OT Interesting video - Page 13 - Cycling Mob: Road Cycling, Mountain Biking and More

01-21-2007, 12:18 PM

On Sat, 20 Jan 2007 21:18:42 -0700, carlfogel wrote:

> Since you don't provide any statistics of your own and don't trust
> statistics that I put up (from a group that's reasonably open to charges
> of being anti-car), I'll let you provide the statistics and math--seems
> like a better idea, doesn't it?

I've pointed you in the right direction. You're so interested, do your
own freaking homework.

Matt O.

01-21-2007, 12:34 PM

On Sun, 21 Jan 2007 15:18:55 -0500, Matt O'Toole
<[Only registered and activated users can see links. ]> wrote:

>On Sat, 20 Jan 2007 21:18:42 -0700, carlfogel wrote:
>
>> Since you don't provide any statistics of your own and don't trust
>> statistics that I put up (from a group that's reasonably open to charges
>> of being anti-car), I'll let you provide the statistics and math--seems
>> like a better idea, doesn't it?
>
>I've pointed you in the right direction. You're so interested, do your
>own freaking homework.
>
>Matt O.

Dear Matt,

I doubt that anyone is interested in doing your work for you, given
that you merely snarl and dismiss cited sources as dishonest without
providing evidence of your own.

Cheers,

Carl Fogel

01-21-2007, 12:52 PM

Bill Baka <[Only registered and activated users can see links. ]> wrote:

>Cows fart Methane, as pointed out by Reagan.

I'm not sure Reagan was the initiator of this particular fact, but
he's not alone in thinking it's part of the puzzle...

[Only registered and activated users can see links. ]

"A United Nations report has identified the world's rapidly growing
herds of cattle as the greatest threat to the climate, forests and
wildlife."

I'm working on a solution - essentially it's a small spark plug that
fires in the presence of stench. Just slip it over a cow's tail, and
voila - no more methane.

OTOH, I suspect that the resulting wildfires might be a bit of an
issue - I guess I still have some developmental work to do...

Mark Hickey
Habanero Cycles
[Only registered and activated users can see links. ]
Home of the $795 ti frame

01-21-2007, 01:01 PM

[Only registered and activated users can see links. ] wrote:

>Mark Hickey writes:
>
>>> As a classic car buff, I learned fast that total production is a
>>> BIG factor in whether or not you can afford the thing. My Corvairs
>>> went to nearly two million copies and many service parts are shared
>>> with all Chevy sixes (1955~1980) so they are cheap to run and hop
>>> up. Every piece you want is available and cheap. These mills are
>>> currently powering brand new sport planes (November cover Sport
>>> Flying) 38 years after 'death'.
>
>> That reminds me of one of the actual real advantages of a rotary, at
>> least for aircraft use. If you lose the cooling system on a
>> water-cooled aircraft motor, you can get into big trouble - you
>> won't get far before the piston engine gets too hot to continue
>> running, and then if you're not within gliding distance of a
>> suitable landing place, you're gonna make the evening news.
>
>That sound like the introduction of the Wankel to cars, offering great
>advantages that seem not to have materialized. In spite of the fewer
>parts and claimed lighter weight, it does not compete economically
>against the piston engine, from manufacture to life on the road.

You're preaching to the choir - I agree with you entirely. There are
few cases where the Wankel is an advantage...

>> A rotary OTOH will continue to run virtually forever (at a somewhat
>> reduced power level) until you can get the plane safely on the
>> ground. It'll be a "throw-away" at that point, but would have
>> potentially saved the aircraft and the pilot/passengers.
>
>Could you explain how that works? This engine has a cooling problem
>when working normally. I don't believe there is a working air cooled
>version for that reason.

There's no "air cooled" rotary, for the reasons you state. My point
isn't that the rotary is capable of normal operation without a working
cooling system, just that a rotary will continue to run even when it's
gotten so hot that it's essentially ruined. That doesn't help with
the overhaul costs, and doesn't matter much in a car - but in an
airplane it could save your life. A piston engine that gets too hot
simply can't produce enough power to continue to turn.

>> Another benefit of the rotary is that they have a very smooth power
>> output at the crankshaft. This has huge benefits for an aircraft,
>> and the PSRU (Propeller Speed Reduction Unit) which gears down the
>> prop speed allowing the engine to run in its efficient RPM range
>> without sending the propeller tips into the (noisy and inefficient)
>> supersonic range (that's the noise you hear when aerobatic planes do
>> vertical dives). The lack of extreme "power pulses" puts a lot less
>> stress on the PSRU and propeller (which can be destroyed by the
>> pulsating power output of a piston engine in certain situations).
>
>It has three ordinary power pulses per rotation of the rotor and has
>an output roughly like a two-stroke per chamber.

