..... but he's too dumb to figger it out by hisself.....
Awl --
In the recent spte Volt threads/fracases, fuknKiddingHisSelf keeps
imploring/challenging me to measure the hp required to climb a grade in my
Honda Shit, I mean, Fit, with a ScanGuage.
Now, Kidding needs a scanguage, cuz Kidding don't know physics or math -- or
much of anything else -- so I figgered I'd tutor him sumpn sumpn on these
fair ngs.
You no need no steenkin scanguage for this, altho you might could use one to
get a baseline hp requirement for LEVEL driving.
But even this can be calc'd with some estimate of CdA, which is actually
listed on the web somewhere, by car make. Plug in to the energy formula for
drag (cubic in velocity), and voila, you gotcher hp.
But generally, iirc, the range for maintaining 60 mph is somewhere between 5
and 20 hp, depending of course on the CdA.
I'll figger 12 hp for the Fit, which don't really matter, cuz it's the hilll
climbing addition hp we are innerested in -- and which dominates, anyway.
It's easier to do all this in metric, so convert the car weight (2500# for
the fit) to kg, 1136.
60 mph is 28.2 m/s.
Now pick yer grade:
The "legal grade limit" for highways is 6% or 3.43 deg (take the arctan of
.06 to verify this).
http://en.wikipedia.org/wiki/Interstate_Highway_standards
You can check the conversions at
http://www.onlineconversion.com
We will calc hp at 3.43 deg (6% grade), AND at a whopping 10 deg (a 17.6%
grade)
To maintain 60 mph at 6%, the *vertical component* of the velocity 28.2 x
sin 3.43 or 1.69 m/s
Applying P = mgv, we get the power required for the *vertical component* of
this grade at 60 mph, which calcs out to 18,783 watts.
Divide by 746 (watts per hp), and the EXTRA hp needed to climb the
interstate maximum grade is a whole 25 hp -- for my Honder Fit.
Add to that the initial hp for level driving at 60 mph (12 hp), and you get
a whopping 37 hp required for a 2500# car climbing the max. allowable
interstate grade.
NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
capable of climbing max interstate grades at 60 mph.
Nest, we'll do the same for a 10 deg slope, or a 17.6% grade -- whopping
indeed -- this would be even hard to climb by foot!
The same process yields 68.6 add'l hp, for a total required 80 hp for the
Fit.... which, btw, has 108 hp..
Give or take -- and barring typos, dumb errors.
So, yeah, on VERY steep hills, the VW would slow down a bit, but BFD....
you'd be hard-pressed to find 17% grades, anyway.
If we do the same calcs for the 3800# BloatVolt, just multiply the above
grade hp by 1.5, and add the level hp.
So the Volt would require 50 hp to maintain 60 mph in max interstate grades,
and 114 hp for the very very steep 17.6% grade.
So what can we conclude from all this, boyzngerlz? Besides the fact that
Kidding is totally fullashit (as usual).....
First, for interstate travel, the BloatVolt has THREE TIMES the required hp
for maximum interstate grade.... !!!!!
Second, for grades as high as 17%, the speed limit is probably way below 60
mph anyway, so you wouldn't even need that calc'd 114 hp, bec proly no one
else is going up that steep a grade at 60 mph either.
So if your dick is less than 3" long, go buy a 650 hp Ford GT, and feel
better about yerself.
If your dick is > 3", and you really wanna save some dough (and oil), write
fuknGM and tell them to lighten up on the fuknHP, ferchrissakes, and put out
a reasonably priced series hybrid car.
--
EA