Comparison of Aerodynamics

Mitsubishi i-MiEV Forum

Help Support Mitsubishi i-MiEV Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

tonymil

Well-known member
Joined
Apr 16, 2012
Messages
274
Location
Latham, NY
I just came across this article that compares the aerodynamics of the Tesla model S, Nissan Leaf, Toyota Prius, Chevy Volt, Mercedes CLA 250 and a 2001 Honda Insight for Hybrid.

http://www.greencarreports.com/news...odel-s-electric-car-wins-the-wind-tunnel-wars

The Tesla did impressively well, but this quote really surprised me, especially considering the Tesla is 1400 pounds heavier:

The numbers get even more interesting: Did you know, for example, that a Model S requires just 14 horsepower to maintain 70 mph, 4 hp less than a Leaf?
 
Rolling resistance wasn't addressed, so weight won't make a difference in aerodynamics. The real world is different, though.

I noticed an old Insight was tested, though if it is like my 2000 Insight, the undercarriage panels are either missing or 'air grabbers'.


tonymil said:
I just came across this article that compares the aerodynamics of the Tesla model S, Nissan Leaf, Toyota Prius, Chevy Volt, Mercedes CLA 250 and a 2001 Honda Insight for Hybrid.

http://www.greencarreports.com/news...odel-s-electric-car-wins-the-wind-tunnel-wars

The Tesla did impressively well, but this quote really surprised me, especially considering the Tesla is 1400 pounds heavier:

The numbers get even more interesting: Did you know, for example, that a Model S requires just 14 horsepower to maintain 70 mph, 4 hp less than a Leaf?
 
skyemoor said:
Rolling resistance wasn't addressed, so weight won't make a difference in aerodynamics. The real world is different, though.

The comparison of horespower to maintain 70 mph would not have come from the wind tunnel test. I think it was thrown in to show "real world" effect of aerodynamics.
 
All I was trying to say is rolling resistance wasn't covered, so weight wouldn't matter in a calculation to estimate horsepower requirements to overcome wind resistance. So we are on the same page.

Here's a nice calculator on this subject;

http://ecomodder.com/forum/tool-aero-rolling-resistance.php

tonymil said:
skyemoor said:
Rolling resistance wasn't addressed, so weight won't make a difference in aerodynamics. The real world is different, though.

The comparison of horespower to maintain 70 mph would not have come from the wind tunnel test. I think it was thrown in to show "real world" effect of aerodynamics.
 
The most important factor is the efficiency of the drivetrain. Then aerodynamic drag, Then weight, and then all other friction.

Aerodynamics swamp all other drag at ~30MPH, and weight doesn't enter into it when driving at a constant speed.

Case in point is the Edison2 VLC - the version that won the X-Prize was ~840 pounds and a Cd of 0.164. It got ~102MPGe.

They then made an electric version, that raised the weight to ~1,140 pounds (an increase of almost 36%) and it got ~245MPGe.

Another example is a Honda 125cc motorcycle - stock weight is 231 pounds and MPG is ~90MPG, but with 80 pounds of aerodynamic shell and taller gearing - it gets 214MPG.

http://ecomodder.com/blog/diy-aero-fairings-honda-125cc-motorcycle-214-mpg/
 
Back
Top