Igor Sikorsky reached full-scale production, with 131 aircraft built. Though most earlier designs used much than one main rotor, it is the single main rotor with anti-torque tail rotor configuration that has become the most common helicopter configuration. Tandem rotor helicopters ar as well in widespread use, due to their better payload capacity. Quad rotor helicopters and other types of multicomputer have been developed for specialized applications. UsesDue to the operating characteristics of the helicopterits ability to take off and land vertically, and to hover for extended periods of time, as well as the aircrafts handling properties under low airspeed conditionsit has been chosen to conduct tasks that were previously not possible with other aircraft, or were time- or work-intensive to accomplish on the ground. Today, helicopter uses include expatriation of people and carg o, military uses, construction, firefighting, search and rescue, tourism, medical transport, and aerial observation, among others.Sikorsky S-64 throw crane lifting a prefab house Sikorsky S-76C+ air ambulance toll 205 dropping water on fire HH-65 Dolphin demonstrating hoist rescue capability AgustaWestland Apache lash bulge helicopter A helicopter used to carry loads connected to long cables or slings is called an aerial crane. Aerial cranes are used to place expectant equipment, like radio transmission towers and large air conditioning units, on the tops of tall buildings, or when an item must be raised up in a remote area, such as a radio tower raised on the top of a hill or mountain.Helicopters are used as aerial cranes in the logging industry to lift trees out of terrain where vehicles cannot travel and where environmental concerns prohibit the building of roads. These operations are referred to as logline because of the long, single sling line used to carry the load. The most grand-scale single non-combat helicopter operation in history was the disaster management operation chase the 1986 Chernobyl nuclear disaster. Hundreds of pilots were involved in airdrop and observation missions, making dozens of sorties a day for some(prenominal) months.Helitack is the use of helicopters to combat wild land fires. The helicopters are used for aerial firefighting (or water bombing) and may be fitted with tanks or carry helibuckets. Helibuckets, such as the Bambi bucket, are usually filled by submerging the bucket into lakes, rivers, reservoirs, or portable tanks. Tanks fitted onto helicopters are filled from a hose while the helicopter is on the ground or water is siphoned from lakes or reservoirs through a hang snorkel as the helicopter hovers over the water source.Helitack helicopters are also used to deliver firefighters, who rappel down to inaccessible areas, and to resupply firefighters. Common firefighting helicopters include variants of the bell shap e 205 and the Erickson S-64 nimbuscrane helitanker. Helicopters are used as air ambulances for emergency medical assistance in situations when an ambulance cannot easily or quickly reach the scene, or cannot transport the patient to a medical facility in time. Helicopters are also used when a patient needs to be transported between medical facilities and air transportation is the most practical method for the untroubledty of the patient.Air ambulance helicopters are equipped to provide medical treatment to a patient while in flight. The use of helicopters as air ambulances is ofttimes referred to as MEDEVAC and patients are referred to as being airlifted, or medevaced. Police departments and other law enforcement agencies use helicopters to pursue suspects. Since helicopters can touch a unique aerial view, they are often used in conjunction with police on the ground to report on suspects locations and movements. They are often mounted with lighting and heat-sensing equipment for night pursuits.Military forces use attack helicopters to conduct aerial attacks on ground targets. Such helicopters are mounted with missile launchers and miniguns. Transport helicopters are used to ferry troops and supplies where the lack of an airstrip would make transport via fixed-wing aircraft impossible. The use of transport helicopters to deliver troops as an attack force on an objective is referred to as Air Assault. Unmanned Aerial Systems (UAS) helicopter systems of varying sizes are