OT - Drag Racing - Unimaginable Acceleration

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With the NHRA Winternationals in my backyard, I thought I'd pass this along.
Dave
Unimaginable Acceleration
a.. One Top Fuel dragster's 500-cubic-inch Hemi engine makes more horsepower than the first four rows of the Daytona 500. b.. A stock Dodge Hemi V-8 engine cannot produce enough power to drive the dragster's supercharger. c.. With 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle. d.. At the stoichiometric 1.7:1 air-fuel mixture for nitromethane, the flame front temperature measures about 7000 degrees Fahrenheit. e.. Nitromethane burn yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, separated from atmospheric water vapor by the searing heat of the exhaust gases. f.. The dual magnetos supply 44 amps to each spark plug. This output is the equivalent of an arc welder in each cylinder. g.. Spark plug electrodes can he totally consumed during a single pass. After half-distance, the engine is dieseling from compression plus the glow of exhaust valves at 1400 degrees Fahrenheit. The engine is shut down by cutting the fuel flow. h.. If a spark plug fails early in the run, unburned nitro can build up in the affected cylinder and explode with sufficient force to blow the cylinder head off in pieces or split the cylinder block in half. i.. In order to exceed 300 mph in 4.5 seconds, Top Fuel dragsters must accelerate at an average of more than 4 g's. In order to reach 200 mph before half-distance, the launch acceleration approaches 8 g's. A Top Fuel dragster reaches more than 300 mph before you have completed reading this sentence. j.. With a redline that can be as high as 9500 rpm, Top Fuel engines turn approximately 510 revolutions from light to light. Including the burnout, the engine needs to survive only 900 revolutions under load. k.. Assuming that oil of the equipment is paid off, the crew works gratis, and nothing breaks, each run costs an estimated $1000 per second. l.. The current Top Fuel dragster elapsed time record is 4.441 seconds for the quarter-mile. (October 5, 2003, Tony Schumacher). The top speed record is 333.25 mph as measured over the last 66 feet of the quarter mile November 9, 2003, Doug Kalitta).
a.. Putting all of this into perspective: you are driving the average $140,000 Lingenfelter twin-turbo Corvette Z06. More than a mile up the road, a Top Fuel dragster is staged and ready to launch down a measured quarter-mile as you pass. You have the advantage of a flying start. You run the Vette up through the gears and blast across the starting line and past the dragster at an honest 200 mph. The "tree" goes green for both of you at that moment. The dragster launches and starts after you. You keep your foot down, but you hear a brutal whine that sears your ear drums, and within three seconds, the dragster catches you and beats you to the finish line, a quarter-mile from where you just passed him. From a standing start, the top fueler spotted you 200 mph and not only caught you but nearly blasted you off the road when he passed you within a mere 1320 feet.
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wrote:

Holy Crap. :)
--
Owen Lowe and his Fly-by-Night Copper Company
Offering a shim for the Porter-Cable 557 type 2 fence design.
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along.
The lateral thinker in me is saying "don't do this activity with false teeth or you'll choke to death". While you're at it, toss the wig and tape the glasses on; also, anyone with a butt plug gets to clean their own car.
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wrote: [snip]
| You have the advantage of a flying start. You run |the Vette up through the gears and blast across the starting line and past |the dragster at an honest 200 mph. The "tree" goes green for both of you at |that moment. The dragster launches and starts after you. You keep your |foot down, but you hear a brutal whine that sears your ear drums, and within |three seconds, the dragster catches you and beats you to the finish line, a |quarter-mile from where you just passed him. From a standing start, the top |fueler spotted you 200 mph and not only caught you but nearly blasted you |off the road when he passed you within a mere 1320 feet.
Not the same numbers, but I recall a race here in Tucson (DMAFB) about 1960 when one of my dirt track buddies brought his super-modified dirt track car to the drag strip and ran a similar race with the Speed Sport Roadster.
http://www.nhra.com/museum/features/feature6.html
Of course the dirt car had the wrong rear end gear for this and only ran about 100 mph flat out but the roadster reeled him in about midtrack. Lyle and Red where way ahead of their time. Never will forget the sound of that car and the tears running down my cheeks from the nitro fumes.
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TeamCasa wrote:

Hey, the Winternationals are in my back yard too!! I can almost throw rocks at those rails from where I'm at. Heard 'em running on Thursday. Too bad they were rained out.
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Mark and Kim, I have been doing some work at Brackett Airport lately. I hope Saturday and Sunday Sunday Sunday will be dry! Dave

along.
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[snip]
Not quite.
v = a * t 300mph = 440 fps 440 fps / 4.5s = 100 feet/sec/sec approx, slightly over 3 g. Still impressive, though.

Not even close.
s = a * (t^2) = v * t half-distance = 660 feet 200 mph = 293 feet/sec 660 feet = 293 feet/sec * t t = 2.25 sec t^2 = 5.07 sec^2 660 feet / 5.07 sec^2 = 130 feet/sec^2 = 4g approx
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
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wrote:

along.
While googling around for a confirmation of the acceleration, I came across a Popular Science article where they talk about the load at launch being about 4.5 g. http://www.popsci.com/popsci/auto/article/0,12543,357237-1,00.html
The article goes on to say that they don't really know how much horsepower the nitro engines produce. They've never put a top fuel nitro engine on a dyno. The best estimate from extrapolations of dyna tests on alcohol are 6000-7000HP.
todd
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Note that to get a dyno value requires that the engine remain running for several seconds, considerably longer than a top fuel engine is able to run (the average life of such an engine is less than 1000 revolutions).
John
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todd wrote:

I wonder who will volunteer first to blow up a $150,000 motor on a dyno so they can measure the hp's?
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ayup. 4g's for 4.5 seconds gives an end speed of just under 400 mph.

