Ch9 - Raligun
A great railgun plays one of the main roles in a silent movie „Le Voyage dans la lune” (A trip to the moon) from 1902. This beautiful Georges Mélies’ movie is considered the first science-fiction movie.
"Gun" is a general name for firearms with a caliber of at least 20 mm. Guns come in many varieties, such as cannons, howitzers, or mortars. They can be self-propelled, installed on tanks, warships or even serve as anti-aircraft weapons.
The very first railguns were built almost 900 years ago and their invention was connected to the invention of gun powder in China. From there, they travelled to Europe, including Poland, where they were first used in the Battle of Grunwald in 1410.
At first, the railguns were a feeble weapon, resembling delicate flares. However, they were steadily improved, the gunpowder became more powerful, and their could reach farther. Railguns strong enough to crush city walls were used 300 years after the first models.
The oldest railguns were extremely heavy – they weighed up to 19 tonnes. To use this giant, a crew of 200 people and 60 oxen was needed. Also, it could only fire 7 times a day.
One of the improvements was slimming the railgun and installing it on a gun carriage. The carriage mobilised the railgun and improved aiming. Another key invention concerned projectiles. At first, they were just canvas bags, but with time their construction changed to a hard shell with explosive material inside.
The ongoing improvements transformed the old railguns into a weapon that, until recently, seemed possible only in science-fiction.
Examples of weapons straight from science-fiction, except used in real world as well, include sonic weapons, laser blinders and kinetic guns.
Sonic weapon is supposed to disable enemies by attacking them with sound waves. It was used in fights with pirates and could knock the enemy down from a distance of 300 metres.
A laser blinder – a dazzler – is a modern weapon designed to disorientate the enemy.
A kinetic gun called a Railgun can shoot with a speed 8 times faster than the speed of sound. It is powered by extreme electric power of 5MA. Its bullets can carry for 550 km. In future, the kinetic guns are supposed to become a basic equipment of the US Navy ships.
Lasers are also considered a new type of weapons. Most recent laser guns are still being tested. The U.S. is carrying out the most advanced tests, where they use laser guns to destroy small unmanned aircrafts and small boats. The current research aims to make them even more powerful.
The U.S. army also possesses aircrafts equipped with a system of laser guns that could disable enemy self-propelling rockets, or ballistic missiles, right after they are launched. This type of weapon is extremely useful, as the aircrafts can refuel in the air and can shoot their targets from hundreds of kilometres away. Their price is another asset – one shot costs as little as 50 dollars.
Modern laser guns are also placed in space. The US government plans to create ait defence system with an enormous space laser (quite Star Wars-like) and couple of smaller terrestrial lasers. This weapon is currently in research phase, but it is extremely promising.
Build
To build this construction, you will need LEGO Education WeDo
Explore
This is how the complete railgun model looks like.
The robot fires projectiles over great distances – be cautious when playing with it!
The robot includes two electronic elements.
1. The hub powers elements connected to it and allows you to program the construction.
2. The motor propels the transmission, which stretches the rubber that fires the projectiles.
This is the main part of the model.
1. This is the barrel; you load the projectile inside.
2. These white bricks stop the piston that pushes projectile forward.
3. On the top, through the opening, you can see whether the railgun is correctly loaded. The black part of the projectile must be placed on the bottom, so that it fits under the white brick that stops the piston.
1. Here you can see the projectiles. Watch out, they get lost easily!
1. This is the piston that pushes the projectile.
1. The railgun fires projectiles by using the energy accumulated in the stretched rubber. You can try to drag the rubber band through the white brick installed at the end.
2. At the front of the barrel, you can see yellow balls, which hold the rubber band in place.
1. The entire model can rotate. All you need to do is turn the handles connected to the tan gear.
2. When the tan gear rotates, it propels the small black gear, which transfers the energy to the base of the railgun.
1. Before you fire, lift the barrel; with several shots, you can test when its range is the greatest.
This mechanism is responsible for stretching the rubber band.
1. The gray worm gear is propelled by the motor.
2. It is meshed with the large gray gear that is connected to the gear transmission consisting of three black gears.
3. This transmission indirectly propels the piston, which stretches the rubber band.
Here you can see how the rubber band gets stretched.
1. The black axle rotates the bricks pulling the band, which push the piston backwards.
2. When the pulling bricks are below the axle, the piston is released and the energy from the rubber band is freed by firing the projectile.
Ready, aim, fire!
Program
Program for the railgun will allow you to fire once. After that, the program will prepare your robot for further tasks.
You will fire by using your keyboard. Therefore, you must begin with the Start On Key Press block.
