Videos: Opening Cybertruck door and charge port cover

[Crissa]

The steel will have higher emissivity than if it had white paint... But that's the paint, not the color. Bare steel will have higher emissivity than if it were coated.

-Crissa

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[ÆCIII]

I can't wait for Sandy Munro to do a tear down on one of the Cybertrucks he's ordered, especially when looking at assembly of the vault sides (some of you know what I'm referring to). I'm hoping I won't have to be referring to it anymore by the time we get to that point though. Fingers crossed.

- ÆCIII

 

[cvalue13]

OK, I'm getting tired of all the misinformation about stainless steel conducting heat to the inside of the vehicle more than other commonly used materials….

Now let's stop spreading the misinformation that stainless steel will turn the Cybertruck into a cooker

So conductivity is the main way metal would transfer heat to the interior of a vehicle?

And since there’s low conductivity, you know that unpainted and unpolished 3mm stainless steel will be cooler than painted metals of other varieties?

 

[Cenakaze]

So conductivity is the main way metal would transfer heat to the interior of a vehicle?

And since there’s low conductivity, you know that unpainted and unpolished 3mm stainless steel will be cooler than painted metals of other varieties?

The main mechanism of heat transfer from sunlight to the body is through IR radiation.

Unfortunately, stainless steel does quite poorly in this area as it's IR absorption rate (~0.4) is higher than white coloured coating with titanium oxide (~0.17). This handy website has the values of various metal surfaces and coatings:
http://www.solarmirror.com/fom/fom-serve/cache/43.html

In short, bare SS will heat up faster than Al with white paint. That said, if you leave a car under the sun for a few hours, it will get hot no matter the body material. In fact, it probably doesn't matter as greenhouse effect will be a big contributor to cabin heat regardless of paint color or body materials.

As for heat conduction from the body to the interior panels, it's complicated and involves conduction through multiple materials (SS/Al to Al unibody to air to interior liners). You can play round with thermal conductivity of different combinations of materials using the equation below:

Thermal Resistance = 1/thermal conductivity

so if the total thermal conductivity of material n is TCn then

Total Thermal Cond. = 1/(1/TC1 + 1/TC2 + 1/TC3...+ 1/TCn)

Reference: https://www.physicsforums.com/threads/combining-thermal-conductivity.720343/

In terms of how hot will the body feel to touch, 15-20 W/mK might be low for metals, it's very high compared to insulators such as wood and plastics.


Using the formula for calculating thermal conductivity, 1.4mm of 6061 Al (152 W/mK) and 0.1mm of paint (0.2 W/mK) gives a combined thermal conductivity of:

TC of 1.4mm 6061 Al = 152* 1000/1.4 = 108,571

TC of 0.1mm paint = 0.2*1000/0.1 = 2,000

Total TC = 1(1/108571 + 1/2000) = 1964

TC of 3mm of 304 Stainless = 20*1000/3 = 6667

So yeah bare SS will definitely feel hotter than Al body with white paint. That said, there's little reason why one would need to touch the hot metal surfaces of a cybertruck, when you can open doors, hatches and gates via buttons that are all made out of plastic. Better yet, you can probably avoid most physical contact with phone controls.

 

[cvalue13]

As for heat conduction from the body to the interior panels, it's complicated and involves conduction through multiple materials (SS/Al to Al unibody to air to interior liners).

Yes thanks, I will as emphasizing that complication and that conduction proper would probably be a minimal way in which heat would transfer from the SS to the cabin ambient temperatures.

Radiation would be the more likely substantive contributor. Especially given the thermal mass of a 3MM sheet envelope.

But judging relative radiation effects, too, I’d understand to be complicated and the effects would depend on a lot of factors, among other things not only the thickness of the SS, but the details of the SS composition (eg 300-series SS have different radiation profiles at different temps), the SS finish (same), what insulation materials are used interior to the SS, etc.


Which is all only to say, unclear what the consequences of the SS will be on cabin temps.

But for the same reasons, dismissing out of hand and shouting down other’s reasonable armchair wonderings is unfair, and to with bluster suggest conduction is the issue and based on that unqualified conclusions can be reached from the armchair, is embarrassing.

Meanwhile, equally interesting will be the effects of cold on the 3mm SS envelope.

Meanwhile-meanwhile, the upward-facing surface of the CT near the cabin is glass of unknown qualities.

Any additional thoughts you have are welcome, as you seem agile with these materials questions

 

[CyberGus]

 

[RayzorBEV]

Just curious, does the R1T have a mode that goes high in front while simultaneously going low in the rear in order to lower the tailgate as low as possible?

I thought "kneel" referred to that, while "squatting" would refer to low in front and back. I'm just curious as to what terminology Rivian uses and whether it can go high front and low rear.

No. Rivian does not yet has a loading mode but future software updates can make this happen.
Rivian and Jeep's "kneel" refers to lowest possible suspension height for easy entry and exit.

 

[PilotPete]

Was there ever a heat study on the DeLorean to see whether stainless steel cooks the interior? I'm hoping it doesn't and unless the wraps have some kind of UV protection, I don't see them charging the "thermals" of the CT.

I don’t know about the DeLorean or SS, but I do know about polished aluminum and some aircraft.

American Airlines made the decision in the 60’s to limit the amount of paint on their aircraft. In the MD-80 or B727, AA estimated they saved some 600 pounds of paint (just having the stripes). This meant the aircraft could carry an additional 600# of whatever was most important for that flight, be it fuel, passengers, or cargo.

AA found that their aircraft had a cooler interior when compared to a painted aircraft on the DFW ramps over a given period of time. The ability of the polished skin to reflect IR waves back out to the environment around it was considered to be the answer. So I would guesstimate the same should be true for the CT.

AA has now determined that the modern jets they fly have sufficient lift capability that the 600# advantage is minimal, and the man-hours involved in keeping the polished aluminum in airworthy condition is too high. As a result, their planes are painted…. Silver Or light grey.

 

[CYBRSMTH]

The truck seems very low to the ground. Not sure if I like that.

It supposedly has air suspension, so you’ll be able to raise it up.

 

[CYBRSMTH]

Definitely giving midsize truck vibes at that ride height, new category upper-midsize truck?

I think it’s very close in size to the Ford F-150, but its air suspension can allow its height to be adjusted.

 

[Crissa]

I don't have sympathy for the 'but I had to park it on the street' crowd, sorry.

I say this and my sister's significant other's car he uses for Lyft/Uber just got smashed sitting on the street in front of their apartment today x-x

Well, that's what insurance is for.

It was silver, btw, but sitting in a row of other cars, so no excuses for the person who hit it and drove off.

-Crissa

 

[JoeRod97]

Size of bed determines what size truck it is. You can lift a Tacoma but it’s still a small truck.

Most truck elevation is to inflate the ego of the driver and little else. Cybertruck comes with a button for that.

I prefer mine low.raise it as needed.dont want step ladder to get in.why are peolle compllaining its too low.have you seen all the lowered trucks on the road? Ease of entry is a must..

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