Non-Living Things That Fly

Lesson 6

Red Bull Air Racing

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The Obsession!

• Humans have been obsessed with finding a way to master the skies for years!

The Wright brothers were the first to achieve sustainable flight with the invention of the first successful airplane in 1903

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The Obsession!

• Prior to this, other inventors and intellects were successful in creating hot air balloons that drifted through the air and gliders that allowed people to descend slowly from areas of high elevation to low elevation

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The Obsession!

• There is now a wide array of man-made machines that fly including but not limited to:
• airplanes, helicopters, rockets, and hot air balloons.

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The Kitty Hawk

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Airplanes

• Airplanes achieve flight in much of the same way as living things do
• There are three main factors that contribute to the flight of airplanes:
• thrust
• angle of attack
• airfoil wing shape

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Take Off

• When a plane takes off from the ground it must begin by giving itself enough momentum to lift off into the air.

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• The plane gains momentum by thrusting itself in a forward direction using its propellers or jets which are usually attached to the wings.

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Take Off

• The propeller, which is powered by a jet, grabs the air in front of the plane and pushes it backward which in turn drives the body of the plane forward.
• With just thrust, the plane will move forward on its wheels but it will not get off the ground.

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Jet Engine

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Jet Engine

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THE WINGS

The Wings

• In order to lift off the ground the wings of the plane must have an angle of attack
• This means that the front of the wings get tilted slightly upwards to allow the rushing air to catch the bottom part of the wing

Angle of Attack

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The Wings

• At a certain point the angle of attack will begin to work against the airplane achieving flight

Angle of Attack

Just like your paper airplanes

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The Wings

• The airfoil shape of the wing forces the air moving over top of the wing to move faster than the air on the bottom of the wing

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The Wings

• Since Bernoulli’s principle states that faster moving air has a lower pressure than slower moving air the plane begins to get lifted off the ground because the higher pressured air starts to push up against the bottom of the wing

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LOWER

PRESSURE

HIGHER PRESSURE

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The Wings

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Airfoil

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Airfoil

CLIMB:

• As the plane is ascending it will keep this angle of attack until it reaches the desired altitude.
• When the plane is finally at the height it needs to be, it can decrease the angle of attack.

CRUISE:

• The airfoil shape of the wing will continue to maintain balance amongst the downward (gravity) and upward (lift) forces acting on the plane, while the propellers and jets continue pulling the airplane forward through the air

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HELICOPTER

Helicopter

• A helicopter’s flight differs from that of an airplane in that the wings or blades of the helicopter are in constant motion (while the wings of an airplane remain still)

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• Helicopters also use the airfoil shape for their blades to take advantage of Bernoulli’s principle which, as stated earlier, explains that faster moving air has lower air pressure than slower moving air.

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Helicopter

• Helicopters also use the airfoil shape for their blades to take advantage of Bernoulli’s principle
• (faster moving air has lower air pressure than slower moving air)

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Helicopter Blades

• The helicopter’s blades begin to rotate because of the engine that they are attached to.
• Once they begin spinning they cut through the air with an angle of attack that begins pushing air downwards.
• Once the blades begin to move at a fast enough speed they generate enough downward force that eventually lifts the helicopter into the air.

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• Each individual blade can be adjusted to change the angle of attack which will allow the helicopter to either raise itself further into the air, stay hovering in the same place, or descend back down towards the ground.

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Multiple Sets of Blades

• Most helicopters have two sets of spinning blades
• The main ones that are at the top of the helicopter and a secondary set that is usually attached to the tail of the helicopter

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Multiple Sets of Blades

• The purpose of the tail blades is to counteract the spinning motion of the main blades. They allow the helicopter to remain stable and controllable in the air.
• They spin in the opposite direction of the main blades to oppose their massive force and to maintain fine control over the machine.
• If it were not for the tail propellor the body of the helicopter would spin in the opposite direction as the main blades

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Multiple Sets of Blades

• The tail propellers are also responsible for giving the helicopter the thrust it needs to move forward or in reverse through the air.
• The helicopter acts a lot like an insect in order to move forward or backward;
• When moving forward it will tilt its nose down and point its main blades in the direction it wants to go.
• When it goes backward it pulls its nose upward tilting the main blades towards the tail of the machine.

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Main and Rear Blade (Primary and Secondary)

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Tail Blade

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ROCKETS

Rockets

• Unlike airplanes and helicopters which exploit specific properties of air and basic physics concepts, rockets work differently
• Rockets focus their attention on thrust which allows them to be propelled through the air

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Rockets

• In reality, rockets are not truly “flying” they are simply being pushed through the Earth’s atmosphere by propellants which consist of fuel and oxygen.
• The main component that allows a rocket to reach its destination is the amount of thrust that can be produced from the propellants that it uses.

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Rockets

• Rockets are made of light metal and aluminum that provide a sturdy shell to protect the contents from harm but at the same time are light in weight.
• The lighter a rocket is, the easier it will be to propel it into space.
• Propellants are either in solid form or liquid form and sometimes a combination of the two types is used.

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Rocket Weight

• A significant amount of a rocket’s weight is the fuel and fuel chambers that it carries.
• For this reason rockets are made in sections so that as different fuel chambers get used up, they can be dropped back down to Earth to reduce the effect of gravity on the rocket.
• In terms of flying, rockets do not really fly unless they break through Earth’s atmosphere and into space where the weight of the air is significantly less compared to here on Earth. At this point rockets will continue to float in the direction they were propelled until they reach their destination (Newton’s First Law).

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HOT AIR BALLOON

Hot Air Balloon

• Hot air balloons use very basic principles to achieve flight. Knowing that hot air is lighter than cold air is at the very heart of hot air balloon flight.
• Essentially, hot air can float within cool air as long as it is captured within a certain area; hence, the envelope or balloon part of the hot air balloon.

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Hot Air Balloon

• As hot air is shot up into the envelope, the temperature of the air inside the balloon increases and begins to become lighter than the air surrounding it.
• This causes the balloon starts to rise into the air taking anything attached to it with it.

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Going Down!

• In order to descend there is a section at the very top of the balloon that is under the control of the pilot and allows him to let hot air out which in turn brings the balance between the air inside the balloon and outside the balloon closer together and slowly brings the hot air balloon back towards the ground.

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Going Up!

• If the pilot would like to ascend again he simply closes the hole on the top of the envelope and shoots more hot air into the balloon using a burner.

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• Hot air balloons are limited in terms of being a reliable mode of transportation since they can only travel in the direction that the winds are going.

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