Dimensions and Weight Distribution Before Ballast

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
Post Reply
User avatar
Stan Pope
Pine Head Legend
Pine Head Legend
Posts: 6888
Joined: Sat Jul 05, 2003 7:01 pm
Location: Morton, Illinois
Contact:

Dimensions and Weight Distribution Before Ballast

Post by Stan Pope » Fri Jan 29, 2010 2:25 pm

I gotta swear you guys to secrecy and please don't tell my grandsons that I'm "telling you their secrets." The boys were here over the last two nights starting their next cars. District Derby is a few weeks out and they think they can make cars even faster than the ones that won their age group in the pack derby.

Anyway, I slipped in and took some measurements. Wheels and axles used in the weight distribution measurements were "unworked" (the nail point shoulders were beaten out since I didn't want to damage the cars by using "fat shouldered nails."

Here are the notes that I took:

Image

I only sketched and measured Andrew's car body ... Alex's wheel base was just a bit longer which accounts for the lighter weight.

My plan is to use this information to plug into the computation tools at http://www.stanpope.net/cmcomput.htm to see if I can do a better job of predicting where the ballast should go. Then compare that against what we find with the usual method in which "ballast arranged on an index card on the car body while we watch scale readings."

Hopefully, we can set the car up at 4.5 OZ and leave 0.5 OZ to move about and give us the ability to adjust the weight distribution anywhere between 4:1 and 9:1, choosing the most effective location from on-track tests.


Stan
"If it's not for the boys, it's for the birds!"

Post Reply