Loss of Tail Rotor Effectiveness (LTE) is a critical low-speed aerodynamic flight characteristic that can occur in certain wind conditions and maneuvers. LTE occurs when the tail rotor is unable to counteract the main rotor's torque, causing the helicopter to yaw uncontrollably. The document outlines four relative wind regions and flight situations that can lead to LTE, as well as techniques for reducing the onset of LTE and recommended recovery procedures.
1) Loss of tail rotor effectiveness (LTE) can occur in single-rotor helicopters at low altitudes and airspeeds below 30 knots due to certain wind directions disrupting the tail rotor's ability to maintain directional control.
2) Three key wind regions - weathercock stability, tail rotor vortex ring state, and main rotor disc vortex interference - can each cause or combine to cause LTE by changing the tail rotor's angle of attack and thrust.
3) If an uncommanded right yaw occurs due to LTE, pilots should apply full left pedal, push the cyclic forward to gain airspeed, and potentially reduce power/collective to arrest the yaw rate while avoiding rapid control inputs
This document provides an introduction to helicopter flight dynamics, including:
- Definitions of helicopter flight dynamics, characteristics of helicopter flight, and scopes and methodologies used.
- Coordinate systems used including gravity, body, wind, and hub axes.
- Transformations between different coordinate systems.
- Angles used to describe helicopter orientation and motion, including Euler angles.
- Prerequisites, syllabus, and references for further study are also included.
This document summarizes the key developments in helicopter technology from Leonardo Da Vinci's early sketches of an aerial screw in 1480 to modern innovations. Some of the major developments discussed include Paul Cornu building the first working helicopter in 1907, the gyroplane laboratoire setting new records for height, distance, and duration in 1933, and the invention of the turboshaft engine in 1951 which provided more power and allowed helicopters to be bigger and faster. The document also explains the aerodynamic principles that allow helicopters to fly using rotating airfoils and discusses how control mechanisms like the swashplate allow pilots to steer helicopters.
The document provides a brief history of helicopters from Da Vinci's early designs to the first transatlantic helicopter crossing in 1952. It then defines and explains key helicopter concepts such as the main rotor, tail rotor, torque, collective, cyclic, NOTAR system, tiltrotor design, and tandem rotor configuration. Key terms like advancing blade, retreating blade, blade stall, translation, hover, and yaw are also defined.
CARE is a charity that provides aviation education courses in Hong Kong. It has partnered with youth organizations since 2009 and established a connection with a UK flight school in 2015. Students who complete CARE's program can receive recommendations to participate in the flight school's private pilot program. The document then describes the electronic flight displays on Airbus aircraft, including the primary flight display, navigation display, and their various modes and symbology relating to flight parameters, navigation, weather radar, and the flight management system.
Autorotation is the process by which a helicopter can descend and land without engine power by using the airflow coming up from the ground or air during descent to turn the rotor blades and maintain control. During autorotation, the helicopter trades altitude for the energy required to spin the rotor blades at a speed that provides enough lift to control the aircraft. The pilot lowers the collective to reduce blade drag and tilt the total aerodynamic force vector forward to maintain rotor RPM as the helicopter descends.
Far 23 PROPELLER ENGINE INTERFERENCE DESIGN Paul Raj
The document discusses regulations regarding aircraft airworthiness set by the Federal Aviation Administration (FAA). It outlines standards for maximum takeoff weights, structural integrity, safety systems, and performance metrics that must be met. It also discusses requirements for aircraft engines and propellers, including standards for blade design and pitch control mechanisms.
This document describes aircraft flight control systems. It discusses the primary flight controls of elevators, ailerons, and rudders and how each control affects the aircraft's pitch, roll, and yaw. Secondary flight controls include trim tabs for stabilizing the elevators, ailerons, and rudder. Auxiliary controls are flaps and high-lift devices that increase an aircraft's lift during takeoff and landing. Flaps extend on the trailing edge of wings to increase their camber and reduce stall speed, while leading edge slats and spoilers disrupt airflow over wings.
1) Loss of tail rotor effectiveness (LTE) can occur in single-rotor helicopters at low altitudes and airspeeds below 30 knots due to certain wind directions disrupting the tail rotor's ability to maintain directional control.
2) Three key wind regions - weathercock stability, tail rotor vortex ring state, and main rotor disc vortex interference - can each cause or combine to cause LTE by changing the tail rotor's angle of attack and thrust.
3) If an uncommanded right yaw occurs due to LTE, pilots should apply full left pedal, push the cyclic forward to gain airspeed, and potentially reduce power/collective to arrest the yaw rate while avoiding rapid control inputs
This document provides an introduction to helicopter flight dynamics, including:
- Definitions of helicopter flight dynamics, characteristics of helicopter flight, and scopes and methodologies used.
- Coordinate systems used including gravity, body, wind, and hub axes.
- Transformations between different coordinate systems.
- Angles used to describe helicopter orientation and motion, including Euler angles.
- Prerequisites, syllabus, and references for further study are also included.
This document summarizes the key developments in helicopter technology from Leonardo Da Vinci's early sketches of an aerial screw in 1480 to modern innovations. Some of the major developments discussed include Paul Cornu building the first working helicopter in 1907, the gyroplane laboratoire setting new records for height, distance, and duration in 1933, and the invention of the turboshaft engine in 1951 which provided more power and allowed helicopters to be bigger and faster. The document also explains the aerodynamic principles that allow helicopters to fly using rotating airfoils and discusses how control mechanisms like the swashplate allow pilots to steer helicopters.
The document provides a brief history of helicopters from Da Vinci's early designs to the first transatlantic helicopter crossing in 1952. It then defines and explains key helicopter concepts such as the main rotor, tail rotor, torque, collective, cyclic, NOTAR system, tiltrotor design, and tandem rotor configuration. Key terms like advancing blade, retreating blade, blade stall, translation, hover, and yaw are also defined.
CARE is a charity that provides aviation education courses in Hong Kong. It has partnered with youth organizations since 2009 and established a connection with a UK flight school in 2015. Students who complete CARE's program can receive recommendations to participate in the flight school's private pilot program. The document then describes the electronic flight displays on Airbus aircraft, including the primary flight display, navigation display, and their various modes and symbology relating to flight parameters, navigation, weather radar, and the flight management system.
Autorotation is the process by which a helicopter can descend and land without engine power by using the airflow coming up from the ground or air during descent to turn the rotor blades and maintain control. During autorotation, the helicopter trades altitude for the energy required to spin the rotor blades at a speed that provides enough lift to control the aircraft. The pilot lowers the collective to reduce blade drag and tilt the total aerodynamic force vector forward to maintain rotor RPM as the helicopter descends.
