Any updates?

BillyGee

Well-known member
First Name
Bill
Joined
Jan 22, 2020
Messages
466
Reaction score
838
Location
Northern California
Vehicles
F350, Yamaha Stryker
Occupation
Technician
Country flag
Solar built-in panel:
I always said the built-in Solar using the vault cover is not that good of an idea. I want my solar panel to follow the sun, not set in stone on the back of the vault which I constantly need access too.

Vault cover:
I don‘t think it should be a mandatory feature. It should be an option. Looking at the vault cover design, the panel has to fold back from the back of the passenger cabin. It makes it harder to have a fold-down back wall so that passenger can get-through from/to the back & front space.
It won't produce much unless there's some kind of passive solar tracking mode you can park the truck in, but it'll still basically be a trickle charger. I can see why most people wouldn't see the benefit, but it's more just a "rule of cool" thing at the end of the day. It'll be nice for when you leave your CT parked at an airport and things like that, but most people wouldn't even notice the few miles it gains most of the time under normal solar conditions.

As for the pass through, I highly doubt we're getting a fold down there, maybe the rear window will retract down for a pass through, but as it stands with the patent filings it looks like the tonneau track will run up the spine of the backseat. Even if it comes standard you can always just leave it rolled up.
Advertisement

 

JBee

Well-known member
First Name
JB
Joined
Nov 22, 2019
Messages
434
Reaction score
435
Location
6000
Vehicles
Cybertruck
Country flag
@Diehard and @Crissa (and @BillyGee on the subject of leaving the vault open)

1624778056298.png


As above, there are only two variables in the vehicle structure that can be varied to reduce aerodynamic drag, either the frontal area, which is the total largest cross section of the vehicle
(typically occurs a the apex of the F150 and CT roof and is a easy to verify value because it can be directly measured) and the Cd drag co-efficient that is due to its shape which is normally calculated experimentally.

Hence removing the F150 frunk, hood, and even the whole front assembly will have zero impact on reducing the cross sectional area of the F150. So we can ignore that part. The skin resistance drag at highway speeds is also irrelevant on smooth surfaces of this length.

That leaves us with induced drag and parasitic drag as "form" drag.

The CT most definitely will have some induced drag, especially if it is driven around like we have seen in videos with about 260mm (10") of ground clearance. That is because the CT profile is essentially a Stealth bomber wing shape and will produce upward lift if enough airflow is deflected. That lift will reduce the lower the CT is set to the ground, but it's pretty clear it will have some lift. Lift is not always a bad thing though, because it also reduces rolling resistance, especially with knobby off road tyres, but at the cost of downforce and traction. Downforce is probably something that won't matter to most truck drivers cruising on a straight highway, and given it could actually help boost range, probably a beneficial tradeoff anyway.

That leaves us with form drag, which is a direct result of the shape that is used to change the oncoming airflow and is a large part of the Cd value in vehicles that don't want to fly:

%2F2%2F2%2F5%2F2%2F22529068%2Fdragcoefficient_orig.png


As you can see from the air flow lines in blue, form drag is typically the result of the airflow either changing direction to fast or not being able to stay laminar whilst navigating the object resulting in what is known as turbulent flow.

aero3.jpg


Turbulent flow is caused by the separation of the smooth laminar airflow over a surface, (as can be seen on top right of the airfoil above) into little vortices that in turn drag as they in turn retard the passing air further away from the body essentially increasing the objects cross section.

BTW This is one of the reasons the CT wants to get rid of the mirrors, because their apparent drag can be visualized as being some 3-4x the size of the mirrors themselves. (See Cd of cone above).
Technically a video camera setup and screen will likely result in better peripheral rear facing vision anyway if done correctly.

This leads us to a CT Vs standard truck comparison (from a fan btw, as there is little no aero info from Ford n Co)

Aerodynamics-Cybertruck-Ram-Raptor.jpg


If you compare the Cd shapes image with the one above it becomes clear what is the main cause for improved range on the CT in comparison to Ford n Co. is actually the tapered closed vault of the CT that reduces the drag, not the "pointiness" of the front of the vehicle. This is because on a standard truck design airflow already becomes turbulent at the rear window and does not more smoothly flow back together like on the CT. You can even see the blobs of blue turbulence in the simulation. As above with the wing this turbulence results in vortices that cause even more drag and retard the vehicle.

