Front Spoilers
I was very impressed by the great level of science
displayed in your
Real World Spoiler Development article. As a matter
of interest, before I read this article I had done some experiments of my own on
my old 89 Honda Accord. My first Air Dam was made of a thick rubber. I tested
vertical and at an angle with the bottom further forward. I was testing for down
force by handling feel (very crude) and for drag measured in coasting distances
and MPG. I found very similar data. I could feel no difference and estimated
about 4% less drag. However, I then tried bending the rubber into a rounded
shape as the front of a bubble. Once that was accomplished I boosted MPG up to
an average of 13% via creating less drag. You may want to try bending your
aluminum air dam to help guild the air by giving it somewhere to go. I believe
your data would support my theory.
Brett
United States
NSU Ro 80
NSU Ro80 - I used to own one in
the UK!
I still like the look of the Ro80. It is elegant.
But when you get up close to them now (there are always a few at car shows in
Canberra each year), all the peripheral stuff looks very old fashioned (which of
course it is!). The wing mirrors, the windscreen wipers, the dashboard (a big
slab of a thing), the steering wheel (huge, with a rim about as thick as a wire
coat hanger!), and lots more.
The engine was run under all manner of conditions
for very long amounts of time by the NSU engineers prior to the car being
launched, and they were genuinely caught-out (as I understand it) by the almost
immediate engine failures displayed in the cars sold to the public. The mistakes
that the engineers made were (a) not giving enough consideration to cold starts
- the time of maximum wear and (b) not employing a rev limiting device (not even
the buzzer that Mazda used), and people really rather stupidly just treated the
engines as though they were indestructible.
The first cars were released in 1967. My car was a
1969, I looked after it, drove it in a sympathetic way when it was cold, and
rarely felt the need to rev the nuts off of it. It still had the contact breaker
and two spark plug engine, going to electronic ignition and one plug was NSU's
first major change, but despite being one of the "duds" my car had done 70,000+
miles when I left for Australia in 1979, and such was the car's reputation that
I had to almost give it away.
It did have starting problems in winter, the spark
timing was absolutely crucial. You could not rely on the NSU dealerships to get
anything right, and of course nobody else wanted to open the bonnet. I very soon
learned how to look after it myself.
For me the very worst thing was the gearbox. Three
forward speeds, through a torque converter, no clutch pedal, and a clutch
operated via a micro switch under a wobbly gear lever knob. This gave the driver
no control whatever over the clutch, the electric switch meant the clutch was in
or out. And the penalty of a torque converter when the car didn't change gears
for itself. The very last year of production (1977) saw it fitted with the
automatic gearbox it should have always had.
It did chew up petrol around town (about 17 litres
/ 100 kms - ouch). It did roll a lot in corners (like a boat!), and yet it felt
very secure to the driver. It was slow off the line, but on a motorway it was
wonderful - effortless, quiet, comfortable, while returning not at all bad fuel
consumption. I once went from Ramsgate in Kent to Newcastle-on-Tyne (very close
to Scotland) and back in a day (don't ask!). According to Google, this is 453
kms each way as the crow flies, so presumably a good deal further by road.
Motorway very nearly all the way. I got 33 MPG (that's 8.56 litres/100 kms!)
that day. And that included 60 minutes at (a highly illegal) 100 MPH. I was
bored, it seemed like a good idea. Coming back to the speed limit of 70 MPH
after an hour was the downer!
The Wankel rotary is dubious in a car, and should
never have been put in a motorbike. In an application where the engine is
started, then a throttle opening is set and left (aircraft, boats, snowmobiles,
chain saws, etc), the poor fuel economy, poor torque and poor emissions can be
engineered-out, and since the rotor tip wear was long ago fixed, all the small
and light and smooth and few moving parts benefits are allowed to come to the
fore.
The Ro80 was certainly a car before its time.
Hindsight probably says that NSU were wrong in not offering the brilliant car
with a conventional engine as an each-way bet - Mazda had that covered with
considerably less than brilliant car designs, and they are still around, and
still persevering with the Wankel design too.
