What is a CO2 drag car?

A CO2 drag car is a small, tethered model racer propelled by the rapid release of compressed carbon dioxide from a disposable cartridge, typically sprinting down a straight track of about 20 meters in roughly a second. Used widely in school STEM projects and competitions, these cars let students experiment with aerodynamics, materials, and manufacturing methods while competing for the fastest time.

What exactly is a CO2 drag car?

In education and hobby racing, a CO2 drag car—also called a CO2 dragster—is a lightweight model vehicle designed to travel in a straight line when a pin pierces a small CO2 cartridge at its rear. The escaping gas provides thrust, pushing the car forward along a guide line to keep it on course. The concept mirrors full-scale drag racing but at desktop scale, making it a hands-on way to learn physics, engineering, and design.

How it works

The propulsion and timing system are simple, standardized, and designed for safety and repeatability. Below is a typical sequence you’ll see at schools and competitions.

1. A loaded CO2 cartridge (commonly 8 grams) is inserted into a rear-mounted housing on the car.
2. The car is placed on a straight, low-friction track and threaded onto a taut guide line (often monofilament) to prevent veering.
3. At the start gate, a puncture pin pierces the cartridge seal, instantly releasing high-pressure CO2 gas.
4. The expanding gas produces thrust, rapidly accelerating the car down the track.
5. Electronic timers at the start and finish record elapsed time to thousandths of a second.

Together, these steps provide a controlled, repeatable sprint where small design improvements can translate to significant time gains over a short distance.

Where you’ll see them

CO2 drag cars feature prominently in organized student competitions and classroom labs focused on design and physics. These are some of the most common settings.

• Technology Student Association (TSA) events in the United States, which run annual CO2 dragster competitions with regularly updated technical rules.
• F1 in Schools, an international STEM challenge in which students design and manufacture miniature F1-style cars propelled by CO2 on a standardized 20 m track.
• Middle and high school technology education classes, maker clubs, and community STEM fairs.

Across these venues, standardized tracks, timing systems, and safety procedures allow fair head-to-head racing and comparable results between teams.

Performance and physics

Because the track is short and the thrust is brief but intense, performance is dominated by acceleration and low drag. Here are the main factors that shape results.

• Thrust: The cartridge releases CO2 at high pressure (hundreds of psi), producing a sharp initial impulse.
• Mass: Lower mass generally improves acceleration, but cars must meet minimum strength and weight rules in competitions.
• Aerodynamics: Streamlined shapes, smooth surfaces, and minimized frontal area reduce drag over the short run.
• Rolling resistance: True-running wheels, low-friction bearings or bushings, and precise axles reduce losses.
• Stability: Proper weight distribution and rigid construction keep the car tracking straight on the guide line.

With optimized designs, cars routinely reach tens of miles per hour—often on the order of 35–60 mph (56–97 km/h)—within about a second on a ~20 m course.

Common materials and build methods

Student teams balance manufacturability, cost, and performance. The materials and methods below are typical in classrooms and competitions.

• Body: Lightweight woods (such as balsa or basswood) or dense foams shaped by hand tools, CNC routers, or 3D printers (where rules permit).
• Wheels and axles: Plastic or composite wheels; carbon fiber or metal axles; low-friction bushings or bearings.
• Finish: Sanding, sealers, and paints to smooth surfaces and reduce aerodynamic drag.
• Guide hardware: Precisely positioned eyelets or tubes for the tether line to minimize snagging and alignment issues.
• Fasteners and spacers: Washers, clips, and shims for axle alignment and wheel spacing.

The practical outcome is a car that’s strong enough to handle launch forces while being as light, straight, and smooth as rules and manufacturing skills allow.

Rules and safety

To ensure safe and fair racing, event organizers publish technical standards. While specifics vary by program and year, the themes below are consistent.

• Dimensions and mass limits: Minimums and maximums for body size, wheelbase, and weight to prevent unsafe or unfair designs.
• Cartridge housing: Required clearances and wall thickness around the CO2 chamber to manage pressure and puncture loads.
• Track interface: Specifications for guide line height and eyelet positions to ensure compatibility with official tracks.
• Protective procedures: Controlled start gates, clear runways, eye protection for handlers, and safe post-race cartridge disposal.
• Inspection: Pre-race checks for rule compliance, structural integrity, and wheel/axle freedom.

These standards keep events predictable and safe while still leaving room for creativity and engineering innovation.

Why educators use them

CO2 drag cars turn abstract physics into tangible outcomes, making them a favorite in applied learning. The benefits below are commonly cited by teachers and mentors.

• Hands-on physics: Students see how mass, drag, and friction affect real performance metrics.
• Engineering process: Teams iterate through CAD, prototyping, testing, and data-driven refinement.
• Interdisciplinary skills: Projects blend design, machining, materials science, and project management.
• Engagement: Fast, competitive races motivate careful documentation and justification of design choices.

This blend of theory and practice helps learners connect classroom concepts to measurable outcomes and teamwork.

Environmental notes

Each race uses a small, sealed CO2 cartridge. While the gas release is brief, responsible practice includes recycling spent steel cartridges and avoiding unnecessary waste during prototyping. Some programs encourage design optimization to minimize material use and emphasize end-of-life planning for parts.

Bottom line

A CO2 drag car is a small, high-acceleration model racer powered by a punctured CO2 cartridge and run on a tethered straight track. It’s an engaging platform for learning physics and engineering, widely used in school competitions and STEM curricula.

Summary

CO2 drag cars are lightweight, tethered model racers propelled by compressed carbon dioxide, typically sprinting ~20 meters in about a second. Popular in programs like TSA competitions and F1 in Schools, they teach core concepts in aerodynamics, materials, and manufacturing through hands-on design and racing. Rules standardize safety and fairness, while teams compete to reduce mass, drag, and rolling resistance for faster times.

What can make a CO2 car go faster?

So, in terms of CO2 dragsters, the less the mass of the vehicle, the faster it goes. Mass is the greatest determining factor for your success on the track. Creating your dragster to have as little mass as possible will be important.

What is the best shape for a CO2 car?

Vehicles have less resistance if they are rounded in the front and tapered off to a point in the rear (teardrop shape).

What does CO2 mean on a car?

carbon dioxide
Every litre of diesel fuel burned will produce 2.6kg of carbon dioxide whilst petrol produces about 2.3kg of carbon dioxide per litre. If drivers spend more time making longer journeys on motorways for example, they should consider a diesel engine for its fuel efficiency and its lower C02 emissions.

How fast do CO2 cars go?

CO2 dragsters can reach speeds from around 35 to 70 miles per hour (56 to 113 km/h), with some reaching up to 79 km/h (49 mph) or even faster depending on the specific competition. These lightweight, CO2-powered cars are propelled by a compressed CO2 cartridge down a flat, level track and can cross a 20-meter (65.5-foot) track in just over a second. 
Factors influencing speed

• Weight: Opens in new tabThe lighter the car, the faster it will go, making mass a crucial design factor, according to HowStuffWorks. 
• Aerodynamics: Opens in new tabThe cars’ design, particularly a rounded front and tapered rear, helps reduce wind resistance and improve speed. 
• Track Length: Opens in new tabThe cars are designed to operate on a standard 20-meter track, which helps dictate their typical speed range. 

Common speeds

• Typical Speeds: Many CO2 dragsters can reach speeds in the range of 35 to 40 mph. 
• Higher End: Some high-performing cars can achieve speeds of 60 to 70 mph or even more. 
• Record Speeds: During one competition, a dragster was clocked at a speed of 68 mph.