# Re: [EVDL] Ultralight car frame/body material research?



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*



> Rob Trahms wrote:
> > I was having a lunchtime discussion with a friend at work about three of the
> > big challenges for EVs, and those are weight, weight and weight. The
> > batteries are heavy, yes, but aside from that, most car frames today are
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

Also, google hypercar. Not sure the current progress on that, but in the
90's the Rocky Mountain Institute had lots of theoretical research on it at
least.

Z



> Jake Anderson <[email protected]>wrote:
> 
> > Rob Trahms wrote:
> > > I was having a lunchtime discussion with a friend at work about three of
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

While some might call them an 'academic excercise', many solar racers use
monocoque composite body techniques. At least, the last two generations of
cars produced at McGill University in the late nineties and early '00s, plus
a handful of others I've come across since.

Our '95 looked a bit like this from the top (set your browser to fixed width
font):
_______________________
| \
| ______________________\
|| Motor |Bats| Driver ||
||________|____|________||
| /
|______________________/

It was in the clasic elongated teardrop shape and was pretty much three
pieces:
The top: cells and canopy/door.
The bottom, simply the floor of the car, the perimeter of the diagram
above.
The structure: depicted in the centre of the diagram above, screwed down to
the floor.

The structure was in three compartments: the driver's bathtub, the battery
box, and the motor compartment. It was made of carbon fibre with a
honeycomb spacer (Nomex) to push the layers apart for better rigidity.
There were also areas where solid carbon inserts were used, whereever we
needed to bolt though, such as the suspension anchore points. The driver
area and battery boxes' top layer was kevlar instead of carbon, to
electrically insulate them (carbon conducts quite well...).

The shell (to and bottom) were kevlar, with a bit of Nomex for support.

Anyway, the design weight was less than 600lbs. It came out quite heavier
because the aeronautics composites layup guys at the factory who sponsored
us were not confidant in our calculations and pushed us to add layers almost
everywhere. A bit of a disappointment, but as students, we caved to their
experience. It came out as solid as a tank and many hundreds of pounds
overweight... Anyway, live an learn.

All to say, there is some research being done, but not always in a
commercialisable arena. I am the first to say that solar cars have no
chance until a breakthrough in cells happens. But the projects aways add to
the body of knowledge of hyper effecient design and shouldn't be overlooked.

Have a look at composite (pedal-) bike structures, they are quite
sophisticated too. And If I recall, there are several race-cars with
composite bodies.

Regards,

-Nick Drouin
Montreal, QC
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

Search for "Ariel Atom"
That is one SWEET ultralight car. It's a roadster though.

Stub



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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

How about Lee Hart's Sunrise EV2? It's body is all composite.

Sent from my iPhone



> Rob Trahms <[email protected]> wrote:
> 
> >
> > I was having a lunchtime discussion with a friend at work about
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

My question is, has anyone heard of any automobile body/frame research going
on in the area of composites or other light/strong materials? It just
strikes me that these materials should be at least as strong as steel and
much lighter, and theoretically just as safe. Yes, they might be more
expensive than steel, but I'd like to see what analysis has been done in
this area just the same.
+++++++++++++++++


You didn't say much,much more expensive than steel but how about carbon
nanotube yarn or sheets:

http://www.nanocomptech.com/html/nanocomp-what-we-do.html

They're already working with prepreg companies. 100 times stronger than
steel is the claim. Definitely not a fly-by-night company. I've seen the raw
stock and production is being scaled.

John Nicholson
-- 
View this message in context: http://www.nabble.com/Ultralight-car-frame-body-material-research--tp22173791p22174980.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

building the TREV article ...