Far 23 PROPELLER ENGINE INTERFERENCE DESIGN Paul Raj
The document discusses regulations regarding aircraft airworthiness set by the Federal Aviation Administration (FAA). It outlines standards for maximum takeoff weights, structural integrity, safety systems, and performance metrics that must be met. It also discusses requirements for aircraft engines and propellers, including standards for blade design and pitch control mechanisms.
This document describes aircraft flight control systems. It discusses the primary flight controls of elevators, ailerons, and rudders and how each control affects the aircraft's pitch, roll, and yaw. Secondary flight controls include trim tabs for stabilizing the elevators, ailerons, and rudder. Auxiliary controls are flaps and high-lift devices that increase an aircraft's lift during takeoff and landing. Flaps extend on the trailing edge of wings to increase their camber and reduce stall speed, while leading edge slats and spoilers disrupt airflow over wings.
This document provides a description and overview of the autopilot and yaw damper system for a B727-200 aircraft. It describes the major components, including the Sperry SP-50 MB V Automatic Flight Control System, which provides three-axis flight stabilization and automatic approach capability. It details the functions of the yaw, roll, and pitch axes, and describes the components that control and provide inputs to each axis, such as rudder power units, aileron servos, elevator power units, and sensors. The document also notes the locations of components throughout the aircraft.
INTRODUCTION:
While a helicopter is a far more complex machine than an aeroplane, the fundamental principles of flight are the same.
The rotor blades of a helicopter are identical to the wings of an aeroplane –when air is blown over them, lift is produced.
The crucial difference is that the flow of air is produced by rotating the wings – or rotor blades – rather than by moving the whole aircraft.
When the rotor blades start to spin, the air flowing over them produces lift, and this can cause the helicopter to rise into the air.
So, the engine is used to turn the blades, and the turning blades produce the required lift.
The document provides information on the landing gear system of the Boeing 737 NG. It describes the main components and operation of the landing gear including:
- The aircraft has two main landing gears and a single nose gear.
- Hydraulic system A normally controls extension, retraction and nose wheel steering. System B provides alternatives.
- Extension and retraction are controlled by the landing gear lever and occur through hydraulic pressure and mechanical locks.
- Sensors monitor gear position and provide inputs to warning systems.
- Manual extension is possible if system A fails using gear releases.
Pilot judgment involves recognizing and analyzing information about oneself, the aircraft, and the environment to make timely decisions that maximize safety. It is a learned skill that can be improved through education and experience. Most aviation accidents stem from a chain of poor judgments, where one bad decision increases the likelihood of subsequent poor decisions. To avoid this, pilots must break the chain of poor judgment at any point using good decision making. This involves considering alternatives and selecting options that preserve safety over other priorities like time or convenience.
This document provides information about helicopter safety procedures for passengers. It outlines the types of helicopters used, prohibited items, check-in procedures, safety equipment, boarding and disembarking procedures, dangers of helicopters, and what to do during flight emergencies. Key safety equipment mentioned includes emergency breathing systems, life jackets, harnesses, and hearing protection. Passengers are instructed to follow crew instructions carefully and be aware of rotor blades, loose objects, and other hazards.
The document summarizes helicopter flight controllers, including the external forces acting on helicopters, different control manners, and the development of helicopter controllers. It describes the aerodynamic forces on the main rotor, tail rotor, fuselage, horizontal and vertical tails. It then explains the control manners of helicopters with main and tail rotors, twin rotor helicopters, and tilt-rotor aircraft. Finally, it discusses early direct control methods and the progression to modern fly-by-wire and fly-by-light control systems.
The document discusses various aspects of aircraft landing gear systems. It describes the advantages of tricycle gear over tailwheel gear, different gear configurations like bogie gear, the purpose of drag struts and squat switches, methods of retractable gear operation and emergency extension, steering for light and heavy aircraft, factors that influence tire wear and inflation, and landing surface weight ratings.
The document describes the main components of aircraft landing gear systems. It lists 15 main components including struts, links, actuators, and cylinders that perform functions like absorbing shock, maintaining wheel alignment, locking the gear in position, and retracting and extending the landing gear. The document also discusses common landing gear materials like high-strength steel, titanium, and aluminum alloys and potential failure modes from fatigue, stress corrosion, impacts, and other sources.
The document summarizes the basic control systems of an aircraft, including primary, secondary, and auxiliary flight controls. Primary controls include elevators, ailerons, and rudders which control pitch, roll, and yaw respectively. Secondary controls include trim tabs which help balance aircraft forces. Auxiliary controls include flaps, spoilers, and slats which provide additional lift, especially at lower speeds. The document describes the purpose and function of each control surface.
This is the Highly Detailed factory service repair manual for the2004 HONDA CRV, this Service Manual has detailed illustrations as well as step by step instructions,It is 100 percents complete and intact. they are specifically written for the do-it-yourself-er as well as the experienced mechanic.2004 HONDA CRV Service Repair Workshop Manual provides step-by-step instructions based on the complete dis-assembly of the machine. It is this level of detail, along with hundreds of photos and illustrations, that guide the reader through each service and repair procedure. Complete download comes in pdf format which can work under all PC based windows operating system and Mac also, All pages are printable. Using this repair manual is an inexpensive way to keep your vehicle working properly.
Service Repair Manual Covers:
General Information
Specifications
Maintenance
Engine Electrical
Engine
Cooling
Fuel and Emissions
Transaxle
Steering
Suspension
Brakes
Body
Heating, Ventilation and Air Conditioning
Body Electrical
Restrains
File Format: PDF
Compatible: All Versions of Windows & Mac
Language: English
Requirements: Adobe PDF Reader
NO waiting, Buy from responsible seller and get INSTANT DOWNLOAD, Without wasting your hard-owned money on uncertainty or surprise! All pages are is great to have2004 HONDA CRV Service Repair Workshop Manual.
Looking for some other Service Repair Manual,please check:
https://www.aservicemanualpdf.com/
Thanks for visiting!
8
This document provides an overview of advanced flight controls. It begins by outlining four learning objectives related to describing aerodynamic forces, standard flight controls, secondary effects of controls, and alternative control types. It then defines the four basic aerodynamic forces and three axes of aircraft movement. Standard flight controls like ailerons, elevators, and rudders are illustrated. Secondary effects like adverse yaw are described. Finally, alternative control types such as stabilators, tailerons, spoilerons, and ruddervators are defined and their advantages and disadvantages discussed.
This document discusses how planes fly through aerodynamic forces. It explains that thrust produced by engines propels the plane forward, while lift forces generated by the wings when air passes over and under them allow the plane to gain altitude and remain airborne. The document also covers the different axes of motion for a plane and how control surfaces like elevators, rudders, and ailerons allow pilots to control pitching, yawing, and rolling movements. Finally, it provides specifications for the Airbus A380 and Dassault Rafale to illustrate different types of modern aircraft.
