Brainstorming Frequency Levitation Landing Heavy Ice Friction
Forces Lift Bernoulli Gravity Height Thrust Frequency Levitation Landing Heavy Ice Friction Landing gear
4 Forces responsible for flight
Lift Gravity Thrust Drag
These forces are opposite to each other
Lift Gravity Thrust Drag
Forces necessary for flight
Lift Thrust Drag Forces are pushes or pulls. Gravity
Definitions Gravity – A force that pulls objects towards the earth.
Lift – acts in the opposite direction to the force of gravity (pushes objects up). Thrust – Pushes the plane forward. 1. Jet engine 2. Propellers Drag - acts in the opposite direction to thrust (pulls plane back). For a plane to rise, the force (F) of lift must exceed (be greater than) the force of gravity. There needs to be an unbalanced force. Vector – a vector shows direction and the magnitude (strength) of a force. Study for test
Diagram LIFT Vectors GRAVITY
Example 1 Forces are equal. Plane not rising or falling.
Wings and Bernoulli’s Principle
When a fluid (water, air) such as air moves quickly it creates low pressure. Air foil
A A A A air A air air A ir ir ir ir ir Fast moving air creates low pressure. Slower moving air creates high pressure.
Air splits up air air Leading edge
Slower air (high pressure) Faster air (low pressure) High pressure always tries to move to low pressure. The High pressure at the bottom of the wing tries to get to the low pressure at the top. The high pressure cannot pass through the wing so it pushes upward. The wing is connected to the body of the plane. As the wing rises (lifts) the plane rises with it.
Drag Drag – is a force that acts in the opposite direction of thrust. Large flat surfaces bring up in a lot of air particles. They do not pass easily through the air. For these surfaces ‘air resistance’ or ‘drag’ is great. To overcome this, planes have a sleek design so that they can easily pass through the air. Designing a plane in such a way is known as “streamlining”. In otherwords it is more aerodynamic!
Non-aerodynamic and Aerodynamic
An Old Truck is boxy and has more drag. Today’s Truck’s are more aerodynamic and streamlined. They have less drag.
Example of aerodynamic car
Today’s cars are more rounded and have less drag.
Newton Newton: everything pushed on, pushes back.
* The high pressure beneath the wing tries to get to the low pressure at the top. In doing so it pushes on the wing and lifts the plane.
Thrust Thrust: Type 1 – Propellers
More common on older type models of planes. Big blades on wings and nose of plane push air back over the plane moving the plane forward (think of you – swimming - you push water back behind you, you move forward). Propeller driven planes are: Cheaper to build More reliable But not so fast as jet engine planes.
Airplane Controls Elevators: These are hinged sections at the back of a plane. They are usually found on the “tail wing” of a plane. Elevators up – rear of the plane is pushed down. The nose goes up. Elevators down – the back of the plane is pushed up and the nose goes down. Going up or down is called the pitch.
Pitch, Roll and Yaw
(See diagram on next slide).
Rudder Rudder: Yaw is the motion of a plane as the nose turns left or right. It is controlled by the rudder. Left rudder – nose turns left Right rudder – nose turns right (See diagram on next slide).
Left and Right Rudder
Ailerons Ailerons – are used to control the roll of a plane (banking).
Right and Left Ailerons
Right aileron up, left aileron down. What happens? plane rolls or banks to the right. Left aileron up, right aileron down. What happens? Plane rolls or banks to the left.
Parts of an Airplane (see handout)
Cockpit Fuselage (body) Jet engine Aileron Horizontal stabilizer Elevator Rudder Vertical stabilizer Wing Trailing edge Leading edge Know the words in red for the test.
Parts of a Plane
Airplane # 1 is banking right
Airplane # 1 is banking right. I know because the right aileron is up and the left aileron is down.
Airplane # 2 is climbing. I know this because the elevators are up.
Airplane # 3 is yawing right
Airplane # 3 is yawing right. I know this because the rudder is turned right.
Review of Notes
Project – Design an Airplane
Birds and Flight Bird wing (See diagram) Leading edge Trailing edge
The picture above shows the side view of a birds wing which is similar to the wing of a glider, airplane, or helicopter blade. When air hits front of wing (leading edge) it splits up. The air flowing over the curved top of the wing has farther to go than the air going under the flat of the wing. For the two streams of air to reach the back of the wing (trailing edge) at the same time, the top stream of air must travel faster (it has farther to go). This fast moving air creates a low pressure area on top of the wing and a high pressure area on the bottom of the wing (Bernoulli’s Law). Since objects (air) tend to go from high pressure to low pressure, lift is created which is how both birds and planes stay up in the air. Note: For the wing to have lift, it must be moving forward through the air.
How Birds Fly Like planes, birds are streamlined, and
built of light materials so that they can fly. Feathers point backwards on a bird. Bills are lighter and more streamlined than the heavy jaws of a person or bear. Most birds bones are hollow and filled with air from the birds lungs, even the wishbone is hollow.
How Bird’s Fly continued… Study for test.
Birds move through the air by pulling themselves forward like a person rowing a boat. They push air down and back with the broad side of their wing, then slightly turn and fold the wing to move it forward. Birds with broad wings can soar and glide for long periods without flapping. Birds have to flap fast to stay in up. Bird wings and airplane wings have a similar shape. This shape provides lift.
Wind Tunnels Study for test
Wind tunnels are a device that allows model planes to be monitored (observed) while the wind is blown over them. The models are tested to see how aerodynamic or streamlined their shapes are. Wind tunnels are valuable because it is much cheaper to test model sized planes than to build very expensive full-sized planes. If the design is bad, then we would have wasted a lot of money.
Rockets versus Airplanes
Need to overcome gravity and air resistance to get into space. As you get further from earth air resistance and gravity decreases. Shape (has fins) Speed – faster Larger engines that require more fuel Space exploration Missions are in months or years After launch gravity reduces with altitude. Rocket engines are more powerful and burn more fuel. They have stages that fall off as they go further into space. Needs lift to overcome gravity provided by thrust and wing shape. Thrust must exceed air resistance. Shape (has wings) Designed for passenger travel (hours) Thousands of flights per day Fly for hours Always has strong gravitational forces on it.
Science Test – November 16th, 2011
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