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Post by Bones on Dec 3, 2007 5:54:54 GMT -7
I have heard that there is an Ideal Place to put weight in the car,Is it true? I would like all your GURU opinions. Thanks.
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Post by A-Line Performance on Dec 3, 2007 8:56:07 GMT -7
Back to physics class - the potential energy (speed) of the car is determined by how far the weight falls. Therefore, if the weight is in the front of the car, it can't fall the last 6 to 7 inches that it would fall with the weight in the rear of the car. I like the weight as far back as the design of the car will allow without making the front end unstable. I think the cg on many of my cars is about 3/8 inch in front of the rear axle - maybe even closer to the axle if the front end will stay stable.
Hope this helps.
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Post by docb on Dec 3, 2007 14:04:42 GMT -7
In reference to the above poll question, I would say some of the weight is centered over the rear axle, some is behind and some is in front for many builders. Perhaps you are asking what it the best placement of the COM. Aline stated he puts his COM 3/8 in front of the rear axles. I have better luck with putting my COM 3/4 - 1 inch in front of my rear axles but that doesn't mean that I don't have any weight behind or centered over the rear axles. The further in front of the rear axles you put your COM, the easier it is to stabilize your car, the further back you go the more PE you get but you may sacrafice stability so it is a trade off. However, you can build very fast cars doing either
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Post by Bones on Dec 3, 2007 14:29:35 GMT -7
Thanks for the info,my COG is usually 3/4 to 1". The people I have been racing with believe our current champ (four years so far) has a "magic" spot he puts his weight and this is why he always wins. I think my son would won last year had I known of this site,COG 3/8 but I had no concept of rail riding. We will see this year.
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Post by docb on Dec 3, 2007 14:41:22 GMT -7
Weight placement alone is not going to win you the race. Good wheel and axle prep and alignment are all very important. Good luck!
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Post by race2win on Jun 14, 2008 9:03:18 GMT -7
I am in A-line's camp on this, every grain of energy you can add and hold control will help. One point to think about, my son and I always extend the weight in the front as far ahead of the front axle as possible as well, this allows maximum leverage against the front axles ( fulcrum ) to counteract the weight on the back of the car. This is how to get optimal placement.
So place front and rear weight as far to the front and back as possible to give maximum axle leverage. Even moving 2 or 3g can stabilize the car from wheelie-popper to optimal rocket.
The smoother the track, the more you can send to the back, if its bumpy move more forward. I like A-line's 3/8" COM, I have found this to be the best starting point for our cars.
We are also moving to tungsten rod. We put it inside brass tubes so when the car is retired we can remove and reuse and the tungsten and its is easier to place empty tube on car then add the tungsten rod & Powder once attached.
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Post by W Racing on Apr 25, 2009 7:19:13 GMT -7
I like to make the body of the car as light as possible. Of course the wheels as light as the rules allow as well.
The lighter the body the heavier the weight that can be used. Also the more forward on the car the weight can be and still acheive the same COM.
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