The document provides an overview of basic aerodynamics and principles of helicopter flight. It discusses the four forces acting on a helicopter - lift, weight, thrust, and drag. It explains airfoils, including their camber, angle of attack, and pitch angle. It describes how the venturi effect and Bernoulli's principle relate to lift and drag on an airfoil. The key factors that determine lift are explained as the coefficient of lift, air density, airfoil velocity, and surface area in the lift equation.
The document provides an overview of changes between the new AC 43.13-1B advisory circular and the old AC 43.13-1A version. Key changes include expanded sections on welding, nondestructive testing, corrosion protection, hardware, and electrical systems. Additional topics such as fiberglass/plastics repair and avionics were also added. The new version aims to provide more detailed guidance and safety information to help aircraft technicians in their inspection and repair tasks.
The document discusses rotor flapping motion in helicopters. It covers three key topics:
1) The equation of rotor flapping motion and three origins of flapping motion: forward speed, controls, and angular velocity.
2) Factors that affect flapping motion, including hinge offset, hub moments, and whether the rotor is hinged or hingeless.
3) How the pilot controls the helicopter through inducing flapping motion by changing blade pitch via the controls.
This document provides a summary of instrument panels and systems on a Boeing 727-200 aircraft. It describes the layout of the main instrument panels used by pilots and crew. It also provides details on the types of instrument indicators and how they are mounted. The document then summarizes several key aircraft systems including the flight data recorder, clocks, and aural warning system. It explains the components and functions of these systems.
Nomenclature and classification of controls in an airplane (slide # 3-4).
Which are the aerodynamic forces acting on airplane (slide # 5).
Working principle of an airplane (slide # 6).
How an airplane flies (basic motions of an airplane) (slide # 7).
How controls play their roles in these motions (slide # 8-22).
Simulate a flight in Cessna Skyhawk (slide # 23-28).
References and Questions & answers (slide # 30).
1. The document discusses regulations regarding airworthiness review certificates (ARCs) in India.
2. It outlines who can issue ARCs for different types of aircraft, including those used in commercial air transport, non-commercial aircraft, and aircraft of different weights.
3. The key requirements for an airworthiness review to be performed in order to issue an ARC are described, including inspecting the aircraft and records to ensure continued airworthiness.
This document summarizes a seminar presentation on the effect of bird strikes on jet engines. It defines bird strikes, describes how they can damage engines, and lists factors that influence damage severity. Small birds may not damage engines but large strikes can break blades and damage rotors. Prevention methods discussed include onboard detection systems, habitat modification at airports, and regulations for ingestion testing. Numerical models can simulate bird impacts using Lagrangian, ALE, or SPH approaches to model bird material behavior under high velocities.
New holland t7060 tractor service repair manualfujdjffjkskemme
The document is a service manual that provides technical specifications and repair instructions for the primary hydraulic power system on tractor models T7030, T7040, T7050, and T7060. It includes details on components like the variable displacement pump, charge pump, power beyond system, and hydraulic schematics. The manual also provides instructions for testing components and replacing parts if needed.
Key Takeaways
Helicopters take advantage of free stream flow along a rotor blade to produce lift and thrust.
The blades on a helicopter’s main rotor have an angle of attack, which plays the same role as a wing in an airplane.
The tail rotor is responsible for stabilizing the helicopter so that it does not rotate under torque from the rotor.
Helicopter aerodynamics
The correspondence between helicopter aerodynamics and airplane aerodynamics spans beyond the need for free stream flow across an airfoil. Helicopter aerodynamics involves the same forces that arise in airplane aerodynamics, but these forces arise in different ways due to fluid flow across the aircraft. In this article, we’ll look more at the basics of how a helicopter generates its lift and thrust with only a single main rotor as well as how the design of the rotor influences helicopter aerodynamics.
Overview of Helicopter Aerodynamics
All helicopters have two rotors that generate the lift and thrust required to steer the aircraft as well as stabilize the helicopter against unwanted rotation. Attached to the engine are the main rotor blades, which rotate against the surrounding air to produce a flow along each rotor blade. Technically, a helicopter’s rotor blades are a set of airfoils, and they can produce lift in the same way as the wing on a fixed-wing aircraft.
A helicopter’s main rotor interacts with the surrounding airflow to manipulate the main aerodynamic forces in the following manner:
Lift: As the rotor blade spins, airflow across the bottom of the rotor blade produces lift to counteract gravity.
Gravity: Obviously a helicopter does not manipulate gravity, but by exerting just enough lift to counteract gravity, the helicopter can hover at a fixed altitude.
Thrust: Unlike fixed-wing aircraft or jets, thrust is not produced by the engine directly. Instead, the rotor is tilted, which orients the lift vector away from the vertical direction.
Drag: As the helicopter moves, airflow across the body creates drag due to the formation of a boundary layer.
It should be clear as to the function of the main rotor: to provide lift and thrust, depending on the relative orientation of the rotor blades and the body. We can now dig a bit deeper into the function provided by each of these elements in helicopter aerodynamics.
Angle of Attack and Tilt on the Rotor Blades
The role of the rotor is two-fold: it converts lift into thrust and it needs to generate lift. The former is accomplished by tilting the rotor using the cyclic pitch control while the latter is determined by the angle of attack of the rotor blades and the length of each rotor blade. Larger blades, faster rotation, and an appropriate angle of attack can produce maximal lift on the helicopter during flight.
During flight, the oncoming free air stream will imbalance the lift provided by the rotor, which will create a rolling motion. This is balanced by designing the rotor to have flapping blades, meaning the blades can natur
The document discusses different types of wind turbines, including their components and how they work. It covers vertical axis and horizontal axis turbines, comparing their advantages and disadvantages. It also discusses factors that impact turbine performance like airfoil design, blade composition, number of blades, drive trains, controls, towers, and more. The goal is to introduce students to the science of wind power through hands-on activities.
This document provides a description and overview of the autopilot and yaw damper system for a B727-200 aircraft. It describes the major components, including the Sperry SP-50 MB V Automatic Flight Control System, which provides three-axis flight stabilization and automatic approach capability. It details the functions of the yaw, roll, and pitch axes, and describes the components that control and provide inputs to each axis, such as rudder power units, aileron servos, elevator power units, and sensors. The document also notes the locations of components throughout the aircraft.
INTRODUCTION:
While a helicopter is a far more complex machine than an aeroplane, the fundamental principles of flight are the same.
The rotor blades of a helicopter are identical to the wings of an aeroplane –when air is blown over them, lift is produced.
The crucial difference is that the flow of air is produced by rotating the wings – or rotor blades – rather than by moving the whole aircraft.
When the rotor blades start to spin, the air flowing over them produces lift, and this can cause the helicopter to rise into the air.
So, the engine is used to turn the blades, and the turning blades produce the required lift.
