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Anyone watch the Roadster demo last night? As expected, it had some peak Elon cringe moments, but you don't have to be a great MC when you have a flying car.
Possibly the greatest product demo of all time.
I just watched it a few hours ago. Simultaneously super cool, and kind of a gimmick.
Probably the cool part is more SpaceX's demonstrated mastery of control of a flying object entirely based on a limited number of relatively low-power thrusters with very limited fuel. Most likely, as Scott Manley covered, they used up effectively their entire tank capacity for each of those demos, and probably takes hours to refill. Based on that, as well as the nature of it, it will probably never be useful outside of demos and stunts.
The suction fan is cool too, and might be possible to actually have on a production car sold to the public. Probably not very useful outside of a racetrack, but what the hell, the edge of the car industry has always been based upon selling ridiculously and impractically fast cars to crazy rich people. It's still cool that somebody made it and it's out there.
I'm still a fan of it. We'd never build anything awesome if all we're ever concerned about is reliving the poor and suffering, who never seem to actually be fixed no matter how much money we throw at it. It's still cool, and sometimes some of that stuff does filter down to actually useful products.
I do wonder how much engineering here they're sharing with SpaceX. Falcon 9 uses and early Starship models used cold-gas Reaction Control System thrusters that would have been a lot like these (except using pure nitrogen instead of air), but surely the different optimal sizing would have meant they didn't use the exact same engines, and other SpaceX engines (small methalox and ullage-gas rockets on newer Starship, hypergolic on Dragon) are even more different. But the control problem for Tesla might be much less tricky. With Falcon 9 the hardest part is that, even with just one main engine active, they can't run at a low-enough power to land without a "hoverslam" that uses that higher power at the last second. Control software for cold gas thrusters that can be throttled arbitrarily up and down is probably easy by comparison.
IMHO the scary thing here for SpaceX fans is the Carbon-Overwrapped Pressure Vessels holding the compressed air. They're at least not dumping Roadster COPVs in liquid oxygen (which led to the unexpected failure mode that lost AMOS-6 a decade ago), nor will they have them in a vehicle full of hundreds of tons of fuel (like during the Starship 36 explosion that also trashed a test stand 16 months ago), but even without a force multiplier like that, hundreds of atmospheres of pressure can be scary stuff. It's still been less than a year since SpaceX had a booster turned to scrap by a COPV rupture.
Yup. The flying "Rocket" model is sales-by-invitation-only; the direct target market there is basically "Hollywood" plus "hectomillionaires who like to drive hypercars". The value here is all indirect, trying to improve the brand status and to attract top engineers.
They're claiming it'll be even on the base-level "Performance" model sold to the public. On the other hand, they're only putting a "Not approved for public road use" asterisk on the "Rocket" model, suggesting that the intermediate limited-release "Thrust" model with just the rear "sub-1s 0-60" thrusters will actually be street-legal. I'm betting that's currently true in the sense of "nobody imagined needing a regulation to cover sub-1s 0-60 so it hasn't been written yet", but it might not be true in the sense of "that regulation won't ever be written". Might not be safe to put a deposit down on the Thrust model, at least not unless you're under the aegis of Florida Man.
It's not clear from the video, but it'd be interesting to see whether they're regulating the high-pressure air to a constant thrust, or just accepting that thrust varies as the tank empties. The former loses efficiency and adds weight, but the latter has a lot of added "fun" in the controls math.
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Safety. A system of thrusters that could provide deceleration, downforce and anti roll over protection could have its place in a modern car.
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