On Heat hazes

When viewing objects through the exhaust gases emanating from the nozzle of aircrafts, one can observe the image to be distorted.

Hot air is less dense than cold air.

And this creates a gradient in the refractive index of the air. 

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The turbulence of the air emanating from the exhaust gases also has a direct
correlation to the degree of distortion of the image. More the
turbulence, more the distortion.

The gradient and the turbulence collectively affects the ability to resolve objects.

Also heat Hazes are not exclusive to aircrafts and can also be observed in cars/bikes too.

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                                                 Source

Pretty cool eh?

Sources: photobucket abc dpreview

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Behold- The Space Shuttle Tile

Designing an orbiter that is able to endure the brutal -250 F in the outer stretches to space to bewildering 3000 F during the reentry is a ridiculously challenging task.

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Space shuttle is the name for the entire setup, whereas the orbiter is the ‘planeattached

The Thermal Armor

Ergo, after churning the minds of the elite scientists and engineers, we
now have the TPS ( Thermal protection system ) that protects the
orbiter from these harsh temperature changes.

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Source

The thermal protection system is like a armor that maintains the outer skin of the orbiter within acceptable temperatures. This is achieved by employing various materials on the outer structural skin.

Wait, what kind of materials?

The tile’s material is an Insulator. These materials do not give away their heat that is contained easily.

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Cardboard, being an insulator protects your hand from the hot coffee. (PC: Nirzar)

Conductors on the other hand are the exact opposite. They love to give away their heat.

This is the reason why touching a hot aluminium / stainless steel ( Conductors ) pan at a moderate 100 C would cause burns, but touching the Space shuttle tile ( An amazing insulator ) at 2200 C is probably not a bad idea!

Perceiving Temperature

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When something feels hot to you, it’s really because there is a large amount of heat transferred between the object and your skin.

And when there is very less heat transfer, we perceive it as cold!

In the case of the space tile, being a really good insulator it is conducting ( transferring out ) the heat that in within it at a remarkably low rate.

Ergo, if we were to touch it, it will feel the same as a quotidian household object.

Cool eh ?

The Pioneers of Distance Flying

Birds are nature’s flying machines.

And when man wanted to conquer the skies, we took a great deal of inspiration for our designs from these living aeroplanes.

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Some of these birds travel thousands of miles and the Albatross is one such phenomenal bird which famously travels 10000 miles in a single journey. ( It is not a marathon, and they do take breaks in between )

The Take-off roll

The Albatross spreads its six foot wings and runs for take off. Depending on the breeze, it might be a few strides or a long run.

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Video Source

But once airborne, it would be a really long time before it sets back on ‘land’ again. I am talking months. ( They usually travel over the sea )

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Video Source

But wait, this must seem very familiar to you.

All our aircrafts take off in the same manner.

They accelerate along the runway and upon hitting the right velocity ( which is dependent on various factors such as length of runway, temperature, and so on ), off they go – soaring the skies!

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V1, Rotate!

If you have watched any documentaries/movies on aircrafts, you must have have noticed the pilot calling in “V1, Rotate!”.

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V1
is the first speed you’ll reach.

If you have a major failure, say an
engine, before V1 the takeoff will be aborted, but after V1 you must take off.

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PC: mdp-eng

That’s why they are called decision speeds; you can go around and land, but
you’re going too fast at that point to stop on an average runway.

V1
& V2 is the rotation speed (or lift off speed). V2 is your climb out
speed, and V3 also exists but has now become dormant.

Reflections

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Man had this crazy dream to glide through the skies alongside birds.

And it is this craziness of the mad-men who dared to believe they could fly that has evolved over an extended time frame as Aviation.

Suck, Squeeze, Bang and Blow – That’s how a jet engine works!

It sucks in air from the surrounding,

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squeezes it up with the compressor, 

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and when fuel is added and ignited, the bang occurs. 

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The air is blown out the back  and this produces Thrust.

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And no, I am not oversimplifying things. It is really that Simple. 😉

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Happy Halloween!

PC: nasa, bbc, imgur,worldofwarplanes.

EDIT: This principle can also be used to understand how your car engine works as well. 

The Miura Fold

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The Miura fold is a method of folding a flat surface such as a sheet of paper into a smaller area. The fold is named for its inventor, Japanese astrophysicist Koryo Miura.

Why it is awesome?

The Miura fold is a form of rigid origami, meaning that the fold can be carried out by a continuous motion in which, at each step, each parallelogram is completely flat.

This property allows it to be used to fold surfaces made of rigid materials; for instance, it has been used to simulate large solar panel arrays for space satellites in the Japanese space program.

The fold can also be unpacked in just one motion by pulling on opposite ends of the folded material, and likewise folded again by pushing the two ends back together.

In the application to solar arrays, this property reduces the number of motors required to unfold this shape, reducing the overall weight and complexity of the mechanism.

Other cool stuff.

Miura folded maps. Snug it into your pocket when not in need and open it up in style when you are lost !

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(Source : http://www.bun-sho-do.co.jp/english/nextg/miura-fold/ , wikipedia )