[lateapex]

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.

[sgarnett]

It depends on the design of the cages.

The truck scale is measuring weight, or downward force due to gravity, not mass. No matter how much you annoy the birds, the total mass of the truck, birds, air, cages, and bird poop remains fairly constant (but see below).

However, if the cages are roomy enough to allow the bird to fly high enough to be in freely circulating air, then the force of supporting the bird is roughly balanced by overcoming friction of the air molecules and the force required to accelerate the spinning, recirculating air.

OTOH, if the birds can only get a short distance away from the floor or a shelf, then the lift is dominated by ground effects and the high pressure area under the wings presses equally up on the wings and down on the truck.

If the truck is well ventilated, then as the birds exert themselves some stored glucose and fat will be metabolized, so that some mass will be dissipated as carbon dioxide. However, the more tangible by-products will still contribute to the weight of the truck even when deposited on the floor.

If the birds are REALLY annoyed and zipping around fast enough, their mass actually increases due to relativistic effects, so if you try too hard you could end up with an infinite tax.

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/tongue.gif)