Pack 242 Cars - 2016

Show off your cool vehicle designs and track burning speedsters!
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rcmoeur
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Pack 242 Cars - 2016

Post by rcmoeur » Thu Mar 10, 2016 8:29 pm

I've uploaded all the car photos we took at last Saturday's Pack 242 Pinewood Derby and placed them on a webpage at:
http://www.richardcmoeur.com/242pwd2016.html

We take four photos of each car: front left, front right, rear left, rear right. This way the boy and family has a record of the car (and we can take a look later if a car in a future year looks a bit "too familiar". ;) )

Our family's cars:
  • 3rd overall - Duncan (our son), "DuncMobile". Standard wedge with a marble "energy source" encased by 1/4" Pb wire "roll cage"/weight. Driver (apparently texting) came from a set of plastic "public safety workers".
  • 4th place, Adult - my "Bus-ted" bus (tall block) - faster than expected, considering the size. Lighting system came from a deceased LED plastic sword.
  • 8th place, Adult - I wasn't planning on making a second car, but my lovely wife wanted an oval car (see 9th place below) and this was the prototype. I looked at it and realized that it resembled a signal once you slapped on the proper color circles, and "Red Light, Green Light" was born.
  • 9th place, Adult - my wife's "Emoji Mojo" car. Given that the little people in her phone are much more important than those annoying meatbags in real life, this was a natural. But even though I gave her the best set of wheels and axles I made this year (in terms of spin-testing), I'm still in the family doghouse because it finished behind my cars. :idk:
We also have event photos on the Pack's Facebook page at: http://www.facebook.com/media/set/?set= ... 2093002250 .



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rcmoeur
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Re: Pack 242 Cars - 2016

Post by rcmoeur » Thu Mar 10, 2016 8:45 pm

One more thing: several of the cars combined rear weighting with forward-placed wheels, and the resulting CG barely ahead of the rear axle made for some... memorable racing. :eek:

One more-extreme example, caught on video: http://www.richardcmoeur.com/scout/2016 ... blycar.mov( QuickTime .mov format)



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Re: Pack 242 Cars - 2016

Post by Speedster » Fri Mar 11, 2016 1:21 am

That wreck was spectacular !!! It looked like it was out of control from the very start. Do you know what caused it to do that?



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rcmoeur
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Re: Pack 242 Cars - 2016

Post by rcmoeur » Fri Mar 11, 2016 11:15 pm

Looking at the video (and from my recollection), the car was fine until it reached the level segment at the end of the vertical curve (track is a 32' {27.7' start to finish} Piantedosi.) That's when something imposes a bit of up force on the car nose, and the dance begins.

As I mentioned above, there were several cars like this this year - rear weighted but with wheels forward (long part of the block to back). The result is a CG barely in front of the rear wheels, and any change in down force in front causes the front to rise and wiggle.



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Re: Pack 242 Cars - 2016

Post by rcmoeur » Fri Mar 11, 2016 11:17 pm

Correction: a frame-by-frame analysis shows yaw beginning around halfway into the vertical curve.



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