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Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

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Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#251

Post by Locke1689 »

toomuchtodo wrote: post #246
Locke1689 wrote: post #240

Earlier quoted context omitted.

That just indicates that you make enough money to buy a more expensive car, not that the Tesla is not significantly more expensive (i.e., about double what you are paying).

That's entirely fair. I didn't look at it that way. What do we consider affordable? I haven't had the time to do this, but you could take US Census data (average/median income per zip code), derive a formula for percentrage of income someone can spend on transportation, and thereby determine what affordable is. A Model S is definitely a luxury item at this time; on the other hand, if it was self-driving, and could ro…

Maybe we're looking at Tesla wrong. They're not selling luxury cars; they're bootstrapping a mobility company by selling to the wealthy.

I would agree with this statement 100%.

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#252

Post by [deleted] »

akerl_ wrote: post #235
danielweber wrote: post #223

Earlier quoted context omitted.

Most normal cars survive "normal" crashes just fine, don't they? Tesla buyers tend to be sports car buyers who want to drive fast. Whether this means we should expect accidents with more force or that Tesla should anticipate this and design accordingly is debatable.

Do you have a citation for that claim?

[deleted]

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#253

Post by lotsofmangos »

nailer wrote: post #241
lotsofmangos wrote: post #237

Earlier quoted context omitted.

Huh? Are you completely and utterly mental? You were stating what you normally do when you read something saying that it is by Elon Musk on Medium. To claim that you have a normal behaviour for a given situation would usually presuppose that it is a situation you have previously encountered, more than once.

http://ycombinator.com/newsguidelines.html

Is that a yes?

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#254

Post by bjeanes »

johnward wrote: post #129
JohnBooty wrote: post #58

In a sense, Teslas are the least safe cars on the road, because I'd kill every single one of you in order to own one.

I would really love to drive a Model S. I'm not sure if all of the Californians on HN realize how special CA is for seeing awesome cars. I saw cars that I never thought I would see in person (in my lifetime) when I was in CA. Not only that but you would see them a handful at a time. I know of 4-5 Model S' in the Pittsburgh area but rarely see exotics.

http://getaround.com/ModelS

I've driven it 3 times now and plan to do so again. $25/hour makes for a really fun weekend outing.

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#255

Post by srg0 »

deletes wrote: post #182
srg0 wrote: post #155

Assuming the underbody plate is only 2mm thick, the Model S is suddenly accelerating 5% slower. To put it otherwise, every acceleration now takes at least 4% more energy (> 0.01 kWh for an acceleration from from 0 to 65 mph). Sounds great for city driving.

Can we see your calculation and reasoning or did you make the numbers up?

Footprint is 2×5 m. Sheet volume is 2×5×0.002 = 0.02 m³. Titanium density is 4507 kg/m³. That gives 90 kg. Without the aluminium deflector.

Normal Tesla Model S curb weight is 2108 kg according to Wikipedia. Extra 90 kg is 4.2% mass increase => 4.2% more kinetic energy at the same speed => more energy consumption to accelerate. It also means, that the same force applied to the heavier Model S will accelerate it slower (a = F/m).

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#256

Post by eric_h »

narrator wrote: post #110
Cthulhu_ wrote: post #78

Earlier quoted context omitted.

And yet, I can't help but feel they're being very, very defensive over it. I can't blame them, of course, given how something trivial like a car fire (trivial given the average frequency of them) is turned into a national news event. At the same time, Tesla's attention to quality and perfection and what-have-you will end up in them being heavily scrutinised. It's not that different from Apple in that respect; random…

> given how something trivial like a car fire (trivial given the average frequency of them) is turned into a national news event. This is how media bias works. They take something trivial like a car fire and make it the most important news item of the day. People start to think it's happening everywhere. There are billions of "newsworthy" things happening all the time. The selection of stories and insinuation layered…

Yeah, it's unfortunate. I actually had to explain the reality of the Tesla car fires to my mother (who is usually very good at seeing through media bias). She was under the impression that the Tesla fires were actually indicative of the car being less safe than normal cars...

