Cybertruck frame in scrap yard shows no midgate and other details

[CybertruckAgent]

Aircraft bodies are notably flexible, and have serious amount of "flex". They also have a more structural skin.

A naked F150 ladder frame weighs about the same as the SS skin of the CT, but admittedly does more for it's structural load carrying capacity than the SS skin, in particular for load carrying and towing.



Unibody is a close cousin to the CT, but I think the casts give it a bit of differentiation. I don't have a problem with how a structure works as such, in the end a good design is the best possible compromise of various competing variables. In this case a cast is there to reduce part counts and improve integration at the lowest possible cost.

From what I can tell there isn't much in the mounting brackets that we can see on the CT rear fender skins to transfer load through them. I also don't think the skin will be foamed or glued onto the cast or cabin for ease of repairability, and to avoid thermal stresses. The aluminium cast also has a different thermal expansion rate than the SS, so attaching them is not a trivial task to make them load bearing, let alone for galvanic reasons.

Couldn’t have said it better

although aircrafts don’t tow and often have low payloads, still apples and oranges.

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[HaulingAss]

Yes it’s a conundrum to non-engineers, but pickups need both strength and flex in the frames, that’s part of the reason the box is separate from the cab on traditional trucks. Not saying a unibody truck doesn’t work, because again the Ridgeline does work, it’s just not heavy duty and its design is more for everyday drivability than hard work, which I think is CT’s target audience.

This is the kind of engineering expertise and logic I expect to see from a realtor. I imagine you might have more expertise when it comes to helping your clients purchase their dream home.

 

[Stuck4ger]

I'm a retired Aviation Ordnanceman, when I saw that in the movie, all I thought was man, could I load some aircraft with that thing....... And I might not have two spinal fusions today

Navy or Marine, am I right?

 

[HaulingAss]

Aircraft bodies are notably flexible, and have serious amount of "flex". They also have a more structural skin.

This is false. Airplane wings are purposefully designed to have "serious amounts of flex" in a horizontal direction and as little twisting flex as reasonably feasible. The flexy nature of the wings acts like a suspension for a plane flying through turbulence. Airplane fuselages, while they do unavoidably flex a small amount under peak landing loads, are actually designed to be rigid, relative to the wings, because it's important for control of the airplane in flight, particularly when taking off and landing, that the horizontal stabilizer does not change attitude, relative to the wings. A flexible fuselage would have the effect of unintended control inputs which would be undesirable in all situations.

 

[CyberGus]

To me this has always been a curiosity of the seemingly conflicting forum assertions on how ‘rigid’ the CT is bring the source of *greater* payload/towing

I think the problem is that thin panels will will bend or shear if they are installed to resist torsional forces. Thicker panels that take the stress if they are firmly affixed.

 

[newwave1331]

Corporate officers have never been limited to one title. And, indeed, neither is Elon. His current, and longest-running, title is CEO. In fact, no other automaker has a CEO with as much tenure as Elon Musk.

Your curb weight is too light for a 500+ mile model, but please explain your "25% regen". That sounds like a lot of braking to me. Curb weight will generally have a smaller influence on real world range compared to how much regen braking there is. I think around 185 kWh of usable capacity is a good estimate for 500 miles of range.

The Technoking comment was more of a joke.

https://www.batterydesign.net/tesla-cybertruck-and-battery-pack/

I was using this website tool to rate the efficiency and their resulting logic to rate range with a 25% gain for regen. I have doubts that a 500 mile pack fits in cybertruck with today's energy density. I estimate about 1200 batteries per layer, so 2400 max with two layers.

0.3 Cd is far-fetched, maybe 0.34 with the diaper. As for weight, I believe a pack with 2376 cells is more about 7800 pounds. I ran the number before off some wild ass predictions I've heard on X spaces. They were saying 500 miles was coming from a 130kWh pack @ less than 6000 pounds .

These are my projections using the website tool.

 

[JBee]

This is false. Airplane wings are purposefully designed to have "serious amounts of flex" in a horizontal direction and as little twisting flex as reasonably feasible. The flexy nature of the wings acts like a suspension for a plane flying through turbulence. Airplane fuselages, while they do unavoidably flex a small amount under peak landing loads, are actually designed to be rigid, relative to the wings, because it's important for control of the airplane in flight, particularly when taking off and landing, that the horizontal stabilizer does not change attitude, relative to the wings. A flexible fuselage would have the effect of unintended control inputs which would be undesirable in all situations.

No, fuselage flex is real and is most noticeable on long slender fuselage like 757/MD80 etc. It wiggles like a pool noodle. Steady state attitude control is why they invented trim and many larger aircraft are FBW anyway, and there pilots only interact with control surfaces through computers that calculate moment to moment changes. (Even my 3kg evtol 120km range UAV has this)

F35 and F22 are actually "unstable airframes" that cannot fly without FBW, this is what gives them both their manoeuvreability and efficiency for range, because any naturally balancing wing induced forces, come at a cost to flight performance. Also a big reason why F35 was delayed.

Accordingly, both fuselage and wing flex (which admittedly is more by design) are controlled by active attitude control. (Along with stall prevention, auto throttle etc)

I remember once going for an aerobatic lesson in a A152, once I got to the top of a loop, both of the doors burst open while we were both hanging in our seatbelts. Caught the instructor by surprise but had no impact on flying or controlling the aircraft. But boy was that thing a pig to fly, so gutless, took us like 15min to climb to enough altitude to do it...only used the larger 172 after that, but that wasn't much faster either. In the 152 I could basically put my arm around the instructor and use his yoke instead, seeing that having your right hand on the throttle had little to no effect anyway.

