> A trick I used was to put the nail/axel in my drill with the wheel mounted
> and added lots of graphite. With the axel spinning quickly in the drill and
> holding the wheel all surfaces became polished/burnished and loaded with
> graphite. My son won 2 trophies that year with that car.
He must have been proud of all the hard work you did!
Joe wrote:
> I have heard and it makes sense to raise one wheel up a little bit to reduce
> friction, but which wheel one of the rear wheels where the weight is or one
> of the front wheel and hope it goes straight with one front wheel?
> Joe
Joe,
Many smart people disagree about whether it is better to have one wheel
raised or not. Truth is, you're not very likely to get your axles
positioned accurately enough for all 4 wheels to carry weight anyway.
Three will be carrying the weight and one will be loafing along. Oh,
it will be turning alright, but it won't be carrying much weight. If
it touches the track at all, it be a result of the slack between the
hub and axle that allows the "high" wheel to drop down to contact the
track. The light wheel will also rub along the center rail, so it
needs to be treated the same as all the others.
That said, most of the faster cars I ever saw had one wheel raised just
a little. You can only raise a wheel on the light end of the car. If
you try to raise a wheel on the heavy end, that wheel will just go down
anyway and raise the one on the opposite corner.
Find a hard, smooth surface and roll the car to see if it rolls
straight or not. If it doesn't, tweak the front axle by bending it
slightly fore or aft until the car rolls straight.
DonkeyHody
"Give a hungry man a fish and he will eat for a day. Teach him to fish
. . . and he will sit in a boat and drink beer all day."
Joe wrote:
> I have heard and it makes sense to raise one wheel up a little bit to reduce
> friction, but which wheel one of the rear wheels where the weight is or one
> of the front wheel and hope it goes straight with one front wheel?
> Joe
I have done a father-son clinic in my shop for years and have helped
build scores of cars. Some argue that if you lift one of the fron
wheels up a bit, and you can keep it running straight, you will have
less friction. Some also argue tilting wheels on edge also helps. I
don't really know if it helps that much. Polishing the axels is
important and aligning the wheels is important. After that, it is
marginal at best for the rest of the stuff.
My goal each year is getting my son to use two or three different tools
that he didn't use the year before. Maybe it is a carving goage, rasp,
a hand router, spokeshave or using stop cuts, or whatever. When I do
the clinic, I bandsaw out the rough shapes for some of the youger
scouts if they want, but I explain it is just as easy to get down to
the lines with spoke shave or chisel or even a sharp pocket knife. I
spend a lot of time going around telling dads to let they boys run the
tools for awhile.
I won my first year, and then spent the better part of a Saturday
watching my son's car getting killed in the District tournament. I was
glad to have him get the experience of winning and losing about
something he cared about. It was good character development, but I
have never had a big desire to repeat the experience. Each year I look
at the completed car and think about spending a half an hour aligning
the wheels. I know that if I do, he will likely win. I spend some
time teaching my son to do it, but I don't do it.
When I have run our pack derby, I deemphasize the fastest car award. I
know about all the bullcrap feel-good awards. However, it isn't a even
playing field for the boys in terms of building and tuning the cars.
It isn't fair to penalize the boys who don't have as much or as skilled
assistance. I make sure each boy get an identical looking award, even
if the award is for the "Best painted block of wood with wheels". Even
though my kids are now teenagers, they still have their cars displayed
on shelves with whatever ribbon they won.
Good luck on you car an enjoy the time with your boy.
LRod wrote:
> On 5 Jan 2006 15:19:13 -0800, "DonkeyHody" <[email protected]>
> wrote:
>
> >You can only raise a wheel on the light end of the car. If
> >you try to raise a wheel on the heavy end, that wheel will just go down
> >anyway and raise the one on the opposite corner.
>
> How do you tell the difference between a car with a wheel raised on
> the light end and one with a wheel raised on the heavy end that
> settled and raised the light end?
>
Only the builder knows for sure . . .
But, if you try (unsuccessfully) to raise a wheel on the heavy end, you
inadvertently lower the body at that location which may cause it to
drag on the center rail. It's better to raise the correct wheel in the
first place so you don't have that problem.