This phenomenon is clearly evident when F1/Nascar cars or semi trucks slipstream eachother by driving close behind eachother. In fact slipstreaming trucks is known to improve the efficiency of both trucks, even the one in front, as the turbulent drag component is displaced behind the rear of the last truck. (see AU roadtrains for comparisons)

130705-cuer-better-image.jpg


A solar car like above has a Cd of around 0.1. Ct is about 0.3. This photo further proves that a blunt nose is ok so long the rear is tapered to minimize flow separation.

This is the main purpose of the sloping CT rear design, including side wings, and inclusion of the vault cover.

Once again what is housed underneath the exterior skin of the vehicle, be that frunk, cabin or whatever, is irrelevant to drawing conclusions about its capability to reduce drag.
 
Last edited:

Crissa

Well-known member
First Name
Crissa
Joined
Jul 8, 2020
Messages
5,923
Reaction score
7,787
Location
Santa Cruz
Vehicles
2014 Zero S, 2013 Mazda 3
Country flag
Once again what is housed underneath the exterior skin of the vehicle, be that frunk, cabin or whatever, is irrelevant to drawing conclusions about its capability to reduce drag.
No, it's not.

The exterior skin of the vehicle has to accommodate whatever shape 'what's housed underneath'. If you put a giant box, like the Lightning has, you end up with a less-good shape.

-Crissa
 

JBee

Well-known member
First Name
JB
Joined
Nov 22, 2019
Messages
434
Reaction score
435
Location
6000
Vehicles
Cybertruck
Country flag
No, it's not.

The exterior skin of the vehicle has to accommodate whatever shape 'what's housed underneath'. If you put a giant box, like the Lightning has, you end up with a less-good shape.

-Crissa
Ok so not the frunk rather it's form/shape.

The Ct has the same effective volume in front of the passenger cabin as the Lightning. The only difference is the windscreen rake and tapered rear superstructure.
(The CT can fit the same size frunk as the Lightning btw)
 

Diehard

Well-known member
First Name
D
Joined
Dec 5, 2020
Messages
1,124
Reaction score
2,043
Location
U.S.A.
Vehicles
Olds Aurora V8, Saturn Sky redline, Frontier, CT2
Country flag
Hence removing the F150 frunk, hood, and even the whole front assembly will have zero impact on reducing the cross sectional area of the F150. So we can ignore that part. The skin resistance drag at highway speeds is also irrelevant on smooth surfaces of this length.
I am not sure what you mean but removing frunk has no impact and why we are talking about it. F150 frunk is a square block, removing it has less impact but still some since the shape of inside of the trunk and it's added surface roughness will increase friction, turbulence and as a consequence CD. Removing CT's frunk will do much more damage to CD as you are turning the cone to cube.

1624797377952.png


It would be more like this for CT and F150:

1624798805854.png



I still feel like I am missing your point about removing frunk. If you are saying that only cross sectional area of the object that matters, even in that regard based on your own post CT has a smaller area. As you can see on top F150 is higher and at the bottom it is lower.


1624799089032.png



The Ct has the same effective volume in front of the passenger cabin as the Lightning.
If you lower CT so that the bottom line of the two align, it becomes more evident how much larger F150 frunk is. besides part of the volume in CT is in cabin not frunk.

Think about it: Ford has all the info about CT that you do (may be more if they have a double agent planted in Tesla). Would they make such a big deal about the funk if they were not sure it will beats CT?

If you compare the Cd shapes image with the one above it becomes clear what is the main cause for improved range on the CT in comparison to Ford n Co. is actually the tapered closed vault of the CT that reduces the drag, not the "pointiness" of the front of the vehicle.
Although I agree that front may not be as important as the back (Keep your mind out of the gutter), in this image they have superimposed the truck on top of the graph so you can not see how much smaller blue area is in CT behind the truck due to the pointy nose.

1624800337910.png
 
Last edited:

JBee

Well-known member
First Name
JB
Joined
Nov 22, 2019
Messages
434
Reaction score
435
Location
6000
Vehicles
Cybertruck
Country flag
I am not sure what you mean but removing frunk has no impact and why we are talking about it. F150 frunk is a square block, removing it has less impact but still some since the shape of inside of the trunk and it's added surface roughness will increase friction, turbulence and as a consequence CD. Removing CT's frunk will do much more damage to CD as you are turning the cone to cube.

1624797377952.png


It would be more like this for CT and F150:

1624798805854.png



I still feel like I am missing your point about removing frunk. If you are saying that only cross sectional area of the object that matters, even in that regard based on your own post CT has a smaller area. As you can see on top F150 is higher and at the bottom it is lower.


