LEAF Wind Tunnel Testing Experience

A few weeks ago I responded to a request for a Nissan LEAF to be used in a wind tunnel survey. This was for an article in a popular car magazine and the testing included four other cars: Mercedes, Prius, Volt, and an absolutely gorgeous new Tesla Model S. The testing was to determine how close the manufacturers’ published coefficients of friction are to actual test results. In general, wind tunnel testing is designed to show a vehicle’s drag, side and down forces, and any aerodynamically caused yaw, pitch, or roll.

The test site actually had two wind tunnels: a smaller one for testing more consumer-oriented vehicles (motorcycles, automobiles, bike riders, etc.) in up to 85mph winds, and a much larger tunnel for higher speeds used primarily by racing vehicles.

Never having seen a wind tunnel before let alone being in one, this was a great experience for me. I was allowed to take whatever pictures I wanted to and I have posted a few. The magazine team is reviewing the data and did not release the actual test results to me; they did however hint that the LEAF came out pretty close to published specs.

Sorry to be so circumspect on the outcomes; I’ll update with details as I learn more, or as the article gets published.

That is fantastic. What a treat. I would love to have participated. Keep us up to date on the article.

I wonder what minor difference the front plate and its frame might make... agree it'll be cool to see the article when it's published.

DaveInAvl said:

I wonder what minor difference the front plate and its frame might make... agree it'll be cool to see the article when it's published.

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Interesting question. Even though North Carolina does not require a front plate, I kept my Ohio plate for chuckles and grins. Possibly not legal but both plates were almost the same: "PLUGS IN" for Ohio on the front and "PLUGS 1N" for North Carolina on the back. When the magazine team took their pictures with the other cars, however, they took my front plate off but the tunnel testing was over by then.

The wind tunnel testing article just came out, published in the June 2014 issue of Car and Driver, p86+. In the photo of the five test vehicles, I'm sitting in my LEAF but the drivers are pretty much unrecognizable. Bottom line: despite the headlamp shape and diffuser fins on the underside of the rear, the LEAF came in 5th out of 5 in the ratings for drag as defined in the article.

SalisburySam said:

The wind tunnel testing article just came out, published in the June 2014 issue of Car and Driver, p86+. In the photo of the five test vehicles, I'm sitting in my LEAF but the drivers are pretty much unrecognizable. Bottom line: despite the headlamp shape and diffuser fins on the underside of the rear, the LEAF came in 5th out of 5 in the ratings for drag as defined in the article.

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Thanks for the update! Assuming they are rating them on CdA, then I'm not surprised that it would be less aerodynamic than the Model S and Volt since it is taller. Likely the Mercedes is also shorter than the LEAF. But I imagine the Prius and the LEAF have similar shapes and areas. I can only assume these two vehicles were quite similar in terms of CdA...

Not surprising since we already knew anecdotally that the range drops quickly on the Leaf at higher speeds, indicating compromised aerodynamics...

SalisburySam said:

Bottom line: despite the headlamp shape and diffuser fins on the underside of the rear, the LEAF came in 5th out of 5 in the ratings for drag as defined in the article.

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But this is why we have the most (edited) head room inside as well

Wow! Very cool! Wish the Leaf had shown better... but I guess it's not a surprise.

BrockWI said:

But this is why we have the most room inside as well

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Except for the Tesla which is much larger than the LEAF.

We also already knew that the weird headlights are there to greatly reduce wind noise around the mirrors, making the car quiet on the highway. If they had been going for 'slippery', then the cars wouldn't have all that gaping space around the wheels, either.

True overall the Tesla is larger, I should have stated I was refering to head room, making the Leaf taller and adding drag. From the Nissan and Tesla web sites

head room Leaf 41.2/37.3 Tesla 38.8/35.3

BrockWI said:

I should have stated I was refering to head room, making the Leaf taller and adding drag.

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Got it, you are exactly correct, and thanks for clarifying. I'm 6'2" and love the headroom in my LEAF...one of the many positive aspects of the vehicle for me. Thought the Tesla has less headroom as published, the seat is far more adjustable. In its lowest position I felt I had about the same perceived headroom, though I did not measure (too busy drooling, dreaming, and gawking).

SalisburySam said:

Though the Tesla has less headroom as published, the seat is far more adjustable. In its lowest position I felt I had about the same perceived headroom, though I did not measure (too busy drooling, dreaming, and gawking).

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I absolutely need the headroom and I still touched the ceiling in the Tesla S after running the seat all the way down so the difference is real. The LEAF headroom is just wonderful, I wish they'd make more cars like that. It has more headroom than the Toyota Tacoma I used to drive!

My wife and I, on the other hand, find all that headroom to be of no valise and would prefer a lower, more aerodynamic vehicle...

bdgotoh said:

I absolutely need the headroom and I still touched the ceiling in the Tesla S after running the seat all the way down so the difference is real. The LEAF headroom is just wonderful, I wish they'd make more cars like that. It has more headroom than the Toyota Tacoma I used to drive!

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