Top mounted weight vs. cylindrical inserts?

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
Post Reply
BattleBorn
Apprentice
Apprentice
Posts: 22
Joined: Tue May 19, 2015 8:55 am
Location: Miami, FL

Top mounted weight vs. cylindrical inserts?

Post by BattleBorn »

I see a lot of car bodies that utilize the cylindrical weights inserted in the body of the car (http://pinecar.woodlandscenics.com/show ... 968/page/1) and I was thinking, wouldn't this provide less potential energy that a weight mounted to the top of the car as in Mark Rober's youtube video? I know it's splitting hairs but the weight would be slightly higher, right?
Speedster
Pine Head Legend
Pine Head Legend
Posts: 1972
Joined: Sat Feb 18, 2012 1:48 pm
Location: Toledo, Ohio

Re: Top mounted weight vs. cylindrical inserts?

Post by Speedster »

If I'm reading the question correctly, I believe you have it backwards. You want the weight as low in the car as possible which will move the CM highest up the arc. Remember, the car is sitting at an angle at the start. Many builders who want nothing but speed use 1/4" tungsten cubes for weight and their car resembles the shape of a Hershey bar.
User avatar
Vitamin K
Pine Head Legend
Pine Head Legend
Posts: 1243
Joined: Sat Apr 20, 2013 7:26 pm
Location: Spotsylvania, VA

Re: Top mounted weight vs. cylindrical inserts?

Post by Vitamin K »

This test by Max-V seems to indicate little difference in performance from a small variation in weight placement height.

That said, it is possible that lower weight gives the rear of the car better stability, which would allow you to set your weight further back with less chance of incurring the "wiggle of death", but I don't have any numbers on that.
BattleBorn
Apprentice
Apprentice
Posts: 22
Joined: Tue May 19, 2015 8:55 am
Location: Miami, FL

Re: Top mounted weight vs. cylindrical inserts?

Post by BattleBorn »

Perfect, that is exactly the question I had. Glad to see the impact is negligible because I already drilled the holes for the cylindrical weights. :)
Post Reply