1624799089032.png





If you lower CT so that the bottom line of the two align, it becomes more evident how much larger F150 frunk is. besides part of the volume in CT is in cabin not frunk.

Think about it: Ford has all the info about CT that you do (may be more if they have a double agent planted in Tesla). Would they make such a big deal about the funk if they were not sure it will beats CT?



Although I agree that front may not be as important than back (Keep your mind out of the gutter), in this image they have superimposed the truck on top of the graph so you can not see how much smaller blue area is in CT behind the truck due to the pointy nose.

1624800337910.png
The discussion resulted from Crissas statement that the large F150 frunk would reduce its range. Fact is only the shape and cross section area affect drag.

Its likely the Ct roof is lower, but we were only taliking about the F150 frunk. The F150 frunk does not increase the total cross section in any way.

I'll make the effort to accurately compare both vehicles size by scaling a F150 photo and placing that in my CT Cad model. That should make things clearer.
 

Diehard

Well-known member
First Name
D
Joined
Dec 5, 2020
Messages
1,124
Reaction score
2,043
Location
U.S.A.
Vehicles
Olds Aurora V8, Saturn Sky redline, Frontier, CT2
Country flag
The discussion resulted from Crissas statement that the large F150 frunk would reduce its range. Fact is only the shape and cross section area affect drag.

Its likely the Ct roof is lower, but we were only taliking about the F150 frunk. The F150 frunk does not increase the total cross section in any way.

I'll make the effort to accurately compare both vehicles size by scaling a F150 photo and placing that in my CT Cad model. That should make things clearer.
I think the arguments are over language more than physics. I know the whole thing is an intellectual exercise but at the end of the day we are stuck with what they produce and will have to Wait until a mortal can get his/her hands on the real thing and review. It is summer, we should get out and enjoy life before next Corona wave hits. I am going for a bike ride.
 

JBee

Well-known member
First Name
JB
Joined
Nov 22, 2019
Messages
434
Reaction score
435
Location
6000
Vehicles
Cybertruck
Country flag
I think the arguments are over language more than physics. I know the whole thing is an intellectual exercise but at the end of the day we are stuck with what they produce and will have to Wait until a mortal can get his/her hands on the real thing and review. It is summer, we should get out and enjoy life before next Corona wave hits. I am going for a bike ride.
No worries. Not looking for an argument. Just useful info. Until the CT came around I was going to get a F150. So both interest me.

Enjoy your bike ride, nearly time for bed for me!
 

Rockvillerich

Active member
First Name
Richard
Joined
May 18, 2020
Messages
39
Reaction score
28
Location
Rockville MD
Vehicles
Cybertruck, tri-motor, and dual motor.
Occupation
Machine fabrication
Country flag
Has there been any news as to when the final design is going to be released? Seems like it was meant to happen a long time back now.
Six months while a million reservation holders continue to wait and wonder.
 

ecotrials

Member
First Name
Paul
Joined
Feb 3, 2020
Messages
17
Reaction score
23
Location
Lafayette, CA (SF Bay Area)
Vehicles
GMC Sierra, electric trials bike
Occupation
Retired
Country flag
Lots of talk about pass through and frank, bit nothing about a noise canceling cabin.

This inferred from Plaid delivery day discussions. Should be great for those opting for off-road tires, even though it will still be loud for folks outside the cabin :) .
Even with high mileage freeway tires it should allow for a quite cabin.

Of course I am ASSUMING this feature will be available for the CT.
 

Diehard

Well-known member
First Name
D
Joined
Dec 5, 2020
Messages
1,124
Reaction score
2,043
Location
U.S.A.
Vehicles
Olds Aurora V8, Saturn Sky redline, Frontier, CT2
Country flag
Lots of talk about pass through and frank, bit nothing about a noise canceling cabin.

This inferred from Plaid delivery day discussions. Should be great for those opting for off-road tires, even though it will still be loud for folks outside the cabin :) .
Even with high mileage freeway tires it should allow for a quite cabin.

Of course I am ASSUMING this feature will be available for the CT.
Nothing is worse than noise when you are taking a nap with eyes drawn on the back of your eyelids to fool FSD.
 

exdxgxe4life

Member
Joined
Jul 16, 2020
Messages
11
Reaction score
8
Location
53150
Vehicles
Cybertruck
Country flag
I'd notice it. I drive about 14 miles to work and park in the CO sun everyday for the next 8-10 hours. It would make my commuting costs next to nothing.
I'm the same as you, but the electricity cost would take you probably 10 or more years before the solar panels would break even. I still want it though
 
Advertisement

 
Advertisement
Top