Physics of HelicoptersPhysics of Helicopters

By: Jais AbecassisBy: Jais Abecassis

Daniel GoodmanDaniel Goodman

Kelsey HopsKelsey Hops

Background Information Background Information

The great Italian Leonardo Da Vinci The great Italian Leonardo Da Vinci had used his inventive mind to had used his inventive mind to create the first drawing of what we create the first drawing of what we know today as the helicopter.know today as the helicopter.

Many of great physicians have Many of great physicians have attempted to develop models of attempted to develop models of the helicopter but they were ALL the helicopter but they were ALL missing 2 essential components: a missing 2 essential components: a true understanding of the nature of true understanding of the nature of lift as well as an adequate engine.lift as well as an adequate engine.

In 1907, two brothers, Jaques and In 1907, two brothers, Jaques and Louis Breguet, with the help of Louis Breguet, with the help of professor Charles Richer created professor Charles Richer created the gyroplane no.1 which hovered the gyroplane no.1 which hovered for a few seconds.for a few seconds.

Since then helicopters have Since then helicopters have evolved tremendously and are used evolved tremendously and are used for many different purposes today.for many different purposes today.

Leonardo Da Vinci’s first sketch of a Leonardo Da Vinci’s first sketch of a helicopterhelicopter

Helicopters 101Helicopters 101

In order for an aircraft to take off, it needs to create lift. Lift is necessary because it a force In order for an aircraft to take off, it needs to create lift. Lift is necessary because it a force that allows the aircraft to overcome its weight which is created by gravity. that allows the aircraft to overcome its weight which is created by gravity.

These two forces oppose each other hence, the heavier the helicopter, the more lift is These two forces oppose each other hence, the heavier the helicopter, the more lift is required.required.

Lift is the force which allows the aircraft to move vertically, for the helicopter to move forward Lift is the force which allows the aircraft to move vertically, for the helicopter to move forward and backward thrust and drag is required.and backward thrust and drag is required.

Thrust is the force which pushes the aircraft forward. Continuous thrust is required due to wind Thrust is the force which pushes the aircraft forward. Continuous thrust is required due to wind resistance also known as drag.resistance also known as drag.

LiftLift

ThrustThrustDragDrag

WeightWeight

Same principle for helicoptersSame principle for helicopters

What makes up a helicopter?What makes up a helicopter?

A helicopter consists of many different and important parts. The blades at the top of the A helicopter consists of many different and important parts. The blades at the top of the helicopter are, as one, called the main rotor. The main rotor could range anywhere from 2 to 8 helicopter are, as one, called the main rotor. The main rotor could range anywhere from 2 to 8 bladesblades

The tail rotor is located at the rear of the helicopter. Tail rotors could range from 2-4 blades. The tail rotor is located at the rear of the helicopter. Tail rotors could range from 2-4 blades. Recently, helicopters were developed which do not have a tail rotor. These special helicopters Recently, helicopters were developed which do not have a tail rotor. These special helicopters are called NOTAR helicopters (NO TAil Rotor).are called NOTAR helicopters (NO TAil Rotor).

NOTAR HelicopterNOTAR Helicopter

Inside the cockpit...Inside the cockpit...

The The collective collective changeschanges the the angle of the blades. This is angle of the blades. This is necessary to control to necessary to control to aircraft. It is located on the aircraft. It is located on the left side of the pilot and is left side of the pilot and is held by the left hand.held by the left hand.

On the On the collectivecollective is the is the throttle. It twists in a throttle. It twists in a clockwise direction.clockwise direction.

The The cycliccyclic is the most is the most important part of the important part of the helicopter. This controls the helicopter. This controls the rotor disk. (ALL the blades on rotor disk. (ALL the blades on the aircraft are connected to the aircraft are connected to the rotor disk.) It is located in the rotor disk.) It is located in front of the pilot.front of the pilot.

The The anti-torque pedalsanti-torque pedals are are located at the feet of the pilot.located at the feet of the pilot.

