Introduction to the propeller

The history of propellers can be traced back to the records in "Tiangong Kaiwu", which was found on the chariots of the Yellow Emperor. In the Tang Dynasty, Li Wei installed a human paddle wheel on the side or the side of the ship, called the "paddle ship" or "wheel ship" (this is the origin of the term "ship" of the descendants). In the Song Dynasty, the Shuijun called it "the wheel smashing", and the record described it as "the ability to spur water, and its line is like flying."

According to Western history, Archimedes first proposed the concept of propellers, and Da Vinci sketched the propellers at the end of the 15th century. In the United States, Fulton invented the steamship, initially using the paddle wheel. By about 1850, the propeller became the main device for generating the thrust of the ship. To this day, propellers are the most widely used, most important, and most efficient propulsion devices in ships. When you are surprised that a container ship weighing 100,000 tons can sail in the sea at a speed of more than 50 kilometers per hour, is it still a propeller? Therefore, it is not an exaggeration to call the propeller a giant wheel that generates thrust.

A propeller consisting of a hub and a plurality of blades fixed radially to the hub, commonly known as a vane. The propeller is installed below the stern waterline, and the host receives power to rotate, pushing the water toward the ship, and pushing the ship forward by the reaction force of the water. The propeller is simple in construction, light in weight and high in efficiency, and is protected below the waterline.

Ordinary transport ships have 1~~2 propellers. The propeller generally has 3~~4 blades. The diameter is determined according to the horsepower and draught of the ship. The lower end does not touch the bottom of the water, and the upper end does not exceed the full water line. The propeller speed should not be too high, and the speed of the small speedboat can reach 400-500 rpm. The material of the propeller is generally made of a bronze or a corrosion-resistant alloy, or stainless steel, nickel-aluminum bronze or cast iron.