Tesla have boldly claimed that one day they’ll ship a Roadster complete with a cold-gas thruster for truly ridiculous acceleration. Whether or not that ever comes to pass remains to be seen, but [Engineering After Hours] decided to try out the technology on an RC car instead.
The thruster uses a pair of disposable CO2 canisters to deliver 1770 g of thrust via a converging-diverging nozzle. Actuated by servos and a simple valve, the system dumps the high-pressure CO2 to help accelerate the car up to speed. Paired with sticky tires and a powerful brushless motor, the plan was to try and beat Tesla’s claimed 1.1 second 0-60mph acceleration figure for the thruster-boosted roadster.
Unfortunately, the high center of gravity of the RC car led to stability issues, largely due to the mounting of the thruster itself. Additionally, the high weight of the car – around 4.3kg – meant that at best, the thruster would only add 0.5g to the vehicle’s acceleration.
While the car didn’t net a quick 0-60 time, it’s still neat to see a cold gas thruster on an RC car. It may not have been a Tesla-beater like some earlier projects, but it was cool all the same. Video after the break.
I had a model car (Monogram or Revell) back in the sixties powered by CO2 capsules… nobody tried to be fancy calling it a “cold gas thruster”, tho.
I had one of the Estes Land Rockets with “re-usable Coldpower Engine” when I was a kid. It had a small, closed aluminum cylinder with a nozzle on one end. You filed it with a compressed air can and a small host. Basically the same thing they sell now to blow the dust out of electronic equipment.
https://plans.rocketshoppe.com/estes/est4001/est4001.htm
Vashon had the market cornered on these for the rocket market – the Freon propellant was spendy but they were a lot of fun. I’m not sure they didn’t supply Estes’ engines for the cars, but we never had them in the hobby shop I worked in.
https://www.ninfinger.org/rockets/catalogs/vashon/vashoncat.html
I don’t recall that vendor. In my area, Eastern US, we and Estes and Centuri. Thanks for the link, brings back a bunch of memories
Every year in junior high school shop class, we built CO2 cars out of Pinewood Derby kits.
We built the cars like a traditional Pinewood Derby, but drilled a large hole in the back for a CO2 cart and put an eyelet on the bottom for a guide wire. The shop teacher had a launcher that consisted of a firing pin inside a collet, two of which were mounted at the right height on a vertical plywood sheet. The track was two pieces of string run through the eyelets and secured by nails in wooden expansion joints in the sidewalk behind the school.
Every student got to race them tournament style. The previous heat’s winner got to kick the board to launch the cars. After the winner was crowned the teacher let those of us who still had rocket motors left over from the previous unit put those in the cars instead. This proved far more exciting, with at least one instance of a car flying into the side of the school.
This is very similar to my own experience in my 8th grade shop class, though we used a timer and ran the cars one at a time. I designed my car with aerodynamics in mind, at least as well as I understood them. It might have actually helped a little bit, because I won 2nd place in my class.
I still have my old CO2 car, even though that was over 30 years ago. I guess I was kinda proud of it.
And I designed mine for absolute minimum mass, carving every possible cubic millimeter out of it, leaving just a thin shell, thinking that high acceleration would win the day.
And it did — until halfway down the track, when the CO2 cartridge ran out. Then the thing was just a ultralight air brake.
I came in flat last. But, heck, I did learn something.
Same experience in the tech class in the 8th. It’s where I first learned how to use a drill press and band saw (also had other areas like a cnc, robot arm, driving sim, and a litany of tech that was underappreciated at the time). Like the you, we raced as well and everyone raced against the teacher who had shaped his car into a rocket like structure (and boy did we immature boys make fun of that thing looking like a particular vibrating toy). In the end, everyone lost against the teacher and at the time, no one really understood why because the class didn’t go into the details of the physics involved. I’ve always wanted to go back and challenge my teacher to another race now that I fully understand a lot of the physics involved but sadly he retired a decade ago and the class has been reconfigured into something completely unfamiliar but also more focused on learning than doing. That class is what made me realize I loved STEM and that athletics weren’t the only option available from my neighborhood.
yep, we did this in 8th grade as well, right down too the rocket motors part. We had a ton of fun. I believe we used these pitsco kits: https://www.pitsco.com/Shop/Dragsters/CO2-Powered
Should he step up to a CO2 fire extinguisher?
Thrust is a force, use Newtons, not g.
Could use R134a or propane as you cold gas propellant.