TESLA CyberTruck Wind Tunnel Testing - SHOCKING Results (w/ Cd figures measured)

[RayzorBEV]

a)
Desc: We (i1Tesla) took the CyberTruck to my local wind tunnel at A2 Wind Tunnel in Mooresville NC. To see the efficiency of the different ride heights. Plus what the mirrors off and tonneau cover open. Shocking results
[Very little cD difference WITHOUT side mirrors! See table below]

Title: TESLA CyberTruck Wind Tunnel Testing - SHOCKING Results
Author: i1Tesla



NOTE:
_ cD values are accurate (relative) when comparing scenerios to each other (eg with and without side mirrors; with and without tonneau cover; etc).
_ However, as explained in the video from a professional at that company --- regarding the below cD table values that the tunnel wasn't built to test taller vehicles like trucks (vs race cars, bikes, etc) and the results could be slightly off. ie. Tesla claims 0.34 vs 0.38+ below. The professional said that tunnels that account for taller vehicles may be off more like 0.01 +/-
h/t: Gurule92

b) cD explanations.
cD values are accurate (relative) when comparing scenarios to each other

• with and without side mirrors
• with and without tonneau cover
• etc

Per the professional in the video ... a flat-faced object that matched the profile like below would be ~1.0 cD and the Tesla CyberTruck value is 0.34 cD (depth and air flow) uses about 34% of that energy / effort / force to go down the highway.

c) Re: [Very little cD difference WITHOUT side mirrors! See table below]
Turns out in this example given the Cybertrucks shape that it makes very little difference so it does not at all seem worth the trouble. I bet dropping 1 MPH is even better efficiency improvement [though I haven't tried ABRP as an example to see that ].

d)
RELATED to another post of mine in the past:
----------------------------------
Related to the aero, I thought this video was quite interesting and likely has been discussed but seemed to go along with your comments.

The below is about how far the 'sails' are angled in (and I thought was a surprising nugget) but the whole video is good on the front and rear air pressures.

Title: How The Cybertruck Is More Aero Than It Looks
5:37 or 337 secs in.

Images create from AirShaper videos

Will the wrap on this CT has any material impact on the Cd? I'm pretty sure Tesla ran their test on a bare CT with no wrap...Hmm

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[chinokie]

Will the wrap on this CT has any material impact on the Cd? I'm pretty sure Tesla ran their test on a bare CT with no wrap...Hmm

That's a good point. And he seemed to conflict himself when he was talking about surface texture...

 

[chinokie]

a)
Desc: We (i1Tesla) took the CyberTruck to my local wind tunnel at A2 Wind Tunnel in Mooresville NC. To see the efficiency of the different ride heights. Plus what the mirrors off and tonneau cover open. Shocking results

I wonder how the rotating wheels would affect the drag??? At 70mph the top of the tire is moving close to 140mph...

 

[scottf200]

Will the wrap on this CT has any material impact on the Cd? I'm pretty sure Tesla ran their test on a bare CT with no wrap...Hmm

That's a good point. And he seemed to conflict himself when he was talking about surface texture...

It sure seemed like this was explicitly talked about. To me it was 100% clear that if the surface is still flat in the same way that (bare, ceramic coating, wrap, etc) that there is NO difference in cD ... or at least not empirically measurable.

<roll the tape>
Here is the transcript (turn on within the video description area).

Question:
14:22 | does the wrap or
14:24 | ceramic coating affect the the
14:26 | coefficient
Answer:
14:26 | no and here's why that
14:28 | you've got skin friction and skin
14:31 | friction has to do with first of all the
14:32 | transition from what's called laminer
14:34 | boundary layer to turbulent boundary
14:36 | layer but that the golf ball effect and
14:39 | all that okay that's something but
14:41 | essentially viscosity always happens
14:44 | there's always skin friction and it
14:46 | doesn't matter if it's Teflon or
14:48 | polished metal it does matter about
14:51 | surface roughness but not that
14:53 | smoothness or slickness per se so in
14:55 | other words if you look at it under a
14:56 | microscope and it looks the same whether
14:59 | it's metal plastic or or or some fancy
15:02 | silicone doesn't matter it's it's going
15:04 | to give you the same uh surface drag
15:07 | over that area you might even want to
15:09 | mention that the the ceramic thing has
15:12 | been tested 100 times and nobody's found
15:14 | oh yeah every time every time we do any
15:16 | kind of Polish or anything like that
15:18 | again if you're not changing the surface
15:21 | texture of the model um then yeah what
15:25 | you coat it with doesn't make any
15:27 | difference.

