Tesla: The Great Short

[Sooner or later]

Originally Posted by island911

5G!? hmmm...

Let's do some quicky math on that. Simple momentum. Forget about acceleration (G) for now. Just how fast would you need to throw countering mass...

Mass₁x Velocity₁ = Mass₂x Velocity₂

Mass₁ = Big battery laden car. 5000_lb
Velocity₁ = 50 mph

Mass₂ = ??? just how much N₂ is on board? maybe 200 lbs? ... a ton? Let's say we have 200_lbs to throw forward to counter/stop the car momentum.
Velocity₂ = ??? just how fast is the exit speed? Sub-sonic? Super-sonic?

5000_lb x 50_mph = 200_lb x Velocity₂

250,000 / 200 = Velocity₂

1250 mph = Velocity₂ --yeah, super-sonic. :-/ And that's not even trying for 5G

Now, I know that there are inefficiencies in actual cold jets, and also that the car can get one G off with braking the wheels...

But let's just imagine that 5G emergency stop with nitrogen thrust. In essence, you are talking about throwing forward a couple hundred lbs of N₂ so fast that it decelerates the massive Tesla at 5G. ...or call it 4G. Still, think of the Jet-wash for whatever bicyclist crossing your path. --well so much for that idea.

So then not straight out the front. Instead we can imagine the jet thrust to push the car to the ground with 4G and use physical braking. Those are going to be some complex force brakes and some fast-acting suspension (do-able)... and some ridiculously expensive - if not impossible- cold jet system. I mean, the scale to achieve forces that high.

meh, all of this is a pattern of capturing imagination so that Musk can capture more money. Don't get me wrong. Putting rocket motors on electric cars... it's great that engineers are employed. Just that IMO there are better things to do. OTOH, I do like this conspicuous consumption that a "Green" car is slurping down by the bucket full. There's something validating there, for my early views of Musk and Tesla.

I was told there would be no maths.

[island911]

Ha! but it's really simple maths, did the maths, and I even spelled out Mass and Velocity. And then deleted a bit on energy and acceleration.

Originally Posted by red-beard

While I agree that this is crazy, most rocket engines/nozzles are supersonic. The PR just needs to be above 1.4, which most likely it will.

Yeah, I was thinking that a converg/diverging nozzle would bring the mass flow a bit above above Mach, but I don't have a feel for or remember those limits....just remembering work-arounds for automotive intake restrictions, and that problems arrive when trying to move gasses above Mach 1. And clearly just trying for some rough calc's for viability.

[Clint Lando]

Originally Posted by Sooner or later

I was told there would be no maths.

its ok
he's in pre-law

[RWebb]

[onewhippedpuppy]

Umm, 5G would likely cause some people to lose consciousness. Not exactly a good thing behind the wheel. Not to mention the impact of the thrust blast both forward and aft of the vehicle. As for flying cars.....lol. The average person barely deserves a driver’s license, and now you’re going to make them into pilots? Flying cars have been hyped since Popular Science in the 1960s, there’s a reason they haven’t come to fruition.

[Sooner or later]

They report earnings after the close today. Concensus is a loss of 54 cents a share.

[Racerbvd]

https://thenextweb.com/cars/2019/07/23/watch-fords-electric-f-150-tow-a-million-pounds-like-nobodys-business/

[biosurfer1]

I know 100+ years of gas engines is a hard thing to just give up, and the charging time is an obstacle....but it sure seems like electric cars give more of what "car guys" are looking for. Tons more torque, faster acceleration, less maintenance, etc. Hard to understand the resistance.

[legion]

Originally Posted by biosurfer1

I know 100+ years of gas engines is a hard thing to just give up, and the charging time is an obstacle....but it sure seems like electric cars give more of what "car guys" are looking for. Tons more torque, faster acceleration, less maintenance, etc. Hard to understand the resistance.

Well, there is the fact that every single electric car on the road I've had to subsidize one way or another (and often multiple ways).

[onewhippedpuppy]

Originally Posted by biosurfer1

I know 100+ years of gas engines is a hard thing to just give up, and the charging time is an obstacle....but it sure seems like electric cars give more of what "car guys" are looking for. Tons more torque, faster acceleration, less maintenance, etc. Hard to understand the resistance.

I agree! My objection is always the fact that my money has been used to subsidize what is currently an inferior technology. When electric can offer the same practicality as IC then I’m totally game. Though then you need to consider the remainder of the equation like charging stations and the electrical grid. Pretty soon pumping dead dinosaurs out of the ground looks pretty green....

[Aerkuld]

I'm always puzzled by the I'm-not-getting-one-because-I-object-to-my-tax-money-being-used-to-subsidize-them mentality. Sure, I understand tax money is used to subsidize these, but why not get one to take advantage of the tax money that's been spent on it? By not buying one you're losing out on a benefit you've already paid for. Heck, you may not want one but at least get your moneys worth.

By the way, thanks for the car! ;-)

[MysticLlama]

…yep, thanks, it did a great job driving me to work today.

I was in in time for the tax break, though I'm conflicted on it big picture. I do think it helped force technology along and lead to the reduction in price as fast or faster than spending an equal amount of $$ on government research and giving away the results, but does open the way for lots of arguments. Something like competitions for dollars seem a bit better.

[Tervuren]

Originally Posted by biosurfer1

I know 100+ years of gas engines is a hard thing to just give up, and the charging time is an obstacle....but it sure seems like electric cars give more of what "car guys" are looking for. Tons more torque, faster acceleration, less maintenance, etc. Hard to understand the resistance.

What you may not realize is that electric cars were more common than gas; and that the switch happened fairly rapidly.

Why? Because it was a better technology.

Electric involves more energy conversions.

Without nuclear power, it isn't practical on a large scale.

[Tervuren]

Originally Posted by Aerkuld

I'm always puzzled by the I'm-not-getting-one-because-I-object-to-my-tax-money-being-used-to-subsidize-them mentality. Sure, I understand tax money is used to subsidize these, but why not get one to take advantage of the tax money that's been spent on it? By not buying one you're losing out on a benefit you've already paid for. Heck, you may not want one but at least get your moneys worth.

By the way, thanks for the car! ;-)

Your post in green is something I told my dad when he wanted a Tesla.

Still, on the other hand, your are perhaps feeding a corruption machine channeling money. No orders, no subsidy.

[island911]

From the perspective of value, people who buy electric cars are getting a great deal. So many others are subsidizing the build. Not just the govt (Fed & local) but also the massive influx of investor money that keeps the selling at a loss viable.

It seems an ego thing... I mean, choosing to sell perhaps 5x more cars at a 10k loss each rather than selling the 1x cars at a 10k profit. Weird. But, oh look how popular...

[speeder]

Originally Posted by Sooner or later

I was told there would be no maths.

No schizzle. My second nephew in a row is doing an applied math degree at a top university, I can’t believe it Once I started smoking weed in JHS, my math brain took a dump and never fully returned.

These modern kids are making me look bad. In all honesty, I don’t think they’re even breaking a sweat doing it.

[Scott R]

Financials for this quarter were just posted, its another sizeable loss, in fact "sizeable" probably doesn't do it justice.

Non-GAAP -1.12
GAAP -2.31

Missed revenue by 90 million.

Shares down 30 points already in after hours trading. Short positions are cracking open the bubbly.

[RWebb]

is it dead yet?

[Scott R]

The Tesla stock story is.

[RWebb]

you may have forgotten, since it's been so many years, but you predicted the company would go under.