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A lesson in Acceleration


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One Top Fuel dragster 500 cubic inch Hemi engine makes more horsepower than

the first 4 rows at the Indy. 500.

Under full throttle, a Top Fuel dragster engine consumes 1 gallon of

nitromethane per second; a fully loaded 747 consumes jet fuel at the same

rate with 25% less energy being produced.

A stock Dodge 426 Hemi V8 engine cannot produce enough power to drive the

dragster's supercharger.

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.

At the stoichiometric 1.7:1 air/fuel mixture for nitromethane the flame

front temperature measures 7050 degrees F.

Nitromethane 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 ½ way, the

engine is dieseling from compression plus the glow of exhaust valves at 1400

degrees 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 the

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 at 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 Engines turn approximately 540 revolutions from light to light!

Including the burnout the engine must only survive 900 revolutions under

load.

The red-line is actually quite high at 9500 rpm.

The Bottom Line; Assuming all the equipment is paid off, the crew worked for

free, and for once NOTHING BLOWS UP, each run costs an estimated $1,000.00

per second.

The current Top Fuel dragster elapsed time record is 4.441 seconds for the

quarter mile (10/05/03, Tony Schumacher).

The top speed record is 333.00 mph (533 km/h) as measured over the last 66ft

of the run, (09/28/03 Doug Kalitta).

Putting all of this into perspective:

You are riding the average $250,000 Honda MotoGP bike. 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

RC211V hard up through the gears and blast across the starting line and past

the dragster at an honest 200 mph (293 ft/sec). The 'tree' goes green for

both of you at that moment. The dragster launches and starts after you. You

keep your wrist cranked 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 1320 foot long race course.

 

That, folks, is acceleration!

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Other interesting notes,

 

They use shorter connecting rods in the front cylinders to increase piston speed which helps them to draw more fuel. If the connecting rods were all the same length, more of the fuel would enter the rear cylinders due to the G's

 

They tune the mixture by measuring the connecting rod bearing thickness. .002" thinner than when installed is about right. After all you can't read spark plugs that are destroyed during the pass.

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