Tungsten Canopy

OCDerbyDad said:
Since the track is a curve and your times are so close, you should use Calculus to confirm.

Simple geometry will do. Look at the letter "O" below. Which is longer, if you trace the inner edge of the letter or the outer edge? The farther away from the center, the greater the circumference; hence the greater the distance traveled from the pin to the flat.

O
 
ChrisF said:
I'm not the sharpest crayon in the box, so I'm hoping you can help me understand why a weight placed higher on a car falls further than a weight placed lower? If you trace out the path each center of mass takes down the track, wouldn't the paths be parallel i.e. Same magnitude of fall?

Weight placed lower in the car falls further. It's because of the angle of the start section. If you exaggerate the angle to lets say 90* (I know it doesn't work but for the example) each weight will be parallel to the earth. As it falls and transitions into the flat portion of the track, the weight at the top of the car does not fall as far as the weight at the bottom of the car. Each weight is no longer parallel to the earth.

Disclaimer: Lower weight does not always equate to a faster car due to losses in rotational inertia.
 
I think of it like this as my father pointed out to me when talking with him about this years ago. Imagine 2 strings one above the other running the length of the track. Now straighten them out and the bottom one is longer.
 
Ok, then let me throw this out there: If putting the canopy on top is a slight disadvantage for the above reasons, would placing the weight underneath be a slight advantage? I actually do have enough space to do this if it increases my speed.
 
BlewBYu said:
Ok, then let me throw this out there: If putting the canopy on top is a slight disadvantage for the above reasons, would placing the weight underneath be a slight advantage? I actually do have enough space to do this if it increases my speed.
IMHO, I say yes. My best UNLM car is built this way, i.e. I glued 2 tungsten plates on the bottom of the car, shifted to the DFW side.. COM is 1/2".
I am currently experimenting with a new SS, using John's lead wheel weights. But I cut the weight in half (not quite, about 1/3) and glued the smaller upper piece to the bottom, so all the weight is low. I am putting 12 cubes behind the axle, six ahead of the axle, and gluing 2 tungsten plates on the bottom of the body (moved to the right (DFW side)), and adjusting them to get the desired COM, which I think is about 1/2 inch. On my track, this seems to be working, but I am still playing around with the placement of the bottom plates. The car's inaugural will me at the MA.