Spoiler/wing on the roof for less drag

[Ingemar]

I’m wondering if a spoiler or wing around the upper edge of the roof would reduce aerodynamic drag? A more rounded shape to direct airflow back down? Could also be a roof rack bar or a led bar.

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[Crissa]

I don't think that would work.

-Crissa

 

[HaulingAss]

I’m wondering if a spoiler or wing around the upper edge of the roof would reduce aerodynamic drag? A more rounded shape to direct airflow back down? Could also be a roof rack bar or a led bar.

The aerodynamic computer simulations I've seen have shown the angle of the roof break to be gentle enough that there is no significant separation of the airflow in that region. This is no mistake as the aerodynamics of the Cybertruck were specifically designed to allow more range with a less expensive battery. That's a primary reason why the Cybertruck is so much better of a value than the other electric trucks that have been revealed.

That the airflow remains unseparated implies a spoiler would do more harm than good.

 

[Ingemar]

The aerodynamic computer simulations I've seen have shown the angle of the roof break to be gentle enough that there is no significant separation of the airflow in that region. This is no mistake as the aerodynamics of the Cybertruck were specifically designed to allow more range with a less expensive battery. That's a primary reason why the Cybertruck is so much better of a value than the other electric trucks that have been revealed.

That the airflow remains unseparated implies a spoiler would do more harm than good.

I am not surprised. Usually when I have an idea, Tesla has already thought of it better

 

[Ogre]

The aerodynamic computer simulations I've seen have shown the angle of the roof break to be gentle enough that there is no significant separation of the airflow in that region. This is no mistake as the aerodynamics of the Cybertruck were specifically designed to allow more range with a less expensive battery. That's a primary reason why the Cybertruck is so much better of a value than the other electric trucks that have been revealed.

That the airflow remains unseparated implies a spoiler would do more harm than good.

Indeed.

Aerodynamics and efficiency is extremely important for every product Tesla makes. To increase range you can either put a bigger battery in, or make the vehicle more efficient. Tesla always chooses to make the vehicle more efficient first.

Remove weight, improve aerodynamics, repeat.

You can bet if there were any easy wins here Tesla has tried them.

 

[JBee]

There could be a benefit to it to smooth out the apex, but it would probably also need to direct airflow in such a way that the airflow around the sides, that meets behind the CT on the vault, so it doesn't create more turbulence.

I've "plaid" around with the CT aero in a fluid dynamics simulator for the camper roof I designed a while back when it first came out, and the effect of changing the apex is fairly trivial because of the ramp over angle. Structurally it could of been round, and even lower, (there's enough space inside for headroom) but I'm pretty sure they went for the sharp apex to keep the design aesthetic knowing the impact was minimal. BTW there is airflow separation after the apex, but it is minimal so the airflow still remains mostly laminar across the back. This is of course with the vault closed, if it's open it is worse, but is moderated by the side wings as this directs airflow across the back as well to keep it moving in the right direction.

The thing I'm uncertain of is the wheel arch and tyre aero, as they are quite exposed on the prototype. I'm expecting the CT to hunker down whilst in highway cruise to reduce the effects, but according to my drawings it won't have less than 200mm clearance, because the tyres touch the arches, which is still quite a bit for airflow underneath. The overall shape also creates dynamic lift at speed btw, so it gets lighter the faster you go.

 

[mhaze]

I’m wondering if a spoiler or wing around the upper edge of the roof would reduce aerodynamic drag? A more rounded shape to direct airflow back down? Could also be a roof rack bar or a led bar.

This might help in boat mode and certainly would help in submarine mode.

 

[Greshnab]

This might help in boat mode and certainly would help in submarine mode.

no submarine mode.. ct's don't sink!!
laughs we will see at least.'

 

[MiguelAznar]

Yeah, but the Titanic didn’t have a spoiler on the roof

 

[Newton]

I wonder at what speed the sharp point would start to drastically reduce efficiency. I love aerodynamics, and being a motorcycle rider, you can feel what the "wind" is doing behind some vehicles. its pretty cool. my complete random guess is somewhere around 85+ it will start to create more turbulence rather than just kinda flow over.

 

[cvalue13]

Yeah, but the Titanic didn’t have a spoiler on the roof

Titanic’s “spoiler” was starboard, just below waterline

 

[Jhodgesatmb]

This might help in boat mode and certainly would help in submarine mode.

I think you can be quite certain that Elon/Franz/Tesla are going to eke out every drop of aerodynamic advantage possible for the Cybertruck and that anything you add on will reduce that advantage but definitely go for it!

 

[PilotPete]

I wonder at what speed the sharp point would start to drastically reduce efficiency. I love aerodynamics, and being a motorcycle rider, you can feel what the "wind" is doing behind some vehicles. its pretty cool. my complete random guess is somewhere around 85+ it will start to create more turbulence rather than just kinda flow over.

The airflow won't separate from the vehicle based on speed. (not until you get transonic, which isn't a concern on the CT) You either have flow separation or you don't. People assume that if you take your tailgate off on a normal truck you improve your mileage. Actually, the reverse is true.

I think you might see a difference in the range with the cover closed vs. open. That is the number I want to know most. That will tell me how well the flow follows the roofline. And the parasitic drag from a spoiler or wing will outweigh any benefit created from soothing the flow. The one thing I could think might help is a set of vortex generators. You see them on the mitsubishi rockets. They are the little triangles across the top of the back windows (not the optimum spot for them). They create little vortices that energizes the airflow and helps it follow the curve of the window as it drops faster than the air wants to change direction. I might even get a stick on test set and put them on my CT and see if it has a range effect. This might help keep the airflow attached to the car over the top and down the back.

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