Acceleration

[J. T. Toad]

ACCELERATION PUT INTO PERSPECTIVE



* One Top Fuel dragster 500 cubic-inch Hemi engine makes more
horsepower (8,000 HP) than the first 4 rows at the Daytona 500.

* Under full throttle, a dragster engine consumes 11.2 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
merely 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 nitro methane
the flame front temperature measures 7050 degrees 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
1/2 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 cylinder heads off the block in pieces or split the
block in half.

* Dragsters reach over 300 MPH before you have completed reading
this sentence.

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

* 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 9500 RPM.

* THE BOTTOM LINE: Assuming all the equipment is paid off, the
crew worked for free, & for once, NOTHING BLOWS UP, each run costs an
estimated $1,000 per second.

0 to 100 MPH in .8 seconds (the first 60 feet of the run)
0 to 200 MPH in 2.2 seconds (the first 350 feet of the run)
6 g-forces at the starting line (nothing accelerates faster on land)

6 negative g-forces upon deployment of twin 'chutes at 300 MPH
An NHRA Top Fuel Dragster accelerates quicker than any other land
vehicle onearth . . quicker than a jet fighter plane . . . quicker
than the spaceshuttle

The current Top Fuel dragster elapsed time record is 4.420 seconds
for the quarter-mile (2004, Doug Kalitta). The top speed record is
337.58 MPH as measured over the last 66' of the run (2005, Tony
Schumacher).

Putting this all 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 & 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 & pass the
dragster at an honest 200 MPH. The 'tree' goes green for both of you
at that moment.

The dragster launches & starts after you. You keep your foot down
hard, but you hear an incredibly brutal whine that sears your
eardrums & within 3 seconds the dragster catches & 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 & not only caught, but nearly blasted you off the road
when he passed you within a mere 1320 foot long race!

That's acceleration !

[Wayne Maybury]

Very impressive stats.

However, I wonder about a 747 producing 25% less energy than a fuel dragster. I looked at the wording and I do not see anything that qualifies this statement so I have to take it that a 747's 4 engines only produce the equivalent of 6000HP. That just doesn't seem correct. Some of the engineers out there should be able to convert thrust into HP and either confirm or refute this statement.

Wayne

[Doug I]

Nitromethane is a slower burning fuel compared to pump gas, and only produces ~11MJ/kg compared to pump gas at ~43. It's advantage is that it can be a mono-propellant in that it doesn't require addition oxygen to burn, and by weight you can pump in 8 times more fuel. The pumps use fuel lines the size of conventional radiator water hoses.

An injected nitro car doesn't have gears - it's geared to spin ~6200 through the trap. The computer controls the ignition advance etc for any rpm during the run, which influences the hp being produced at a particular speed.

With you doing 200mph and the Rail doing a 4.5 second run you'll tie at the trap. There'll just be a slight difference in your speeds.

[Doug I]

ohhhh and 1lb thrust = ~3.1 hp

actually ..... no

the dynamic conversions are a little complicated

[Wayne Maybury]

Typical thrust for 747 engines is 55,000 lbs per engine (some are well over 66,000 lbs but most are ~55,000). So total thrust is 220,000 lbs for all 4 engines. How much HP is that?

Wayne

[J. T. Toad]

thanks for ruining a cute and funny LOUNGE story which would make any Top Fuel NHRA giggle with excitement.

Is there really any conversion from Thrust to HP? Only for specific examples.

Aerospaceweb.org | Ask Us - Convert Thrust to Horsepower

"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)."

although at cruise a loaded 747 burns 1 gal/sec.

so, was this 747 in question, taxiing without chalks removed?

YouTube - 747 vs. truck

performing a fly by?

Jumbo jet pilot sacked for ‘fly-by’ at 28 feet - Times Online

or at takeoff?

YouTube - Extremely short runway 747 takeoff

someone write Mythbusters.... they'd should have fun with this one.

MythBusters : Adam : Jamie : Kari : Grant : Tory : Discovery Channel


Side note: As this is an election year, we all should be mindful of any statistical analysis which elicits a dramatic response in order to sway opinion and create a fervor of emotion to rally public opinion.

[J. T. Toad]

hmmm.... Could a 747 survive Mach flight?

Phantom F4f's had to nose over for supersonic flight...

Super sonic fuel consumption in airplanes is not so linear....

"Furthermore, aircraft are equipped with throttles that allow a pilot to adjust the amount of thrust an engine produces. A good example is the SR-71 Blackbird equipped with Pratt & Whitney J58 turboramjets that produced a combined static thrust of 65,000 lb (289 kN). Even though the Blackbird could reach speeds in excess of Mach 3, however, it actually needed very little of this thrust in cruise flight. Most of the thrust was required to accelerate through the speed of sound, but once at Mach 3, the SR-71 engines were throttled back to only 30% or so."

this reminds me....ah, the classics,

"http://imdb.com/title/tt0086197/"

Take an F18 which needed full after-burner (major raw fuel pumping) to brake the envelope, compared to F-22 which doesn't.