WUPS! have to disagree

That's an _average_ acceleration.
Which assumes constant acceleration.
Real-world, the acceleration is _not_ constant.
It decreases with time.
If one assumes 8g at 'launch', decreasing linearly to 3+ g by the end of the first second, and constant 3+ g to the end of the quarter-mile, the elapsed time is approx. 4.5 seconds, and final velocity is approx 330MPH.
This is consistent with documented hardware performance. <grin>
It doesn't precisely match the stated conditions, in that one is past the halfway mark at 2.2 sec, with a speed of 242 mph. This is _not_ unexpected, because the rate of decrease of acceleration (hows that for confusing? :) is not constant; at high acceleration, the acceleration bleeds off faster than when it's lower.
8+ g _initially_ (i.e., 'at launch') *is* believable. It's a 'peak' value, not a 'sustained' one.
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I finally got it! Now I know why sex is dangerous and racing is safe! (it used to be the other way around)
wrote:

along.
unexpected,
is
than
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Doug, Your calculations remind me of the time when my Caltech (applied physics) professor determined that no matter how much horsepower a top fuel vehicle produced, it was mathematically impossible to cover the 1/4 mile any faster than 6.2 seconds. (1974)
Dave
wrote:

along.
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TeamCasa writes:

I recall an article--vaguely, mind you--in Hot Rod Magazine back when it was a couple, three years old that made the point that, IIRC, anything over 140 or 150 mph in the quarter mile was impossible. That was shredded within a year, I think. We're kicking around somewhere in the early '50s here, so figure most running was done with flathead V8s and OHV straight 6s at the time. It was also done with stock tires, since gluey slicks holding almost no air were a long way from being developed. I remember dragging with snow tires we buffed down to near blad states to get a wider profile and that was several years later.
I see now the big deal in motorcycles is the "naked" look. No fairing. Jeez, how things do change. That's the way they ALL came when I was younger.
Charlie Self "Health food makes me sick." Calvin Trillin
http://hometown.aol.com/charliediy/myhomepage/business.html
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This is a multi-part message in MIME format. --------------070009020901020202090407 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit
Charlie Self wrote:

Hah! Before you know it, kids will be bringing back the "eighties" look. ................. DOH!
--------------070009020901020202090407 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1"> <title></title> </head> <body text="#000000" bgcolor="#ffffff"> Charlie Self wrote:<br> <blockquote type="cite" cite=" snipped-for-privacy@mb-m27.aol.com"> <pre wrap="">TeamCasa writes:
</pre> <blockquote type="cite"> <pre wrap="">Doug, Your calculations remind me of the time when my Caltech (applied physics) professor determined that no matter how much horsepower a top fuel vehicle produced, it was mathematically impossible to cover the 1/4 mile any faster than 6.2 seconds. (1974) </pre> </blockquote> <pre wrap=""><!----> I recall an article--vaguely, mind you--in Hot Rod Magazine back when it was a couple, three years old that made the point that, IIRC, anything over 140 or 150 mph in the quarter mile was impossible. That was shredded within a year, I think. We're kicking around somewhere in the early '50s here, so figure most running was done with flathead V8s and OHV straight 6s at the time. It was also done with stock tires, since gluey slicks holding almost no air were a long way from being developed. I remember dragging with snow tires we buffed down to near blad states to get a wider profile and that was several years later.
I see now the big deal in motorcycles is the "naked" look. No fairing. Jeez, how things do change. That's the way they ALL came when I was younger.
Charlie Self "Health food makes me sick." Calvin Trillin
<a class="moz-txt-link-freetext" href="http://hometown.aol.com/charliediy/myhomepage/business.html ">http://hometown.aol.com/charliediy/myhomepage/business.html </a></pre> </blockquote> <br> Hah!&nbsp;&nbsp; Before you know it, kids will be bringing back the "eighties" look.&nbsp;&nbsp; .................&nbsp;&nbsp; DOH!<br> </body> </html>
--------------070009020901020202090407--
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Mark and Kim Smith remarks:

I think they went past that without looking. Clothing one of my granddaughter's was wearing on Sunday was more '70s, and early at that.
I expect pretty soon the college boys will be back to wearing worn chambray work shirts and torn jeans, just as if they'd actually worked for a living, just as did the '60s and '70s types.
Charlie Self "Health food makes me sick." Calvin Trillin
http://hometown.aol.com/charliediy/myhomepage/business.html
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Sounds to me like he was in the wrong career field. MIght've been better suited to meteorology or political polling.
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com
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And I remember a high school physics teacher who "proved" to the class that ice cubes would come to a boil faster than a pan of room temp. water with the same volume due to the rate of temperature change being so much higher.
He also "proved" that an atomic bomb would produce a straight-line wind of about 400MPH 120 miles away from the detonation point. I don't remember what power he assumed for the bomb, but I still don't believe it.
Mike
wrote:

Mike Patterson Please remove the spamtrap to email me.
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On Tue, 24 Feb 2004 15:26:06 -0500, Mike Patterson

Let's not find out.
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Doug Miller wrote:

.....
(Drumming fingers on table, biting lip ...)
Your assuming acceleration constant.
Your premise is faulty.
This is as nice as I can be.
--
Mark

N.E. Ohio
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