The document provides information on the landing gear system of the Boeing 737 NG. It describes the main components and operation of the landing gear including:
- The aircraft has two main landing gears and a single nose gear.
- Hydraulic system A normally controls extension, retraction and nose wheel steering. System B provides alternatives.
- Extension and retraction are controlled by the landing gear lever and occur through hydraulic pressure and mechanical locks.
- Sensors monitor gear position and provide inputs to warning systems.
- Manual extension is possible if system A fails using gear releases.
Pilot judgment involves recognizing and analyzing information about oneself, the aircraft, and the environment to make timely decisions that maximize safety. It is a learned skill that can be improved through education and experience. Most aviation accidents stem from a chain of poor judgments, where one bad decision increases the likelihood of subsequent poor decisions. To avoid this, pilots must break the chain of poor judgment at any point using good decision making. This involves considering alternatives and selecting options that preserve safety over other priorities like time or convenience.
This document provides information about helicopter safety procedures for passengers. It outlines the types of helicopters used, prohibited items, check-in procedures, safety equipment, boarding and disembarking procedures, dangers of helicopters, and what to do during flight emergencies. Key safety equipment mentioned includes emergency breathing systems, life jackets, harnesses, and hearing protection. Passengers are instructed to follow crew instructions carefully and be aware of rotor blades, loose objects, and other hazards.
The document summarizes helicopter flight controllers, including the external forces acting on helicopters, different control manners, and the development of helicopter controllers. It describes the aerodynamic forces on the main rotor, tail rotor, fuselage, horizontal and vertical tails. It then explains the control manners of helicopters with main and tail rotors, twin rotor helicopters, and tilt-rotor aircraft. Finally, it discusses early direct control methods and the progression to modern fly-by-wire and fly-by-light control systems.
The document discusses various aspects of aircraft landing gear systems. It describes the advantages of tricycle gear over tailwheel gear, different gear configurations like bogie gear, the purpose of drag struts and squat switches, methods of retractable gear operation and emergency extension, steering for light and heavy aircraft, factors that influence tire wear and inflation, and landing surface weight ratings.
The document describes the main components of aircraft landing gear systems. It lists 15 main components including struts, links, actuators, and cylinders that perform functions like absorbing shock, maintaining wheel alignment, locking the gear in position, and retracting and extending the landing gear. The document also discusses common landing gear materials like high-strength steel, titanium, and aluminum alloys and potential failure modes from fatigue, stress corrosion, impacts, and other sources.
The document summarizes the basic control systems of an aircraft, including primary, secondary, and auxiliary flight controls. Primary controls include elevators, ailerons, and rudders which control pitch, roll, and yaw respectively. Secondary controls include trim tabs which help balance aircraft forces. Auxiliary controls include flaps, spoilers, and slats which provide additional lift, especially at lower speeds. The document describes the purpose and function of each control surface.
This is the Highly Detailed factory service repair manual for the2004 HONDA CRV, this Service Manual has detailed illustrations as well as step by step instructions,It is 100 percents complete and intact. they are specifically written for the do-it-yourself-er as well as the experienced mechanic.2004 HONDA CRV Service Repair Workshop Manual provides step-by-step instructions based on the complete dis-assembly of the machine. It is this level of detail, along with hundreds of photos and illustrations, that guide the reader through each service and repair procedure. Complete download comes in pdf format which can work under all PC based windows operating system and Mac also, All pages are printable. Using this repair manual is an inexpensive way to keep your vehicle working properly.
Service Repair Manual Covers:
General Information
Specifications
Maintenance
Engine Electrical
Engine
Cooling
Fuel and Emissions
Transaxle
Steering
Suspension
Brakes
Body
Heating, Ventilation and Air Conditioning
Body Electrical
Restrains
File Format: PDF
Compatible: All Versions of Windows & Mac
Language: English
Requirements: Adobe PDF Reader
NO waiting, Buy from responsible seller and get INSTANT DOWNLOAD, Without wasting your hard-owned money on uncertainty or surprise! All pages are is great to have2004 HONDA CRV Service Repair Workshop Manual.
Looking for some other Service Repair Manual,please check:
https://www.aservicemanualpdf.com/
Thanks for visiting!
8
This document provides an overview of advanced flight controls. It begins by outlining four learning objectives related to describing aerodynamic forces, standard flight controls, secondary effects of controls, and alternative control types. It then defines the four basic aerodynamic forces and three axes of aircraft movement. Standard flight controls like ailerons, elevators, and rudders are illustrated. Secondary effects like adverse yaw are described. Finally, alternative control types such as stabilators, tailerons, spoilerons, and ruddervators are defined and their advantages and disadvantages discussed.
This document discusses how planes fly through aerodynamic forces. It explains that thrust produced by engines propels the plane forward, while lift forces generated by the wings when air passes over and under them allow the plane to gain altitude and remain airborne. The document also covers the different axes of motion for a plane and how control surfaces like elevators, rudders, and ailerons allow pilots to control pitching, yawing, and rolling movements. Finally, it provides specifications for the Airbus A380 and Dassault Rafale to illustrate different types of modern aircraft.
The document provides an overview of basic aerodynamics and principles of helicopter flight. It discusses the four forces acting on a helicopter - lift, weight, thrust, and drag. It explains airfoils, including their camber, angle of attack, and pitch angle. It describes how the venturi effect and Bernoulli's principle relate to lift and drag on an airfoil. The key factors that determine lift are explained as the coefficient of lift, air density, airfoil velocity, and surface area in the lift equation.
The document provides an overview of changes between the new AC 43.13-1B advisory circular and the old AC 43.13-1A version. Key changes include expanded sections on welding, nondestructive testing, corrosion protection, hardware, and electrical systems. Additional topics such as fiberglass/plastics repair and avionics were also added. The new version aims to provide more detailed guidance and safety information to help aircraft technicians in their inspection and repair tasks.
The document discusses rotor flapping motion in helicopters. It covers three key topics:
1) The equation of rotor flapping motion and three origins of flapping motion: forward speed, controls, and angular velocity.
2) Factors that affect flapping motion, including hinge offset, hub moments, and whether the rotor is hinged or hingeless.
3) How the pilot controls the helicopter through inducing flapping motion by changing blade pitch via the controls.
This document provides a summary of instrument panels and systems on a Boeing 727-200 aircraft. It describes the layout of the main instrument panels used by pilots and crew. It also provides details on the types of instrument indicators and how they are mounted. The document then summarizes several key aircraft systems including the flight data recorder, clocks, and aural warning system. It explains the components and functions of these systems.
Nomenclature and classification of controls in an airplane (slide # 3-4).
Which are the aerodynamic forces acting on airplane (slide # 5).
Working principle of an airplane (slide # 6).
How an airplane flies (basic motions of an airplane) (slide # 7).
How controls play their roles in these motions (slide # 8-22).