 

[Cyberman]

Finally a worthwhile CT vid.
Any chance you will go back with some of the aftermarket stuff, like roof racks etc?

Yes, roof rack test would be awesome.

 

[JBee]

It sure seemed like this was explicitly talked about. To me it was 100% that if the surface is still flat in the same way that (bare, ceramic coating, wrap, etc) that there is NO difference in cD ... or at least not empirically measurable.

<roll the tape>
Here is the transcript (turn on within the video description area).

Question:
14:22 does the wrap or
14:24 ceramic coating affect the the
14:26 coefficient
Answer:
14:26 no and here's why that
14:28 you've got skin friction and skin
14:31 friction has to do with first of all the
14:32 transition from what's called laminer
14:34 boundary layer to turbulent boundary
14:36 layer but that the golf ball effect and
14:39 all that okay that's something but
14:41 essentially viscosity always happens
14:44 there's always skin friction and it
14:46 doesn't matter if it's Teflon or
14:48 polished metal it does matter about
14:51 surface roughness but not that
14:53 smoothness or slickness per se so in
14:55 other words if you look at it under a
14:56 microscope and it looks the same whether
14:59 it's metal plastic or or or some fancy
15:02 silicone doesn't matter it's it's going
15:04 to give you the same uh surface drag
15:07 over that area you might even want to
15:09 mention that the the ceramic thing has
15:12 been tested 100 times and nobody's found
15:14 oh yeah every time every time we do any
15:16 kind of Polish or anything like that
15:18 again if you're not changing the surface
15:21 texture of the model um then yeah what
15:25 you coat it with doesn't make any
15:27 difference.

I'd like to add to that that the CT doesn’t go, fast enough for skin friction to have an effect. But a bit larger suface undulations will affect it, like golf ball dimples or shark skin, or poorly applied wrap that flaps in the wind etc.

 

[chilam]

There's 2 liftgate open modes... you can have it partially open (tailgate tilted upward a little for carrying longer materials to prevent it sliding out) by unhooking the tailgate cable and use the other position. You might want to test that partially open mode as well.

 

[Qball]

Fantastic information, much appreciated. However it’s really not all that shocking or it’s along the line of what we thought.

 

[scottf200]

Fantastic information, much appreciated. However it’s really not all that shocking or it’s along the line of what we thought.

They did do a good job on it.

I think that it is shocking how little difference removing the side mirrors made. Many thought it would be a bigger deal based on past threads and general information about removing them on normal cars. Even Tesla made them easy to remove on the CT but it makes virtually no difference.

 

[Ward L]

Thank you for the wind tunnel information! Reminds me of my college studied of fluid dynamics! I still am most surprised the CT has a higher CD than the Rivian. How can that be? As long as we are ugly, I wonder how much fender wheel covers would reduce the CD. Won't ever happen, but still wonder. Recall the old Lincolns with the wheel covers as part of the body? You could not see the tire. I saw another study where the exposed front wheels really caused a lot of air drag. I wonder if adding little vanes to the front of the hood would reduce the CD, like they do on airplanes.

 

[scottf200]

Thank you for the wind tunnel information! Reminds me of my college studied of fluid dynamics! I still am most surprised the CT has a higher CD than the Rivian. How can that be? As long as we are ugly, I wonder how much fender wheel covers would reduce the CD. Won't ever happen, but still wonder. Recall the old Lincolns with the wheel covers as part of the body? You could not see the tire. I saw another study where the exposed front wheels really caused a lot of air drag. I wonder if adding little vanes to the front of the hood would reduce the CD, like they do on airplanes.

