The Power to Move
I have difficulty believing that a velomobile
uses only 1/10th as much power as a normal bike to do 36 km/h, about 30-40 W.
Sure, the drag factor is lower, but the cross-sectional area is up. When I read
the article I had just done back-of-an-envelope calculations on what speed a
Kawasaka z9 motorcycle would do if fitted with the 144V Advanced DC electric
motor that people do electric conversions to cars with. It turned out that
motor's 20 kW rated power power would get it to about 160 km/h, and its 60 kW
peak power would get it to about 225. Put that motor in a velomobile that only
requires 35 W to do 36 km/h, take it out to the Desert Lake Racers Association
meet on the Lake Gairdner salt flats, and it'd do 425 km/h. Mmmmmmmmmmm. Its
hard to believe. Really hard.
Gordon Drennan
Australia
Refer to Page 188, Bicycling Science, by David
Gordon Wilson, emeritus professor of engineering at Massachusetts Institute of
Technology (MIT).
Normal upright commuting bike - frontal
area: 0.55 square metres; drag coefficient: 1.15; power to overcome air
resistance at 36 km/h: 345 watts.
Faired long wheelbase recumbent - frontal
area: 0.42 metres square, drag coefficient: 0.11, power to overcome air
resistance at 36 km/h: 25.8 watts.
Because anything other than traditional diamond
framed bikes are banned from open competition, people don't realise how
far pedalling has progressed.
New Falcon Intake
Hi, after reading your interesting article on
improving the intake on the EF Falcon (revisited negative boost), i did the
same, great story!!! However i went further with the idea and managed to gather
more cold air without hacking the bonnet or front guards, thought you might be
interested....
http://img70.imageshack.us/img70/2042/new1002101rz6.jpg
http://img396.imageshack.us/img396/485/new1002109qw5.jpg
http://img115.imageshack.us/img115/986/new1002107fx5.jpg
Daniel
Australia
Thanks for that, but we don’t remember hacking
the bonnet or the front guards...
Diesels
Hi, I'm enjoying your articles very much. A
lot of info. But do you have more info on diesel engines, since I've seen only
stuff that can be used on gasoline engines. I would appreciate that very much
because I'm driving a diesel 4x4 SUV
Arvin
We have a lot more coverage of diesels coming
up.
Spacesaver Pressures
An interesting thing happened to me today. Was
buying 4 new tyres for my Honda Jazz (love it!) and the consultant at Bob Jane
didn't know what kPa were! I am 44 years old and have managed to get my head
around kPa when I only have to think about occasionally, filling my and partners
tyres, checking work vehicle (bus). However, they sell, fit and maintain tyres
on a daily basis. I also requested my spacesaver spare tyre (TUST), be filled to
manufacturers 420 kPa. The consulant and mechanic were almost argumentative
about this being to much - "way to high". I pointed out that it is a speciality
tyre. They continues trying to convince me less was better.
I guess my concern is, that in the 10 minutes
research I did on arriving home, that if TUST's can reduce cornering and
stopping abilities significantly, they were advocating putting only about 40 psi
into it. I am sure this would be dangerous and further reduce performance.
Perhaps an article may be in order re this issue and would be happy for a
response when you can.
PS love all the tech stuff you write about. I love
my Honda Jazz Auto, very good on fuel, inovative design etc. Why can't Holden
and Ford stop worrying about Kw and just make better more relevant cars! After
all, we can all get to the speed limit in seconds, so what exactly do you do
with your 300 Kw then? We get the last laugh at the bowser, don't we!!
Michael Stanley
Australia
New Electric Car Batteries
I appreciate your viewpoints on vehicles.
Noting that a personal vehicle is a ways off, I wish to point out that battery
technology has made a leap forward with nanotechnology being applied. That being
said, it should be noted that GM has bought up the patent rights on the
(seemingly) best of two products out and is now saying they will use the other
battery already being used (A123, power tools) for their car batteries. It
should also be noted that GM back in the ninties bought up the patent rights to
the osmonic battery, which never saw the light of day on the open market while
pulling their electric cars off of the road. In other words, all I see is
another ploy to delay the all electric plug-in covered with photo voltaic cells.
With most travel in the US consisting of two miles one-way, the use, and price
of gas, would drop like a rock if we switched over to the new battery
technologies. Heck, we would even have to pour in fuel stabilizers for the
plug-in hybrids. Just taking a hybrid now and installing an available battery
add-on from A123 puts one in the 150mi/gal. range. You should check it out.
Oh, and before I forget, you should also check the output of those available
batteries and recharge times. Lithium batteries using nanotechnology has solved
the 'burning batteries' problem.
The two lithium nanobatteries are Altairnano
and A123. The life cycle for the Altairnano is put at around twenty-three years
or 10,000 charges. The life cycle for the A123 is around 2,000 cycles which is
higher than the current lithium batteries at around 750 cycles. Also, the
recharge time is a lot lower with the newer batteries. These nanobatteries have
done away with fire hazard of lithium batteries.
Jay Coleman
United States
EF Falcon Intake
Did you do any 'after' flow recordings of the EF
Falcons air intake system at different points
Doug
Australia
No we didn’t.
Too Wide
The Human powered car (velomobile) might in
theory be able to go on a cycleway, but in practice my mountain bike often has
trouble fitting through all the gates/posts/narrowings that such paths
include. It couldn't be done in a velomobile.
Patrick
McAuliffe
Australia
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