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Hot Car mkII

Reduce Drag by reducing the temperature of the surrounding medium.
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A while ago, an idea was posted suggesting heating the air around the car by making its skin a heating element. The consensus seemed to be that the heating process would take more energy than the reduced drag would save. However, this is not the only way to heat the air. Exhaust is plenty hot already, especially as it comes out of the engine. I think that if you ducted the engine exhaust to the nose of the car and released it there through a bunch of tiny pores, you could have the car ride in a bubble of hot air. At the very least, you could put the exhaust pores on the leading edges of the vehicle's airfoils should it have any. (I presume such a technology would be best applied to racecars.)

If this sounds crazy, consider that the Shkval underwater rocket uses a similar technology. Water is of course much denser than air, but hey we're talking about racecars so tiny differences in performance are VERY worth it.

Madcat, Mar 28 2005

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       Only if you do it in such a way that would reduce exhaust backpressure. You might pick up some venturi effect suction if you designed it right. Tiny pores would too easily get clogged with particulates, though.   

       Of course a study of the downdraft would need to be done. Racecars rather like sticking to the road.
RayfordSteele, Mar 29 2005
  

       And all the cars would be black.
zeno, Mar 29 2005
  

       The Shkval uses it to access an entirely different phenomenon, supercavitation, rather than simply to provide boundary layer control.
david_scothern, Mar 29 2005
  

       //you could have the car ride in a bubble of hot air// This would be great for convertibles in cold weather. Apart from the fact that the hot "air" would be exhaust fumes.
AbsintheWithoutLeave, Mar 29 2005
  

       Ooh, exhaust gases pouring over the car... where's the fresh air intake again?
spacer, Mar 31 2005
  

       Bleed air. Old concept.
bristolz, Mar 31 2005
  

       "I think that if you ducted the engine exhaust to the nose of the car and released it there through a bunch of tiny pores, you could have the car ride in a bubble of hot air."   

       And then everybody died....
WSCAmsterdam, Dec 05 2005
  

       The key, it seems, would be to use the exhaust indirectly. In other words, duct the exhaust through a heat exchanger that heats the air that you're talking about. That's the way that airplane cabin heaters in small aircraft work.   

       Let's not forget about boundary layer turbulence though. I'm not sure what aerodynamic effects are likely, but I imagine that they are not trivial.
zigness, Dec 05 2005
  

       I think a heat exchanger on the hood would be the way to go here. If you can weld or solder pipes made of copper or aluminum to the outter panels of the car (on the inside where the air isn't causing friction) then you could use exhaust heat to heat the outside of the panels, but be sure to vent it to enough area so that it doesn't harm humans who happen to touch them.
kevinthenerd, May 31 2006
  

       i think if you blow something out the front of a car it would deminish the arodynamicy and slow you down plus you might die because exhaust is deadly and unless the car is in reverse you will die plus you will die
permafried, Nov 03 2011
  
      
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