Simulate a flight in Cessna Skyhawk (slide # 23-28).
References and Questions & answers (slide # 30).
1. The document discusses regulations regarding airworthiness review certificates (ARCs) in India.
2. It outlines who can issue ARCs for different types of aircraft, including those used in commercial air transport, non-commercial aircraft, and aircraft of different weights.
3. The key requirements for an airworthiness review to be performed in order to issue an ARC are described, including inspecting the aircraft and records to ensure continued airworthiness.
This document summarizes a seminar presentation on the effect of bird strikes on jet engines. It defines bird strikes, describes how they can damage engines, and lists factors that influence damage severity. Small birds may not damage engines but large strikes can break blades and damage rotors. Prevention methods discussed include onboard detection systems, habitat modification at airports, and regulations for ingestion testing. Numerical models can simulate bird impacts using Lagrangian, ALE, or SPH approaches to model bird material behavior under high velocities.
New holland t7060 tractor service repair manualfujdjffjkskemme
The document is a service manual that provides technical specifications and repair instructions for the primary hydraulic power system on tractor models T7030, T7040, T7050, and T7060. It includes details on components like the variable displacement pump, charge pump, power beyond system, and hydraulic schematics. The manual also provides instructions for testing components and replacing parts if needed.
Key Takeaways
Helicopters take advantage of free stream flow along a rotor blade to produce lift and thrust.
The blades on a helicopter’s main rotor have an angle of attack, which plays the same role as a wing in an airplane.
The tail rotor is responsible for stabilizing the helicopter so that it does not rotate under torque from the rotor.
Helicopter aerodynamics
The correspondence between helicopter aerodynamics and airplane aerodynamics spans beyond the need for free stream flow across an airfoil. Helicopter aerodynamics involves the same forces that arise in airplane aerodynamics, but these forces arise in different ways due to fluid flow across the aircraft. In this article, we’ll look more at the basics of how a helicopter generates its lift and thrust with only a single main rotor as well as how the design of the rotor influences helicopter aerodynamics.
Overview of Helicopter Aerodynamics
All helicopters have two rotors that generate the lift and thrust required to steer the aircraft as well as stabilize the helicopter against unwanted rotation. Attached to the engine are the main rotor blades, which rotate against the surrounding air to produce a flow along each rotor blade. Technically, a helicopter’s rotor blades are a set of airfoils, and they can produce lift in the same way as the wing on a fixed-wing aircraft.
A helicopter’s main rotor interacts with the surrounding airflow to manipulate the main aerodynamic forces in the following manner:
Lift: As the rotor blade spins, airflow across the bottom of the rotor blade produces lift to counteract gravity.
Gravity: Obviously a helicopter does not manipulate gravity, but by exerting just enough lift to counteract gravity, the helicopter can hover at a fixed altitude.
Thrust: Unlike fixed-wing aircraft or jets, thrust is not produced by the engine directly. Instead, the rotor is tilted, which orients the lift vector away from the vertical direction.
Drag: As the helicopter moves, airflow across the body creates drag due to the formation of a boundary layer.
It should be clear as to the function of the main rotor: to provide lift and thrust, depending on the relative orientation of the rotor blades and the body. We can now dig a bit deeper into the function provided by each of these elements in helicopter aerodynamics.
Angle of Attack and Tilt on the Rotor Blades
The role of the rotor is two-fold: it converts lift into thrust and it needs to generate lift. The former is accomplished by tilting the rotor using the cyclic pitch control while the latter is determined by the angle of attack of the rotor blades and the length of each rotor blade. Larger blades, faster rotation, and an appropriate angle of attack can produce maximal lift on the helicopter during flight.
During flight, the oncoming free air stream will imbalance the lift provided by the rotor, which will create a rolling motion. This is balanced by designing the rotor to have flapping blades, meaning the blades can natur
The document discusses different types of wind turbines, including their components and how they work. It covers vertical axis and horizontal axis turbines, comparing their advantages and disadvantages. It also discusses factors that impact turbine performance like airfoil design, blade composition, number of blades, drive trains, controls, towers, and more. The goal is to introduce students to the science of wind power through hands-on activities.
This document summarizes various flight concepts and controls for helicopters. It describes translational lift that occurs at low forward speeds. It also discusses autorotations that allow helicopters to land safely in an engine failure, as well as retreating blade stall that can occur at high speeds. It provides details on the cyclic, collective, and pedal controls and how they affect the rotor system to control the helicopter in different axes of flight.
The document discusses the major flight controls of a helicopter - collective pitch control, cyclic pitch control, and antitorque pedals. The collective pitch control adjusts the pitch of all main rotor blades simultaneously to control altitude. The cyclic pitch control tilts the main rotor disk to control horizontal movement. The antitorque pedals control the pitch of the tail rotor blades to counteract torque from the main rotor. Throttle or a governor system maintains a constant main rotor RPM as collective pitch is adjusted.
Wind Turbine Generator (WTG) Yawing And Furling Mechanismsmareenotmarie
Wind turbines need mechanisms to yaw into the wind and furl or stall blades to regulate speed. Yawing mechanisms have included tail vanes, fantails, and electronic drives. Furling mechanisms include horizontal and vertical furling to reduce rotor area, coning, variable geometry, and blade pitching. Passive stall and mechanical brakes provide overspeed protection. Small turbines often use tail vanes and passive stall while large turbines employ active yaw drives, variable pitch control, and mechanical brakes.
This document summarizes different aspects of wind turbines. It discusses how wind power is calculated based on air density, swept area of the turbine, and wind speed. It describes the main types of wind turbines according to power output and design, including horizontal axis and vertical axis turbines. It also summarizes different blade configurations based on the number of blades and how blade design factors like twist and taper optimize power capture. Additionally, it outlines considerations for siting wind turbines and control mechanisms used in turbines of different sizes to regulate power in high winds.
Autorotation is an emergency procedure where the engine is disengaged from the main rotor to allow the rotor blades to continue turning via the upward airflow. During autorotation, the pilot lowers the collective to reduce lift and drag, causing the helicopter to descend and maintain airflow and rpm. Kinetic and potential energy are used to arrest the descent rate and ensure a soft landing. Autorotation procedures and airspeeds vary between helicopter models and are outlined in their manuals.
Wind energy comes from the uneven heating of the Earth's surface by the sun, which causes atmospheric pressure differences and wind. There are two main types of wind turbines: horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs). HAWTs generally have higher efficiency while VAWTs have some advantages like not requiring yaw mechanisms. Key components of a wind turbine include the blades, hub, main shaft, gearbox, generator, and tower. Blades are typically made of composite materials and have airfoil cross-sections to generate lift from wind. The presentation analyzed factors affecting wind turbine power output and provided comparisons of different turbine designs. Nepal has potential for wind power development based on data from weather stations
Aerodynamics of a_rotary_wing_type_aircraftdarshakb
This document provides an overview of basic aerodynamic concepts related to rotary wing aircraft, including definitions of key rotorcraft components and terminology. It describes principles such as lift, drag, torque, dissymmetry of lift, and retreating blade stall. Key concepts covered include how rotor blades generate lift via angle of attack and airspeed, how flapping helps compensate for differences in advancing and retreating blade lift, and factors that influence helicopter performance such as ground effect and density altitude.
