6 ms·

The cab forward design that OP prefers is so much more sensible and practical than the "standard" cab design that's so common in the US. The Tesla Semi is more

The cab forward design that OP prefers is so much more sensible and practical than the "standard" cab design that's so common in the US. The Tesla Semi is more aerodynamic than its peers though. I wonder how you can improve the aerodynamics without having a narrow front or sloped windshield.

ErikCorry 4y ago
The cab-forward design is driven by Europe having a max length for trucks that includes the tractor, whereas in the US the max length doesn't include the tractor. For this reason I don't expect to see the Tesla Semi in Europe soon.
- Alupis 4y ago
  Which means more cabin room, which means more comfort for resting/sleeping/relaxing in addition to driving for folks that literally live in these vehicles for days or weeks at a time. > For this reason I don't expect to see the Tesla Semi in Europe soon I'm not expecting to see the Tesla Semi in the US soon either... it's a product in search of a problem.
bombcar 4y ago
The most "aerodynamic" shape is a teardrop, with a relatively flat front end, so they could probably do something with that. The "roll down window" thing is relatively easy to solve if they want to; you either make a seat that can slide to the side or redesign the front end. I expect a redesign of the cab when the truck isn't selling every single one they can make.
- three_seagrass 4y ago
  Not to mention skirts and tails on the trailer do more to improve aerodynamics than truck modifications. Still, every bit counts I guess.
  - bombcar 4y ago
    And the only time I see those tails unfurled is when it's an owner-operator driving at 55 (they know they're getting paid by the mile and so run as fuel efficient as they can).
- rootusrootus 4y ago
  > make a seat that can slide to the side I wonder if that would even be sufficient. The sloped sides mean that even if the driver can sit directly next to the window, there's still a hard limit on how close he can get to whatever he is next to.
- teo_zero 4y ago
  A teardrop has a "relatively flat front end" just as every rounded shape has a point where its tangent plane is vertical, even a sphere, the "less flat" shape I can think of! It doesn't mean you can place a vertical windscreen in that point and still claim you're copying a teardrop's shape.
modeless 4y ago
Yeah he seems to not understand the importance of aerodynamics, as demonstrated by his complaint that you need extra power to run the AC because of the sloped windshield. The Tesla Semi will be consuming around 100 kW at cruising speed. Air resistance is the largest single contributor to that consumption. AC is likely to take something like 6 kW even at the highest setting. I'd bet that even in worst case heat the difference in AC consumption between vertical and sloped windshield (1 kW? less?) will be totally swamped by the improved aerodynamics. And then in the winter extra heat capture will be an advantage rather than a disadvantage. There are some good points in here but there's clearly a strong bias.
- rootusrootus 4y ago
  > you need extra power to run the AC because of the sloped windshield My impression was the the complaint about the sloped windshield was primarily about snow; the air conditioning complaint had more to do with the enormous size. It's a big glass greenhouse.
  - modeless 4y ago
    > "The angled windscreen means [...] cab overheating [...] You can solve it with A/C of course. Which will use even more power, shortening your range." He is explicitly claiming that the angled windshield will increase power consumption and shorten range. I think it's pretty clear that the opposite is true even in the worst case.
    - simondotau 4y ago
      A larger but well insulated cab could have a lower A/C energy cost than a smaller but less well insulated cab. More air volume doesn't dramatically change the energy footprint when a stable temperature is being held for a long period of time. With sufficient insulation, the main consequence will be greater hysteresis, i.e. bringing the cab to temperature might consume more energy.
      - modeless 4y ago
bamboozled 4y ago
I think the issue is, they designed a truck being worried about aerodynamics than anything else. They made it aerodynamic and forgot to ask about how it actually should work in practice.

ErikCorry 4y ago

The cab-forward design is driven by Europe having a max length for trucks that includes the tractor, whereas in the US the max length doesn't include the tractor. For this reason I don't expect to see the Tesla Semi in Europe soon.

Alupis 4y ago
Which means more cabin room, which means more comfort for resting/sleeping/relaxing in addition to driving for folks that literally live in these vehicles for days or weeks at a time. > For this reason I don't expect to see the Tesla Semi in Europe soon I'm not expecting to see the Tesla Semi in the US soon either... it's a product in search of a problem.

bombcar 4y ago

The most "aerodynamic" shape is a teardrop, with a relatively flat front end, so they could probably do something with that. The "roll down window" thing is relatively easy to solve if they want to; you either make a seat that can slide to the side or redesign the front end. I expect a redesign of the cab when the truck isn't selling every single one they can make.

three_seagrass 4y ago
Not to mention skirts and tails on the trailer do more to improve aerodynamics than truck modifications. Still, every bit counts I guess.
- bombcar 4y ago
  And the only time I see those tails unfurled is when it's an owner-operator driving at 55 (they know they're getting paid by the mile and so run as fuel efficient as they can).
rootusrootus 4y ago
> make a seat that can slide to the side I wonder if that would even be sufficient. The sloped sides mean that even if the driver can sit directly next to the window, there's still a hard limit on how close he can get to whatever he is next to.
teo_zero 4y ago
A teardrop has a "relatively flat front end" just as every rounded shape has a point where its tangent plane is vertical, even a sphere, the "less flat" shape I can think of! It doesn't mean you can place a vertical windscreen in that point and still claim you're copying a teardrop's shape.

modeless 4y ago

Yeah he seems to not understand the importance of aerodynamics, as demonstrated by his complaint that you need extra power to run the AC because of the sloped windshield. The Tesla Semi will be consuming around 100 kW at cruising speed. Air resistance is the largest single contributor to that consumption. AC is likely to take something like 6 kW even at the highest setting. I'd bet that even in worst case heat the difference in AC consumption between vertical and sloped windshield (1 kW? less?) will be totally swamped by the improved aerodynamics. And then in the winter extra heat capture will be an advantage rather than a disadvantage. There are some good points in here but there's clearly a strong bias.

rootusrootus 4y ago
> you need extra power to run the AC because of the sloped windshield My impression was the the complaint about the sloped windshield was primarily about snow; the air conditioning complaint had more to do with the enormous size. It's a big glass greenhouse.
- modeless 4y ago
  > "The angled windscreen means [...] cab overheating [...] You can solve it with A/C of course. Which will use even more power, shortening your range." He is explicitly claiming that the angled windshield will increase power consumption and shorten range. I think it's pretty clear that the opposite is true even in the worst case.
  - simondotau 4y ago
    A larger but well insulated cab could have a lower A/C energy cost than a smaller but less well insulated cab. More air volume doesn't dramatically change the energy footprint when a stable temperature is being held for a long period of time. With sufficient insulation, the main consequence will be greater hysteresis, i.e. bringing the cab to temperature might consume more energy.
    - modeless 4y ago

bamboozled 4y ago

I think the issue is, they designed a truck being worried about aerodynamics than anything else. They made it aerodynamic and forgot to ask about how it actually should work in practice.