<http://autospeed.com/cms/A_110989/article.html 
<http://autospeed.com/cms/A_110989/article.html>>

<http://autospeed.com/cms/A_110990/article.html 
<http://autospeed.com/cms/A_110990/article.html>>

<http://www.unisa.edu.au/solarcar/Trev/default.asp 
<http://www.unisa.edu.au/solarcar/Trev/default.asp>>

Gary Krysztopik
www.ZWheelz.com
San Antonio, TX





> Rob Trahms wrote:
> > I was having a lunchtime discussion with a friend at work about three of the
> > big challenges for EVs, and those are weight, weight and weight. The
> > batteries are heavy, yes, but aside from that, most car frames today are
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

Hi Rob and All,



> >Rob Trahms wrote:
> >> I was having a lunchtime discussion with a friend at work
> >> about three of the big challenges for EVs, and those are
> >> weight, weight and weight.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*

----- Original Message ----- 
From: "Rob Trahms" <[email protected]>
Subject: [EVDL] Ultralight car frame/body material research?


> My question is, has anyone heard of any automobile body/frame research 
> going
> on in the area of composites or other light/strong materials?

> The aircraft industry has done this (they had too), and you'll notice that
> they don't build planes out of steel - it's kind of a show-stopper 
>
> Anyhoo, thoughts from y'all?

There is actually A LOT of research going on, the big limitation is money. 
Assuming a traditionally sized concept of "car," a steel car frame can be 
built for a few hundred dollars, an aluminum car frame costs about 3 times 
as much, a full carbon fiber tub and shell costs a couple hundred thousand, 
and a carbon fiber monocoque you don't want to know, even more advanced 
technologies go even further. This is why vehicles like the Corvette have 
metal frames with carbon fiber skins, it isn't until the upper reaches of 
exotics that full carbon fiber is used. This is why much of the research 
money is going to lightweight steel, it keeps the costs down, and lowers the 
weight.

With that said, you want to take a look at Lotus vehicles for conversion, 
for quite some time they have been using Aluminum tubs. A non-functioning 
Lotus Espirit will certainly cost less than a newer one, and the later 
models had a large engine, so there's quite a bit of room for motor and 
batteries.

In the end though weight is just intertial force. When accelerating it 
drains the system, when coasting it increases range, and when braking it 
forces the machine faster, it also stores more energy in the forward motion 
which increases energy available for regen (even though the motor added the 
energy in the first case).

Beyond this, in many ways, the bigger impact are the wind resistance and 
rolling resistance. Treating the wind and rolling resistance offers major 
gains in efficiency, particularly at moderate and higher speeds. At low 
speeds the wind resistance in particular doesn't matter, but this weakens by 
the time you reach 25 mph.

There are basically two different sources of wind resistance that are 
important here, I'll call then push and suck. Push wind resistance happens 
on front edges of the vehicle. These are actually quite easy to find if you 
have a shotgun microphone, push wind resistance typically causes turbulence, 
and turbulence are noisy. Treating push wind resistance is a matter of 
tracing the noise forward and finding a solution to the source, usually 
shaving something off.

Suck wind resistance is more difficult, it happens on the trailing edges of 
the vehicle, and is relatively noiseless because the turbulence doesn't 
smash against the vehicle, and worse, in most vehicles it is the larger 
component. Look to careful choice of spoilers to shape the windflow to 
minimize these.

In terms of the first change, I would recommend putting a flat bottom on 
your vehicle, at least as much as possible, this will significantly improve 
aerodynamics. Even a sheet of butcher paper will probably have a fair effect 
until it tears apart.

Of course we all know the discussions about low rolling resistance tires.

Changes in just these two resistances will change your range more than all 
but the most egregious weights. Of course all bets are off is you climb 
steep hills.
Joe 

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*



> Joseph Ashwood <[email protected]> wrote:
> 
> >
> > There is actually A LOT of research going on, the big limitation is money.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*



> Rob Trahms wrote:
> > My question is, has anyone heard of any automobile body/frame research going
> > on in the area of composites or other light/strong materials?
> 
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Ultralight car frame/body material research?*



> On 24 Feb 2009 at 9:00, Lee Hart wrote:
> 
> > In my case, we're building the Sunrise EV2 with a composite chassis and
> > body (see www.sunrise-ev.com). The body and chassis each weigh about 200 lbs,
> ...


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