1.1 sec 0-60

[eytonxav]

I do not see how there would be enough tire grip to achieve this Tesla claim:
https://interestingengineering.com/tesla-roadster-spacex-pack-0-60-in-11-seconds

 

[Midpack]

I do not see how there would be enough tire grip to achieve this Tesla claim:
https://interestingengineering.com/tesla-roadster-spacex-pack-0-60-in-11-seconds

With “cold air rocket thrusters positioned at the rear” providing the acceleration, any performance tire would do, the added acceleration isn’t applied to the (rear) wheels - they’re just free rolling. Better tires would be needed for cornering and top speed more than 0-60 times.

 

[Car-Guy]

Who needs tire grip with rocket thrusters.... Seriously, rocket thrusters? C'mon Man.

I'm getting 3.0 to 3.2 consistently in my Jeep but that's using AWD and not rocket thrusters. I still get some wheel spin on all four tires and the tires I have are massive. Honestly I can't see how you can get much below 3.0 flat in a street legal production car even with AWD unless you have drag tires, a prep'd surface and probably a professional drag driver.

And while I'm at it, I don't even see how the new C8 mid engine can claim a 2.8 with only RWD and street tires.

 

[ERD50]

Who needs tire grip with rocket thrusters.... Seriously, rocket thrusters? ....

No, I don't think they are serious. He talks about them, but I don't think they are even actually on the prototype, it's all talk/joke. I'm surprised it's not dated 4/1.

On YouTube, the "Engineering Explained" guy recently did a video analyzing the super fast acceleration claims. He said, unless you are using rocket boosters, you can estimate best case 0-60 times from the best case 60-0 braking times (usually given in distance, but some calculus can turn that into a time estimate). On most high performance cars braking is limited by tire grip, so that is your acceleration limit as well.

But it is an approximation, weight distribution is towards the front while braking, towards the rear while accelerating, but close.

And he also rants about some "not counting the first foot of motion" or something. It's like saying "here's my 0-60 time, but I really stopped the timer at 55 mph - that's OK, right?". But by that measure, a Tesla is reported to be at sub 2.0 second times, and probably close in real life.

edit/add: That is with stock, street legal tires, not a prep'd surface, and no special driver. When you punch it in a Tesla (and many other modern cars), the power is delivered to keep the tires from slipping to maximize accel.

But yeah, rocket boosters!

-ERD50

 

[calmloki]

Yawn. call me when the hover version shows up.

 

[stepford]

Well shoot, if they're using rockets why not add a little thrust vectoring for some 7g turns - who needs an F-16?

PS. A quick calculation suggests they'd need to dump several hundred kg of gas out of their rocket nozzles in 1.1 second at several hundred m/s exit velocity to achieve the acceleration they claim. Let's assume (just to appease the neighbors) that they keep the nozzles subsonic at say, 200 m/s - are they really gonna carry around 1000 or so pounds of propellant for this stunt?

 

[Car-Guy]

Yawn. call me when the hover version shows up.

ok



https://www.msn.com/en-us/news/tech...n-tesla-roadster-into-a-hover-car/ar-BB1dD2L3


"The most notable discussion on The Joe Rogan Experience, in terms of actual upcoming products, involved Musk's idea about a car — precisely, Tesla's upcoming Roadster supercar — that hovers in the air."

 

[Car-Guy]

PS. A quick calculation suggests they'd need to dump several hundred kg of gas out of their rocket nozzles in 1.1 second at several hundred m/s exit velocity to achieve the acceleration they claim.

That sounds like one heck of a carbon footprint to me.

 

[OldShooter]

Let's see; a carefully prepared surface, racing rubber on all driven wheels, tires carefully heated for optimum adhesion, maybe even heat the surface. With that and enough low-end torque, a firm "maybe."

But, hey, people have been lying about speed probably since the first horse ride but certainly since the dawn of automobiles. Tesla seems to have a much longer nose than most of the manufacturers, so Occam suspects they are simply lying.

For myself, I only want to see a 55mph to 85mph acceleration time of 3 seconds. That gives me a 3-second passing exposure on a two-lane road.

 

[MRG]

Don't know, I'd read a different story that did a better job explaining the physics especially the issues with traction and the thrusters. Gotta say 0-60 in 1.1 seconds would be past insane. My Y does this in 3.5 and you better be paying attention.