The document provides information about the flight control systems on the Boeing 737 NG, including:
- The primary flight controls (ailerons, elevators, rudder) are powered by redundant hydraulic systems and can operate manually if needed.
- Secondary flight controls like flaps and slats are powered by hydraulic system B or have emergency electric operation.
- The document then describes the various flight control components in more detail, including ailerons, spoilers, elevators, stabilizer, and related switches.
Vibrations in helicopters can come from many moving parts and cause wear, damage, and discomfort. There are different types of vibrations including low frequency vibrations from the main rotor that can be felt as beats, and medium frequency vibrations that may come from the tail rotor or accessories. Vibrations are measured electronically or by feel and must be corrected to minimize negative impacts. Correcting vibrations involves static or dynamic balancing procedures to fix out of balance or out of track issues with the main or tail rotors.
There are three main types of helicopter rotors: single rotor, dual rotor, and tilt rotor. Single rotor helicopters are the most common but have limited weight capacity. Dual rotor helicopters like the Chinook have counter-rotating rotors for control and lift. Tilt rotor helicopters can hover like a helicopter and fly fast like an airplane. Rotor blades use different mechanisms for control including feathering, flapping, and lead/lag movement. Forces on the rotor like torque and dissymmetry of lift are counteracted through techniques such as tail rotors and adjusting rotor pitch.
WTGs require mechanisms to yaw and furl the rotor to maximize energy capture and protect components from damage. Yawing turns the rotor into the wind as it changes directions using techniques like miller-driven capstans, fantails, tail vanes, and electronic yaw drives. Furling decreases the rotor's frontal area by methods like horizontal and vertical furling, coning, blade pitching, and aerodynamic stall. Small household WTGs commonly use passive tail vane furling while medium-large WTGs employ variable pitch blades, mechanical brakes, and active yaw drives to precisely control rotor orientation and speed. These mechanisms allow WTGs to efficiently operate across changing wind conditions while protecting the system from over
This document discusses various methods for controlling the power output of wind turbines. It begins by explaining that wind turbines are designed to operate most efficiently at typical wind speeds around 15 m/s, and power must be limited at higher wind speeds to prevent damage. Both mechanical and electrical control methods are described, including passive stall regulation, active pitch control, and combinations of the two. The document also covers other control aspects like yaw orientation and safety features to prevent cable twisting.
The document discusses propeller systems and how they generate thrust/lift. It explains that propeller blades work similarly to aircraft wings by generating higher pressure on one side and lower pressure on the other. The angle of attack of the blades can be adjusted to optimize thrust at different speeds. A controllable pitch propeller allows the blade angle to be adjusted in flight for takeoff, cruise, and landing. The helix angle, which is produced by the corkscrew motion of the blade tips, also affects thrust generation.
The document discusses autopilot systems and steering gear controls on ships. It provides details on:
- How autopilots work to automatically steer the ship and reduce workload in heavy weather by learning a ship's handling characteristics.
- The different control modes and settings used on autopilot control units, including proportional, integral, derivative controls and weather compensation settings.
- Limitations of autopilot use in rough conditions, tight spaces, slow speeds, or during maneuvers.
- Procedures for changing between manual and autopilot steering, testing equipment, and emergency steering protocols.
This document discusses wind energy and wind turbines. It begins with definitions of wind and wind energy, explaining that wind is created by differences in atmospheric pressure and wind energy harnesses the kinetic energy of wind to generate electricity. It then describes the key components of wind turbines, including blades, gearboxes, generators, and control systems. The document outlines the basic process of how wind turbines convert kinetic wind energy into electrical energy. It also discusses the types of wind turbines, classes based on output, and some of the largest wind farms currently operating in India.
The document discusses principles of flight for rotary wing aircraft, specifically focusing on propellers. It defines key terms like blade angle and angle of attack. It explains the aerodynamic forces acting on propeller blades, including lift, drag, thrust, and rotational drag. It also discusses how fixed and variable pitch propellers are affected by changes in airspeed, and factors that can cause take-off swings for nose-wheel and tail-wheel aircraft.
1) A helicopter uses rotating wings called blades to fly unlike airplanes which use fixed wings. It can take off and land vertically.
2) The four fundamentals of helicopter flight are straight-and-level flight, turns, climbs, and descents. Forces acting on a helicopter include lift, weight, thrust, and drag. It also experiences unique effects like pendular action, coning, and gyroscopic precession due to its rotating blades.
3) Helicopters can take off, land, and hover vertically. During takeoff, the main rotor tilts forward to generate horizontal thrust to accelerate. Hovering requires enough lift and thrust to equal the helicopter's weight and drag produced by
The document summarizes the basic control systems of an aircraft, including primary, secondary, and auxiliary flight controls. Primary controls include elevators, ailerons, and rudders which control pitch, roll, and yaw respectively. Secondary controls include trim tabs which help balance aircraft forces. Auxiliary controls include flaps, slats, spoilers and other high lift devices which aid in takeoff and landing. The document describes the purpose and function of each control surface and system.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Reimagining Your Library Space: How to Increase the Vibes in Your Library No ...Diana Rendina
Librarians are leading the way in creating future-ready citizens – now we need to update our spaces to match. In this session, attendees will get inspiration for transforming their library spaces. You’ll learn how to survey students and patrons, create a focus group, and use design thinking to brainstorm ideas for your space. We’ll discuss budget friendly ways to change your space as well as how to find funding. No matter where you’re at, you’ll find ideas for reimagining your space in this session.
2. Overview Understanding LTE phenomena Conditions leading to LTE Flight characteristics of LTE Main Rotor Disc Vortex Interference (285° to 315°) Weathercock stability (120° to 240°) Tail Rotor Vortex Ring State (210° to 330°) Loss of translational lift (all azimuths) Other factors Reducing the onset of LTE Recommended recovery techniques
3. Understanding LTE phenomena LTE is a critical, low-speed aerodynamic flight characteristic. LTE is not related to a maintenance malfunction. LTE is not necessarily the result of a control margin deficiency.
4. Understanding LTE phenomena (cont’d) Tail rotor trim thrust: the exact amount of tail rotor thrust required to prevent the helicopter from yawing either left or right. The required tail rotor thrust in actual flight is modified by the effects of the wind Relative wind directions or regions form an LTE conducive environment
5. Conditions leading to LTE Any maneuver which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind There is greater susceptibility for LTE in Right Turns. Correct and timely pilot response to an uncommanded right yaw is critical.