DonkeyHody
"We should be careful to get out of an experience only the wisdom
that is in it - and stop there; lest we be like the cat that sits down
on a hot stove-lid. She will never sit down on a hot stove-lid
again---and that is well; but also she will never sit down on a cold
one anymore." - Mark Twain
Rich wrote:
> My dad walked up and told the scout master that this was my last day
> in scouts.As we where leaving the derby started and all the other dads where
> having a good time racing THERE cars.On the way home my dad tried to explain
> to me that when you are involved in something for you that it should be up
> to you to do your best. I did not understand at the time.
It's good that you have been able to find wisdom in your dad's course
of action. I think you could have learned many more valuable lessons
by staying in Scouts.
I wasn't involved in Scouts as a kid. But as a dad, I see tremendous
benefit to the boys from the experience of Boy Scouts (much more than
Cub Scouts or Weblos). I'm very glad my son has the privilege to
participate.
DonkeyHody
"We should be careful to get out of an experience only the wisdom
that is in it - and stop there; lest we be like the cat that sits down
on a hot stove-lid. She will never sit down on a hot stove-lid
again---and that is well; but also she will never sit down on a cold
one anymore." - Mark Twain
Leon wrote:
> "Larry Bud" <[email protected]> wrote in message
> news:[email protected]...
> >> A trick I used was to put the nail/axel in my drill with the wheel
> >> mounted
> >> and added lots of graphite. With the axel spinning quickly in the drill
> >> and
> >> holding the wheel all surfaces became polished/burnished and loaded with
> >> graphite. My son won 2 trophies that year with that car.
> >
> > He must have been proud of all the hard work you did!
> >
>
> LOL.. He did the rest. I was not crazy about my 7 year old with an electric
> drill with a nail chucked up in it spinning between his fingers.
Fair enough, just giving you a hard time ;-)
Andy Dingley wrote:
> What happens if you race the same set of cars against each other
> repeatedly? Are there _really_ "fast" cars ?
>
Yes, Virginia, there are really fast cars.
Scouting has a huge presence on our military bases overseas. While we
were in Japan, my son participated in large pack races two years in a
row. Each year, over 90 cars raced a double elimination tournament
with the winner of each race determined by a best 2 out of 3 trips down
the track against the same opponent. That meant the slowest cars went
down the track at least 4 times and the fastest cars went down several
dozen times.
Each year, there was one car that crossed the finish line first every
single time it ran. The first year, it was someone else's car. The
second year, it was my son's.
When we came back to the States, we repeated the feat two more years at
smaller pack races.
Fast cars don't just exist in the fantasies of kids young and old.
They are real, and we built 'em.
DonkeyHody
"A poor workman quarrels with his tools." - American Indian Proverb
"Joe" <[email protected]> wrote in message
news:[email protected]...
> I have heard and it makes sense to raise one wheel up a little bit to
reduce
> friction, but which wheel one of the rear wheels where the weight is or
one
> of the front wheel and hope it goes straight with one front wheel?
> Joe
>
>
Thank you all for your input we will be keeping all four wheels on the track
Joe
Leon wrote...
>
> "Joe" <[email protected]> wrote in message
> news:[email protected]...
> >I have heard and it makes sense to raise one wheel up a little bit to
> >reduce
> > friction, but which wheel one of the rear wheels where the weight is or
> > one
> > of the front wheel and hope it goes straight with one front wheel?
> > Joe
Joe, you can't raise a rear wheel, or the car will sit cocked.
You can raise a front wheel and adjust the steering by tweaking the other
front wheel so that the car runs true.
> If any thing you will be increasing friction. The only real
> friction is between the axel and the wheel. If you eliminate 1 wheel the
> other 3 wheels will have more friction. Use tons of graphite on the wheels
> and axel.
It doesn't increase or decrease friction (all else being equal) to ride
on only three wheels. The total drag from friction is the same in both
cases. However, potential energy can be saved if the car runs true down
the track, because the lifted wheel will not be rotating full speed when
the car crosses the finish line. The lower momentum of that wheel must be
conserved, and the only place for it to go is into the forward momentum
of the car. So, there is some potential benefit from raising a wheel.
I don't mean to downplay the importance of lubricant and polished bearing
surfaces. That's paramount.