 

[eytonxav]

An average driver would have a medical emergency with that level of acceleration. I didn't take the rocket booster option literally. For reference a top fuel dragster does 0 - 100 in ~ .8 sec.

 

[Car-Guy]

An average driver would have a medical emergency with that level of acceleration. I didn't take the rocket booster option literally. For reference a top fuel dragster does 0 - 100 in ~ .8 sec.

+1

Ah, but a top fuel dragster isn't street legal, definitely using drag tires , prep'd tracks, professional drivers and running thousands of HP more than any production car... Oh, and they rebuild their engines after each run or two. Wonder how many G's they pull.

 

[mountainsoft]

I can tell I'm getting old, because I don't see any reason WHY you would need to accelerate that quickly. Sure it would be fun once or twice, but in daily driving it's not something most people need. It always annoys me that people practically rear end me at a stop light because they see a green light and floor it. I mean, you have to stop again at the next light, so what's the hurry? Not to mention, anything loose in the vehicle is going to go flying, tissue box, groceries, etc. You'll get to your destination in record time, but groceries will be thrown all over your trunk.

 

[eytonxav]

Ah, but that's not street legal, definitely using drag tires , prep'd tracks, professional drivers and running at least a couple thousand HP more than any production car... Oh, and they rebuild their engines after each run or two.

A couple of thousand more, they make 11K HP.

 

[Car-Guy]

A couple of thousand more, they make 11K HP.

Yep, the top guys are... I edited my post when I thought about it. Even the shadetree guys are making thousands+ of HP in the barn builds.

 

[Dtail]

Who needs tire grip with rocket thrusters.... Seriously, rocket thrusters? C'mon Man.

I'm getting 3.0 to 3.2 consistently in my Jeep but that's using AWD and not rocket thrusters. I still get some wheel spin on all four tires and the tires I have are massive. Honestly I can't see how you can get much below 3.0 flat in a street legal production car even with AWD unless you have drag tires, a prep'd surface and probably a professional drag driver.

And while I'm at it, I don't even see how the new C8 mid engine can claim a 2.8 with only RWD and street tires.

Some of the supercars can do 2.8 and below in 0-60.
Possibly the Bugatti, Lambo top model car, Koenigsegg.

 

[ERD50]

I can tell I'm getting old, because I don't see any reason WHY you would need to accelerate that quickly. Sure it would be fun once or twice, ...

I'm with you on that. I'm actually fascinated by the technology and engineering that goes into making a car do that, but that's about it.

I was in a Tesla and the driver demonstrated the max acceleration. OK, it's quick, I was pushed back in my seat (but I miss the engine noise, which is part of the experience IMO), but I was really like "so what, what's the point?". Wouldn't a roller coaster ride give you more G's in more directions, for a few bucks for a ride? I don't get the excitement, but to each their own.

...

But, hey, people have been lying about speed probably since the first horse ride but certainly since the dawn of automobiles. Tesla seems to have a much longer nose than most of the manufacturers, so Occam suspects they are simply lying.

For myself, I only want to see a 55mph to 85mph acceleration time of 3 seconds. That gives me a 3-second passing exposure on a two-lane road.

A couple of thousand more, they make 11K HP.

Well, I think other people have tested the 0-60 times, and have a number pretty close. You don't need to (and shouldn't, IMO and experience) trust Tesla's numbers.

Related to HP and specs though (and it is amazing how much power those drag racers get out of an engine for a few seconds), I think the whole idea of reporting horsepower on production cars is pointless. The real point for a regular drive is, as mentioned above, passing times, and 0-60 times (if you need to merge from a stop). Those numbers are affected by the transmission, the torque curve of the engine, tires, etc. And it gets crazier with hybrids and EVs. You can't just sum the HP of the engine and motors in a hybrid, they have different torque curves anyhow. Just publish the results of 0-60, and maybe 40-60, 50-70/80. That's what you want to know. A single HP # tells you very little.

-ERD50

 

[OldShooter]

 

[Car-Guy]

Some of the supercars can do 2.8 and below in 0-60.
Possibly the Bugatti, Lambo top model car, Koenigsegg.

