Derby Talk

No, I was being a little bit of a wiseguy- that's how surfboards are made!

Needs a raincap on that exhaust stack...congrats on the win!

Resin over foam? Surf's UP!

I belive the original post (elsewhere on the forum) made a claim for some time improvement. But any calculation I have made involving the wind resistance terms is on the order of hundreds of ergs, while the available potential energy is on the order of 16+ million ergs. That's why I ignore wind resi...

Given that the sliding friction is quite low in this case, it is going to be tough to give the youngest of the Scouts a solid grasp of the principles. One way that I have considered, though, is to attach a line to the front of the car, with the other end attached to a weight scale (think fish scale)...

Congrats, Stan, although I realize you made the boys do the work!

I NEVER thought about this foam being considered moving parts! I guess that is since the original intent was to avoid sliding masses which would provide a small boost off the slope. I don't really understand how the foam could be a washer- the stuff is stuck inside the wheel, and unless I missed the...

I was just thinking if the knife gouged it out, but if you got a reasonably smooth cut (SHARP implements), that's probably good enough for PWD purposes.

True enough about the wire. I have a spool of it I use to make return springs for some tools I developed. But it's company property, and it would be a pain to straighten, in any event. It's cheap and easy to come by, in any event. FWIW, some of the guys at WIRL get down to .030 wire for their axles!

Might that be considered a bushing or a bearing? It's harder than ABS, that's for sure.

btw, some organizations dictate a minimum axle diameter...larger than .060".

My question is how to shrink the bore! All those rules I see bandied about on wheel modification do not address this. Is all fair in love and bore?

As advertised, a new thread about filling the wheels. For those who are sticklers for the rules (and for those of us who follow them to the letter of the law with malice aforethought): If a kid came to you with foam-filled wheels, or with foam core disks inserted in them, would he be disqualified? A...

I'm not sure how smooth the "Great Stuff" would shave off. It certainly fills things in, though. I'd be concerned with keeping it off the remainder of the wheel- you know what a pain it is to remove, if you've used it! If a person wanted to use it, and is looking for stiff/sound deadening,...

From a strictly geometric consideration of the change in the amount of potential energy due to lowering the centroid (not the same as reducing the MoI) by 1/2 inch yields about .0009 seconds. That's analytic, so you'll likely never see it on the track. Interestingly enough, I vaguely recall reading ...

I do know that Graphite fills in cracks well! Just look at my wife's kitchen sink... White with Graphite filled scratches. I keep telling her the gray will go away... Simply adjust your oxyacetylene torch to an oxidizing flame and wave it around in the sink- those pesky little carbon molecules will...