GM vs Cybertruck battery size & $

[PilotPete]

These days, FEA behind the simulations are mighty accurate and it is not that magical. It is just matter of how accurate the model is. CT is definitly great (If you drive fast a lot).

https://electrek.co/2022/07/26/tesl...surprises-aerodynamic-performance-simulation/

What I am really curious about is how a Cyber SUV/Station Wagon/Van Cd differ from CT. And will we get one?

Add the mirrors, And then look at the airflow in that area. After that, add a small 30degree wedge in front of that piece, and see if there is any difference around the back of the tailgate.

Sometimes you intentionally add “energy” into the airflow to help the air adhere to a surface or make a turn somewhere. Look at a modern F1 car as an example.

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[SparkChaser]

Add the mirrors, And then look at the airflow in that area. After that, add a small 30degree wedge in front of that piece, and see if there is any difference around the back of the tailgate.

Sometimes you intentionally add “energy” into the airflow to help the air adhere to a surface or make a turn somewhere. Look at a modern F1 car as an example.

Aircraft have vortex generators to maintain laminar flow.

 

[scottf200]

If by real world you mean highway range, yes. However neither the R1T nor Lightning will get those numbers either when cruising at highway speeds. The Cybertruck will in all likelihood take a bigger hit relative to its EPA range compared to their competitors, just like other Tesla vehicles. When towing in particular, pack size will be king.

My angle for the 1000 lbs was once it you are at cruising speed ... ie. not accelerating.

" The weight difference will be insignificant ... once you are at speed. "

These days, FEA behind the simulations are mighty accurate and it is not that magical. It is just matter of how accurate the model is. CT is definitly great (If you drive fast a lot).

https://electrek.co/2022/07/26/tesl...surprises-aerodynamic-performance-simulation/

What I am really curious about is how a Cyber SUV/Station Wagon/Van Cd differ from CT. And will we get one?

Add the mirrors, And then look at the airflow in that area. After that, add a small 30degree wedge in front of that piece, and see if there is any difference around the back of the tailgate.

Sometimes you intentionally add “energy” into the airflow to help the air adhere to a surface or make a turn somewhere. Look at a modern F1 car as an example.

I posted areo pict and info in a standalone thread but can't find it (admin has delete threads?). Anyway there is a post on it. https://www.cybertruckownersclub.co...cybertruck-dimensions.8233/page-9#post-144241

 

[sstevens805]

I have a R1t and in conserve mode it is rated at 350 miles which is easy to obtain (large pac with 21" wheels) but best to use all purpose around town to save tire wear.

Can you explain the tire wear? Does the suspension lower in conserve and change camber angles increasing wear on the inside treads?

 

[PilotPete]

Aircraft have vortex generators to maintain laminar flow.

Some do. I’ve seen 23 VGs on the single side of a wing. Technically, it’s not laminar when you introduce VGs, but you are correct that the purpose is to energize the airflow to keep it attached to some surface. And the F1 cars have them by the dozens. There are other aero devices that conceptually do the same thing, but they aren’t VGs.

There is this paper on their use in cars… https://www.semanticscholar.org/pap...ubey/5db427e242a6ad66124c343888e956edbe2955f7

 

[cmugler]

with R1T the tire wear in conserve mode is caused by all the power going to front tires, if you do gentle starts tires are fine, I use conserve mode on trips and all purpose (power goes to both axles) locally

 

[Diehard]

My angle for the 1000 lbs was once it you are at cruising speed ... ie. not accelerating.

" The weight difference will be insignificant ... once you are at speed. "


I posted areo pict and info in a standalone thread but can't find it (admin has delete threads?). Anyway there is a post on it. https://www.cybertruckownersclub.co...cybertruck-dimensions.8233/page-9#post-144241

Very interesting about the vortex. Would have never thought of it. However I think the dude was going a bit overboard with making everything sound like an aerodynamic design choice.

 

[cvalue13]

If we go down that rabbit hole, how often truck owners use bed of the truck? or car owners drive their cars during ownership? Taxi and trains seem to be the solution not CT.

a bit different of a rabbit hole

assuming you're in the car-making business, you’re left next only with the issue of whether you have or can fit 200kWh in a given platform

 

[scottf200]

with R1T the tire wear in conserve mode is caused by all the power going to front tires, if you do gentle starts tires are fine, I use conserve mode on trips and all purpose (power goes to both axles) locally

On my 2017 Model X, I have 'range mode' that biases the rear over the front and I use it for road trips. Not sure what is going on with the Rivan, but I do not seem to have excess tire wear on front vs rear.

Note that any acceleration and the front immediately "kicks in."

Testing using ScanMyTesla software connected to canbus.

With range mode

Regen uses both still.

 

[HaulingAss]

That VIN comes back to a 2012 Volt, so probably not under warranty. However, I'd bet that battery is repairable.

