On Fri, 14 Mar 2008 18:04:34 -0700, XS11E wrote:
> Leon van Dommelen <rammm@[EMAIL PROTECTED]
> wrote:
>
>> On Fri, 14 Mar 2008 12:06:23 -0700, XS11E wrote:
>
>> Hum. Seems to be the exact opposite of the idea of spoilers.
>
> I don't believe it's intended as a spoiler, simple a replacement for the
> original plastic thingy that disintegrates quickly.
It says "increasing down force by creating higher suction pressures
between the panel and road." And that is also used to support the
claim of increased cooling.
The way that people with no real knowledge of fluid mechanics selling
products often reason is that the incoming air speed in the gap between
car bottom and road is the car velocity, because it is "in front of the
car." Then they know that if you decrease the flow area, you speed up
the flow, and that Bernoulli says that lowers pressure. Unfortunately,
nonsupersonic flows are quite capable of sensing an obstruction ahead
and going around it in a more comfortable way. Having essentially
stagnation pressure below your car is not ideal. (And there are some
other problems with flow area reduction and Bernoulli, such as three-
dimensionality and viscous effects, but anyway.)
>> And in my experience, that plastic Mazda cover is pretty tough.
>
> Not tough enough in my experience, mine is bent, folded, spindled,
> stapled and mutilated to borrow a phrase...
>
> My interest in the aluminum one is that it should last and can be bent
> back into shape if needed, rather than tearing as the original cover
> did. (I don't know how, it was pretty beat up when I got the car)
Driving over big stones on the million dollar highway or over exhaust
parts will do it. ;) It may well be true that the aluminum cover
might not tear and can be bend back into usable shape after an
encounter. But, IIRC, you can get about 4 plastic covers for the
price of this aluminum one. And my plastic cover was never torn so
bad that it really *had* to be replaced. And my best guess at this
time would be that there will be no measurable difference in down force
between the covers.
But I have an open mind, all of this is just guessing. I am waiting
for Bruce to tell us how right I am. (OK, wrong is also theoretically,
possible, but I consider it unlikely.)
Leon ;)
--
Leon :) Bess :) Bozo .)
|