being developed by companies for military reconnaissance and surveillance duties.Naval forces also use helicopters equipped with dipping sonar for anti-submarine warfare, since they can operate from small ships. Oil companies charter helicopters to move workers and parts quickly to remote drilling sites located out to sea or in remote locations. The speed over boats makes the high operating cost of helicopters cost effective to ensure that oil platforms continue to flow. mingled companies spe cialize in this type of operation. Other uses of helicopters include, but are not limited to * Aerial photography * Motion picture photography Electronic news gathering * Reflection seismology * Search and Rescue * Tourism or recreation * Transport Design features Parts and functions The simple rotor of a Robinson R22 Robinson R44 rotor breaker point The simple rotor of aRobinson R22showing (from the top) * The following are driven by the link rods from the rotating part of theswash denture. * Pitch hinges, allowing the blades to twist about the axis of rotation extending from blade root to blade tip. * Teeter hinge, allowing one blade to rise vertically while the other falls vertically.This motion occurs whenever translational relative face-lift is present, or in response to a cyclic control input. * Scissor link and counterweight, carries the main shaft rotation down to the upper swash plate * Rubber covers protect moving and stationary shafts * Swash plates, transmitting cycl ic and collective flip over to the blades (the top one rotates) * Three non-rotating control rods transmit pitch information to the lower swash plate * Main mast leading down to maingearbox Safety Limitations HAL Dhruvperforming aerobatics during theRoyal International Air Tattooin 2008.Royal Australian NavySquirrelhelicopters during a display at the 2008 Melbourne Grand Prix The main limitation of the helicopter is its low speed. There are several reasons a helicopter cannot fly as fast as a fixed-wing aircraft. When the helicopter is hovering, the outer tips of the rotor travel at a speed contumacious by the length of the blade and the RPM. In a moving helicopter, however, the speed of the blades relative to the air depends on the speed of the helicopter as well as on their rotational velocity. The airspeed of the advancing rotor blade is much higher than that of the helicopter itself.It is possible for this blade to exceed thespeed of sound, and thus produce vastly increased d rag and vibration. Because the advancing blade has higher airspeed than the retreating blade and generates adissymmetry of lift, rotor blades are designed to flap lift and twist in such a way that the advancing blade flaps up and develops a smaller angle of attack. Conversely, the retreating blade flaps down, develops a higher angle of attack, and generates more lift. At high speeds, the force on the rotors is such that they flap high-spiritedly and the retreating blade can reach too high an angle and stall.For this reason, the maximum safe forward airspeed of a helicopter is given a design rating calledVNE,Velocity, Never Exceed. In addition it is possible for the helicopter to fly at an airspeed where an excessive amount of the retreating blade stalls, which results in high vibration, pitch -up, and roll into the retreating blade. During the closing years of the 20th century designers began working onhelicopter noise reduction. urban communities have often expressed great dislike of noisy aircraft, and police and passenger helicopters can be unpopular.The redesigns followed the closure of some city heliports and government pull through to constrain flight paths innational parksand other places of natural beauty. Helicopters also vibrate an unadjusted helicopter can easily vibrate so much that it will shake itself apart. To reduce vibration, all helicopters have rotor adjustments for top of the inning and weight. Blade height is adjusted by changing the pitch of the blade. weightiness is adjusted by adding or removing weights on the rotor head and/or at the blade end caps. Most also have vibration dampers for height and pitch. Some also use mechanical feedback systems to sense and counter vibration.Usually the feedback system uses a mass as a stable reference and a gene linkage from the mass operates a flap to adjust the rotorsangle of attackto counter