Aeromodelling

Helicopters are really amazing flying machines. As helicopters fly is what makes them versatile as aircraft and explains why it’s perfectly suited for tasks of military use for fire fighting and search and rescue services.
Helicopters have been around for centuries - well, the principle anyway - but it was Igor Sikorsky, built and flew the first fully controllable and recognizable helicopter, about 70 years old. The modern-day helicopter tour had begun.

Why are so many helicopters
A normal airplane can fly to the front, top, bottom, left and right. A helicopter is all this and has the ability to fly backward, rotate 360 degrees on the spot and float the air, that is to say without directional movement.
Helicopters are limited in their speed, but the incredible agility mentioned above is what makes them so useful in so many situations.Directions can be used in helicopterBefore arriving a helicopter can move and the associated name of control

Control of a helicopter
Helicopters require a different method of control as aircraft and are much more difficult to master, in the early days at least.
A hub assemblyA conventional rotor helicopter has its main rotor of the fuselage consists of 2 or more rotor blades extending from a central rotor head, or hub assembly.
An essential component is the swash plate is located under the head and from a non-revolving restaurant and a revolving disc. This swash plate with the pilots and can stick to tilt in any direction to the cyclical motion that the pilots, or up and down to leverage the collective movement (tilting and up / down movement, of course, together).
But first, to explain how the main rotor blades are moved by the pilot to control the movement of the helicopter, we need to understand pitch.
Each rotor blade has a cross section (wing) similar to an airplane wing, and how the blades rotate through the air, they generate lift in exactly the same way as a wing does. The amount of lift generated is determined by the pitch angle (and speed) of each rotor blade as it moves through the air.
This pitch angle of the knife has two forms of control - collective and cyclic ….

Collective control
The collective control by moving a lever, rises from the cockpit floor to the left of the pilot seat, which in turn raises or lowers the swash plate on the main rotor shaft without tilting technology.
The leverage only moves up and down and relates directly to the desired motion of the helicopter, lifting the lever will lead to the helicopters, while the reduction will cause the helicopter to sink.Since the swash plate rises or falls, it changes the pitch of rotor blades simultaneously and in equal measure.Since all the blades are changing pitch, the change in the lift remains constant during each full rotation of the blades. Therefore, there is no tendency for the helicopter, in any direction other than straight up or down.

Following are the effects of collective control over the swash plate and rotor blades.
The rod begins with the swash plate at the top of the rotor blades - as the record rises or falls, so that all blades are tilted exactly the same way and height.
Of course, real head-rotor systems are much more complicated than this picture shows, but the basics are the same.Effect of the collective control of the swash plate and rotorsAt the end of the collective lever is the throttle, explained further down the page.

Cyclical control
The cyclical checks are carried out by moving the control stick, rises from the cockpit between the pilots stick to its knees, and can run in all directions except the top and bottom.
As the collective control, these cyclical movements stick with the directional movement of helicopters; cyclical moving the stick forward, the helicopter will fly to the front, while the stick again slowed down the helicopter and makes it even fly backward.Moving the stick to the left or right makes the helicopter to roll and turn in those directions.
The cyclic control technology works by tilting the swash plate and increase the pitch angle of a rotor blade to a certain point in the rotation, while the angle decreases when the blade has spun about 180 degrees.
Since the pitch angle changes so that the lift on every blade changes and as a result of the helicopter becomes “unbalanced” and as evidence of which side is the smaller amount of lift.

The following are the effects of cyclical control of the swash plate and rotor blades.
Since the swash plate is tilted, the opposing poles are moving in opposite directions. The position of the rods - and hence the pitch of each blade - differs in a particular point on the rotation, allowing different amounts of lift around the rotor disc.Effect of cyclic control of the swash plate and rotors
To understand the cyclical control Another way is the picture rotor disc (the imaginary circle on the helicopter by the spinning blades) and a flat plate sat at the top of the cyclic stick.
Since the Stick is leaned on in any direction, so that the angle of plate changes very slightly (ignore the entire drive away from the centre). This change corresponds directly to the angle, what is happening to the rotor disc simultaneously, namely the side of the plate, that would be the higher side of the disc rotor generate more lift, and vice versa.

Rotary (Yaw) control
A tail very rotorAt the rear of the helicopter’s tail boom is the tail rotor - a vertically mounted blade very similar to a conventional airplane propeller.
The tail rotor is used to control yaw or rotation, the helicopter (that is the way the nose shows) and to explain this, we must first understand the word torque.
Torque is the force that causes rotation, and a helicopter is by turning the main rotor blades when the blades are spinning then the natural response to focusing on the fuselage of the helicopter to rotate in the opposite direction of the Rotors.Of course, if this torque is not controlled, the helicopter would only spin-round hopeless!
To beat the reaction of the torque, the rear rotor is used and is connected with rods and gears on the main rotor, so that is when the main rotor turns.
Since the tail rotor turns it generates thrust, exactly the same thing as a propeller plane. This sideways thrust prevents the helicopter fuselage of spin attempt against the main rotor, and the pitch angle of the tail rotor blades can be changed by the pilot to control the amount of thrust produced.Controlling helicopter tail rotor of Yaw
The increase in the pitch angle of the tail rotor thrust, which in turn push the helicopter in the same direction as the main rotor blades. Decreasing the pitch angle reduces the amount of thrust, and so the natural force, torque over the lease of the helicopter turn in the opposite direction of the main rotors.
The pilot controls the pitch angle of the tail rotor blades of two pedals at his feet, in exactly the same way as the rowing motion in an airplane.
NOTARY is an alternative method of Yaw control of some helicopter - instead of a tail rotor thrust to produce compressed air is blown out of the tail boom by moving slots.
These slots are peddles by the pilots to push the more slots are open, so that more air, and vice versa.
NOTAR helicopters to respond Yaw Control in exactly the same way as tail rotor models, but have a great advantage Security - tail rotors can be very dangerous during the operation on or near the ground.

Throttle Control
The throttle is a “twist-grip” at the end of the collective leverage and is directly linked to the movement of the lever, so that engine speed is always true to a certain collective attitude.
During normal flying, constant speed (RPM) is maintained and the pilot needs only to the “fine tuning” of the throttle settings, if necessary.
The engine speed and thus main rotor blade speed, can be kept at a constant rate because of the cyclic and collective pitch control of the main rotor blades.
There is a direct correlation between motor performance and Yaw Control - rotate faster main rotor blades produce more torque, so that a greater slope is necessary, the tail rotor blades to generate more thrust.
It is noteworthy that each control is easy to understand and operate, the difficulty in dealing with all 4 controls, where the coordination must be perfect!
A helicopter pilot once told me that flying a helicopter is a bit like a stack cups balancing on your nose - only much more expensive, if you drop it!