Jim
Toller wrote...
> You are kidding, I hope. The angular momentum of the wheel would be tiny;
> and any force you would save by not generating it would be a drop compared
> to the rest of the forces.
Not kidding. It can produce a measurable result. That's not to say it's
particularly important in the grand scheme of things, and I did try to
make that clear.
> I have heard that raising a wheel reduces friction, but the odds of having
> it track as well as 4 wheels is not good.
Well, it doesn't reduce friction, and it is true that it's harder to get
the car to track as well with only three wheels. But not impossible.
Since I haven't seen it mentioned here, I should point out a
very important performance factor that is usually neglected, and that is
the track itself. A car which could perform extremely well on a top-
quality track often fares poorly on a bad track. For example, on a bumpy
track, you can't push the weight back as far as you'd like (and could get
away with on a smooth track).
Jim
Leon wrote...
> The increased friction would be where the wheel and the axel come in contact
> with each other. The carried weight would be 1/3 greater for each wheel and
> axel if 1 wheel were eliminated.
True. The axle load on a car with four wheels would be 1/4 the car's
total weight. It would be 1/3 on a car with a lifted wheel. But the axle-
wheel friction is directly proportional to the axle load. That is, for
any given wheel:
f = c * (1/4)m = cm/4
where f is the friction, c is a constant, and m is the car's weight.
So t_4 = 4f = 4cm/4 = cm
where t_4 is the total friction from wheel drag in the 4-wheel case.
Similarly, with three wheels, as you noted, we have, f = cm/3, but
now there are only three wheels, so the total friction is
t_3 = 3f = 3cm/3 = cm
Since c is the same in both scenarios, t_4 = t_3. That is, the total
friction is the same in both cases.
Jim
Andy Dingley wrote...
> What happens if you race the same set of cars against each other
> repeatedly?
You get more accurate results. :-)
> Are there _really_ "fast" cars ?
Certainly!
Ideally, the rules are devised so as to limit the available performance
improvements to those that can be accomplished by an eight to ten year-
old boy with a reasonably knowledgeable mentor and rudimentary tools.
When I was doing this stuff, we added open and unlimited categories to
give the more zealous mentors the opportunity to satisfy their urges
without taking over their boys' cars.
Jim
I remember my first pine wood derby. Mydad watched and gave me some
instruction when I was building my car. I was so proud of what I had built
and my dad saw that I was. The day of the derby we walked in and there where
cars that looked like indy cars and formula 1 cars some even had spark plug
wires.My dad walked up and told the scout master that this was my last day
in scouts.As we where leaving the derby started and all the other dads where
having a good time racing THERE cars.On the way home my dad tried to explain
to me that when you are involved in something for you that it should be up
to you to do your best. I did not understand at the time. Growing up and
getting married raising my own kids I get it know. Im 46 now. My daugther is
20 my son 18. I do help my kids but I dont do what they should be doing for
themselves. They are turning out to be very self sufficent. Dont get me
wrong I love my kids but its nice to see that they can do things on there
own and make good decisions. THANKS DAD.
"Joe" <[email protected]> wrote in message
news:[email protected]...
>I have heard and it makes sense to raise one wheel up a little bit to
>reduce
> friction, but which wheel one of the rear wheels where the weight is or
> one
> of the front wheel and hope it goes straight with one front wheel?
> Joe
>
>
I remember my first pine wood derby. Mydad watched and gave me some
instruction when I was building my car. I was so proud of what I had built
and my dad saw that I was. The day of the derby we walked in and there where
cars that looked like indy cars and formula 1 cars some even had spark plug
wires.My dad walked up and told the scout master that this was my last day
in scouts.As we where leaving the derby started and all the other dads where
having a good time racing THERE cars.On the way home my dad tried to explain
to me that when you are involved in something for you that it should be up
to you to do your best. I did not understand at the time. Growing up and
getting married raising my own kids I get it know. Im 46 now. My daugther is
20 my son 18. I do help my kids but I dont do what they should be doing for
themselves. They are turning out to be very self sufficent. Dont get me
wrong I love my kids but its nice to see that they can do things on there
own and make good decisions. THANKS DAD.
"Joe" <[email protected]> wrote in message
news:[email protected]...