Which is a lot more pulses (and smoother pulses) than the typical four
cylinder opposed motor it would replace in an airplane.

>[Only registered and activated users can see links. ]
>
># Unlike a piston engine, where the cylinder is cooled by the incoming
># charge after being heated by combustion, Wankel rotor housings are
># constantly heated on one side and cooled at the other, leading to
># very high local temperatures and unequal thermal expansion. This
># places high demands on the materials used. A further problem caused
># by the shape of the seals in Mazda engines is that carbon particles
># can become trapped between the seal and the casing, completely
># jamming the engine and requiring a partial stripdown to rectify.
># Such engines should never be started and run unless the engine will
># reach operating temperature; most such instances of jammed engines
># occur when a car is started and moved a few meters, e.g. from a
># garage to a driveway. In these situations it is better to manually
># push the car.
>
>This is only a short piece of a fairly exhaustive and positive
>analysis of the Wankel. After reading this, the question arises, why
>these engines are not in general use. As I said, it sounds much like
>the recumbent bicycle description. If it is really so good, why
>aren't they taking over the market?

Way back in the '70s, there were those who felt that the rotary could
be refined to produce efficiencies on par with a piston engine. 30-40
years later, that's obviously not gonna happen. It remains a good
solution for a couple very narrow niche markets - your recumbent
analogy is very appropriate.

Mark Hickey
Habanero Cycles
[Only registered and activated users can see links. ]
Home of the $795 ti frame

01-21-2007, 01:58 PM

On Sat, 20 Jan 2007 01:14:39 -0500, Matt O'Toole
<[Only registered and activated users can see links. ]> wrote:

>On Fri, 19 Jan 2007 09:07:50 -0600, Tim McNamara wrote:
>
>> You can't pinpoint current air quality problems from a single source or
>> even a single nation. There are lots of contributors. Cars. Trucks.
>> Coal fired powerplants. Industry.
>
>Actually the sources can be pinpointed pretty well. Certainly there are
>lots of sources, but the lion's share of air pollution is from motor
>vehicles.

Assuming a "pinpoint" can look remarkably like the interstate highway
system in the U.S.

Pat

Email address works as is.

01-21-2007, 07:43 PM

In article <45b338ae$0$80050$[Only registered and activated users can see links. ]>,
[Only registered and activated users can see links. ] writes:

>> But the long-&-short of it is: the suburbs get more of their own
>> generated air pollution than Vancouver Proper.
>
>
> Our winds come from NNW except before rain, when it turns to SSW.
> That means the openings are there but we make the stuff faster than it
> can be blown away.
>
> Although this application loads slowly, I like to check it before
> going on a longer ride:
>
> [Only registered and activated users can see links. ]

That's a beauty.

It's fascinating to observe how terrain affects air flow.

I know of one particular site here, where there are flags
at three different heights; those flags can be flying
simultaneously in three different directions.

I've been mostly using this weather site, as it gives the
moon phases and star chart (my commute to work is at night):
[Only registered and activated users can see links. ]
But it only gives the most general wind directions. Not that
it matters, because I'd use the same route to work regardless
of the wind, or any other conditions. It's the only route
available to me.

Riding to work on a clear, warm, full-moon summer night
is delightful (except for a certain bridge.)

cheers,
Tom

--
Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats curlicue vcn dot bc dot ca

01-22-2007, 12:10 AM

In article <45b1c3f0$0$80118$[Only registered and activated users can see links. ]>,
[Only registered and activated users can see links. ] wrote:

> Ryan Cousineau writes:
>
> >>>> The Wankel is dead!

> > I used a comparator on Nissan's website to pair up the Nissan 350Z,
> > Mitsubishi Eclipse V6, and the Mazda RX-8:
>
> [Only registered and activated users can see links. ]

> > But then, I think the state of batteries is finally good enough that
> > the next decade will see the end of IC engines as the powerplant of
> > choice for mainstream cars. And I say this as someone who has a
> > great fondness for IC engines.
>
> I had a ride in a Tesla the other day and other than a 200mile range,
> it outperformed any sport car I've seen. My friend who did the demo
> told me of a Dodge Viper that was ahead of him on the freeway on-ramp.
> As the monster brute did a maximum acceleration and moved over to its
> rightful place, farther left on the road, the Tesla shot by using
> traction control to keep from developing white smoke at the rear
> wheels. I'm sure that didn't go down well with the beast of a car and
> its driver, but that is what electric drive can do.
>
> [Only registered and activated users can see links. ]
> [Only registered and activated users can see links. ]
>
> Jobst Brandt

You lucky duck! I have been following the Tesla's development with great
interest, since it seems to be the first EV able to properly compete in
an automotive niche.

