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Tesla Roadster

tesla.com

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Re: Tesla Roadster

#601

Post by Danihan »

gregornobis wrote: post #574
tdiggity wrote: post #131

Earlier quoted context omitted.

Founder series limited to 1000 requires full deposit, that's $250 mil Base model requires $45k deposit. Not sure what semi requirements are. Even if they are biting off more than they can chew, they can gauge reaction and devote more/less to this. I'm thinking that these ventures give their engineers a space to get really creative and push the envelope. And, these advancements make their way into the mainstream model…

$250mil sounds a lot - until you remember they currently burn through $400mil of cash in a month

They also just laid off a ton of people, so maybe that burn rate is going to lower quite a bit.

Re: Tesla Roadster

#602

Post by perbu »

justacat wrote: post #582
TimTheTinker wrote: post #141

Earlier quoted context omitted.

This isn’t CGI :-) https://mobile.twitter.com/DavidHodge/status/931391188065705...

This video freezes right before the excitement, I can tell because the sound keeps going. I blame a very complex conspiracy.

Safari doesn't grok the video on my setup. Firefox does.

Re: Tesla Roadster

#603

Post by pixelHD »

jon_richards wrote: post #314
ardit33 wrote: post #17

The Tesla roadster specs are insane! No exotic carmaker will be able to match it (taking price as a consideration). (no Ferrari, or Lambo, can get that close. This is Formula 1 acceleration speeds). Plus 620 miles of range, and it is a 4 seater. Expensive as hell, but this is exotic car territory. Base Specs Acceleration 0-60 mph1.9 sec Acceleration 0-100 mph4.2 sec Acceleration 1/4 mile8.8 sec Top SpeedOver 250 mph…

Ah, but do the doors go like this ^(o_o)^ or like this \(o_o)/ not like this

almost got kicked out of class for laughing too hard

Re: Tesla Roadster

#604

Post by dmcginty »

I'd really like to see a clearer shot of the steering wheel (steering device?) I'm curious why they decided to go with something that looks more like a plane's yoke than a normal wheel. Is this something that's common with supercars?

Re: Tesla Roadster

#605

Post by wallace_f »

dntrkv wrote: post #599
wallace_f wrote: post #517

Earlier quoted context omitted.

The OP is right that 8 sec 1/4 is extremely impressive, but he is wrong that there are few production cars that can run 8s. No production car runs anything close. The fastest 1/4 mile production cars are supercars such as the Veyron and 918, which are at or just under a 10seconds. Remember, an increase from 20->18 seconds is roughly a 10% increase in acceleration; 10->8 is roughly 20% increase over an already ludicro…

>The fastest 1/4 mile production cars are supercars such as the Veyron and 918, which are at or just under a 10seconds. Except for the Dodge Demon, which does the 1/4 in 9.65

The 9.65 time is impressive, and the engineering team design as well. However, the claim is arguably disingenuous. Consider one needs a long time to go through a list of impractical things to prep the car to actually achieve that time, such as laying down what is literal tire glue to the road.

Re: Tesla Roadster

#606

Post by wintermute2001 »

bilkoo wrote: post #554
dkhenry wrote: post #448

Earlier quoted context omitted.

You have been reading too many finance blogs. Their finances are far from a mess, they are just not what finance people like to see. They have cash on hand and a roadmap to execute on. If they don't execute they will go out of business, and they will take my money as an investor with them. I'm OK with that and as long as they continue to have a path to profitability I am all on board. I want to see them burning money…

> struggling to produce their most important car ever Isn't this part of not executing the roadmap as planned? Put another way, how do you know if they are on the right trajectory to profitability? How much are they ahead/behind?

Tesla projected that it would produce 5K Model 3s per week by the end of 2017. In all of Q3 they produced 260! That kind of shortfall is clearly not part of any plan, unless it's one drawn up by GM and Ford. Source: http://autoweek.com/article/green-cars/tesla-model-3-product...

