Acceleration explained

Richard

Final Approach
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Ack...city life
"DEFINITION OF ACCELERATION"
(courtesy of KB Performance Pistons)




One top fuel dragster 500 cubic inch Hemi engine makes more horsepower than the first 4 rows of stock cars at the Daytona 500.
It takes just 15/100ths of a second for all 6,000+ horsepower of an NHRA Top Fuel dragster engine to reach the rear wheels.

Under full throttle, a dragster engine consumes 1-1/2 gallons of nitro methane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced. A stock Dodge Hemi V8 engine cannot produce enough power to drive the dragster's supercharger. With 3,000 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.

At the stoichiometric (stoichiometry: methodology and technology by which quantities of reactants and products in chemical reactions are determined) 1.7:1 air/fuel mixture of nitro methane, the flame front temperature measures 7,050 deg F. Nitro methane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.

Dual magnetos supply 44 amps to each spark plug. This is the output of an arc welder in each cylinder. Spark plug electrodes are totally consumed during a pass. After halfway, the engine is dieseling from compression, plus the glow of exhaust valves at 1,400 deg F. The engine can only be shut down by cutting the fuel flow. If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.

In order to exceed 300 mph in 4.5 seconds, dragsters must accelerate an average of over 4G's. In order to reach 200 mph (well before half-track), the launch acceleration approaches 8G's.


Dragsters reach over 300 miles per hour before you have completed reading this sentence.


Top fuel tires turn approximately 540 revolutions from light to light! Including the burnout, the tires must only survive 900 revolutions under load. The redline is actually quite high at 9,500 rpm. Assuming all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs an estimate $1,000.00 per second.

The current top fuel dragster elapsed time record is 4.428 seconds for the quarter mile (11/12/06, Tony Schumacher, at Pomona, CA). The top speed record is 336.15 mph as measured over the last 66' of the run
(05/25/05 Tony Schumacher, at Hebron, OH).


Putting all of this into perspective:
You are driving the average $140,000 Lingenfelter "twin-turbo" powered Corvette Z06. Over a mile up the road, a top fuel dragster is staged and ready to launch down a quarter mile strip as you pass. You have the advantage of a flying start. You run the 'Vette hard up through the gears and blast across the starting line and pass 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 hard, but you hear an incredibly brutal whine that sears your eardrums and within 3 seconds, the dragster catches and passes you. He beats you to the finish line, a quarter mile away from where you just passed him.

Think about it, from a standing start, the dragster had spotted you 200 mph and not only caught, but nearly blasted you off the road when he passed you within a mere 1,320 foot long race course.


... and that my friend, is ACCELERATION!
 
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Good luck reaching a 2000 hour TBO like that. ;)
 
Wow, that's a great writeup.
 
Hmmm. So he spots you 200mph then 1000ft later he cleans your clock at 150% of your wide open velocity.

Take him in the twisties that begins 100ft past the start line. Just make sure he starts on the outside of the turn because he's going to be crossing the line...
 
They should get an engine monitor and consider running LOP :rofl::rofl::rofl:
With two fuel pumps and three sets of injector nozzles per cylinder, I don't think economy is a concern.:D

There are two false statements in that, the 15/100 of a second for full power to be at the rear wheels, and the 8 gs (It's about 5.5 max), and the problem with both is traction. It takes a bit longer, tuned by individual lane conditions by adjusting the semicentrifugal clutch (I used a Crowerglide). Driving, you don't just pin the throttle on the launch, you have to stagger/stage the pedal and let it slip just a bit other wise you either smoke the tires or get into wheel hop, either of which will cost you the race, and possibly cause you to crash, not to mention shaking you so f-ing hard you can't see anything.
 