How does a helicopter work?How does a helicopter work?As the blades turn in a counter clockwise direction, air flows underneath them, similar to air flowing beneath the wings of a plane.

When the blades are spinning, there is an increase in pressure below the blades, and a decrease of pressure above it.

As the rotor blades turn, a relative wind is created in the opposite direction of the rotor system.

When more lift is wanted to take off, the collective is pulled upward increasing the angle at which each individual blade spins at.

How a helicopter works continued...How a helicopter works continued...

At the same time as the At the same time as the blades are turning, torque is blades are turning, torque is created which cause the created which cause the cabin to turn in a clockwise cabin to turn in a clockwise directiondirection

The tail rotor produces thrust The tail rotor produces thrust to oppose the torque created to oppose the torque created and it also helps prevent the and it also helps prevent the helicopter from turning in the helicopter from turning in the opposite direction as the opposite direction as the main rotor. The anti-torque main rotor. The anti-torque pedals are used to control pedals are used to control the thrust of the tail rotor.the thrust of the tail rotor.

The most torque is generated The most torque is generated when the helicopter is when the helicopter is hovering or when its hovering or when its traveling at a high speed and traveling at a high speed and this is when the anti-torque this is when the anti-torque medals are mostly used.medals are mostly used.

The motor The motor blades spin blades spin clockwiseclockwise

The fuselage tends to spin The fuselage tends to spin anti-clockwiseanti-clockwise

QuickTime™ and a decompressor

are needed to see this picture.

How a helicopter works continued...How a helicopter works continued...

Unlike a plane, a helicopter has the ability to move 360 degrees. Unlike a plane, a helicopter has the ability to move 360 degrees.

Once the helicopter is in the air, it has the ability to “aim” its thrust. According to Newton’s Once the helicopter is in the air, it has the ability to “aim” its thrust. According to Newton’s Third Law, “every action as an equal and opposite reaction. Third Law, “every action as an equal and opposite reaction.

He does this using the cyclic. The pilot points the cyclic in his intended direction, by doing so, He does this using the cyclic. The pilot points the cyclic in his intended direction, by doing so, he changes the angle of the rotator disk. The disk points the thrust in the opposite direction of he changes the angle of the rotator disk. The disk points the thrust in the opposite direction of where you want to go. This action causes a reaction which pushes the helicopter in the desired where you want to go. This action causes a reaction which pushes the helicopter in the desired direction. direction.

Types of dragTypes of drag

There are 3 types of drag that a pilot could experience during flightThere are 3 types of drag that a pilot could experience during flight

The first type is called The first type is called Profile Drag Profile Drag

This is the frictional resistance of the blades passing through the air. This is the frictional resistance of the blades passing through the air. The angle of attack (the angle at which the blades are changed to create lift) does not significantly affect this type of drag.

The second type is called The second type is called Induce DragInduce Drag

This type of drag is created when the extra air at the end of the blades form a vertex This type of drag is created when the extra air at the end of the blades form a vertex causing a slight decrease in pressure below the blade which therefore decreases lift.causing a slight decrease in pressure below the blade which therefore decreases lift.

The final type of drag is called The final type of drag is called Parasite DragParasite Drag

This drag is formed when any object is affecting the aerodynamics of the aircraft. This This drag is formed when any object is affecting the aerodynamics of the aircraft. This occurs all the time. When the windshield is dirty there is a slight amount of parasite occurs all the time. When the windshield is dirty there is a slight amount of parasite drag. As well as when rescue helicopters carry water under it, there is more resistance drag. As well as when rescue helicopters carry water under it, there is more resistance hence more parasite drag.hence more parasite drag.

ConclusionConclusionThroughout our project, we’ve learned the basics of helicopter flight. We have learned how lift is created through the blades, how a dusty exterior can create more drag, and many other interesting points. This project really opened our eyes to what it takes to fly a helicopter, although we only covered the basics of flight, where as there are so many other things to take into consideration.