Re: Tesla Roadster

#607

Post by Unklejoe »

runeks wrote: post #591
Unklejoe wrote: post #480

Has the 8 second quarter mile been confirmed to be done in stock trim (i.e., no special tires or other modifications)? The reason I ask is because that is EXTREMELY impressive. I tune EFI systems on race cars as a hobby, and any car in the 8 second range usually needs to run slicks or drag radials to have enough traction. Even all wheel drive cars (GTRs, DSMs, EVOs, etc.) usually run 4 slicks once they get to that sp…

> Even if they had to put slicks on the car to reach that time, that still puts it on par with 1000 HP dedicated drag cars. Horsepower is a misleading figure, because 1000 HP means a maximum of 1000 HP at some engine RPM. So, in other words, if a gasoline car delivers 100 HP @ 0-2000 RPM, and only delivers 1000 HP between 5500-6000 RPM, we call it 1000 HP. The Tesla delivers its power constantly, from 0 RPM and — mor…

> — its torque is also constant and available from 0 RPM

I don't think torque is constant. The power is constant, and torque gradually decays as RPM increases as per the following equation:

HP = Torque x RPM ÷ 5252

Most 1000 HP drag cars are in their power band from the time the driver lets go of the trans brake until the race is over (unless it's a stick shift, but most drag cars are automatic).

Like any other conventional automatic, there is a torque converter between the engine and the transmission which allows the engine to spin faster than the transmission input shaft.

At the starting line, the driver engages the transmission brake, which locks the transmission and allows him to floor the engine, which brings it up to the optimal RPM (and spools the turbos if so equipped). It's almost the same as if you were to hold the brake and floor the accelerator at a red light. The only difference is that the brakes on a drag car wouldn't be able to hold it back, so they use the transmission instead.

Then, when it's time to start, he lets go of the trans brake and the power is instantly delivered to the wheels.

There usually isn't an issue with not having enough power at the starting line. It's actually the opposite. High power cars usually have to limit their starting RPM to avoid doing a wheelie or losing traction.

Re: Tesla Roadster

#608

Post by Sohcahtoa82 »

mmjaa wrote: post #293
aerovistae wrote: post #231

Earlier quoted context omitted.

may i ask what you do for a living

If you can afford one of these cars, you probably don't do anything for a living.

I work in cybersecurity. I'll have to set money aside for a couple years to make a considerable down payment, but I might be able to afford one of these.

Re: Tesla Roadster

#609

Post by 0xbear »

ajnin wrote: post #458
0xbear wrote: post #123

Earlier quoted context omitted.

It’s physics, there’s no way around it. You expend a ton of energy——battery heats up. Without massive radiators there’s nowhere for that heat to go.

No, it's incorrect, physics does not mandate that battery should heat up as you expend energy. Ideally all the energy would go into kinetic energy and be dissipated by friction losses due to air or contact between the road and the tires. The battery heats up only because the process of tranferring the chemical energy from the batteries to the car motion is imperfect, and there are internal losses do to the internal r…

It does. It will heat up. To quote a physics textbook: “Power transfer between a voltage source and an external load is at its most efficient when the resistance of the load matches the internal resistance of the voltage source.” IOW in the configuration where the power transfer is at its most efficient, battery has to dissipate as much thermal energy as motor(s) are consuming. Too much internal resistance and most of the thermal energy ends up in the battery. Too little, and your motors aren’t going to do their best. But in either case even with the load that’s not 100% matched, you do end up with a ton of heat dissipation in the battery when a heavy car like this is driven hard.

Re: Tesla Roadster

#610

Post by ska »

clarkmoody wrote: post #596
burger_moon wrote: post #584

Earlier quoted context omitted.

Right but to hit an 8 second 1/4 you're trap speed is 170-190 depending on how fast your 1/8 mile was. There simply isn't even distance to accelerate linearly in 1/4 to hit 8 seconds without leaving the line like a bat out hell. The suspension on most of these cars is also far from normal. There's very few cars in the world which make an8 second pass on independent rear suspension. Most of these cars have straight ax…

Accelerating at 1.28g (41.25 ft/s2) for 8 seconds will get you to exactly a quarter mile. x = 0.5*a*t^2 = 0.5 * 41.25 ft/s2 * (8s)^2 = 1320 ft = 1/4 mi Under that acceleration, your final speed is 225 mph v = a*t = 41.25 ft/s2 * 8s = 330 ft/s = 225 mph

Accelerating at > 1g off the line has its own set of issues - without extra downforce from somewhere you have traction problems regardless of tires, street tires just make it worse.

This is why you see so many approx 2.9s 0-60 times in higher end sports cars, it's hard for aerodynamics to affect it much over the first couple of seconds.

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