Derby Talk

The angle on the FDW is very similar to what we ran last year. I can vouch for that setup.

http://www.derbytalk.com/viewtopic.php?f=19&t=5440" target="_blank

That is true, but if you can reduce drag without changing COM much (very light materials) then you might see a measurable reduction in time, as Grubartez indicates that he has seen with his cars. The change in COM I was talking about was not from the weight of the fenders themselves. It was discuss...

I'd personally rather see track testing results than wind tunnel alone. Just because a design is more aerodynamic doesn't mean it's faster. Changes to make it more aerodynamic can affect the COM and concentration of weight and those changes could more than offset any gains due to being more aerodyna...

Yes, like those. Many of those guys who race in the adult leagues seriously have tracks and timers. It may not be "clear they do any aerodynamic good". But it is clear that the fenders lower times. These guys test with and without and would not be using them if they weren't doing better wi...

In looking at the fenders used on the fastest cars in the adult leagues, it appears they use them in front of the back wheels and it is a full fender, top to bottom. Since the wheel is rotating, the top of the fender keep air resistance off a portion of the wheel that is both moving forward and rota...

I think with those times, that may have been a 49' Best Track.

We had that problem this year. When the can says 48 hours, it means 48 hours no matter how dry it feels. We applied a second coat after 24 hours this year and it all bubbled up!

We bought a kit that goes all the way up to 50,000 grit this year and I noticed on the video that my wife shot that we beat everyone we raced (Pack and District) to the bottom of the hill this year. Not big margins, but an advantage none the less. We did not do work on the treads of the wheels and d...

The 4 degrees positive was something I learned here from builders more skilled than me, by the way.

I certainly wouldn't want to have to testify that it's exactly 4 degrees, but it's close to that. I don't think the number matters so much as this: there needs to be enough camber on the FDW to lift the inside edge of the wheel off the track, but not so much that you are riding on the little dots on...

I posted this with the picture under pictures, but also wanted to put it here since there is a lot more information than with the typical picture. We completed our derby career this weekend with a District Championship. The closest car to us was 3/4 of a car length behind. Here are the specs on our ...

Thanks for the comments. In our five years, we won the pack five times. At the District we were first twice, second once and fourth twice. This, however, was by far the fastest car we ever built. Just when you are starting to get things right, it comes to an end....

One thing I forgot. We did attempt to shave 1/16" off the front dominant side. We shaved too much. Very close to 1/8". The wheels had almost exactly the 1 3/4" clearance required by our rules. I'm not sure if this extra reduction actually helped, but it certainly did not hurt the perf...

http://www.flickr.com/photos/15351720@N07/4412744320/ http://www.flickr.com/photos/15351720@N07/4412744320/?rotated=1&cb=1267930924453" target="_blank We completed our derby career today with a District Championship. The closest car to us was 3/4 of a car length behind. Here are the s...

Our holes were drilled using The Block this year too. It produced by far the most accurate holes we've ever had. I've seen several postings stating possible negative things about The Block, but I don't think I've ever seen a negative thing written about The Block by someone who has actually used it....