6. Flight characteristics of LTE Tests have identified four relative wind azimuth regions and aircraft characteristics that can, either singularly or in combination, create an LTE conducive environment. These azimuths shift depending on the ambient conditions. These characteristics are present only at airspeeds less than 30 knots and apply to all single rotor helicopters Tail rotor does not stall during this periode
7. Flight characteristics of LTE (cont’d) Tail rotor does not stall during this period. The aircraft characteristics and relative wind azimuth regions are: Main Rotor Disc Vortex Interference (285° to 315°) Weathercock stability (120° to 240°) Tail Rotor Vortex Ring State (210° to 330°) Loss of translational lift (all azimuths)
10. As the main rotor vortex passes the tail rotor, the tail rotor angle of attack is reduced.
11.
12. The helicopter will make a slow uncommanded turn either to the right or left
13. The helicopter can be operated safely in the above relative wind regions if proper attention is given to maintaining control.
14.
15. The net effect of the unsteady flow is an oscillation of tail rotor thrust.
16. LTE can occur when the pilot overcontrols the aircraft.
17.
18. Other factors Factors significantly influencing the severity of the onset of LTE: Gross Weight and Density Altitude. Low Indicated Airspeed. Power Droop.
19. Reducing the onset of LTE Tail rotor rigged correctly Maintain maximum power on rotor rpm When maneuvering between hover and 30 knots: Avoid tailwinds. Avoid out of ground effect (OGE) hover and high power demand situations. Be especially aware of wind direction and velocity when hovering in winds of about 8-12 knots (especially OGE). Be aware when a considerable amount of left pedal is being maintained. Be alert to changing aircraft flight and wind conditions.
20. Recommended recovery technique Apply full left pedal. Simultaneously, move cyclic forward to increase speed. If altitude permits, reduce power. As recovery is effected, adjust controls for normal forward flight. Collective pitch reduction effect. The amount of collective reduction. If the rotation cannot be stopped and ground contact is imminent, an autorotation may be the best course of action.
21. Conclusion Understanding LTE phenomena Conditions leading to LTE Flight characteristics of LTE Main Rotor Disc Vortex Interference (285° to 315°) Weathercock stability (120° to 240°) Tail Rotor Vortex Ring State (210° to 330°) Loss of translational lift (all azimuths) Other factors Reducing the onset of LTE Recommended recovery techniques
Editor's Notes
Loss of Tail Rotor Effectiveness (LTE) is a critical, low-speed aerodynamic flight characteristic which can result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, can result in the loss of aircraft control. LTE is not related to a maintenance malfunction and may occur in varying degrees in all single main rotor helicopters at airspeeds less than 30 knots. LTE is not necessarily the result of a control margin deficiency. The anti-torque control margin established during Federal Aviation Administration (FAA) testing is accurate and has been determined to adequately provide for the approved sideward/ rearward flight velocities plus counteraction of gusts of reasonable magnitudes. This testing is predicated on the assumption that the pilot is knowledgeable of the critical wind azimuth for the helicopter operated and maintains control of the helicopter by not allowing excessive yaw rates to develop
In a no-wind condition, for a given main rotor torque setting, there is an exact amount of tail rotor thrust required to prevent the helicopter from yawing either left or right. This is known as tail rotor trim thrust. In order to maintain a constant heading while hovering, the pilot should maintain tail rotor thrust equal to trim thrust. The environment in which helicopters fly, however, is not controlled. Helicopters are subjected to constantly changing wind direction and velocity. The required tail rotor thrust in actual flight is modified by the effects of the wind. If an uncommanded right yaw occurs in flight, it may be because the wind reduced the tail rotor effective thrust. The wind can also add to the anti-torque system thrust. In this case, the helicopter will react with an uncommanded left yaw. The wind can and will cause anti-torque system thrust variations to occur. Certain relative wind directions are more likely to cause tail rotor thrust variations than others. These relative wind directions or regions form an LTE conducive environment.
Any maneuver which requires the pilot to operate in a high-power, low-airspeed environment with a left crosswind or tailwind creates an environment where unanticipated right yaw may occur. There is greater susceptibility for LTE in Right Turns. This is especially true during flight at low airspeed, since the pilot may not be able to stop rotation. The helicopter will attempt to yaw to the right. Correct and timely pilot response to an uncommanded right yaw is critical. The yaw is usually correctable if additional left pedal is applied immediately. If the response is incorrect or slow, the yaw rate may rapidly increase to a point where recovery is not possible. Computer simulation has shown that if the pilot delays in reversing the pedal control position when proceeding from a left crosswind situation (where a lot of right pedal is required due to the sideslip) to downwind, control would be lost, and the aircraft would rotate more than 360° before stopping. The pilot must anticipate these variations, concentrate on flying the aircraft, and not allow a yaw rate to build. Caution should be exercised when executing right turns under conditions conducive to LTE.
Extensive flight and wind tunnel tests have been conducted by aircraft manufacturers. These tests have identified four relative wind azimuth regions and resultant aircraft characteristics that can, either singularly or in combination, create an LTE conducive environment capable of adversely affecting aircraft controllability. One direct result of these tests is that flight operations in the low speed flight regime dramatically increase the pilot's workload. Although specific wind azimuths are identified for each region, the pilot should be aware that the azimuths shift depending on the ambient conditions. The regions do overlap. The most pronounced thrust variations occur in these overlapping areas. These characteristics are present only at airspeeds less than 30 knots and apply to all single rotor helicopters. Flight test data has verified that the tail rotor does not stall during this period. The aircraft characteristics and relative wind azimuth regions are:
Extensive flight and wind tunnel tests have been conducted by aircraft manufacturers. These tests have identified four relative wind azimuth regions and resultant aircraft characteristics that can, either singularly or in combination, create an LTE conducive environment capable of adversely affecting aircraft controllability. One direct result of these tests is that flight operations in the low speed flight regime dramatically increase the pilot's workload. Although specific wind azimuths are identified for each region, the pilot should be aware that the azimuths shift depending on the ambient conditions. The regions do overlap. The most pronounced thrust variations occur in these overlapping areas. These characteristics are present only at airspeeds less than 30 knots and apply to all single rotor helicopters. Flight test data has verified that the tail rotor does not stall during this period. The aircraft characteristics and relative wind azimuth regions are:
Winds at velocities of about 10 to 30 knots from the left front will cause the main rotor vortex to be blown into the tail rotor by the relative wind. The effect of this main rotor disc vortex is to cause the tail rotor to operate in an extremely turbulent environment. During a right turn, the tail rotor will experience a reduction of thrust as it comes into the area of the main rotor disc vortex. The reduction in tail rotor thrust comes from the air flow changes experienced at the tail rotor as the main rotor disc vortex moves across the tail rotor disc. The effect of this main rotor disc vortex is to increase the angle of attack of the tail rotor blades (increase thrust). The increase in the angle of attack requires the pilot to add right pedal (reduce thrust) to maintain the same rate of turn. As the main rotor vortex passes the tail rotor, the tail rotor angle of attack is reduced. The reduction in the angle of attack causes a reduction in thrust and a right yaw acceleration begins. This acceleration can be surprising, since the pilot was previously adding right pedal to maintain the right turn rate. This thrust reduction will occur suddenly and, if uncorrected, will develop into an uncontrollable rapid rotation about the mast. When operating within this region, the pilot must be aware that the reduction in tail rotor thrust can happen quite suddenly and the pilot must be prepared to react quickly and counter that reduction with additional left pedal input
Tailwinds from 120° to 240°, like left crosswinds, will cause a high pilot workload. The most significant characteristic of tailwinds is that they are a yaw rate accelerator. Winds within this region will attempt to weathervane the nose of the aircraft into the relative wind. This characteristic comes from the fuselage and vertical fin. The helicopter will make a slow uncommanded turn either to the right or left depending upon the exact wind direction unless a resisting pedal input is made. If a yaw rate has been established in either direction, it will be accelerated in the same direction when the relative winds enter the 120° to 240° area unless corrective pedal action is made. If the pilot allows a right yaw rate to develop and the tail of the helicopter moves into this region, the yaw rate can accelerate rapidly. It is imperative that the pilot maintain positive control of the yaw rate and devote full attention to flying the aircraft when operating in a downwind condition. The helicopter can be operated safely in the above relative wind regions if proper attention is given to maintaining control. If the pilot is inattentive for some reason and a right yaw rate is initiated in one of the above relative wind regions, the yaw rate may increase.
