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.-- Ling, Aug 20 2012 Sounds like supercavitation. Does it work in air?-- Wrongfellow, Aug 20 2012 So, you're going to tote around the weight of a helium tank. Hmm...-- RayfordSteele, Aug 20 2012 //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.-- Loris, Aug 20 2012 I am deeply disappointed that the helium is not instead mentioned as amusement for the vehicle occupants.-- Grogster, Aug 20 2012 // injection //
<pedant>
"ejection"
</pedant>-- 8th of 7, Aug 20 2012 //helium// sp. "hydrogen".-- FlyingToaster, Aug 20 2012 //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.-- MaxwellBuchanan, Aug 20 2012 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).-- MaxwellBuchanan, Aug 20 2012 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.-- Ling, Aug 20 2012 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.-- bungston, Aug 20 2012 Hydrogen, oxygen (watching the capitalisation), and ignition. Best of all, it's environmentally friendly except for the odd roasted cyclist-- Ling, Aug 21 2012 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?-- rcarty, Aug 21 2012 random, halfbakery