Derby Talk

I've been looking around the Internet the past few weeks, looking for some Derby trivia notes that I can use to fill in spots between races during our Derby coming up this Saturday. If anyone has some notes or links that contain some fun facts I would appreciate it. For example, I found these:

http://pinewoodderby.org/pinewood/about

Did You Know?

• A fast Pinewood Derby® car can reach a speed of nearly 20 miles per hour. Pretty good for a little block of wood!
• If a Pinewood Derby® car racing down the track was enlarged to the size of a real automobile, it would be speeding at more than 200 miles an hour. That’s fast!
• The first Pinewood Derby® was run in 1953 at the Manhattan Beach Scout House near Los Angeles when Cubmaster Don Murphy introduced the idea to Pack 280C.
• Over the years, Cub Scouts have built close to 100 million Pinewood Derby® racers. That’s a lot of cars!
• If you lined up all the Pinewood Derby® racecars, bumper-to-bumper, they would reach more than 7,000 miles—far enough to stretch from Charlotte, North Carolina, to the North Pole!
• If every Pinewood Derby® car made this year took just one run down the track, the combined distance would be from the Earth to the Moon and back. That’s out of this world!
• Reader’s Digest magazine included the Pinewood Derby® in its 2006 Best of America list as “a celebrated rite of spring.” Way to go, Cub Scouts!
• No Pinewood Derby® car has ever used a drop of gasoline. Gravity rules!

I'm looking for more of the same style of fun facts, thanks.

20mph? I don't recall that as accurate. Isn't the typical race closer to 10mph (peak speed)?

For DayCamp we used to do alot of cutting of boards to length. One engineer in the group would actually calculate the amount of 'dust' created by counting cuts and the kerf of the blade. I wonder what the average volume of pine dust generated each season would be?

When I calculated the speed several years ago I came up with just under 10 mph as well. I did a bit of math, just because I was curious. (Also I think my Dad asked.) The cars are about 7 inches long. A sedan like the Maxima I used to have BK (before kids) is about 16 feet long. Our track is 32 feet (four 8' sections) but the ending gate is about 3 feet short of the end of the track, so I went with a 29 foot estimate. Fast cars run that track in 2.3 seconds (or faster), and 2.3 seconds for 29 feet becomes 8.66 miles per hour of actual speed. Converting that to scale (7" scaled up to 16') gives a scale MPH of over 235 miles per hour!

dna1990 wrote:Isn't the typical race closer to 10mph (peak speed)?

Typically, yes, assuming a ~4'-high starting gate. Maximum speed is mostly a function of the starting height of the CoM relative to the flat of the track.

The statement was what "a fast Pinewood Derby® car can reach." Arguably, that could be the terminal velocity.

FatSebastian wrote:The statement was what "a fast Pinewood Derby® car can reach." Arguably, that could be the terminal velocity.

You know, that should have occurred to me. With very simple math an average of 10 mph over the course of the track could imply 20 mph at the end, or at least at the fastest point. A car starts at rest (0 mph) and finishes at 20 mph would average 10 mph (0 + 20) / 2 = 10. So I guess the 20 mph could be correct if measured at the point in time where the car was going the fastest.

Maybe you could list websites dedicated to PWD?
OR a list of specialized commercial tools?

My goal is to get tidbits of information I can pass out in between races and kid interviews and stuff. Web addresses are probably something that would work better on a reference sheet.

If anyone has Derby cartoons, we could project those in between races too, at times when the computer isn't busy.

Ooh,
How 'bout you collect pictures of strange/wonderful/unusual cars?
Project those when the computer isn't busy?

That's a cool idea too. I think I saw someone else on this board say they did that with a secondary projector so that there was a slide show of over 600 car pictures going on throughout the derby. I'm going to work towards that for our district derby this year, but I don't think I have time to set it up for Saturday.

Keep the ideas / suggestions coming.

drathbun wrote:So I guess the 20 mph could be correct if measured at the point in time where the car was going the fastest.

It could be correct, but the starting gate would still have to be abnormally tall.

For a typical track, 20 mph is physically impossible. An object free-falling four feet, neglecting all other losses (atmospheric drag, friction, momentum transfer to the wheels, etc.) will only reach ~11 mph maximum. Of course a car with wheels spinning along a track and through the air would be slower than this.

To reach ~20 mph, the track would need to be over 13 feet tall!

Wow, there's a lot of math on that page. Maybe someday I will go read it. For now, I get that the terminal velocity point your making is that an object dropped from 4' has a limited amount of acceleration that will occur, and the maximum speed when dropped straight down will be as you say. But since the derby car doesn't go straight down, it essentially covers more ground during the acceleration phase of the track. Does that increase the velocity at all, in terms of what could be measured as a combination of downward and forward travel?

Does a car dropped from the starting gate get to the floor at the same time a car rolling down the ramp gets to the floor, assuming similar weights? If so, then the car on the ramp is going faster because it traveled farther, right?

Feel free to call me an idiot if you like, I can take it.

drathbun wrote:Does that increase the velocity at all, in terms of what could be measured as a combination of downward and forward travel?

No.

drathbun wrote:Does a car dropped from the starting gate get to the floor at the same time a car rolling down the ramp gets to the floor, assuming similar weights?

No. It takes longer for an object to travel down a ramp than to free-fall. How fast a car accelerates (speeds up) is a function of the angle of the ramp. A ramp with an angle of 0 degrees (horizontal) doesn't allow acceleration at all. A ramp at 90 degrees (vertical) allow maximum acceleration (free-fall). But the speed as a function of height is the same in principle (neglecting effects like wheel spin and air drag) for both. With a steeper incline, the speed doesn't increase so much as the time it takes to reach that speed (height) is lessened.

Got it. So I'll make sure I change my first trivia note to reflect the proper speed.

I need a high-speed camera and a track painted with a grid pattern so I can measure exactly how fast a car is going at any point in time. Will one of you sign the permission slip for my wife so I can do that?

According to: http://www.funtrivia.com/en/subtopics/P ... 66678.html Q: Which year did the Pinewood Derby become an officially recognized part of the Cub Scout program? A: 1955. The BSA officially incorporated the Pinewood Derby into the Cub Scout program in 1955. Plans for tracks and car specifications first appeared in the October 1954 issue of "Boys' Life" magazine.

What about the spinoffs from the PWD? From http://en.wikipedia.org/wiki/Pinewood_derby

Awana has the Awana Grand Prix.
Christian Service Brigade uses the name Shape N Race Derby.
Royal Ambassadors have RA Racers.
Royal Rangers use a different kit with an original style narrow wheel, adjustable screw axle and wooden dowel axle housing.
Scouts Canada has the kub kar rally for Cub Scouts, beaver buggies for Beaver Scouts, and scout express trucks for Scouts.
Valve cover racing is an event at some car shows using vehicles made from valve covers.
Woodcar Independent Racing League open to anyone of any age
YMCA chule cars use the same kit as the Royal Rangers.

The missed the GMC Motorhome Enthusiasts, CSCA, CVSN, Muscle Car Derby and some others.

I was looking for some triva around the 18 wheelers, but couldn't find any.

There's also:

Lutheran Pioneers
Master Clubs
Boy Scouts - some troops do run their own races

Some companies have even run a PWD type race as a special event for employees.

I would not include valve cover racing, as it is using a different race vehicle.