Title: How The Cybertruck Is More Aero Than It Looks

There are several things on the CT and the Rivian that help drag including the front wheel front profile.

Have you watched the CT Aero video above?

Also please view the Rivian Areo video below as it talks about Rivians secret sauce.

YT vid: Rivian R1T Aerodynamics - Is the claimed drag coefficient of 0.30 correct?

 

[ModelXer]

a)
Desc: We (i1Tesla) took the CyberTruck to my local wind tunnel at A2 Wind Tunnel in Mooresville NC. To see the efficiency of the different ride heights. Plus what the mirrors off and tonneau cover open. Shocking results

* Very little Cd difference WITHOUT side mirrors! See table below. " c) " section highlights area
* Does wrap, ceramic coating, etc help: NO -- link to post/transcript

Title: TESLA CyberTruck Wind Tunnel Testing - SHOCKING Results
Author: i1Tesla



NOTE:
_ Cd values are accurate (relative) when comparing scenerios to each other (eg with and without side mirrors; with and without tonneau cover; etc).
_ However, as explained in the video from a professional at that company --- regarding the below Cd table values that the tunnel wasn't built to test taller vehicles like trucks (vs race cars, bikes, etc) and the results could be slightly off. ie. Tesla claims 0.34 vs 0.38+ below. The professional said that tunnels that account for taller vehicles may be off more like 0.01 +/-
h/t: Gurule92

b) Cd explanations.
Cd values are accurate (relative) when comparing scenarios to each other

• with and without side mirrors
• with and without tonneau cover
• etc

Per the professional in the video ... a flat-faced object that matched the profile like below would be ~1.0 Cd and the Tesla CyberTruck value is 0.34 Cd (depth and air flow) uses about 34% of that energy / effort / force to go down the highway.

c) Re: [Very little Cd difference WITHOUT side mirrors! See table below]
Turns out in this example given the Cybertrucks shape that it makes very little difference so it does not at all seem worth the trouble. I bet dropping 1 MPH is even better efficiency improvement [though I haven't tried ABRP as an example to see that ].

d)
RELATED to another post of mine in the past:
----------------------------------
Related to the aero, I thought this video was quite interesting and likely has been discussed but seemed to go along with your comments.

The below is about how far the 'sails' are angled in (and I thought was a surprising nugget) but the whole video is good on the front and rear air pressures.

Title: How The Cybertruck Is More Aero Than It Looks
5:37 or 337 secs in.

Images create from AirShaper videos

I'd say it's very interesting that the outside mirrors make very little difference, but everyone seems hot to remove them. I can see removing them for off-roading so as to avoid damage. But why remove them on public roads? Seeing traffic on the side Isn't important? Catching a citation that may make it to your insurance company's attention Isn't important? Hmm.

 

[RayzorBEV]

I'd say it's very interesting that the outside mirrors make very little difference, but everyone seems hot to remove them. I can see removing them for off-roading so as to avoid damage. But why remove them on public roads? Seeing traffic on the side Isn't important? Catching a citation that may make it to your insurance company's attention Isn't important? Hmm.

This only means that Tesla had spent a lot of time optimizing the shape to minimize drag and wind noise

 

[chinokie]

I'd say it's very interesting that the outside mirrors make very little difference, but everyone seems hot to remove them. I can see removing them for off-roading so as to avoid damage. But why remove them on public roads? Seeing traffic on the side Isn't important? Catching a citation that may make it to your insurance company's attention Isn't important? Hmm.

Maybe people, like me, just like the look w/o the mirrors and we can get the full functionality with the cams.

Why you care so much about other people's motivations?

 

[ModelXer]

This only means that Tesla had spent a lot of time optimizing the shape to minimize drag and wind noise

Yes, I'm sure they did. I wish they had incorporated a spot mirror at the outside edge.

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