Re: double HP for 10 MPG???????

[Daniel Youngquist <dany@domain.elided>]

On Tue, 3 Mar 1998, John Fleck wrote:

> I would like to see the documentation or the source for your claime to
> double HP for every 10 MPH. I as well as some associates dont feel
> this is correct. Are you saying a 400 Hp hot rod race car after 160
> needs to go to 800 HP to get another 10 MPH? just trying to clarify. 

I let that one go the first time around, 'cause I figured it just wasn't
relevant to Scouts. :)  What physics actually says is that resistance
increases as the square of speed; in other words, double the speed, 4x
the resistance.  So if it takes, say (I'm guessing here) 35HP to keep a
car moving at 60mph, then it would take about 389HP to keep it moving at
200mph.  That would have to be one _really_ built Mustang 5.0 (that's
what those folks had, right?), and it makes several big assumptions:

* the tires don't fly apart.  If they really went anywhere near 200mph
on street tires, I don't care what speed rating, they're a lot braver
than I am.

* the gears were such that the engine didn't fly apart.  3.08's with
overdrive would do it; 200mph would be somewhere around 6000 RPM.

* the car is aerodynamically stable at 200mph.  Remember it was designed
to run at speeds where aerodynamic stability doesn't matter, and all
those neat ground effects and spoilers are purely for looks.  Who knows
what they'll do at 200, good or bad.

* the road is good enough for 200mph.  I've been to 130 a few times, in
a Mustang and in a '69 Charger, which is a lot heavier and more stable
than a Mustang, and trust me, I _wouldn't_ want to be on most freeways
at anywhere near 200.

Well, that's probably enough 200mph stuff for the Scout list. :)

Daniel Youngquist / dany@domain.elided / 541-688-9263 // VISA & MasterCard
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