' Honey, I shrunk the Lucid Air '.
 

ROAD & TRACK road-tested the Lucid Air, at a constant 65-mph, on I-580, in California, something real motorists might do.
On the 113-kWh pack, they saw 484-miles range.
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With back-of-the-envelope calculations I played 'what if we lowered the Lucid down to Hucho's Cd 0.09?'
* Dropping from Cd 0.21 to 0.09 is a 57 % drag reduction.
* Using the old/new delta -Cd vs delta -mpg relationship @ 65 mph produces a 31.4% mpg-e improvement, increasing range to 636-miles. ( 190-mpg-e vs 144.7-mpg-e )
* 177.6 Watts / mile.
* 9.78- hours drive time / charge.
* 152 extra miles range.
* Equivalent to adding a phantom 35.4 kWhs.
* No appreciable weight gain.
* Elucidation hallucination.:rolleyes:

Is there a fellow here on EM that has a Prius with a boat tail he calls " champrius " ?
I found him on instagram.

He has added a full boat tail / bellypan / gap fillers / grille block / smaller mirrors etc.

He has posted pictures that show he has got 60+ mpg .
I believe this is purely with the aeromods, but I'm not sure that is even possible.

Since the car has a published Cd of .26, what is the new Cd of the car ?

Stock, the car was getting around 45 - 48 mpg.

60+ mpg Prius
 

We'd need:
* year model
* test conditions
* pre-test warmup
* testing methodology, instrumentation, data capture
* no 'hypermiling'
* O.E.M. mpg baseline only from that methodology
* modified mpg of modified Prius, captured during identical methodology, with results normalized to standard SAE air density
* large enough 'sampling' to be statistically significant
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The modified shape can be the only variable allowed. Nothing else about the Prius can be changed unless it's independent effects can be parsed out and quantified. Not even tire pressure. Identical weight.
Technically, all testing should take place on the exact same course. Round trip. Or the sample of sufficient magnitude that it represents a sample as large as that used to establish the OEM baseline. The larger the database, the less background noise during comparisons.
Meteorological data must be accounted for.
Road conditions.

Ok. Nevermind.
Let's just give a hypothetical example.
All things being equal except aeromods, what would the cars Cd be if the car started out with a .26 Cd and 46 mpg
Ending with a Cd of (blank) and 60 mpg.

what would the cars Cd be
 

We need a test velocity, as the relationship is variable with respect to speed.:)
( Aerodynamic power is varying as a function of the cube of the velocity, while rolling-resistance is following a linear 'curve,' up to standing-wave velocity )

Prius @ 60 mpg @ 65 mph = Cd 0.116
 

If say, the original, OEM, 46-mpg was obtained at 65-mph, in order to get 60-mpg ( all other things equal ) would require Cd 0.116.
It's doable.

Are you thinking of this car?

That's the one !

I am the one you've been looking for :)
 

Howdy!

I'm the creator and owner of Champrius. The car got 46 mpg in 2009, but in 2018 (when I bought it), it was down to a mere 39 mpg. After a tune-up and some mechanical love, I was able to get it to 41 mpg as a baseline.

Then I started my aeromod odyssey, which brought the car up to 66 mpg at peak. I use the car to go on extended camping trips, so when she's fully laden in the real world she got 61 mpg. Then a series of tragedies befell her (engine, cat, etc.) and the mpg dropped to a mere 55. :(

Oh, all those numbers are at cruise control @65mph, which is 75%+ of my driving. Real world numbers, and not benchmarked. So we\'re looking at +50% increase in fuel economy through aeromods.

Last but not least, I believe the other fellow on this thread made a major calculation error. There\'s no way in hell Champrius has a 0.116 Cd. The fricking Aptera has a 0.13 Cd. My best guesstimate is that she had a 0.21 Cd, and my goal for the next version Champrius 4.0 is to hit 70 mpg or near 0.185 Cd.

How many campers does it accomodate?

He can be cranky, but we love him. I just realized BamZipPow\'s [ Does anyone know this car] last post was in 2020.

