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First BSA car race experience

Posted: Sun Feb 03, 2019 11:39 pm
by gcode
This was my first time building cars with my boys. Both went undefeated (youngest ran in open) and the one in scouts is going to district. This was on a 2 lane wood track with no timing system. He beat every car by several lengths except one which he beat by a length. We built these pretty quickly (minus paint part) and I afraid people at district are going to a lot faster. We can test on the wood track (about 40ft) but I dont know how to judge how fast we are going.
Car is
4.9 ounces (raced at 5.0)
balances about .9 in front of the axles
polished axles (rear bent 2.5)
aligned so moves 1" over 5 ft (rear wheels seem to rub side of track)

Anything else to do or check or do?

Thanks

Re: First BSA car race experience

Posted: Mon Feb 04, 2019 5:49 am
by Speedster
Welcome to Derbytalk, gcode. Are you a College Physics Instructor?
There's lots of things you can do but whether or not you should is another matter.
You say you aligned it. Are you on 3 wheels? Did you bend the dominant front axle? Are you on graphite only? Exactly what do you mean, "rear wheels seem to rub side of track"? Do you mean the rear wheel that follows the Dominant front wheel rubs the rail all the way down to the finish line or the car bounces back and forth off the rail?

Might we see a picture of the car?

Re: First BSA car race experience

Posted: Mon Feb 04, 2019 8:05 am
by gcode
Nope, just a dad who watched a few videos online.

I tried to square up the rear wheels, then angled one front wheel to make it pull over to the right one inch over 5ft. Its still on 4 wheels per BSA rules. The rear wheels rubs once the front moves over and touches. I'll try to get pics tonight.

Re: First BSA car race experience

Posted: Mon Feb 04, 2019 11:18 am
by Speedster
gcode, this is what I would actually do. Run the car as it is and watch what it does at District. For whatever scientific reason, you might just happen to have a really fast car.
Next, I would buy the magazine, "Build a Winning Pinewood Derby Car" 2013 Edition. I just received 10 of them and they indicated they still have some in stock. The cost is $9,99. The address is Fox Chapel Publishing, 1970 Broad Street, East Petersburg, PA 17520. Phone: 717-560-4703. Fax:717-560-4702. www.FoxChapelPublishing.com. This book is all about speed. Once you and your son read this book a couple of times the basics of the Physics of the Pinewood Derby will be behind you and you can start Fine Tuning the Basics. Yes, the answers are all on Derby talk but the book will give you a permanent record of what you have learned. Lots of Great pictures.
I wish your Team the Very Best.

Re: First BSA car race experience

Posted: Sat Mar 02, 2019 5:12 pm
by gcode
We won our class in district, car is still undefeated. Averaged 3.0122 @ 208.25. They said there wasnt any races above district, is that true? Only complaint I had and about 85% of the others was the metal box they checked length with was inaccurate. They were saying almost all the cars were to long. I measured ours before going so I was 100% sure it wasnt 7" and I had to shave off a 1/16" at the race. Got home and measured it and now its way under 7".

Re: First BSA car race experience

Posted: Sat Mar 02, 2019 7:25 pm
by Speedster
I've heard lots of crazy things happening at Inspection stations but they usually have to do with weight. A bunch of cars that are too long? For being crazy, this one might be hard to beat.

Re: First BSA car race experience

Posted: Sat Mar 02, 2019 8:13 pm
by Derby addict
Congrats on winning districts gcode