Wednesday, January 9, 2008

How does a helicopter works?

Hi! We met again! Today i am going to post about helicopters.It is really interesting so look on...And please dont think that i copied and paste...i did add things into every post...



DIRECTION:
Rotorhead and Transmission
The helicopter has two jet turboshaft engines. These drive the transmission shafts, which turn the rotor blades. As the blades sweep through the air, they form what is called the "rotor disc."

Now,i will tell you about how the helicopter move forward,backward or stay in the air.

Changing the angle or tilt of the helicopter's rotor blades tells the aircraft whether to move forward or backward or to hover motionless in the air



The blades connect on top of the driveshaft at the rotorhead, which spins the blades. The rotorhead in turn is controlled by a swashplate, which transfers the pilot's instructions to the control arms on each rotor blade. By raising and lowering each blade at a precise point in its revolution, the pilot tilts the rotor disc in the desired direction for the helicopter to hover or turn or go forwards, backwards, climb or descend.

Now,see how it move forwards...



FORWARD:
In flight, the pilot tilts the swashplate forward. This tilts the nose of the helicopter down and pushes the helicopter forwards.

Lets see how the pilot control the helicopter.

CONTROL:
Pilot and controls
The pilot uses three controls to fly the helicopter:

A cyclic control stick tilts the rotor disc in the desired direction and controls speed. To turn, the pilot pushes the cyclic control left or right.

The collective pitch lever connects to the swashplate and changes the pitch of the rotor blades in unison. This enables the helicopter to climb or descend.

Foot pedals connected to the tail rotor blades' control arms work together with the cyclic to make left or right turns.



Now,is how it take off and hover.



Keeping the rotor disc level, the pilot raises the swashplate to tilt the rotor blades equally until the helicopter rises. To hover, the pilot constantly adjusts the controls to maintain height, position and direction, while adjusting the rotor blades' speed and holding the blades' pitch level.

After this,we shall look at how it lift.



The rotor blades have an airfoil shape, like the wing of an airplane: curved on top and flat on the bottom. When they rotate, the pressure of the slower-moving air flowing under the blade is greater than the faster-moving air above it. This difference in pressure pushes the blades up, giving the helicopter the lift it needs to fly.

Then,now we shall look at how it flew backward.



BACKWARD
Pulling the cyclic control backwards makes the swashplate tilt the rotor disc in a backwards direction.

Finally,how it balance.



If a helicopter like the Jayhawk didn't have a tail rotor, the torque would force the fuselage (body) to rotate in the opposite direction of the spinning rotor blades. The tail rotor compensates for this by providing lateral thrust in the opposite direction, holding the fuselage stationary.

Ihave came to the end of the post...Thank you for your kind attention!

Posted by gloomy_prognostication at 7:36 PM

Monday, January 7, 2008

Rockets!

How does a rocket works???

Hi,everyone...today i am going to tell you how does a rocket works.It is really interesting!I will show you a video and give a brief explantion about the video.


VideoJug: How Does A Rocket Work?

Who created rockets?

Rockets have been around for over 2000 years. The Chinese used them first as fireworks in ceremonies.
But it was an American, Robert Goddard who in 1926 first experimented with true liquid fueled Rockets.
During the Second World War, Nazi Germany developed the first real modern day rocket, the V2 vengeance rocket.

How does it works?

