h a l f b a k e r yOK, we're here. Now what?
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
I think there are some torpedoes that use air
bubbles at the nose to reduce drag.
Same thing, but release hELIUM for a land speed
record machine.
[link]
|
| |
Sounds like supercavitation. Does it work in air? |
|
| |
So, you're going to tote around the weight of a helium tank. Hmm... |
|
| |
//So, you're going to tote around the weight of a helium tank. Hmm...// |
|
| |
My understanding is that at current land-speed record speeds - costs associated with the weight of the machine are pretty-much insignificant, compared to the other forces involved. |
|
| |
I think it's an increasingly silly record anyway. Not that that's a bad thing, particularly - just that people should appreciate the silliness. |
|
| |
I am deeply disappointed that the helium is not instead mentioned as amusement for the vehicle occupants. |
|
| |
//helium// sp. "hydrogen". |
|
| |
//Helium//: cptlzn. "helium" |
|
| |
But, that aside, interesting. You'd be better off
in/ejecting a vacuum, though. Better yet, drive in
reverse - measurements repeatedly show a lower
pressure at the rear of a fast-moving vehicle. |
|
| |
It would also be good to calculate how much
helium would be needed. |
|
| |
Assume, if you would be so kind, that the helium
is ejected through multiple pores on the surface
of the machine. Assume also, if you don't mind
assuming, that the layer of helium is 1mm thick
(there is a very good reason for assuming this
thickness - I just have no idea what that reason
is). |
|
| |
Assume also, if you do not mind strolling hand-in-
hand further down the wave-tossed beach of
supposition with me, that this boundary layer is
static with respect to the surrounding air (ie, it is
sloughed off the vehicle at the same speed the
vehicle is moving). |
|
| |
Assume yet further, as we dip our toes into the
foamy wavelets of imagination, that the vehicle is
a cylinder, 2m in diameter, and travels one mile
(1600m). |
|
| |
Having come this far, there is no point turning
back up the beach and returning to the hotel for
tea and scones. We might as well, therefore,
plunge into the sewage-laden ocean of
calculation. |
|
| |
The car will slough off a 1mm thick skin of helium,
with an area equal to the car's circumference (say
6m) times the length of its travel (1600m). This
equates to a piffling 10 cubic metres of helium. |
|
| |
Allow, next, for a 100-fold thickening in the layer
of "sloughed" helium (for no good reason; but
perhaps it is more conveniently ejected only at
the nose of the vehicle, and must be thicker to
withstand turbulence and suchlike as it travels the
length of the car). This still equates to only 1000
cubic metres of helium. A 1000-bar pressure
vessel would be heavy, but not so heavy
compared to the mass of the vehicle, and would
store the necessary helium in only a cubic metre. |
|
| |
So, as I often say to my students, you know, this
is not really such a stupid idea. |
|
| |
The main problem, I suspect, would be persuading
the judges that the pressurized helium was not
being used as a form of energy input (but perhaps
that doesn't matter). |
|
| |
Yeah, what MB said ^. I simply waggled my thumb and squinted
with one eye and thought: "Yup, that should do it". |
|
| |
By the way, capital h on helium has been corrected. |
|
| |
The problem with this is you underestimate your market. This should be offered as an aftermarket addon for car enthusiasts of all flavors, who want that extra umph. |
|
| |
But listen... come close.. I know what is less dense than helium. Even hydrogen. Even hELIUM. |
|
| |
FLAME! Flames are hot! And barely dense at all. Really what you need for speed is a flame emitter at the front of the car. Plus the sheer awesomeness of it. |
|
| |
Hydrogen, oxygen (watching the capitalisation), and ignition. Best
of all, it's environmentally friendly except for the odd roasted
cyclist |
|
| |
Didn't the batmobile have that, the one with the <POW> (KAZOOO) {SMURF} action sequences? No I just checked it was at the back. That would have just produced drag wouldnt it have? |
|
| |