Video, review physics and the pinewood derby

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sporty
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Video, review physics and the pinewood derby

Post by sporty »

I placed this in section, for a review and also for link.


www.pinewoodphysics.com

dvd video



I was able to watch this video recenty, I have to tell you for the cost, it is a good long video and has value for your dollar.

They do a very good job and in very good detail of the basics and physics of pinewood derby.

The set screw method for alignment was neat and interesting to watch.

It is less modern when it comes to tools and the current goodies out on the market.

But it does provide a great 1st timers view into pinewood derby. So I recommend it for new scouts and parents new to pinewood derby.

For more advanced pinewood derby families, this has less to offer, but still a pleasing view of information.

Sporty
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Re: Video, review physics and the pinewood derby

Post by ohiofitter »

That is a cool video. It's a shame it's 2 hours long...this could be a great video to play at the pack meeting when we hand out the cars....although I'm sure if you have the software to edit video......you could make a condensed version
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Re: Video, review physics and the pinewood derby

Post by Nitro Dan »

I also purchased this video. Since I run our packs workshop, I was mainly looking for the ideas they use to show cubs how the physics in Pinewood Derby works. It was very informative, and I got a lot out of it. IMO, definitely worth it for the money.

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Re: Video, review physics and the pinewood derby

Post by jpswensen »

ohiofitter wrote:That is a cool video. It's a shame it's 2 hours long...this could be a great video to play at the pack meeting when we hand out the cars....although I'm sure if you have the software to edit video......you could make a condensed version
The length was one of the things we struggled with while we were making it. Our solutions was to make the menu selection from the main menu fine-grained enough that you only need to show parts of the video. We even received feedback from a high school physics teacher that she showed one section of the video every day at the start of class and made pinewood derby an end-of-the-semester project.

This still isn't a solution if you want to watch a condensed version of the whole thing, unfortunately.
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sporty
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Re: Video, review physics and the pinewood derby

Post by sporty »

jpswensen,


Thanks for coming and posting at Derby Talk. !!!


We look forward to add ons and changes.

Certainly with all the new techniques being used, tools, different graphites and the different metals out there.

I do wonder if there is a axle sleeve that is able to take a set screw. instead of just using a set screw into the wood. but a easier way to adjust alignment. instead of applying force to the set screw by pushing the axle into the wood more.

It would be neat to see a hollow set screw that holds the axle, where you could just use a flat head to raise and lower the axle for fine tuning of alignment.

This I think would work better and easier than the current method suggested, but could be wrong.

I tossed this out to a vendor, in hopes he would sell something like this.


you will have to forgive the crued drawings, But i think i got it close enough to understand, what I think we need to have a vendor offer to do this for alignment.

Image

Image

As I mentioned crued picture example, due keep in mind that you would have to likely remove the axle to move the set screw.

I might try and think of a better design, so that the axle would not have to be removed. I only spent a few minutes on this.

Anyone got a better design for that movement process for alignment, feel free to post it.

Sporty
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Re: Video, review physics and the pinewood derby

Post by jpswensen »

I discussed your suggestion, as well as several others, with some of my mechanical engineering colleagues who are better at structures and mechanism design. They made the following comments and suggestions:
1) They didn't think that the multiple set screw technique was too difficult, considering the extra machining that would be necessary to implement a single screw mechanism. That being said, they did have a couple of ideas for a single screw mechanism:
a) Create a circular rack and pinion mechanism that can be inserted into a pre-bored hole. This is the least feasible of all the methods, but could be possible. Considering the size of the set screws used, and the desire to make cars as thin as many make them, a mechanism this small would be hard and expensive.
b) Use a stiff spring on one side and a set screw on the other to get the desired wheel angle. Of course, this depends on whether you want (or are allowed by your rules) to leave the spring in place as there is no way to remove it after the axles are epoxied in place. This was the technique they most recommended if you were set on doing a single screw mechanism,
c) Create a more elaborate wheel alignment fixture that combine the dynamic wheel alignment structure described in the video with the ability to adjust the axles. That is, make a fixture that hold the car in place and attaches 4 linear slides to the axles. This fixture would allow the wheels to touch the carriage traveling underneath the car so you can move the carriage, adjust the wheel angles, and repeat.
d) As to the method suggested above, their only concern was that in order to align the axle with the hole in your set screw, you may not be able to achieve the desired wheel angle. You could be off from the desired position by as much as half the pitch of the screw (either turning forward or back to the nearest point at which the hole in the set screw aligned with the axle holes.
2) As a side note, they also made the point that tapping the wood and inserting a helicoil (of course with a transverse hole to align with the axle hole), then inserting the set screws on the inside of the helicoil would be a superior solution and reduce the risk of stripping the threads in the wood (particularly that late in the car construction process). Using a helicoil would also be ideal if implementing the single set screw with stiff spring on the opposite side of the axle. Depending on the stiffness of the spring, you could easily strip the threads in the wood from the force exerted by the compressed spring. Once again, some race rules would not allow you to have a helicoil in the car.

John Swensen
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