The only way to make that thing go faster to where you wanted to go, was to go nose down, and make sure you booked a connecting flight to heaven.

 

[Bill837]

Navy or Marine, am I right?

Yep, Army and AF refer to themselves as either Ammo troops or Armament troops. Oddly they use the same exclamation with only the A or O being used...

 

[Rutrow]

The good news is that the Cybertruck has a midgate.
The bad news is that it's only for squirrels

Are you trying to change the CyberTruck standard unit of measurement?!? Somebody's not gonna be happy...

 

[JBee]

The Technoking comment was more of a joke.

https://www.batterydesign.net/tesla-cybertruck-and-battery-pack/

I was using this website tool to rate the efficiency and their resulting logic to rate range with a 25% gain for regen. I have doubts that a 500 mile pack fits in cybertruck with today's energy density. I estimate about 1200 batteries per layer, so 2400 max with two layers.

0.3 Cd is far-fetched, maybe 0.34 with the diaper. As for weight, I believe a pack with 2376 cells is more about 7800 pounds. I ran the number before off some wild ass predictions I've heard on X spaces. They were saying 500 miles was coming from a 130kWh pack @ less than 6000 pounds .

These are my projections using the website tool.

I'd like to start a new dedicated thread tomorrow to discuss CT performance, charge and range predictions and calculations in detail. These interest me.

 

[cvalue13]

I think the problem is that thin panels will will bend or shear if they are installed to resist torsional forces. Thicker panels that take the stress if they are firmly affixed.

well, I was pointing out the flip side of that coin, which view would go:

to achieve payload and towing performance, requires frame flex (up to a point of failure)

as a result , you don’t want panels ‘in the way’ of that flex

Not suggesting there’s not some theoretical alternative, only that absent an understanding that alternative it’s not clear to me how to resolve the seeming contradiction when people from the armchair say eg “more rigid means better payload/towing” as though *that* is the baseline assumption/common wisdom needing no further explanation


Basic bamboo vs oak vibes

 

[CybertruckAgent]

This is the kind of engineering expertise and logic I expect to see from a realtor. I imagine you might have more expertise when it comes to helping your clients purchase their dream home.

100% haha, I’m actually fantastic at helping folks purchase their dream homes! Anyone in middle tennessee hmu @bobhoffrealtor

 

[newwave1331]

I'd like to start a new dedicated thread tomorrow to discuss CT performance, charge and range predictions and calculations in detail. These interest me.

Great idea because I think predictions are better with more feedback/correction.

I've been running calcs on different pack sizes and weigh estimates and how they effect range, curb weight, 0-60, payload, towing and weight ratings. We have a wide range of technical experience and nonsense on the forum. Once I get some feedback on my predictions, I'll know what category I fit into.

It would be nice to get some real grounding before launch event so we don't go into it with unreasonable expectations. Also, what limiting factor do we need to monitor progress on to meet the goals of the customer in the future.

 

[FutureBoy]

4 years in and we are still arguing about what the SS does, if there is an exoskeleton, what even is an exoskeleton, if it doesn't have an exoskeleton then what is it, where is the load being carried, etc.

I can't wait till we start getting deliveries so we can start talking about actual experiences instead.

 

[HaulingAss]

No, fuselage flex is real and is most noticeable on long slender fuselage like 757/MD80 etc. It wiggles like a pool noodle. Steady state attitude control is why they invented trim and many larger aircraft are FBW anyway, and there pilots only interact with control surfaces through computers that calculate moment to moment changes. (Even my 3kg evtol 120km range UAV has this)

F35 and F22 are actually "unstable airframes" that cannot fly without FBW, this is what gives them both their manoeuvreability and efficiency for range, because any naturally balancing wing induced forces, come at a cost to flight performance. Also a big reason why F35 was delayed.

Accordingly, both fuselage and wing flex (which admittedly is more by design) are controlled by active attitude control. (Along with stall prevention, auto throttle etc)

I remember once going for an aerobatic lesson in a A152, once I got to the top of a loop, both of the doors burst open while we were both hanging in our seatbelts. Caught the instructor by surprise but had no impact on flying or controlling the aircraft. But boy was that thing a pig to fly, so gutless, took us like 15min to climb to enough altitude to do it...only used the larger 172 after that, but that wasn't much faster either. In the 152 I could basically put my arm around the instructor and use his yoke instead, seeing that having your right hand on the throttle had little to no effect anyway.

The only way to make that thing go faster to where you wanted to go, was to go nose down, and make sure you booked a connecting flight to heaven.

Airframe flex is a matter of degree. I stand by my statement that airplane fuselages are not very flexible, relative to the wings. The Cybertruck chassis will flex too, but much less than traditional body on frame truck construction. The result will be much better driving dynamics on the road.

Amongst the Cybertruck engineering community at Tesla, almost all of whom have probably driven the Cybertruck, is that they are seriously impressed with how well it drives. That doesn't imply there is zero chassis flex, but it's certainly very little relative to existing trucks. Sometimes it seems like you just want something to take issue with.

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