>I have heard and it makes sense to raise one wheel up a little bit to
>reduce
> friction, but which wheel one of the rear wheels where the weight is or
> one
> of the front wheel and hope it goes straight with one front wheel?
> Joe
>
>
>
> It doesn't increase or decrease friction (all else being equal) to ride
> on only three wheels. The total drag from friction is the same in both
> cases. However, potential energy can be saved if the car runs true down
> the track, because the lifted wheel will not be rotating full speed when
> the car crosses the finish line. The lower momentum of that wheel must be
> conserved, and the only place for it to go is into the forward momentum
> of the car. So, there is some potential benefit from raising a wheel.
>
You are kidding, I hope. The angular momentum of the wheel would be tiny;
and any force you would save by not generating it would be a drop compared
to the rest of the forces.
I have heard that raising a wheel reduces friction, but the odds of having
it track as well as 4 wheels is not good.
"Joe" <[email protected]> wrote in message
news:[email protected]...
>I have heard and it makes sense to raise one wheel up a little bit to
>reduce
> friction, but which wheel one of the rear wheels where the weight is or
> one
> of the front wheel and hope it goes straight with one front wheel?
> Joe
It will steer towards the side rail with an unbalanced situation like you
describe. If any thing you will be increasing friction. The only real
friction is between the axel and the wheel. If you eliminate 1 wheel the
other 3 wheels will have more friction. Use tons of graphite on the wheels
and axel.
A trick I used was to put the nail/axel in my drill with the wheel mounted
and added lots of graphite. With the axel spinning quickly in the drill and
holding the wheel all surfaces became polished/burnished and loaded with
graphite. My son won 2 trophies that year with that car.
As a grandfather I have made many Pinewood Derby cars for scouts in our
family. The kids designed them, I did the body work, they painted and
finished wheels and hop-up. We had many winners.
My daughter was Den Mother for her son's Cub pack and helped run the
derby. In her final year she entered the race against the dads, and she
smoked them!
The track always had a 3/8" center strip to keep cars on track so our
main concern was clearance underneath the body.
Glenn
>"Leon" wrote in message
>>>Tom Watson wrote in message
>>> On Thu, 5 Jan 2006 20:33:30 -0700, Jim Wilson
>>> wrote:
>
> >Leon wrote...
> >>
> >> "Joe" < wrote in message
> >>
> >> >I have heard and it makes sense to raise one wheel up a little bit
>
> We will not be raising no wheels, mon.
>
> We playto the straight and natural blue.
>
> "Jim Wilson" wrote in message
> >
> > It doesn't increase or decrease friction (all else being equal) to ride
> > on only three wheels. The total drag from friction is the same in both
> > cases.
>
> The increased friction would be where the wheel and the axel come in
contact
> with each other. The carried weight would be 1/3 greater for each wheel
and
> axel if 1 wheel were eliminated.
Except for paying for the weddings, I am now more glad than ever that all I
had was daughters.
--
www.e-woodshop.net
Last update: 12/13/05
"Larry Bud" <[email protected]> wrote in message
news:[email protected]...
>> A trick I used was to put the nail/axel in my drill with the wheel
>> mounted
>> and added lots of graphite. With the axel spinning quickly in the drill
>> and
>> holding the wheel all surfaces became polished/burnished and loaded with
>> graphite. My son won 2 trophies that year with that car.
>
> He must have been proud of all the hard work you did!
>
LOL.. He did the rest. I was not crazy about my 7 year old with an electric
drill with a nail chucked up in it spinning between his fingers.
On 5 Jan 2006 18:28:13 -0800, "Glen" <[email protected]> wrote:
>Some also argue tilting wheels on edge also helps
What happens if you race the same set of cars against each other
repeatedly? Are there _really_ "fast" cars ?
On a really bizarre note, has anyone ever heard of pinewood derbies
being held in the UK, or particularly Northern Ireland? It sounds like
a great idea.
"WConner" <[email protected]> wrote in message
news:Ynwvf.4$em5.1@trnddc05...
>" making sure the wheels are aligned straight."
>
> When our sons did this, I sawed two kerfs in a 2x4 block and set the
> wheels in them for alignment. They did well, years later I did the same
> for a grandson, his didn't do worth a darn.
