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Propeller

technology Maturity 7-9 Next article →

A propeller is a clever tool used to move things through fluids. These fluids can be water or even the air around us.

Ship-propeller 2000
Ship-propeller 2000

The device has a center part called a hub. Several blades grow out from this hub like the spokes of a wheel. These blades are set at a specific angle called a pitch. This angle creates a shape known as a helical spiral.

Pratt & Whitney Canada PW100 Dash 8 OE-LGD 01
Pratt & Whitney Canada PW100 Dash 8 OE-LGD 01

When the propeller spins, it creates linear thrust. This thrust is the force that pushes a boat or plane forward.

Controllable pitch propeller schematic
Controllable pitch propeller schematic

How does this movement actually happen? It works by using a rule called Bernoulli's principle. As the blades rotate, they move through the fluid. This motion creates a difference in pressure between the two sides of the blade.

Cavitating-prop
Cavitating-prop

This pressure difference exerts a force on the fluid itself. Because the fluid is pushed, the propeller moves in the opposite direction. It is a step-by-step way of turning spinning motion into forward travel. This is how a ship moves through the ocean or an airplane moves through the sky.

Propellers have been around in different forms for a very long time. The idea comes from a way of moving water called sculling. Instead of moving a blade back and forth, inventors attached it to a rotating shaft.

Archimedes screw
Archimedes screw

This allowed the blade to move in a continuous circle. Long ago, in Ancient Mesopotamia, King Sennacherib used bronze water screws. Later, a man named Archimedes used a screw to lift water for farms. These early tools were meant to move water, not to move ships.

Many inventors tried to make propellers work for travel. In 1775, David Bushnell built a submarine called the Turtle. It used a propeller that a person could turn by hand or foot.

Archimedes screw
Archimedes screw

In 1827, Josef Ressel made a successful screw-propelled ship called the Civetta. It reached a speed of 6 knots in 1829. Later, in 1835, two men named Francis Pettit Smith and John Ericsson worked on new designs. Smith built a boat that used a wooden propeller.

F. P. Smith's original 1836 screw propeller patent
F. P. Smith's original 1836 screw propeller patent

When his two-turn propeller broke and became a single turn, the boat actually went faster!

These inventions changed how we explore our world. Smith used his single-turn design on a ship named Archimedes in 1839. This ship helped prove that propellers were better than old paddlewheels.

Illustrirte Zeitung (1843) 21 335 1 Archimedische Schraube des Dampfschiffes Archimedes
Illustrirte Zeitung (1843) 21 335 1 Archimedische Schraube des Dampfschiffes Archimedes

Paddlewheels can be affected by how deep a ship sits in the water. A screw propeller is more steady and efficient. Today, we see this technology everywhere. It is in the huge ships in the ocean and the planes high in the clouds. The simple idea of a spinning blade continues to move us forward.

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🖼️ Images & Media (16)
File:Ship-propeller 2000.jpg
Ship-propeller 2000.jpg
File:Pratt & Whitney Canada PW100 Dash 8 OE-LGD 01.JPG
Pratt & Whitney Canada PW100 Dash 8 OE-LGD 01.JPG
File:Archimedes screw.JPG
Archimedes screw.JPG
File:F. P. Smith's original 1836 screw propeller patent.jpg
F. P. Smith's original 1836 screw...
File:EricssonCounterRotatingScrews.png
EricssonCounterRotatingScrews.png
File:Illustrirte Zeitung (1843) 21 335 1 Archimedische Schraube des Dampfschiffes Archimedes.PNG
Illustrirte Zeitung (1843) 21 335 1...
File:Great Britain propeller and rudder wideshot.jpg
Great Britain propeller and rudder wideshot.jpg
File:Precision air ATR72 5423a.gif
Precision air ATR72 5423a.gif
File:RMS Olympic's propellers.jpg
RMS Olympic's propellers.jpg
File:Cavitating-prop.jpg
Cavitating-prop.jpg
File:Cavitation Propeller Damage.JPG
Cavitation Propeller Damage.JPG
File:Propeller & anti-cavitation plate & Schilling rudder.jpg
Propeller & anti-cavitation plate &...

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