With two fuel pumps and three sets of injector nozzles per cylinder, I don't think economy is a concern.:D

There are two false statements in that, the 15/100 of a second for full power to be at the rear wheels, and the 8 gs (It's about 5.5 max), and the problem with both is traction. It takes a bit longer, tuned by individual lane conditions by adjusting the semicentrifugal clutch (I used a Crowerglide). Driving, you don't just pin the throttle on the launch, you have to stagger/stage the pedal and let it slip just a bit other wise you either smoke the tires or get into wheel hop, either of which will cost you the race, and possibly cause you to crash, not to mention shaking you so f-ing hard you can't see anything.
Okay, so we apparently have another area that Henning has experience in! Wow!
 
Okay, so we apparently have another area that Henning has experience in! Wow!

I think I heard Henning say that Wesley Crusher has unique talents but don't let him know. :D
 

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Okay, so we apparently have another area that Henning has experience in! Wow!

Some Guys living down the street when I was a little kid who had a Modified Eliminator 67 Camaro and a used car lot, that kinda adopted me as a little brother, was what got me into all this kinda stuff. Been turning wrenches since I was 8, driving since about 11 (tossed into an MG Midget at Imperial auto auction with a "Get it to the lot, I'll follow you". Did my first hard pass down the 1/4 at 14, got my first taste of Fuel in a F/A (Fuel Altered) 47 Anglia at 15, nothing like the sting of nitro and 1900hp to make your **** hard, not that that's a problem at 15.:D
 
Geez, and my first taste of driving was doing a burnout in a 1974 Volvo 240 wagon with a 4-speed + overdrive at the age of 10.

Mom wasn't happy about that...
 
One of the motorcycle magazines had a story about a guy who drag raced top fuel bikes. There was a race in which one of the plugs arced and nearly electrocuted him.
 
Hey Keith, what sort of fuel flow do you see on your locomotives at full tilt boogie?

On the ship I was on in the Navy, we got fifty gallons NSFO/mile moving 4,000 tons of cargo 18 knots.

-Skip
 
Some Guys living down the street when I was a little kid who had a Modified Eliminator 67 Camaro and a used car lot, that kinda adopted me as a little brother, was what got me into all this kinda stuff. Been turning wrenches since I was 8, driving since about 11 (tossed into an MG Midget at Imperial auto auction with a "Get it to the lot, I'll follow you". Did my first hard pass down the 1/4 at 14, got my first taste of Fuel in a F/A (Fuel Altered) 47 Anglia at 15, nothing like the sting of nitro and 1900hp to make your **** hard, not that that's a problem at 15.:D

Um, what's the oldest age at which that combo has proven to be effective? I've kinda always thought drag racing might be fun . . .
 
Um, what's the oldest age at which that combo has proven to be effective? I've kinda always thought drag racing might be fun . . .

There's no max age for that effect, especially if you get a good whiff of the exhaust. The fun thing about Fuel Altered now is it's an exhibition class so you get paid just to show up. I've always wanted to use a '65 Volvo P 1800. I had one (my ex wife now has it) that I was gonna cut a mold off of to make the body. Thing about F/A is you don't have all the aerodynamic perks of F/C, but you get to use old body styles (F/C has to be less than 5 years old), and you're limited to iron blocks, so comparatively, it's much cheaper than running F/C or T/F. It is a lot of fun, mentally as much or more so than physically. Half the fun of making the run is seeing how the last thing you did worked out.
 
Hey Keith, what sort of fuel flow do you see on your locomotives at full tilt boogie?
-Skip

