Balance - side to side.

[Citius]

I'd like to know what are the effects on a car that is identical except for one factor. Car 1 has its weighting at the centerline of the car. Car 2 has its weight split with 1/2 at the outside left and 1/2 on the outside right. (Think old putter vs. newer heel and toe weighted putter.)
Thanks, Citius

[ProQuest]

Greetings Citius:

Interesting question. I'm not the resident expert, but Randy Davis of Maximum Velocity did a study on weight placement and determined that better performance is achieved when the weight is spread over a larger area. This assumes that the center of gravity is maintained in the same location. The reason why spreading the weight improves performance is unclear, but Randy theorized that it had to do with a vibration dampening effect. Applying Randy's findings to your question, I would think that side to side placement would be preferable to centerline weight placement.

Don't know if this helps, but its all I got. Good luck.

ProQuest/Steve H.

[Parrot Racing]

Steve, I thought the same thing, then I read somewhere, I think from stan pope, that the more compact the weight is, the less "rotational inertia" ( whatever that is). Now I have to go look it up, because I may have it backwards.
Enrico
Parrot Racing

[ProQuest]

Hey Enrico:

Please let me know what you find. I'd love to learn that I could change the way I place weight in my cars and maybe go a little faster. Later.

ProQuest/Steve H.

[Parrot Racing]

Steve, I just copied and pasted it, it was on derbytalk.com, which is a great site if you are into math and physics equations regarding pw racing.
But to be honest with you, I have had more success with the cars that had the weight spread over a larger area.



Stan Pope
Moderator



Joined: 05 Jul 2003
Posts: 2690
Location: Morton (Peoria Area), Illinois
Posted: Fri Jul 20, 2007 11:36 pm Post subject: Re: Concentrating the Driving Mass.

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There is a very practical reason for concentrating the added mass: it makes it easier to control the ultimate Center of Mass (CM) of the finished car!

The theoretical implications include its effect on the whole car's rotational inertia. This comes into play when the car changes its orientation, such as when it moves on a curved part of the track or hits a bump, but the effect is very small. MaxV published some comparisons during the last year or so in his free email newsletter. IIRC, his tests indicated that the more concentrated mass was better, at least at the location he chose for the CM.
_________________
Stan
"If it's not for the boys, it's for the birds!"

[ProQuest]

Hey Parrot:

I'm not sure what study Pope is referring to, but from what I recall, Randy's conclusions were exactly the opposite of what he states them to be. I.e., Maximum-Velocity's study found that spreading the weight is better. I'll go back and reread the study (if I can find it) and correct this if I'm mistaken.

Citius:

There you have it. It may be a case of "there is no right answer." Probably the lesson is that where you put your center of gravity (or center mass and the experts say) is far more important than whether the weight is spread side to side or centered. Sorry I couldn't be more definitive, but I will update this if I get better information. Best of luck.

ProQuest/Steve H.

[Citius]

Thanks Guys,

I think it comes down to a trade off between - stability (wide weighting) vs. agility [steering/suspension] (centerline weighting)

On the bad news track my son's scout pack has ....we will stress stability. If I can get a car off to WIRL, I will try the theoretical advantages of central weight placement.

Measure 2X, cut 1X & think 100X !

Citius