Aptera track testing continues in California...

  • Thread starter Thread starter Kerbe
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Kerbe said:
This article and YouTube video are about coastdown testing to check rolling resistance and aerodynamic resistance IRL. https://aptera.us/apteras-first-coastdown-test/
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"Aptera’s ultra-streamlined shape and lightweight build give it an exceptionally long coastdown time"

Certainly the Aptera's lightweight build saves energy, but the coastdown test doesn't use energy, does it? Wouldn't a heavier Aptera coast further?
 
insightman said:
"Aptera’s ultra-streamlined shape and lightweight build give it an exceptionally long coastdown time"

Certainly the Aptera's lightweight build saves energy, but the coastdown test doesn't use energy, does it? Wouldn't a heavier Aptera coast further?
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As I understand it, this is a test of aerodynamic drag and rolling resistance. On a nearly flat surface, a vehicle's inertia wouldn't amount to all that much.
 
Kerbe said:
As I understand it, this is a test of aerodynamic drag and rolling resistance. On a nearly flat surface, a vehicle's inertia wouldn't amount to all that much.
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My point was that, contrary to Aptera's claim, with all other factors being equal, a lighter vehicle will have a shorter coastdown time, even if by only a few seconds. A styrofoam Aptera shape with the same bearings and tires would have a much shorter coastdown time. I was surprised Aptera's engineers didn't check its publicist's text to catch that mistake.

It's the Aptera's aerodynamics, bearings, and low-rolling-resistance tires that contribute to its exceptional coastdown time, not its "lightweight build." I'm assuming the coastdown time test in no way factors in the energy required to get the vehicle to 60 mph before it coasts to a stop.
 
insightman said:
My point was that, contrary to Aptera's claim, with all other factors being equal, a lighter vehicle will have a shorter coastdown time, even if by only a few seconds. A styrofoam Aptera shape with the same bearings and tires would have a much shorter coastdown time. I was surprised Aptera's engineers didn't check its publicist's text to catch that mistake.

It's the Aptera's aerodynamics, bearings, and low-rolling-resistance tires that contribute to its exceptional coastdown time, not its "lightweight build." I'm assuming the coastdown time test in no way factors in the energy required to get the vehicle to 60 mph before it coasts to a stop.
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A heavier vehicle is also going to have greater rolling resistance...
 
insightman said:
My point was that, contrary to Aptera's claim, with all other factors being equal, a lighter vehicle will have a shorter coastdown time, even if by only a few seconds. A styrofoam Aptera shape with the same bearings and tires would have a much shorter coastdown time. I was surprised Aptera's engineers didn't check its publicist's text to catch that mistake.

It's the Aptera's aerodynamics, bearings, and low-rolling-resistance tires that contribute to its exceptional coastdown time, not its "lightweight build." I'm assuming the coast down time test in no way factors in the energy required to get the vehicle to 60 mph before it coasts to a stop.
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Yep, agreed. Coast down stops when all kinetic energy is dissipated.... and there is more kinetic energy to be dissipated with greater mass. Engineers should have caught or corrected it.
 
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