Derby Talk

Great analogy... er, cover story!


Cutting boards will never be the same.




-T

It's for the wife to race, she even helped with it... she's a geologist at a gold mine, so... I keep telling people I married a real gold digger, which is funny if you look at my bank account. :wink: Tell me about it... nobody told me I could be an engineer working for who I work for doing what I d...

Very cool design! This is a "dad's" car right? No way I'd let it pass without the 100 question routine for the dad and probably next Cub on a race day if I was asked to believe a kid built it... now don't get me wrong, a kid could build this with adult guidance... seriously!... but I'd hav...

This is a tough cookie... same track, level floor... ? Yet you dropped .1 seconds? WOW! Is there any way the track ramp angle can be different for each setup? Did you re-graphite right before the race and not break in the graphite to the "sweet spot"? Are there differences in how the races...

(.015s= 15/1000ths) is about 2-3 inch of distance, track depending. Explanation: most tracks hit 7-10 MPH, maybe 12 tops 7mi/hr * 5280ft/mi = 36,960 ft/hour 36,960 ft/hour * hour/3600seconds = 10.2667 ft/s 10.2667 ft/s * 12in/ft = 123.2 in/s 123.2 in/s * 0.015s = 1.84 in repeating for 12mi/hr... 3.1...

Thanks all! Turns out my wife video'd the run... after several folks doing independent reviews of it, we are on consensus that there was a timing error... but the error was probably not at the finish line. That said, camera flashes probably had NOTHING to do with it. (none of us can spot a camera fl...

Very cool!

-T

Does anybody have reasonbly firm evidence that corroborates flash photography upsetting an optical timer? We saw some unbelievably "quick" times this year that had to be re-run at District. Any way to combat this if it is in fact a problem? (other than telling folks for the literally 5th t...

Our approach was document "this year's cars" and if we had a suspect car, show the owner the picture of why we were concerned and ask questions... ... i.e. ask the Scout how they built it, did they have fun, etc. We unearthed a kit car but the dad would not own up to it... he did get caugh...

I wrote this for fun 2 years ago: Pinewood Derby vs Real Car Pinewood Wheel Diameter = 1.18” Real Car Tire Diameter = 25.7” (245/45/17 tire) Pinewood Top Speed = 12 MPH (3,418RPM@wheel) Real Car Equivalent = 261 MPH (3,418RPM@wheel) Pinewood Wheel Revs per Run = 97 (30 foot track) Real Car Equivalen...

Our rules are very clear that no bushings are allowed, this included fill and drill.

-Terry

This has been tagged square on the head: what matters is the wheel spacing, not the body width.


-Terry

We trued the edge but left rounded corners for both the "coming" and "going" passing of track protrusions...

and polished and graphited.


-T

Yikes, that looks like a ROCKET!


Should SCREAM!


When do you race?


What is your rear cant angle?


Right front wheel lifted... Dom Front Wheel is front left?

Any cant (and which direction) on the DFW?





What is your rear COM placement?

What is the up/down (CMz) weight placement?


-T

all things equal save you added 2oz to the heavier car and kept the COM at the same location... 7oz should be faster. Doc Jobes software showed that the real huge improvement is 1-2oz range... adding weight really adds to the max velocity (no pun intended) you hit on the track... up around 5-8oz thi...