Cybertruck aerodynamics drag coefficient = 0.39 Cd in new simulation

[SparkChaser]

Funny. I’ve read that tests with open bed pickup trucks effected no-adverse aerodynamics. None at all. Zero loss.

Results here

Pretty good dive into it here. The difference is not huge but a difference none the less.

Insert from MythBusters - Tailgate Up or Down 2 (from More Myths Revisited) fuel consumption test - YouTube

 

[JBee]

The high CT bed sidewalls and long angled rear roof glass will help a lot with creating clean airflow even with a open vault cover, provided nothing is sticking out.

 

[JBee]

This is why the adjustable air suspension is so important. Crank it down to the lowest level for highway cruising to increase range. Crank it up when you go off-road. Super important in an EV truck!

The simulation is about 50mm (2") higher than the lowest CT height we've seen. The 50mm will help, but the other parts of the model like wheel aches and wells etc, are unlikely to be the same in the production model. In particular having RWS means they can tighten up the front wheel well dimensions considerably and rear wheels need to be shrouded and have aero mudguards to guide airflow.

Plus that air curtain from the front. The air curtain can actually be used for better form air on the sides of the vehicle when it seperates off the rear.

 

[Tinker71]

Pretty good dive into it here. The difference is not huge but a difference none the less.

Insert from MythBusters - Tailgate Up or Down 2 (from More Myths Revisited) fuel consumption test - YouTube

I dare you to contact them to redo the test at 75 mph.

 

[electricAK]

The high CT bed sidewalls and long angled rear roof glass will help a lot with creating clean airflow even with a open vault cover, provided nothing is sticking out.

I'd love to see a CFD simulation that compares the CT with vault cover open vs closed. I agree the bed is so protected that open vault cover might be totally fine. Those side wings are awesome.

Again, I'd argue the reason the side wings exist is for aerodynamics, not for looks. The look/style of the CT is a derivative of aerodynamic design, not the other way around. (Except the sharp angles...that was just to make it look digital/futuristic)

 

[JBee]

I think the side wings were are leftover from just making a sharp edged wedge shape with the right proportions to slice through the air like a stealth bomber. (Like the side picture on my first post)

Even the roof apex angles and side window slant aren't random. The design equation was how do we get a polygon with the least amount of sides to slip through the air.

 

[JStat]

I'd like to see a third-party parts supplier to manufacture a diffuser for this truck.

 

[rr6013]

I think you may be misreading things. I see the following in your links:
"<Snip>

Good catch!
Went back over my reading history and reread. It was a misread.
Thx.

 

[Diehard]

can someone explain why cone has a better Cd than angled cube? I have a hard time believing if we cut off CT in half, we get better range.

and why streamlined body has a better Cd than half of it?

I wonder what is the Cd on this:

 

[JBee]

can someone explain why cone has a better Cd than angled cube? I have a hard time believing if we cut off CT in half, we get better range.

and why streamlined body has a better Cd than half of it?

I wonder what is the Cd on this:

The best way to visualise Cd is to imagine that any change of airflow around a body creates the "displacement of air particles", and displacement causes those particles to give up their inertia (they naturally want to stay where they are) which creates a opposite reaction force.

Simply, air does not want to move, but if you move it you need to move it in such a way that it comes back to it's original state with the smallest amount of change. So ideally you'd have a shape that puts everything back exactly where it came from.

In the case of the cone vs angled cube, the cone is round, and therefore angled in 3D from one single point of air penetration. This is not shown correctly in the 2D picture you posted where the cube has a unspecified length line and is not a point. So cutting the CT doesn't help aerodynamics either.

As for the half streamlined body, that shape is actually the shape of a airfoil wing, meaning it will create "induced drag" and also lift in the direction of the curved surface. Lift costs energy and is not for free, so the Cd is higher.

 

[CyberGus]

This thread is a real drag

 

[Diehard]

The best way to visualise Cd is to imagine that any change of airflow around a body creates the "displacement of air particles", and displacement causes those particles to give up their inertia (they naturally want to stay where they are) which creates a opposite reaction force.

Simply, air does not want to move, but if you move it you need to move it in such a way that it comes back to it's original state with the smallest amount of change. So ideally you'd have a shape that puts everything back exactly where it came from.

In the case of the cone vs angled cube, the cone is round, and therefore angled in 3D from one single point of air penetration. This is not shown correctly in the 2D picture you posted where the cube has a unspecified length line and is not a point. So cutting the CT doesn't help aerodynamics either.

As for the half streamlined body, that shape is actually the shape of a airfoil wing, meaning it will create "induced drag" and also lift in the direction of the curved surface. Lift costs energy and is not for free, so the Cd is higher.

This even answers the questions I didn’t know I have. I wish some of my professors were half as gifted in communication.

 

[WHIZZARD OF OZ]

https://electrek.co/wp-content/uploads/sites/3/2022/07/1657882323685.mp4

Tesla Cybertruck electric pickup surprises in aerodynamic performance simulation

Now a new study of the Tesla Cybertruck’s aerodynamic performance shows that the electric pickup truck has a drag coefficient of about 0.39 Cd.

Aleix Lázaro Prat, a CFD Engineer for Numeric Systems, used the company’s aerodynamic simulation technology to produce the study that they released on LinkedIn.

The engineer shared the positive aspects of the design from his study:


However, he also saw plenty of room for improvement:


It’s important to note that Numeric Systems don’t have the final geometry of the Cybertruck, and therefore, it shouldn’t be completely representative of the final product.

There are factors like the lack of side mirrors that we don’t know if or how will be implemented in the production version of the truck next year.

When first revealed in 2019, l ran some 'guesstimates' on Cd for CT and shared that the most likely would be at Cd 0.33 with a best case Cd 0.30

Elon wrote something along the lines of 'it should have Cd 0.30'