Acceleration Defined in Vivid Terms

Prof

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A friend sent this to me...not sure of the accuracy but it makes for some good reading:

"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 through the pass, 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 engines turn approximately 540 revolutions from light to light! Including the burnout, the engine 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 friends, is ACCELERATION!
 
That's been around for a while, and there are some interesting things in there. Problem is, some of them are not true.

Since I am an engineer, and love to ruin peoples fun, here is the truth about the power output of a 747.


Luckily, we do have access to data from a NASA report that does provide all the data we need to illustrate a sample case. The data is provided for a Boeing 747-200 cruising at Mach 0.9 at 40,000 ft (12,190 m). In this example, the aircraft's engines produce 55,145 lb (245,295 N) of thrust, only a quarter of its rated static thrust, to cruise at a velocity of 871 ft/s (265 m/s). Using the equations provided above, we calculate the power generated by the 747 to be 87,325 hp (65,100 kW).

And here is the link for anyone that's interested.

http://www.aerospaceweb.org/question/propulsion/q0195.shtml
 
look maw, no Viagra !!!!!!!:rock: :rock: :rock:
 
Silverback said:
That's been around for a while, and there are some interesting things in there. Problem is, some of them are not true.

Since I am an engineer, and love to ruin peoples fun, here is the truth about the power output of a 747.


Luckily, we do have access to data from a NASA report that does provide all the data we need to illustrate a sample case. The data is provided for a Boeing 747-200 cruising at Mach 0.9 at 40,000 ft (12,190 m). In this example, the aircraft's engines produce 55,145 lb (245,295 N) of thrust, only a quarter of its rated static thrust, to cruise at a velocity of 871 ft/s (265 m/s). Using the equations provided above, we calculate the power generated by the 747 to be 87,325 hp (65,100 kW).

And here is the link for anyone that's interested.

http://www.aerospaceweb.org/question/propulsion/q0195.shtml
As long as we're talking 747's I have a few questions.

What is the fuel consumption rate at take off, fuel capacity of the tanks and approximate fillup cost?:D
 
Okay, I will ruin another one for you.

"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 friends, is ACCELERATION!"



At 200 MPH you are travelling at 293.33 feet per second. Assuming that you are no longer accellerating and maintain that constant rate of speed it will take you 4.50 seconds to go 1320 feet, or a 1/4 mile. The dragster would have to be on a good run to just catch you at the 1/4 mile mark. He would not pass you at 3 seconds.

Now don't get me wrong here. The rate of acceleration is remarkable. And I almost shudder to think what they would be doing if NHRA had left them unrestricted like the old days. Unfortunately tire technology could not keep up, so they had to find a way to control them. If tires were not the limiting factor I would guess that their speeds would be in the 370+ range.
 
2 points
A: obviously silverback is right... a 747 does have more horsepower than a top fuel dragster... and compared to space & defense planes... the 747-200isn't very powerful

the 747-200 has 54,750 lb of thrust
the C-17 globemaster 3 punches out ~161,760 lb of thrust <of course there's no restrictions on the C-17>.... and of course you won't see a 747 taking off on a 5000 foot runway <boeing says 7600 feet they're being modest:D >

B: Max fuel capacity on a 747-200 is 52,410 US. Gal... u do the math... and no they don't run on shell 93 :p
 
The three space shuttle main engines generate the equivalent of 37 million horsepower. The fuel pump alone delivers 71,000 horsepower, the oxygen pump delivers about 23,000. Just as a basis of comparison, the fuel pump alone is the equivalent horsepower of 28 Locomotives. And with the horsepower of the oxygen pump, that's the equivalent of 11 more locomotives. Now that is ACCELERATION!!!:rock: :burnout:
 

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black pearl said:
The three space shuttle main engines generate the equivalent of 37 million horsepower. The fuel pump alone delivers 71,000 horsepower, the oxygen pump delivers about 23,000. Just as a basis of comparison, the fuel pump alone is the equivalent horsepower of 28 Locomotives. And with the horsepower of the oxygen pump, that's the equivalent of 11 more locomotives. Now that is ACCELERATION!!!:rock: :burnout:
That my friend is a lot of acceleration,And a nice pic too.:D Thanks mang.
 
What fun!

Where is Bill with his "you can't have too much horsepower" line?
 
nycstev said:
So about .13 MPG for a 747..not bad huh?:D

Whats a fillup cost?

I gave you the tank size... do I need to do everything for you?:p
it has 52,410 gallons... let's assume 4 bucks a gallon (which is a terrible assumption by the way)

that's $209,640 and while we're making terrible assumptions let's keep going... let's ALSO assume that you've got 452 passengers... let's also assume that their destination consumes all 52,410 gallons... that means that each passenger is spending $463.81 to just cover the fuel...

again.... these assumptions are completely innaccurate... that much i'm sure of :D
 
Talking about acceleration is one thing......

Experiencing is another.......

I got to do a full burner take off in an F-16......

Experience........
 
tidnab said:
I gave you the tank size... do I need to do everything for you?:p
it has 52,410 gallons... let's assume 4 bucks a gallon (which is a terrible assumption by the way)

that's $209,640 and while we're making terrible assumptions let's keep going... let's ALSO assume that you've got 452 passengers... let's also assume that their destination consumes all 52,410 gallons... that means that each passenger is spending $463.81 to just cover the fuel...

again.... these assumptions are completely innaccurate... that much i'm sure of :D


Real question should have been " how much is jet fuel":D
 
Prof said:
What fun!

Where is Bill with his "you can't have too much horsepower" line?
I'm right here!:D

For any of you that have never gone to a Top Fuel event, you must go, there is nothing like it.

Bill.
 

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