>
> Walt Conner
Sounds like a good reason to buy that new tablesaw you've been wanting.
On Thu, 5 Jan 2006 20:33:30 -0700, Jim Wilson
<[email protected]> wrote:
>Leon wrote...
>>
>> "Joe" <[email protected]> wrote in message
>> news:[email protected]...
>> >I have heard and it makes sense to raise one wheel up a little bit
We will not be raising no wheels, mon.
We playto the straight and natural blue.
Tom Watson - WoodDorker
tjwatson1ATcomcastDOTnet (real email)
http://home.comcast.net/~tjwatson1/
Yeap, the graphite is key, as well as, making
sure the wheels are aligned straight. Make sure
to roll along a flat surface and it maintains a
true straight line. Trophies two of three
years. The one year an axle came lose. Ha!
Thunder
On Thu, 05 Jan 2006 20:24:19 GMT, "Leon"
<[email protected]> wrote:
>
>"Joe" <[email protected]> wrote in message
>news:[email protected]...
>>I have heard and it makes sense to raise one wheel up a little bit to
>>reduce
>> friction, but which wheel one of the rear wheels where the weight is or
>> one
>> of the front wheel and hope it goes straight with one front wheel?
>> Joe
>
>It will steer towards the side rail with an unbalanced situation like you
>describe. If any thing you will be increasing friction. The only real
>friction is between the axel and the wheel. If you eliminate 1 wheel the
>other 3 wheels will have more friction. Use tons of graphite on the wheels
>and axel.
>
>A trick I used was to put the nail/axel in my drill with the wheel mounted
>and added lots of graphite. With the axel spinning quickly in the drill and
>holding the wheel all surfaces became polished/burnished and loaded with
>graphite. My son won 2 trophies that year with that car.
>
"Jim Wilson" <[email protected]> wrote in message
news:[email protected]...
>
> It doesn't increase or decrease friction (all else being equal) to ride
> on only three wheels. The total drag from friction is the same in both
> cases.
The increased friction would be where the wheel and the axel come in contact
with each other. The carried weight would be 1/3 greater for each wheel and
axel if 1 wheel were eliminated.
On 5 Jan 2006 15:19:13 -0800, "DonkeyHody" <[email protected]>
wrote:
>You can only raise a wheel on the light end of the car. If
>you try to raise a wheel on the heavy end, that wheel will just go down
>anyway and raise the one on the opposite corner.
How do you tell the difference between a car with a wheel raised on
the light end and one with a wheel raised on the heavy end that
settled and raised the light end?
--
LRod
Master Woodbutcher and seasoned termite
Shamelessly whoring my website since 1999
http://www.woodbutcher.net
Proud participant of rec.woodworking since February, 1997
On Thu, 05 Jan 2006 22:53:44 GMT, "WConner" <[email protected]>
wrote:
>If you search the Internet, you should find a site with all kinds of tips
>for faster cars, our son did but I don't know where.
>
>"He must have been proud of all the hard work you did!
>
>This is supposed to be a father/son project, unfortunately some sons don't
>get to touch them.
>
>Scoutmaster
>
I think that this depends on the judgment of the parent and the age of
the child.
Last year, the first year that my boy was in a PineyWood Darby, he was
seven, and I let him draw the car and then I roughed out the blank on
the bandsaw, according to his drawings.
He then used the rasp and various grades of abrasives to bring the car
to its final shape.
He did the finishing.
I knew, nothing about the preparation of the wheels and axles.
He came in Third in his pack and was well satisfied.
This year he will be Eight. I will explain the physics of weight
placement, friction, etc.
He will true the wheels and polish them.
He will true the axles and polish them.
We will not cut out on the bandsaw, because I am too afraid of my
eight year old running it.
We will use a coping saw.
What I learn wd from last year is that we should build two cars. I
will build one and show him the steps. He will build the other, step
by step with me.
He should learn a lot from this.
Above all, I want the boy to have fun. I don't want it to become a
serious exercise.
We will use our best efforts to produce a car that does as well as it
can.
Tom Watson - WoodDorker
tjwatson1ATcomcastDOTnet (real email)
http://home.comcast.net/~tjwatson1/