Apart from having apples fall on his head, Sir Isaac Newton told us in his third law of physics of 1687 that: ‘for every force, there is an equal and opposite force'.
It means that...If you throw something out backwards then the force needed, pushes in the opposite direction with equal force.
Blow a balloon up and then let it go and it flies around the room. Rockets work in the same way.
Modern rockets use mainly two forms of fuel. Solid fuel rockets. Or Liquid fuelled rockets.
As was the case in the largest rocket ever built.
In late 1960's and early 70's NASA developed the Saturn 5 rocket that took men to the Moon.
This was built in 3 stages, each stage containing its own fuel and engines.
A rocket engine looks more like a large plumbing project with pipes, valves, nozzles and pumps.
In liquid fueled rockets, a mixture of pure liquid oxygen is mixed with a fuel, usually hydrogen gas or kerosene, in a combustion chamber.
The gases are super cooled liquid to conserve space on board.
The fuels mix together in a combustion chamber and are ignited with a plasma lance.
The sudden expansion of the gases rushes out into the dome chamber synonymous with rocket engines.
The heat and thrust produced by this explosive mix firing out into the domed shaped engine causes tremendous upward thrust.
And this thrust pushes the rocket forward.
The rocket gathers speed.
The fuel continues to burn and expand outward from the engines pushing the rocket on.
When the fuel in that stage of the rocket is exhausted, it is jettisoned and another, smaller stage takes over.
This works exactly the same but now pushes the rocket even faster and higher.
After only a few moments that too is jettisoned and a final stage takes over.
The rocket needs to exceed over 40 thousand km/h, which is enough to escape the Earth's gravity, and the rocket is now in space.
With the space shuttle, NASA use a mixture of liquid and solid fuel booster.
The space shuttle consists of 3 main separate parts. The shuttle orbiter.
The giant orange tank is a fuel tank for the shuttle's liquid fueled main engines.
But the main thrust is provided by the two solid boosters along the side.
These are filled with a solid rocket fuel, contained in a casing. There is a hole bored directly down the centre of the rocket.
Once these are lit there is no way to shut them off.
Not like the liquid fuelled rockets that have valves and nozzles controlling the fuel.
These two boosters fire off like a giant party rocket, burning from the inside out down the central hole.
The combustion takes place inside the fuel cell itself, with virtually no moving parts.
When all of the fuel is used up the boosters are jettisoned and they parachute down into the sea to be collected and used again.

Finally,i have come to the end of it.Thank you for your attention!!!!

Posted by gloomy_prognostication at 8:53 PM

Sunday, January 6, 2008

Mechanical toy done by other people.

HI again,today i am goin to post about mechanical toy that is made by other people.I feel that the toy is quite cute...lets take a look...i will also tell u how it works.

The mechanical toy below is based on a cam mechanism. As the toy is pulled along the heads of the ‘ducks’ move up and down.



As the toy is pulled along by a child, the eccentric cam rotates as it is fixed to the axle and the wheels. The heads and connecting rods move up and down as the axle and eccentric cam revolve.



Posted by gloomy_prognostication at 12:40 PM

Saturday, January 5, 2008

Footwears

Hi everyone,i am behind shedule and today i am goin to tell your about footwears.Do your know when is the first footwear being invented?

Sandals were the most common footwear in most early civilizations, however, a few early cultures had shoes. In Mesopotamia, (c. 1600–1200 BC) a type of soft shoes were worn by the mountain people who lived on the border of Iran. The soft shoe was made of wraparound leather, similiar to a moccasin. "As late as 1850 most shoes were made on absolutely straight lasts, there being no difference between the right and the left shoe."




Interesting?Now i am going to talk to you about rubber soles shoes.Do you know when and who inveted the rubber soles shoes/sneakers?Dont know?Let me tell you then...

First Rubber Soled Shoes/Sneakers

The first rubber soled shoes called plimsolls were developed and manufactured in the United States in the late 1800s. In 1892, nine small rubber manufacturing companies consolidated to form the U.S. Rubber Company. Among them was the Goodyear Metallic Rubber Shoe Company, organized in the 1840s in Naugatuck, Connecticut. This company was the first licensee of a new manufacturing process called vulcanization, discovered and patented by Charles Goodyear. Vulcanization uses heat to meld rubber to cloth or other rubber components for a sturdier, more permanent bond.
On January 24, 1899, Humphrey O'Sullivan received the first patent for a rubber heel for shoes.

From 1892 to 1913, the rubber footwear divisions of U.S. Rubber were manufacturing their products under 30 different brand names. The company consolidated these brands under one name.When choosing a name, the initial favorite was Peds, from the Latin meaning foot, but someone else held that trademark. By 1916, the two final alternatives were Veds or Keds, with the stronger sounding Keds being the final choice.

Keds® were first mass-marketed as canvas-top "sneakers" in 1917. These were the first sneakers. The word "sneaker" was coined by Henry Nelson McKinney, an advertising agent for N. W. Ayer & Son, because the rubber sole made the shoe stealthy or quiet, all other shoes, with the exception of moccasins, made noise when you walked. In 1979, the Stride Rite Corporation acquired the Keds® brand.