On a six axle locomotive typically 4000hp, in run 8, (full throttle) it burns roughly 160-180 gallons per hour. Generally speaking they are almost all 16 cylinders, 4 stroke for GE locos, and 2 stroke for EMD (Electromotive Division of GM, though no longer owned by GM). At full throttle they turn about 975 RPM and idle at about 250 RPM. By switching the traction motors from series to parallel, to series-parallel, and so forth, they optimize torque. They actually sound like they are changing gears at times. Computers precisely control current to each motor, comparing ground speed, as determined by downward looking radar to the linear speed calculated by the control system based on wheel diameter, which is based on calculations of mileage put on a new (42" diameter) wheel, using standard wear rates. If there is a discrepancy in measured and calculated speed on any one axle, wheel slip is detected and current to that axle is adjusted. The goal is to keep the wheel right at the edge of wheelspin in order to produce the most tractive effort. Tractive effort (pulling force) is expressed as percent adhesion. On dry rail a new loco generates about 28-30% adhesion. 30% adhesion on a 400,000 pound loco would mean it generates about 120,000 pounds of pull on the coupler. That's why it's a good thing to have a heavy loco, but not so heavy as to destroy track structures. Some of the really huge articulated steam locos weighed over a half a million pounds, but had surprisingly little tractive effort. More than you ever needed to know.

See the big boy:http://en.wikipedia.org/wiki/Union_Pacific_Big_Boy


 
On a six axle locomotive typically 4000hp, in run 8, (full throttle) it burns roughly 160-180 gallons per hour. Generally speaking they are almost all 16 cylinders, 4 stroke for GE locos, and 2 stroke for EMD (Electromotive Division of GM, though no longer owned by GM). At full throttle they turn about 975 RPM and idle at about 250 RPM. By switching the traction motors from series to parallel, to series-parallel, and so forth, they optimize torque. They actually sound like they are changing gears at times. Computers precisely control current to each motor, comparing ground speed, as determined by downward looking radar to the linear speed calculated by the control system based on wheel diameter, which is based on calculations of mileage put on a new (42" diameter) wheel, using standard wear rates. If there is a discrepancy in measured and calculated speed on any one axle, wheel slip is detected and current to that axle is adjusted. The goal is to keep the wheel right at the edge of wheelspin in order to produce the most tractive effort. Tractive effort (pulling force) is expressed as percent adhesion. On dry rail a new loco generates about 28-30% adhesion. 30% adhesion on a 400,000 pound loco would mean it generates about 120,000 pounds of pull on the coupler. That's why it's a good thing to have a heavy loco, but not so heavy as to destroy track structures. Some of the really huge articulated steam locos weighed over a half a million pounds, but had surprisingly little tractive effort. More than you ever needed to know.

See the big boy:http://en.wikipedia.org/wiki/Union_Pacific_Big_Boy



That ought to make the Sperry Rail guys happy, I can't count how many times I sliced my fingers on an engine burn sliver while doing a hand test on it. Burns are also where transverse defects start from all the pounding there.
 
On a six axle locomotive typically 4000hp, in run 8, (full throttle) it burns roughly 160-180 gallons per hour. Generally speaking they are almost all 16 cylinders, 4 stroke for GE locos, and 2 stroke for EMD (Electromotive Division of GM, though no longer owned by GM). At full throttle they turn about 975 RPM and idle at about 250 RPM. By switching the traction motors from series to parallel, to series-parallel, and so forth, they optimize torque. They actually sound like they are changing gears at times. Computers precisely control current to each motor, comparing ground speed, as determined by downward looking radar to the linear speed calculated by the control system based on wheel diameter, which is based on calculations of mileage put on a new (42" diameter) wheel, using standard wear rates. If there is a discrepancy in measured and calculated speed on any one axle, wheel slip is detected and current to that axle is adjusted. The goal is to keep the wheel right at the edge of wheelspin in order to produce the most tractive effort. Tractive effort (pulling force) is expressed as percent adhesion. On dry rail a new loco generates about 28-30% adhesion. 30% adhesion on a 400,000 pound loco would mean it generates about 120,000 pounds of pull on the coupler. That's why it's a good thing to have a heavy loco, but not so heavy as to destroy track structures. Some of the really huge articulated steam locos weighed over a half a million pounds, but had surprisingly little tractive effort. More than you ever needed to know.

See the big boy:http://en.wikipedia.org/wiki/Union_Pacific_Big_Boy



That's great info, thanks.

The restored UP Challenger just went through our area, what an impressive machine!


Trapper John
 
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