[Doug I]

Static thrust to horsepower is easy. It's zero. Doing a static thrust test on our 747 gives a result of 220,000 pounds, but the motion caused is zero (at least we HOPE it's zero) so hence the work done is zero and the hp is zero.

Let's look at the dynamic thrust. Our 747 is cruising at Mach 0.9 at 40,000 feet. To do this it requires ~55,100 pounds of thrust. Taking into account the mass and distance moved and hence the work done that 55,100 pounds equates to ~87,300hp. So from this 1 pound = 1.6hp

Now let's look at a supersonic aircraft. We're at Mach 1.8 at 55,000 feet and are requiring ~11,600 pounds of thrust. Taking into account the mass and distance moved and hence the work done that 11,600 pounds equates to ~36,600hp. So from this 1 pound = 3.1hp

Doug

[wtm442]

Originally Posted by J. T. Toad

ACCELERATION PUT INTO PERSPECTIVE
* Under full throttle, a dragster engine consumes 11.2 gallons of nitro methane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.

That would be almost 50 gallons burned in a 1/4 mile run! No way! I hope you are not going to tell me that the small tank on the front end contains more than 50 gallons.

Total nitro for a single pass including burnout is about 14 gallons total.

Other than that, some very impressive numbers. But to get the full effect, you have to inhale the nitro when they warm up an engine in the pits. Then you have to get as close to the finish line and listen to both dragsters as they go thru the lights at full song without your fingers in your ears. Goose Bumps! Been there, done that!

[Doug I]

Originally Posted by wtm442

... But to get the full effect, you have to ...

be sitting in the hot seat hoping you don't over pedal it off the line, it doesn't explode behind you, a tire doesn't come apart, working at keeping it straight and keeping the other guy out of sight .....

What's really amazing that all that hp can come out of a relatively small engine and that the tires can hook it to get you a 1/4 of a mile away in well under 5 seconds.

[J. T. Toad]

I liked this description from Wikipedia....

"Rather, it is because a Top Fuel engine cannot be run at its maximum power output for more than about 10 seconds at a time without overheating (or perhaps exploding) as would be necessary to take a reliable power reading."

[DAVID GAGNARD]

That would be almost 50 gallons burned in a 1/4 mile run! No way! I hope you are not going to tell me that the small tank on the front end contains more than 50 gallons.

Total nitro for a single pass including burnout is about 14 gallons total.

Waren, you beat me to it............

David

[Ron61]

David,

I have a two page tech sheet that the NRA put out a year or so ago that lays out the whole thing about top fuel dragsters. It uses Tony Schumachers dragster as the example. I won't list the whole thing as it would take a page as they even tell the number of screws used to fasten the slicks to the wheels.
But for fuel. The fuel system can PUMP 77 gallons per minute at wide open throttle. The engine will consume 22.75 gallons of fuel during warm up, burnout, staging, and the quarter mile run.

Last but not least: If Tony makes it to the finals he will have had 18 seconds of racing. If he made it to the finals of every race in the season, his total racing time for the season would be less than 7 minutes.

Ron

[imagine2frolic]

If that is true, and you could keep up with it? That's hot enough for a weinie roast.....LOLOLOLOLOL

[DAVID GAGNARD]

Ron;

I could see 20 to 22 gallons per run, but not 50!!!!!!!!!!!!!

not too many years ago, they would use about 15 gallons of fuel per run.........

7 minutes of racing for the year!!!!!!!!!!!! that's why I like road racing, lots of seat time............we get a 30 minute practise session in the morning, then a 10 minute qualifying session and a 12 lap/20 minute race...........

David

[Doug I]

I2F - yeah but in 4.5 seconds would it be medium or well done?


David - and that's just 1 day too.

[Ron61]

David,

That is one reason I was never to interested in drag racing. Lots of travel, money, and one bad run and you are through for the day. At least in road racing if you aren't leading after the first lap you don't have to load up and go home. I thought the 22.75 gallons per run was about right from what I hear them say when I do watch the drags. These two pages they published on Schumachers top fuel dragster really had some surprising statistics. I never dreamed it took that much power just to run the blower.

Ron

[DAVID GAGNARD]

Ron;

I drag raced for about three years.....it was always hurry up and get in line, then wait,wait, and wait some more for your pass.......then you lose in the first round and get to go home early.......got old realllllllllll quick..........

At least in road racing I get seat time, even if I don't win (which I haven't) I get to run all the laps and have fun..........

David

[Ron61]

David,

I used to go with a friend of mine that was into drag racing and I worked on his car some with him. That was way back in the days of several stock classes and it was just a souped up 56 Chevy and ran in the 14s I think it was. But we would spend 4 hours driving each way for him to make one pass and come home. I just couldn't see spending 10 hours for less than 15 seconds of racing.
I like to road race and even like it when there are no other cars on the track as you can try different things. We have a long winding old no longer used highway that goes up through some of the low hills here and that is where I and some friends used to go to race or try the cars out. And it didn't cost anything but the gas. I think the open track days here are now around $300 for a day and depending on the number of cars you may not get much time on the track. That is why I kind of liked the driving schools as then you were assured of so much time on track.

Ron