Winds within this region will result in the development of the vortex ring state of the tail rotor. As the inflow passes through the tail rotor, it creates a tail rotor thrust to the left. A left crosswind will oppose this tail rotor thrust. This causes the vortex ring state to form, which causes a nonuniform, unsteady flow into the tail rotor. The vortex ring state causes tail rotor thrust variations which result in yaw deviations. The net effect of the unsteady flow is an oscillation of tail rotor thrust. This is why rapid and continuous pedal movements are necessary when hovering in left crosswind. In actuality, the pilot is attempting to compensate for the rapid changes in tail rotor thrust. Maintaining a precise heading in this region is difficult. LTE can occur when the pilot overcontrols the aircraft. The resulting high pedal workload in the tail rotor vortex ring state is well known and helicopters are operated routinely in this region. This characteristic presents no significant problem unless corrective action is delayed. When the thrust being generated is less than the thrust required, the helicopter will yaw to the right. When hovering in left crosswinds, the pilot must concentrate on smooth pedal coordination and not allow an uncontrolled right yaw to develop. If a right yaw rate is allowed to build, the helicopter can rotate into the wind azimuth region where weathercock stability will then accelerate the right turn rate. Pilot workload during vortex ring state will be high. A right yaw rate should not be allowed to increase.
The loss of translational lift results in increased power demand and additional anti-torque requirements. This characteristic is most significant when operating at or near maximum power and is associated with LTE for two reasons. First, if the pilot's attention is diverted as a result of an increasing right yaw rate, the pilot may not recognize that relative headwind is being lost and hence, translational lift is reduced. Second, if the pilot does not maintain airspeed while making a right downwind turn, the aircraft can experience an accelerated right yaw rate as the power demand increases and the aircraft develops a sink rate. Insufficient pilot attention to wind direction and velocity can lead to an unexpected loss of translational lift. When operating at or near maximum power, this increased power demand could result in a decrease in rotor rpm. The pilot must continually consider aircraft heading, ground track, and apparent ground speed, all of which contribute to wind drift and airspeed sensations. Allowing the helicopter to drift over the ground with the wind results in a loss of relative wind speed and a corresponding decrease in the translational lift. Any reduction in the translational lift will result in an increase in power demand and anti-torque requirements.
Gross Weight and Density Altitude. An increase in either of these factors will decrease the power margin between the maximum power available and the power required to hover. The pilot should conduct low-level, low-airspeed maneuvers with minimum weight. Low Indicated Airspeed. At airspeeds below translational lift, the tail rotor is required to produce nearly 100 percent of the directional control. If the required amount of tail rotor thrust is not available for any reason, the aircraft will yaw to the right. Power Droop. A rapid power application may cause a transient power droop to occur. Any decrease in main rotor rpm will cause a corresponding decrease in tail rotor thrust. The pilot must anticipate this and apply additional left pedal to counter the main rotor torque. All power demands should be made as smoothly as possible to minimize the effect of the power droop.
In order to reduce the onset of LTE, the pilot should: Ensure that the tail rotor is rigged in accordance with the maintenance manual. Maintain maximum power-on rotor rpm. If the main rotor rpm is allowed to decrease, the antitorque thrust available is decreased proportionally. When maneuvering between hover and 30 knots: Avoid tailwinds. If loss of translational lift occurs, it will result in an increased high power demand and an additional anti-torque requirement. Avoid out of ground effect (OGE) hover and high power demand situations, such as lowspeed downwind turns. Be especially aware of wind direction and velocity when hovering in winds of about 8-12 knots (especially OGE). There are no strong indicators to the pilot of a reduction of translational lift. A loss of translational lift results in an unexpected high power demand and an increased anti-torque requirement. Be aware that if a considerable amount of left pedal is being maintained, a sufficient amount of left pedal may not be available to counteract an unanticipated right yaw. Be alert to changing aircraft flight and wind conditions which may be experienced when flying along ridge lines and around buildings. Stay vigilant to power and wind conditions
Apply full left pedal. Simultaneously, move cyclic forward to increase speed. If altitude permits, reduce power. As recovery is effected, adjust controls for normal forward flight. Collective pitch reduction will aid in arresting the yaw rate but may cause an increase in the rate of descent. Any large, rapid increase in collective to prevent ground or obstacle contact may further increase the yaw rate and decrease rotor rpm. The amount of collective reduction should be based on the height above obstructions or surface, gross weight of the aircraft, and the existing atmospheric conditions. If the rotation cannot be stopped and ground contact is imminent, an autorotation may be the best course of action. The pilot should maintain full left pedal until rotation stops, then adjust to maintain heading. The various wind directions can cause significantly differing rates of turn for a given pedal position. The most important principle for the pilot to remember is that the tail rotor is not stalled. The corrective action is to apply pedal opposite to the direction of the turn. Avoiding LTE may best be accomplished by pilots being knowledgeable and avoiding conditions which are conducive to LTE. Appropriate and timely response is essential and critical. By maintaining an acute awareness of wind and its effect upon the aircraft, the pilot can significantly reduce LTE exposure.