The easiest way to explain and understand different scientific principles and basics is to use practical experiments and models. The same technique of teaching holds true when you want to teach students different concepts of physics like motion, aerodynamics, mass, friction, and wind resistance. One of the easiest ways to explain these concepts to students is to use model racing cars which are powered by cartridges filled with pressurized CO2 or carbon dioxide gas. These cars are known as CO2 dragsters. These CO2 powered vehicles are also known as Land Speed Record Assault Vehicles or LSRAV. These cars are generally made of basswood. In this article, we give you answers to all your questions about dragsters that run on pressurized CO2.
Principles Behind LSRAV
There are some important principles of physics that come into play when you are making and running a dragster that is propelled by CO2. There are several forces that affect the motion and velocity of the car. The most important ones are mass, friction, thrust, and drag or resistance to wind. Let us take a look at how each of these forces is important for a dragster to function properly.
The mass of the car will inversely affect the velocity of the car. The lighter a car is, the faster it will go. It is therefore important that if you are constructing the car yourself, then you keep it as light as possible.
Friction can play a huge constricting role in the smooth functioning of your dragster. Creating friction is unavoidable when you have a vehicle with moving parts. Reduce friction as much as possible by ensuring that the axles rotate freely and by making sure that the wheels do not rub against the body of the car.
This refers to the aerodynamics principles in question. When any object moves, it is met with resistance with increase in speed. This resistance while pushing against the car reduces the speed of the vehicle. The more aerodynamically stable the design of the car, the lower the drag faced. It is difficult to create an extremely aerodynamic car.
This is the propelling force behind a CO2 dragster and is based on Newton's Third Law of Motion that states that for every action there is an equal and opposite reaction. Dragsters that use CO2 as a propellant move when CO2 is escaping rapidly from the cartridge that is placed in the car. The placement is such that the gas escapes in a rearward fashion. Because Newton's Third Law of Motion is in practice the car moves forward, overcoming any resistance in the process.
Parts of a CO2 Dragster
While you can easily buy a kit in order to make a dragster of this kind, it is also possible to make it from scratch. Either way, there are some key parts that make up this CO2 powered model vehicle.
Wheels help the model automobile to move forward. The axles present in the wheels causes friction. The drag force produced by the axle helps control the speed of the car and stop it. Some of the major companies that produce these vehicles and kits for the same use a high quality plastic for the tires which are easily bendable and do not contain any extra molds.
Axles are rods which provide grip to the wheels and position it at the center. Axles are made of aluminum, steel, or brass. While most students use aluminum to construct axles, steel is preferable as it easy to construct. Of course with aluminum there is the added advantage of less weight.
CO2 cartridge is the source of power for the dragster. The choice of CO2 cartridge for dragster may vary depending upon the amount of pressure they need to have. The kind of cartridge used depends on the purpose as well.
The body of the car is constructed with the help of a piece of wood by drilling and shaping it. In general, basswood and balsa wood is used. Balsa wood is easy to work with and it is light in weight. Power tools are used to shape the body.
Once you have the main components ready, it is up to you to put it all together and create a model car that would make you proud at a CO2 model car racing event.
Types of CO2 Dragsters
There are many different types of dragsters propelled by CO2 that you can make or use. Given below are the three main types.
This design for a dragster miniature has wheels that are externally placed and an extremely narrow chassis. It is one of the easiest models to make. The design is also such that it causes a reduction in the mass of the car, thus increasing speed efficiency. But because it has a thin frame, it is prone to breaking easily. Also it is not as aerodynamically stable as it could be.
If you are a constructing a shell car, then the design will be such that it will have internal wheels and a bullet shape. These cars are more difficult to build because the wheels need to be placed inside, thus requiring special parts. But the design is such that it is aerodynamic thus giving it a higher speed capability.
If you are looking for a dragster that can be customized greatly, then the show car design is the one you should choose. These are not made to be fast. They have wheels placed externally and the design in itself is detailed. Performance is not of importance with these models.
Co2 dragsters can be customized to a great extent using paint, decals, and add-ons. These model cars are a part of the curriculum in engineering colleges in several countries as they allow students to understand some of the most basic of principles.