Barry dal Herbert
Australia
Well to Wheel of Electric Cars
I was just reading an old article called
Alternative Cars, Part 1 Electric. The article was
generally good, but I've found a few omissions which, unfortunately, means that
electric cars aren't as good as the writer thought.
The writer states that electricity generation is
very efficient. Unfortunately, this isn't quite correct... A CSIRO paper states
that brown coal (ie: Victorian power generation) conversion efficiency is 27%
(http://users.bigpond.net.au/Bioenergyaustralia/Reports/csiroc02.htm).
In addition to this, the power distribution
network is generally around 35% efficient. When the efficiency of the car's
batteries, electric motor, etc is taken into account (totalling approximately
50%), electric cars (from the power station to the wheel) is around 4.7%
efficient. Adding in the effect of mining and transporting the brown coal, this
comes down to around 4.6% efficient. Adding in regenerative braking will
increase the efficiency to around 6.9%. Brown coal emits around 93000 tonnes of
CO2 per Petajoule of heat, leading to 1.35 kg of total CO2 emission per
Megajoule of energy at an electric car's wheels.
A typical small car is around 10% to 15%
efficient. The CO2 emissions prior to petrol going into a car's fuel tank is
around 15% - 20% of that of the fuel's lifecycle emissions (http://www.nrc.nl/redactie/Europa/milieudefensie.pdf).
Without going into the theory, this means that the
energy used in producing petrol (from the well to the fuel pump) is
approximately 20% of the energy value of the fuel - ie: extraction, refining,
and transportation of petroleum fuel is 80% to 85% efficient. This means that
the "well to wheel" efficiency of a small car is around 8.0% to 12.7% efficient
(more for hybrids). The information in the above link states that the CO2
emisson of liquid petroleum fuel (petrol, diesel, kerosene, oil) is
approximately 2.5 kg per litre. The actual value (from detailed chemical and
thermodynamic analysis) for petrol is 2.285 kg of CO2 per litre of petrol, which
equates to 0.066 kg of CO2 per Megajoule. When the above efficiencies are put
into the equation, this results in 0.52 kg to 0.825 kg of CO2 per Megajoule of
energy at the car's wheels.
All up, this means that where the electricity
supply comes from non-renewable sources, using an electric car will result in up
to 2.5 times the CO2 emission of a similarly sized petrol car.
However, in defence of the electric car, once we
have high enough percentage renewable energy, the use of an electric car will
result in up to 100% reduction of CO2 emissions. In other words, the electric
car is only as good as the electricity generation system that provides its
energy.
I trust that this information proves to be
informative.
Danny Barrett
Australia
As you have said, the energy efficiency of an
electric car primarily depends on how the electricity is generated.
Assessing the Alternatives is - we think - the
definitive article on the topic.
Lighter Commodore
They're making the Commodore lighter: http://www.drive.com.au/Editorial/ArticleDetail.aspx?ArticleID=56210&vf=2&IsPgd=0
About bloody time.
Ash
Australia
Water Injection
With energy on (what appears to be a never ending)
increase and as the owner of a VW turbo diesel automobile and an "over the road"
Volvo powered tractor trailer vehicle, I found it interesting to read your
article about water injection systems. In an never ending quest to improve my
fuel mileage, I too have wondered if water injection would be feasable. May I
refer you to a couple of websites I've discovered that made clear any doubts
that I had. They are; Aquamist.com located in the UK and the other is
Snowperformance.com located here in the USA. Horefully they will answer
questions and doubts that you have. I purchased a (damnably expensive) Snow kit
and am in the process of acquiring a suitable tank to be mounted a midship
behind the cab of my Volvo truck. Because of the corrosive nature of the
water/methanol mix I will be using, I need a tank made of stainless steel with a
capacity of 60 to 70 gallons. Again, very expensive. To affirm to what you made
have heard (or read) about the weather here on the desert floor in
Phoenix,Arizona..........it is hot, oh boy is it hot here!
Ray
United States
We’re interested to see how you get on with the
truck.
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