the vibration. Adjustment is difficult in part because measurement of the vibration is hard, usually req uiring cultivate accelerometers mounted throughout the airframe and gearboxes. The most common blade vibration adjustment measurement system is to use a stroboscopic flash lamp, and observe painted markings or coloured reflectors on the underside of the rotor blades. The traditional low-tech system is to mount coloured chalk on the rotor tips, and see how they mark a linen sheet.Gearbox vibration most often requires a gearbox overhaul or replacement. Gearbox or drive train vibrations can be passing harmful to a pilot. The most severe being pain, numbness, loss of tactile discrimination and dexterity. - - - - - - - - - - - Helicopter Types Legend for Category of Engines P Piston Engine T -Turbine Engine NOTEThis Chart is provided as a guide only. Manufacturer Type Designator pretending Number of Engines Minimum Crew Requirement Aerospatiale-SNIAS Sud Aviation ( hitch Eurocopter) - See Eurocopter - - Agusta A109 Agusta A109A, A109E, A109C, A109S 2T 1 A119 Agusta A119, A119MKII 1 T 1 A139 Agusta AB139 2T 1 VFR 2 IFRBell Helicopters BH04 Iroquois (all model 204 205 and CH-118 H-1 Series) 212S Eagle Single 1T 1 BH06 Jet Ranger (all model 206 CH-136 H-58 serial Kiowa) 1T 1 BH06T place 206 Twin 2T 1 BH12 Bell 212 series (all CH135 H-1N series) 2T 1 VFR 2 IFR BH214 Bell 214 series (all models except 214ST) 1T 1 BH22 Bell 222 222B 222U 2T 1 BH23 Textron (Model 230) 2T 1 BH41 Bell 412 2T 1 VFR 2 IFR BH47 Bell 47 series (all model 47 series H-13 Ranger) 1R 1 BH47T Turbine supply BH47 1T 1 BH407 Bell B407 1T 1 BH427 Bell B427 2T 1 B429 Bell 429 2T 1 BH430 Bell B430 2T 1 BHST Bell 214ST 2T 1 VFR 2 IFR Boeing (Vertol) Company Ltd. (new company name Columbia Helicopters Inc. ) HV07 Labrador (all model 107 H-46 Seaknight) 2T 2 HV34 Chinook (all model 114 H-47 series) 2T 2 BV44 All model 42/44 (H-21 series) 1P 1 Brantly Helicopter Corp. HB42 HB-42 All model 1R 1 HB43 All model 305 1P 1 Bristol BR71 Sycamore 171 1P 1 Canadian Home Rotors Inc. BABY Safa ri (Baby Belle) 1P 1 Cessna Aircraft Co. C1C Skyhook (all models) 1P 1 Doman Helicopters Inc. DM52 All model D-10B 1T 1 Eagle R&D HELCY Helicycle 1T 1Eurocopter (Includes Aerospatiale-SNIAS Sud Aviation and Messerschmidt) EC20 EC 120B 1T 1 EC25 EC225 Super Puma 2T 2 EC30 EC 130 B4 Astar (all models SA350 Series) IT 1 EC35 EC 35 2T 1 EC45 EC 145 / Bolkow-Blohm 117 2T 1 VFR 2 IFR EC55 EC 155B 2T 1 MBK7 Bolkow-Blohm 117, EC 145 2T 1 VFR 2 IFR MBH5 MBB 105 (Messerschmidt -Bolkow-Blohm) 2T 1 VFR S313 Alouette II (SE313/3130) 1T 1 S315 Alouette III Model 315 1T 1 S316 Alouette III Model 316/3160 1T 1 S318 Alouette II Model SA318 1T 1 S319 Alouette III Model 319 1T 1 S330 Puma all model SA330) 2T 1VFR 2 IFR S332 Super Puma (all model SA332) 2T 2 S342 Gazelle (all model SA341 and 342) 1T 1 S350 Astar (all model SA350 series) 1T 1 S355 Twin Star (all model SA355 series) 2T 1 S360 Dauphin (all model SA360 series) 1T 1 S365 Dauphin (all model SA365 series) 2T 1 VFR 2 IFR Enstrom EH28 Model F-28 1P 1 EH48 Model 480 1T 1 Hiller Aircraft Division HL11 All model FH-1100 (OH5A series) 1T 1 HL12 All model UH-12 series (H-23 series) 1P 1 HL2T Turbine powered HH12 1T 1 HL36 All model 360 series 1P 1 Kaman Aerospace Corp. HK12 K-1200 1T 1 Kamov KA32 Kamov KA32 2T 1 Mcdonnell-Douglas Helicopters (formerly Hughes) HU30 All model 269/300 series and Schweizer Model 300C 1P 1 HU50 All model 369/500 series 1T 1 HU52 Model 520N 1T 1 HU60 Model 600N 1T 1 EXPL All models MD900 2T 1 Messerschmidt (See Eurocopter) - See Eurocopter - - Mosquito MOZY Mosquito XE 1P 1 Revolution Helicopter M500 Revolution Mini 500 1P 1 Robinson Helicopter Co. RH22 Robinson 22 1P 1 RH44 Robinson Model R44 1P 1 RotorWay ROTO Executive, Scorpion 1P 1 ROTOT JetExec, Exec90 R162F 1T 1Schweizer HU33 Models 269D and 330SP 1T 1 Sikorsky Aircraft Division SK51 All model S-51 series 1P 1 SK55 All model S-55 series 1P 1 SK55T Turbine powered S55 1T 1 SK58 All model S-58 series 1P 1 SK 58T Turbine powered S58 2T 1 SK61 All model S-61 series (HSS-2 CH-124 H-3 Sea King) 2T 2 SK62 All model S-62 series 1T 1 SK64 All model S-64 series 2T 2 SK76 All model S-76 series 2T 1 VFR 2 IFR SK92 All model S-92 series 2T 2 upright Aviation Technologies S52 VAT Hummingbird 1P 1 Example of helicopter design Helicopter Technical Drawing