I've read that too... Amazingly quick for street legal cars. Over the years I've actually seen one Bugatti and several Lambos on the road... Never saw a Koenigsegg anywhere, even at car shows. I haven't kept up with the prices, but at well over a million a copy for a high end Bugatti and Koenigsegg, I probably won't be seeing many of those. OTOH, some Lambo's may be within my price range... Actually considered the Urus at one time.

Anyway, I guess I'll just keep puttering along in my "slow cheap Jeep" and give them the extra ~2 tenths of a sec.

 

[Dtail]

I've read that too... Amazingly quick for street legal cars. Over the years I've actually seen one Bugatti and a several Lambos on the road... Never saw a Koenigsegg anywhere, even at car shows. I haven't kept up with the prices, but at well over a million a copy for a high end Bugatti and Koenigsegg, I probably won't be seeing many of those. OTOH, some Lambo's may be within my price range... Actually considered the Urus at one time.

Anyway, I guess I'll just keep puttering along in my "slow cheap Jeep" and give them the extra ~2 tenths of a sec.

I have seen the Koenigsegg at the NY car show. It was quite amazing.
I also saw my first Urus on the road the other day. He hit the gas and it sounded quite nice.

 

[Bamaman]

No one needs a vehicle that's so fast. Because few people on this earth are capable of adequately controlling such a high performance vehicle.

It'd be nice if someone would figure out how to get more miles between charging than coming up with the most torque and horsepower. And it'd be nice if EV's weren't so danged complicated. Even an electrical engineer would have trouble figuring out one of them.

After all, it's still just transportation. And it shouldn't cost so much to get from point A to B anyway.

And when are places like California going to build power plants? There's not enough juice out there to power homes--much less all the automobiles. Solar and Wind? Forget them.

 

[OldShooter]

No one needs a vehicle that's so fast.

That's not why they are bought. They are bought by owners who are insecure enough to want to impress others with their expensive and relatively useless toys. IOW, ego.

Because few people on this earth are capable of adequately controlling such a high performance vehicle.

The good news being that almost almost none of the ego cars are ever driven in situations where control becomes even slightly marginal. The most common counterexample is driving in rain, where loss of adhesion is much closer than most people, even in grocery getters, realize. Even on the "track days" sometimes organized for these cars, it is a rare driver who gets in over his head. Driven on the edge, a car gives all kinds of little signals that it is not happy. For an amateur driver, these are frightening and hard to ignore.

Probably the biggest risk issue is the supercar owner who thinks it is thrilling to drive fast in a straight line, typically on a freeway with other traffic. Crowded freeways with untrained drivers blasting along nose-to-tail scare me far more than any scare I ever had on a race track among trained and experienced drivers.

 

[calmloki]

ok



https://www.msn.com/en-us/news/tech...n-tesla-roadster-into-a-hover-car/ar-BB1dD2L3


"The most notable discussion on The Joe Rogan Experience, in terms of actual upcoming products, involved Musk's idea about a car — precisely, Tesla's upcoming Roadster supercar — that hovers in the air."

Just so. Bunch of old grumps on here insisting that Elon have a perfect record of veracity on all his statements - I'm tickled that he is a dreamer that says all sorts of wacky stuff and then makes some of it happen. Landing a rocket segment on its tail on a floating target bettering the paperback sci-fi cover art of the 50s-60s? Launching his roadster with mannequin into space? naming his kid X Æ A-12? Why not? A man's reach should exceed his grasp, and Elon provides a lot of entertainment and a pretty good list of accomplishments.

 

[Car-Guy]

__________________
Ignoramus et ignorabimus

Love your signature.

 

[MichaelB]

Just so. Bunch of old grumps on here insisting that Elon have a perfect record of veracity on all his statements - I'm tickled that he is a dreamer that says all sorts of wacky stuff and then makes some of it happen. Landing a rocket segment on its tail on a floating target bettering the paperback sci-fi cover art of the 50s-60s? Launching his roadster with mannequin into space? naming his kid X Æ A-12? Why not? A man's reach should exceed his grasp, and Elon provides a lot of entertainment and a pretty good list of accomplishments.

He’s also doing what CEOs are supposed to do, which is to promote his brand, push awareness, and always try to increase share of heart. This thread is proof.