Track Times

Commercial tracks.
sdupont1
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Re: Track Times

Post by sdupont1 »

The wheels were lightened to about 2.5g each. Our rules allowed lightened wheels but the official bsa markings and mold # needs to be intact. You will notice that people don't always tell you everything. Thats what makes it fun. Here is a couple pics. In the back section is 8 tungsten plates along with the extra lead that you see on top. My son wanted to go thinner but I got scared. He calls it Skinny Minny.

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3 Cub Dad
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Re: Track Times

Post by 3 Cub Dad »

sdu,

one word - WOW!

That is awesome. I agree, much thinner and I'd be afraid a hard stop could snap it! It doesn't look like the dominant RR is inset at all, is it?

We kind of went with a similar design theme for my oldest's car this year, but no where near as thin! (you've given us a new target for next year!)

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We were using lead for weight, so the holding area had to be a little thicker. In this case, we hollowed out from the top, put in the weight, and then used wood putty to somooth it out for painting.

On your car, I can still see the grain on top, so you had to have come from the bottom? How thick are the plates? Did you inset or attach them to the bottom? (I'm getting ideas for next year!)

Followed the same idea for my adult car below:

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In this case, I left the weight about an ounce light, and left cavities on the bottom for tungsten putty. Right now most of this is at the front, but I'm going to try some tests with it moved back this week! The wheels on this one are about 2.2g apiece, H-grooved. (adult class, no rules) For the kids class, we don't allow lightening!
sdupont1
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Re: Track Times

Post by sdupont1 »

The RR wheel is not inset. Now that you say that, why is it indented somewhat? Looks like 1/8".
sdupont1
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Re: Track Times

Post by sdupont1 »

Also forgot to mention, moved some weight around and now the COM is .375". On 35' best track:

2.523

And still its incredibly stable.
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3 Cub Dad
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Re: Track Times

Post by 3 Cub Dad »

The idea of the inset on the dominant wheel of the RR is that if it is riding the rail, but the rear wheels are tracking straight, it keeps the rear wheel on the dominant side from rubbing. This inset on this car is about 1/8th". (it was intended to be closer to 1/16th, but the cut was made on the wrong side of the line. Wheels are still wide enough apart to pass inspection, and it gives a cushion to keep the rear off the rail.

I've got a 42' Best Track in the basement. After I tweak the COM, I'll have to take a section out and see if I can come anywhere near your time! Right now it runs about 3.091 on the 42'. If I did the math right, yours should run about 3.028 over 42'. Don't know if I can make up that much!
sdupont1
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Re: Track Times

Post by sdupont1 »

you have the ability to test. You have a track. Get as aggressive as you can get and still run straight. The wedge looks like it still has the mold marking on the tread surface and the other looks like your running H treads. You should be able to get that time running H treads. We have to run flat or no modification to the tread surface.
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3 Cub Dad
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Re: Track Times

Post by 3 Cub Dad »

On the wedge you can see the mold marks, but they're flat across. We aren't really allowed to modify the wheels for the boys cars. The H-tread is for the adult "no-rules" races!

Got home and decided to move the weight around! Was only able to get the COM back to a little under 3/4" in front of the axle. Still running straight, but only dropped an average of 0.02 seconds, (yea I know, I'm greedy!) Since the rear wheels were moved back, the COM is a little under 1 1/2" from the rear. I even tried just puttting the putty on the back of the car. Got the COM down under 3/4, but I just don't have enough to play with to get it down to 0.5". But hey, it's running faster than it was! I think the lead inside, plus the thickness of the wood, doesn't gove me the mobility that tunsten would. I've got some planning to do for next year's car! And some more playing to do for districts!
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