Search found 151 matches

by priority
Tue Mar 02, 2010 12:54 pm
Forum: Commercial
Topic: 20' Test Track
Replies: 4
Views: 12751

Re: 20' Test Track

Needed a break from other stuff and stumbled across this thread. The physics of the 20' best track are not exactly what I thought would happen before I actually experienced it. First, the run time of a well tuned car is just over 2 seconds on this track. Second, it is very difficult to translate the...
by priority
Sun Feb 07, 2010 4:32 pm
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

Doc Jobe has just released Lecture 26 addressing the impact of the changes in the 2009 wheel. http://www.pinewoodderbyphysics.com/pdf%20files/Lecture%2026.pdf Lots of good reading and some nice diagrams for those interested in precise measurements and characteristics of the new wheels. At a minimum,...
by priority
Thu Jan 28, 2010 7:28 am
Forum: Car & Semi-Truck Construction
Topic: Rail rider - how much steer?
Replies: 3
Views: 4245

Re: Rail rider - how much steer?

Our current pack runs on a 32' wooden Piantedosi that I would estimate to be about 8-10 years old. The sides of the rails have visible saw blade marks. We had three cars this year and the one with ~1" steer per ~4' was the fastest. This pack does not allow running of cars on the track except fo...
by priority
Sun Jan 24, 2010 1:59 pm
Forum: Car & Semi-Truck Construction
Topic: rear end wiggle
Replies: 19
Views: 15282

Re: rear end wiggle

pinederbymom wrote:hi
Well, we just got home from the race and we won! First place! I'm so thankful for your help.
Congrats!!!! :clap: :clap: :clap:
by priority
Sat Jan 23, 2010 6:58 am
Forum: Car & Semi-Truck Construction
Topic: rear end wiggle
Replies: 19
Views: 15282

Re: rear end wiggle

I agree that a slight cant (to push the rear wheels to the axle heads) is most likely the best solution. The other alternative that you probably don't want to hear is to replace the wheels. We had one of 3 essentially identical cars come down with a case of the wiggles this year. We run flat rear ax...
by priority
Tue Jan 19, 2010 7:04 am
Forum: Car & Semi-Truck Construction
Topic: Optimal COG distance below axle plane?
Replies: 45
Views: 38727

Re: Optimal COG distance below axle plane?

Hmmm... I have some 90 fps web cams lying about... Does anyone know of software that will record at 90 fps from a webcam? I bought a Philips "90 fps" webcam a couple of years ago "for purely scientific reasons", but all the software (even what Philips provided with the webcam) I...
by priority
Fri Nov 06, 2009 6:43 am
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

MaxV's latest newsletter has a wealth of information on the new wheels (and a tidbit on the "not-so-new" axles) including good recommendations for Pinewood Derby leaders http://www.maximum-velocity.com/pinewood-derby-blog/2018/06/pinewood-derby-times-v9i2/ . His discussion on whether to re...
by priority
Tue Sep 29, 2009 7:07 am
Forum: General Topics
Topic: How to figure the Moment of Inertia???
Replies: 12
Views: 13085

Re: How to figure the Moment of Inertia???

...precise measurements of wheel cross-sections are not done with calipers and/or micrometers... At the risk of sounding like a politician, let me say it all depends on what you mean by the meaning of the word "precise".... ;) With calipers, you can get within roughly 10% of the "tru...
by priority
Sat Sep 26, 2009 3:58 pm
Forum: General Topics
Topic: How to figure the Moment of Inertia???
Replies: 12
Views: 13085

Re: How to figure the Moment of Inertia???

Does any one know this equation and can put it into layman terms for me My personal favorite way of avoiding getting wrapped around the proverbial axle when engaging in omphaloskepsis on MOI is to use one of Doc Jobe's spreadsheets. :shhh: :shhh: :shhh: It is cleverly hidden in his Lecture 5 ( http...
by priority
Tue Sep 22, 2009 12:55 pm
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

Maybe Allen should give that big-wig a call back. I agree 100%. Allen has worked in this shop for as long as I my sons have been in scouting and I have never seen him disturbed by anything before, but, IMHO, he was hacked this time. I inferred from some of his comments that he was going to get on t...
by priority
Tue Sep 22, 2009 6:40 am
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

I had an entertaining visit to the North Houston (Champions) Scout Shop yesterday evening. I decided to stop by the Scout Shop on the way home to see if there was any stock of the new wheels. The answer was no, but one of the guys working there asked me if I could use some help when he saw me diggin...
by priority
Fri Sep 11, 2009 9:20 am
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

FYI, I just got the 100th Anniversary Edition of the Big Rig kit. All of the wheels are the NEW style! I stopped by the Scout Shop on the North Loop in Houston. One Big Rig was in stock and it had the new wheels. So, Mr. Slick may be onto something. Not conclusive proof, but a nice correlation may ...
by priority
Tue Jun 02, 2009 12:33 pm
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

no joy on finding the 2009 wheels. Bummer! Hope you can snare some new wheels somehow and get us some quality measurements to augment / confirm those already posted. Most are too subjective to be useful! .... citizen of the Nation of Texas! .... I checked the Camp Strake Scout Shop just south of Co...
by priority
Tue Jun 02, 2009 8:22 am
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

Please tone it down a bit! Stan- I bolded your response to make sure you know I didn't miss it. :rofl: What the heck...I going for try number 2 with (hopefully) less of a rant tone. :angel: :angel: :angel: :angel: Let's turn to the more important aspect of what I was attempting, to convey-namely ho...
by priority
Mon Jun 01, 2009 10:01 pm
Forum: General Topics
Topic: New BSA Wheel and Axle??
Replies: 273
Views: 220509

Re: New BSA Wheel and Axle??

With the newer tube packaging for the wheel/axle sets, I wonder if you can just do a visual inspection of the hubs. You can also look for the registered trademark symbol ® on the outer sidewall (older wheels have the TM symbol). I did get a chance to stop by the Champions Scout Shop on the north si...