It's a twin long mattress, and normally just sleeps me. I can confirm that it can sleep two reasonably if they are (ahem) cozy. :)

Also, the fridge is only 30L, the size of a big cooler. The longest I can boondock is 2 weeks, before I start running out of things like food, water, or sanity. :confused:

Since aerohead apparently isn't around to defend his thread today...

I spent 2 years living in the back of my Subaru Legacy. The difference is I only slept in it during my work week, which was only 3-4 (2 or 3 nights) days out of the week. My long hours meant most of the day was spent at work, with only food and workouts/showers occupying my 3 hours of non-work waking hours.

Lived with my folks the rest of the week, doing laundry and going on outdoor adventures. I was banking something like 90% of my net paycheck in those days, which allowed me to make a 20% downpayment on my first house.

Great minds think alike redpoint5!

I spent 20+ years primarily living out of vehicles, ranging from RV, vans, to cars. Instead of owning a home I travelled the world and retired early. I'm now designing the Aerosol, the world's most advance solar electric RV, and will probably end up using it as my retirement home. I might also *actually* build a house; I've become interested in ICF and Passive House in recent years. But I don't want to do anything hasty like live in a stationary box unless I have to. :p

On a totally different topic, I've seen signatures with those round ecomodder badges in them. You have three in yours. How does one do that?

First, one must create a vehicle in their "garage" and add fuel entries. I see you've done this.

On the "view fuel log" page, at the bottom, this graphic is generated automatically. You can right click and "copy image URL" and then paste it into the signature line.

Here's yours,

https://ecomodder.com/forum/fe-graphs/sig11014a.png

You would paste this in your signature without the asterisk [*IMG]https://ecomodder.com/forum/fe-graphs/sig11014a.png[/IMG]

As an aside, this image can be embedded in most other forums. I often find myself embedding images which are hosted here on other forums.

Cd 0.116
 

I'm the nut-case who guestimated the Cd 0.116 requirement.
I'd be happy to revisit the calculations.
I do not have an accurate:
1) frontal area
2) all-up average travel weight
3) tire manufacturer
4) tire model
5) inflation pressure
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6) I was presuming zero hybrid function, just constant speed driving, only on the engine ( according to Emission Analytics, your hybrid system increases composite mpg by 48% because of regen ). It's impossible to calculate anything if the hybrid assist is affecting performance.
7) I'm driving a 2009 Prius right now. It's never indicated above 43.3-mpg on long highway travel, gentle rolling hills, @ 65-70, with AC 'ON.'
Thanks in advance for any additional data.

More... data!
 

Hey aerohead! Nice to meet you.

Let's see.

1) Whatever the frontal area is stock, my area is now -43 sq in that. -20 sq in per mirror, and -3 sq in from the antenna delete. (I heard a great quote from the lead developer on the Aptera. "We produce as much drag with the whole Aptera as the Ford F-150 does with both mirrors." :)

2) Empty, the weight is = stock-420 lbs. (That's the 66 mpg figure.) Laden it's stock+520 lbs (That's the 61 mpg figure.) I'm including myself in those figures already. That actually has a significant impact on rolling resistance.

3) Pirelli 4) P4 FOUR SEASONS PLUS - P185/65R15 88T

5) 44 psi, the max on the sidewall

6) Hmm... this alone may gank this particular approach. The self-coasting and engine idling the Toyota does accounts for a great deal of its fuel economy. To give some perspective, on my test route I go generally uphill first and then downhill on the way back. When I was testing v3.0, that barely moved between 40-45. But on the return trip how well and long it coasted made up the lion's share of the mpg, pushing it past 60 mpg. That's a +40% variance, which is primarily on "electric" and not the engine power.

In fact, there's a long, increasing slope on the way back and I get very fine data from precisely *where* along the slope the engine turns off, and then secondly when it starts the reverse blue arrow (i.e. regenerative power).

By the way, just FYI, my "testing methodology" is real world. I have the AC set to 72 F, the radio on (because I love music), lights on (if needed), wipers on (if needed), etc. So I get variance because of weather, et al. During testing I'm not too worries about it. I only consider real mpg to be a full tank of gas, i.e. driving in the real world for 500+ miles. That averages out conditions enough to make meaningful statements. But even then, there are confounds (like relative elevation of origination and destination points, etc.)

Hope this helps!