How about the shoes laces you tie on your shoes?Do you know when is it invented?Continue to read then...

Shoelaces

An aglet is the small plastic or fiber tube that binds the end of a shoelace (or similar cord) to prevent fraying and to allow the lace to be passed through an eyelet or other opening. This comes from the Latin word for "needle." The shoestring (string and shoe holes) was first invented in England in 1790 (first recorded date March 27). Before shoestrings, shoes were commonly fastened with buckles.

Rubber and rubber again...Now rubber heel...

Rubber Heel

The firt rubber heel for shoes was patented on January 24, 1899 by Irish-American Humphrey O'Sullivan. O'Sullivan patented the rubber heel which outlasted the leather heel then in use. Elijah McCoy invented an improvement to the rubber heel.

Sports shoes is the common thing needed for running...Have you heard of sports sandals?Read on...

Sport Sandals

The term "sport sandals" was first coined by Ken Young. Young's sandal patent (with nylon webbing) was issued on April 2, 1974 - U.S. Patent # 3,800,444.



Shoes that absorbs odour?Amazing?!READ MORE AND MORE!!!

Odor-eaters

Herbert Lapidus of Westchester, New York, invented the odor-eater insole in the early 1970s. Lapidus claims he invented the product because his wife had very smelly feet. Odor-eaters are latex inner soles for shoes that contain activated charcoal to neutralize odors.

Posted by gloomy_prognostication at 12:01 PM

Monday, December 31, 2007

Colours,textures and proportion

Colour is one of the first things people notice about a product.
This is why the choice of colours is important when designers are designing a product.
Designers often work with specific groups of colours.

*Neutral colours
---->have low *saturation;they are not bright or *intense.

*Contrasting colours
---->also known as complementary colours,are directly opposite each other on the colour wheel.

*Pastel colours
---->are colours that are less intense.

Surfaces of different products are call the textures.

They are many textures such as smooth,rough and some are bumpy with patterns or grooves.

Textures are use to enhance the look or the function of a product.

Size is important in design.

When u are designing things ,you should try to make sure that parts of different sizes look right when they are fitted together.In other words, you should make sure that the different parts are in proportion to each other.

A design has good proportions when parts of different sizes look right together.

Posted by gloomy_prognostication at 4:49 PM

Lines & Shapes

There are many lines and shapes. Here are some of the example.

*vertical lines
---->demand attention, like a tall building.











*Wide and jagged lines
---->give a sense of boldness and strength.











*Curved lines
----> represent smoothness and gentleness.

*Slanted lines
---->suggest movement ,like the front of a racing car.

*Short and crisp lines
---->imply youthfulness and fun.

*Lighting bolts or electrical signals
---->Portray action and energy.

*Wavy lines
---->Convey a flowing movement.

*Horizontal lines
---->Are passive and motionless like a park bench.

*Delicate and elegant lines
---->Present an uninterrupted flow.

Geometric shapes have striaght lines or regular curves.
They are often symmetrical.eg.rectangle,circle,square and triangle.

Organic shapes are shapes we see in nature.
They have free-flowing lines and are often non-symmetrical.

Simple shapes can be combined into a more complex shape.

Posted by gloomy_prognostication at 4:29 PM

Function & Aesthetics

Design is about creating a product that does its job well.

The actions or activities a product should perform are called its functions.
Desgin is also about creating a product that has a distinctive look or feel about it.

The overall look or appearance of a product is called its asthetics.

When you are considering a solution to a design problems, you need to consider the product functions as well as its aesthtics.

You may use words such as modern, old-fashioned, masculine, plain, streamline, boxy, sophisticated, elegant, angular, curvy, bulky and slender.

Ergonomics

Design is also about creating products that are comfortable and safe to use.

That are some important points to take note;

-Hold the product




-Carry the product^^^

-Work with the product^^^^








-Wear the product








-Sit on the product

When you want your design to be ergonomic, you need to consider these few points;

-Safety
-How the user would use the product
-Proportion
-Size
Texture

You may also consider their adjustable parts and the layout of information.

The ergonomic consideration for a product can be linked closely to the product function and aesthetics.

Posted by gloomy_prognostication at 3:52 PM