Helium and the Hybrid ….
I saw an interesting episode of Mythbusters last night got me thinking. On that episode they filled footballs to 13 PSI first with air and launched them, and then deflated and filled them to 13 PSI with Helium and launched them. When the balls were thrown with equal force the one with Helium would float like a blimp and go farther, right? Well they showed the answer is NO ! The balls with air averaged an inch or so further (negligible give the total distance the ball flew). On a .scale the Helium filed balls were lighter (that makes sense). Bottom line, they determined because the helium balls were lighter, they had less momentum, so the fact they “floated” further was offset by less momentum.
So what does this have to do with Hybrids? Well I figure a hybrid (HCH with 12.3 Gal. fuel tank used here for an example) when full of gas and everything else is equal, weighs 76.875 (12.3 gal x 6.25 #/gal @ 72 degrees F ) pounds more then when it's gas tank is empty.
So does a lighter car necessarily go further then a heavier car, if both have the same amount of energy applied? I have not gone through my first full tank of gas yet, but from my crude experimenting (average MPG driving the same route to and from work) it seems the car is getting worst mileage the lighter is gets. I know we have some real good engineers in this forum that could probably apply some Static and Dynamics formulas to prove which way mileage trends as the car becomes lighter, but since auto makers try to make cars as light as possible, I would expect my results go opposite with what is expected.
Larry
'06 Magnetic Pearl HCH #7264
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