I would bet the battery is totally trashed. It's ancient technology, not even on par with a 2012 Model S.

And it's a hybrid.

 

[HaulingAss]

If we go down that rabbit hole, how often truck owners use bed of the truck? or car owners drive their cars during ownership? Taxi and trains seem to be the solution not CT.

Our F-150 doesn't even get started up unless we are going to tow or use the bed.

Of course, my Cybertruck will not follow that rule at all! At least not for the first year or two.

 

[HaulingAss]

These days, FEA behind the simulations are mighty accurate and it is not that magical. It is just matter of how accurate the model is. CT is definitly great (If you drive fast a lot).

Computer simulation is still a bit limited when doing drag analysis, even using an accurate model, which is why it's still followed up with wind tunnel testing. The image above does not show what's going on with the airflow as it leaves the rear of the vehicle which is incredibly important for a low Cd. For all we know, the turbulence circled area at the rear window could assist with the airflow filling in behind the Cybertruck more efficiently.

 

[Diehard]

Computer simulation is still a bit limited when doing drag analysis, even using an accurate model, which is why it's still followed up with wind tunnel testing. The image above does not show what's going on with the airflow as it leaves the rear of the vehicle which is incredibly important for a low Cd. For all we know, the turbulence circled area at the rear window could assist with the airflow filling in behind the Cybertruck more efficiently.

Image above does not but the link I provided shows exactly what happens to the air flow. I do get your point that it could potentially assist but this kind of assistance to me is like tax right off. It may be reducing the damage somewhere else but even if it does, it often causes more damage than it reduces.



I am not a pro and have no working experience in the area but if I have to assume turbulence is good or bad, I always assume it is bad. Moving air molecules takes energy. In a turbulent motion, you increase the distance air molecules have to travel and overall increase the speed at which they travel. That is more energy.

On simulations, a lot of companies already doing a bulk of their testing in simulation. Boeing is planning to tackle the problems they have had lately by doing their design and testing in virtual world and hand it off to robots for building. Real world is already mostly obsolete. How do you really know I am not a chat bot? For that matter, do you really know for a fact you are not one? Can you prove it?


Edit: speaking of drag, anyone here itching to do math, can tell me how much a truck with .46 Cd have to reduce it‘s speed from 80 mph to waste the same amount of energy as one with .3 at 80 mph? All other things being equal, I get 64.6 mph. Is that right?

 

[PilotPete]

I am not a pro and have no working experience in the area but if I have to assume turbulence is good or bad, I always assume it is bad. Moving air molecules takes energy. In a turbulent motion, you increase the distance air molecules have to travel and overall increase the speed at which they travel. That is more energy.

Edit: speaking of drag, anyone here itching to do math, can tell me how much a truck with .46 Cd have to reduce it‘s speed from 80 mph to waste the same amount of energy as one with .3 at 80 mph? All other things being equal, I get 64.6 mph. Is that right?

D,

Regarding turbulence, it is not that simple. As some of us discussed, there are devices called "VGs" or Vortex Generators. They intentionally create little vortexes, or "tornados". That is "turbulence" or energized airflow. But this energy allows the air to flow over a surface that it wouldn't be able to follow without it. Do they cause some level of drag? Yep! But the small amount they cause is offset by the additional lift, or elimination of drag to a much larger area. Again, look at a modern F1 car. They have little curved spikes all over the car. They are there to manage the airflow either away from something, or towards something, or to keep the flow attached to a surface for one reason. Golf balls are the greatest common example of "a little turbulence is a good thing". Take the turbulence from the dimples away, and you can't get the ball to travel anywhere near as far. Or to put it in more grasp-able terms, I still can't hit a dimpled ball as far as John Daly could hit a smooth ball, but a serious golfer could.

As for your cd truck comparison, assuming all else is equal (tires, size, temp, rolling resistance, etc) this is what I get...

Fair=0.5∗Cd∗A∗rho∗V2

Where:
Fair is the air resistance force (the force that opposes the motion of the truck).
Cd is the coefficient of drag (0.46 for one truck and 0.3 for the other).
A is the frontal area of the truck.
rho is the air density.
V is the velocity of the truck. (V2 is "Squared")

Off the top of my head, and only 1/2 way through my coffee after flying through 9 time zones yesterday, this is the equation;
0.5∗0.46∗A∗rho∗(802)=0.5∗0.3∗A∗rho∗(80−x)2
(again, the little 2 means squared)
Since I let the app do my math due to my severe lack of caffeination and extreme laziness, I get;
x≈−24.71

Meaning that the 0.30cd going 80 has roughly the same drag as the .46cd doing 55.29.

 

[Crissa]

I definitely could hit a dimpled ball further than a smooth ball, and that's all that mattered to me.

-Crissa

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