Floating rotor brain teaser - F-Body Road Racing and Autocross Forums

Since this reply gets slightly off topic, I decided to post it in general discussion. It is in response to Snorkelface’s question in this brake thread:
http://frrax.com/rrforum/index.php?act=ST&...=15&#entry32147
QUOTE: “OK, I have to ask what makes a "Floating Rotor" design just that?”

Answer:
Depending on the final target weight of the rotor, they disperse about 9 to 12 oz of anti-gravity granules into the mold before pouring in the molten iron. It does wonders for unsprung weight, and greatly reduces shipping costs.

This reminds me of my childhood in Nepal. My dad was a truck driver, and one of his regular jobs was delivering birds to a pet store supplier. When we were pulling on the scales to be weighed for road tax, he would have me get out and bang on the side of the trailer to get the birds to flap their wings and hover in their cages. We both thought that this would make our load weigh less. When I was older, I realized that this did not affect the weight at all. But now that I am really old, I understand that it would have some effect on the weight. Maybe some of our resident physicists would care to “weigh” in on this, since I have explained why floating rotors float.

lateapex View Member Profile	Dec 9 2004, 05:53 AM Post #1
Advanced Member Group: Advanced Members Posts: 382 Joined: 23-December 03 From: Kathmandu, Nepal Member No.: 2	Since this reply gets slightly off topic, I decided to post it in general discussion. It is in response to Snorkelface’s question in this brake thread: http://frrax.com/rrforum/index.php?act=ST&...=15&#entry32147 QUOTE: “OK, I have to ask what makes a "Floating Rotor" design just that?” Answer: Depending on the final target weight of the rotor, they disperse about 9 to 12 oz of anti-gravity granules into the mold before pouring in the molten iron. It does wonders for unsprung weight, and greatly reduces shipping costs. This reminds me of my childhood in Nepal. My dad was a truck driver, and one of his regular jobs was delivering birds to a pet store supplier. When we were pulling on the scales to be weighed for road tax, he would have me get out and bang on the side of the trailer to get the birds to flap their wings and hover in their cages. We both thought that this would make our load weigh less. When I was older, I realized that this did not affect the weight at all. But now that I am really old, I understand that it would have some effect on the weight. Maybe some of our resident physicists would care to “weigh” in on this, since I have explained why floating rotors float.

lateapex View Member Profile	Dec 10 2004, 06:41 PM Post #2
Advanced Member Group: Advanced Members Posts: 382 Joined: 23-December 03 From: Kathmandu, Nepal Member No.: 2	Great job Sean, The size of the cages is key. I had not considered the metabolism of food components into heat lowering body weight (and therefore the requisite downward directed air pressure to stay aloft if hovering close to bottom of small cage) and the effect of the hotter interior trailer environment relative to outside temperature (hot air balloon effect). I don’t think that extraordinary ventilation would be required as the weighing of the truck would last only 20 seconds. I like your full-orbed, expansive thinking, and subtle humor. But, no matter what their fear level, I do not believe that any of the birds would approach the speed of light, assuming that they were operating in only one time-space continuum at a time. Maybe another member could introduce another dimension to the analysis. Remember, this is not Corner Carvers. We all play nice.