Virtually every previous EV I've looked up has featured useless
performance (I always figured the NEV class should have revived the
"Ner-a-car" brand), rotten range, or both.

200 miles is probably enough for a lot of people. I own a New Beetle (it
looks great, but the vehicle is about as user-serviceable as a turbine
engine) and it goes 350-400 km on a tank.

Since I bought the car 2 years ago or so, I believe the longest one-day
mileage I put on it was about 200 km.

So something like a Tesla would suit almost all of my driving (well...I
skirt the "seats two" issue, and the rather larger "costs $90,000"
issue).

The remaining issues amount to battery pack replacement costs (cited at
$20,000 after 100,000 mi or so), price, and my desire for a sedan. Well,
and meeting their range and durability claims.

The trick of starting with the lightest, best-handling sports car around
was a stroke of genius, and making it hella fast was twice as good.

But I'm going to reserve a tiny bit of optimism until these things
actually go and drive around the real world with real drivers in the
real seats. Eating the pudding, and all that.

[explanation of "eating the pudding" joke for Jobst:
[Only registered and activated users can see links. ] ]

--
Ryan Cousineau [Only registered and activated users can see links. ] [Only registered and activated users can see links. ]
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

01-23-2007, 05:00 AM

On Tue, 16 Jan 2007 19:05:59 -0500, "Ken C. M."
<[Only registered and activated users can see links. ]> wrote:

>Okay well it's not totally OT but sort of. I found this little video
>clip on google.
>[Only registered and activated users can see links. ]
>
>Shows the reason not to leave your carbon fiber ride laying around in
>someones driveway.
>
>Ken

What struck me was the absence of a steel tube in the demo. Why? Would
it show that steel is as tough as Ti at a much lower price?

larry

01-23-2007, 06:05 AM

Mark Hickey wrote:
> A Muzi <[Only registered and activated users can see links. ]> wrote:
>
> >As a classic car buff, I learned fast that total production is a BIG
> >factor in whether or not you can afford the thing. My Corvairs went to
> >nearly two million copies and many service parts are shared with all
> >Chevy sixes (1955~1980) so they are cheap to run and hop up. Every piece
> >you want is available and cheap. These mills are currently powering
> >brand new sport planes (November cover Sport Flying) 38 years after
> >'death'.
>
> That reminds me of one of the actual real advantages of a rotary, at
> least for aircraft use. If you lose the cooling system on a
> water-cooled aircraft motor, you can get into big trouble - you won't
> get far before the piston engine gets too hot to continue running, and
> then if you're not within gliding distance of a suitable landing
> place, you're gonna make the evening news.

Can't really think of a general aviation A/C with liquid cooling tho.
None of the ones I have flown, bunch of Cessnas from 150/2 thru the
T-210. Military trainers, none were, T-34, T-28. Even WWll, except for
the Merlin/Griffon types, most were aircooled radials.
>
> A rotary OTOH will continue to run virtually forever (at a somewhat
> reduced power level) until you can get the plane safely on the ground.
> It'll be a "throw-away" at that point, but would have potentially
> saved the aircraft and the pilot/passengers.
>
> Another benefit of the rotary is that they have a very smooth power
> output at the crankshaft. This has huge benefits for an aircraft, and
> the PSRU (Propeller Speed Reduction Unit) which gears down the prop
> speed allowing the engine to run in its efficient RPM range without
> sending the propeller tips into the (noisy and inefficient) supersonic
> range (that's the noise you hear when aerobatic planes do vertical
> dives). The lack of extreme "power pulses" puts a lot less stress on
> the PSRU and propeller (which can be destroyed by the pulsating power
> output of a piston engine in certain situations).
>
> >A vehicle or power plant with 100K copies is not going to be a cheap
> >project over the long run.
>
> True enough... as an owner of a mid-80's Alfa Romeo, I know the pain
> of trying to find parts for an "unusual car"... (the oil pump I just
> bought set me back over $250).
>
> Mark Hickey
> Habanero Cycles
> [Only registered and activated users can see links. ]
> Home of the $795 ti frame

01-23-2007, 07:50 AM

p.k. wrote:
> [Only registered and activated users can see links. ] wrote:
> >> One of my best friends in engineering school couldn't correctly
> > pronounce "aluminum."
>
> and Americans can't spell aluminium!

You can blame Humphry Davy for that one.
<http://en.wikipedia.org/wiki/Aluminium#Spelling>

The element does give us one of the hardest tongue twisters in English,
whichever way we choose to spell it.

"Are you copper-bottoming 'em, my man? No, I'm aluminiuming 'em, Mum."
"Are you copper-bottoming 'em, my man? No, I'm aluminuming 'em, Mom."

--
Dave...