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#257

Post by TrainedMonkey »

sliverstorm wrote: post #231
DVassallo wrote: post #227

Earlier quoted context omitted.

True. Here's what happens to a Ford Focus that crashes into a concrete wall at ~100mph: https://www.youtube.com/watch?v=LmRkPyuet_o

Ah yes, because a Tesla would leave you unscratched if you collided with the same immovable wall?

Reminded me of a joke I heard a while ago:

"Just released car has amazing safety features that prevent any damage to the vehicle. Amazing advance of technology was made available by near instantaneous braking. Even going 100 mph a car can come to a complete stop instantaneously. After that wipers are deployed automatically to wipe off remains of a driver from windshield."

Any significant change of momentum will harm humans no matter how tough the car is. Newer cars are actually less rigid to provide a cushion to human drivers in case of such collision.

Edit: I meant less rigid in right places. If you observe crash test you could see how neatly car folded around drivers cage. Thanks drglitch for pointing that out.

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#258

Post by toomuchtodo »

josephlord wrote: post #245
toomuchtodo wrote: post #228

Earlier quoted context omitted.

My Infiniti payment is something like ~$550/month. To go to a Model S would only cost me ~$800 more per month, which is 5 hours of my time from a billable perspective. Yes, the payment is higher, but I'd have no fuel expenses (currently ~$350/month), so technically its only $450 more a month (3 hours of my time).

So at 3 hours per month you are talking about 36 hours per year or three to four days of holiday (depending on the length of your work day). That sounds significant to me. It might be worth it but there are other ways to spend that time and money.

We each value our time differently. 3 hours per month is more than acceptable to me.

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#259

Post by squigs25 »

squigs25 wrote: post #124
blisterpeanuts wrote: post #92

Earlier quoted context omitted.

But titanium is less dense than steel, hence preferred when weight is important. For an electric car, weight is paramount, I would think.

Actually, nope! While it requires more initial force, that extra energy due to added mass is stored in kinetic energy, and contrary to popular belief, it does not affect efficiency. There was actually a myth busters episode about this. Electric cars would store this added energy in their regenerative breaking, so it shouldn't affect energy consumption. Also, the added weight of steel over titanium would be negligible…

TO answer everyone's questions below, think about the following example:

You have one car that's 1,000 lbs and one that's 10,000 lbs. When you start each car, it will take a lot more energy to bring the 10k lb car up to the same speed as the 1k lb car, but after that, the effects of drag will weigh more heavily on the lighter car (F=ma, so the rate of deacceleration is a lot higher for a smaller mass), causing constant fluctuations in the motor shutting on and off.

With the the 10k car, the transitions would take much longer. The time in between accelerations would be longer, and the motor would be on for longer spurts. You gain a great deal of efficiency for simply leaving a mechanical system running vs constantly modulating a mechanical system (i.e. shutting it on and off).

This would work in favor of the heavy car being more efficient.

Of course, the heavier your car is the worse your 0-60 split would be, so for a performance car that's a negative.

Also, the heavier car would experience greater bearing resistance + friction. This is really difficult to quantify, and my gut is that it's outweighed by the momentum advantage.

But overall, for a car that ways 2k lbs, a 5% increase in mass is pretty negligible, especially for casual highway and local driving.

Re: Tesla Adds Titanium Underbody Shield and Aluminum Deflector Plates to Model S

#260

Post by drglitch »

TrainedMonkey wrote: post #257
sliverstorm wrote: post #231

Earlier quoted context omitted.

Ah yes, because a Tesla would leave you unscratched if you collided with the same immovable wall?

Reminded me of a joke I heard a while ago: "Just released car has amazing safety features that prevent any damage to the vehicle. Amazing advance of technology was made available by near instantaneous braking. Even going 100 mph a car can come to a complete stop instantaneously. After that wipers are deployed automatically to wipe off remains of a driver from windshield." Any significant change of momentum will harm…

Newer cars are more rigid in just the right places (e.g. driver cage) - they do have larger/softer crumple zones that permit the damage to be absorbed along a longer time period. By prolonging the total crumple/crash time, the peak energy is decreased, thereby avoiding injuries from force overload during deceleration.
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