Fastest and most powerfull but not useable for long!
Discussion
From our other bit posted by FM.
Some interesting Top Fuel dragster facts:
* One dragster's 500-inch Hemi makes more horsepower then the first 8 rows at Daytona
* Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume.
* The supercharger takes more power to drive than a stock hemi makes.
* Even with nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.
* Dual magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
* At stoichiometric (exact) 1.7:1 air/fuel mixture (for nitro), the flame front of nitromethane 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.
* 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 off its fuel flow.
* If spark momentarily fails early in the run, unburned nitro builds up in those cylinders and then explodes with a force that can blow cylinder heads off the block in pieces or blow the block in half.
* Dragsters twist the crank (torsionally) so far (20 degrees in the big end of the track) that sometimes cam lobes are ground offset from front to rear to re-phase the valve timing somewhere closer to synchronization with the pistons.
* To exceed 300mph in 4.5 seconds dragsters must accelerate at an average of over 4G's. But in reaching 200 mph well before 1/2 track, launch acceleration is closer to 8G's.
* If all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs $1000.00 per second.
* Dragsters reach over 300 miles per hour before you have read this sentence.
Amazing the details that come to light with such a highly squeezed engine...
Some interesting Top Fuel dragster facts:
* One dragster's 500-inch Hemi makes more horsepower then the first 8 rows at Daytona
* Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume.
* The supercharger takes more power to drive than a stock hemi makes.
* Even with nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.
* Dual magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
* At stoichiometric (exact) 1.7:1 air/fuel mixture (for nitro), the flame front of nitromethane 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.
* 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 off its fuel flow.
* If spark momentarily fails early in the run, unburned nitro builds up in those cylinders and then explodes with a force that can blow cylinder heads off the block in pieces or blow the block in half.
* Dragsters twist the crank (torsionally) so far (20 degrees in the big end of the track) that sometimes cam lobes are ground offset from front to rear to re-phase the valve timing somewhere closer to synchronization with the pistons.
* To exceed 300mph in 4.5 seconds dragsters must accelerate at an average of over 4G's. But in reaching 200 mph well before 1/2 track, launch acceleration is closer to 8G's.
* If all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs $1000.00 per second.
* Dragsters reach over 300 miles per hour before you have read this sentence.
Amazing the details that come to light with such a highly squeezed engine...
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? The engine in a dragster is internal combustion, that in a 747, well, it's a turbine, so ccs are not really comparable.
If you did the measurements, though, a 747 engine is bigger...
dont know what a jumbo can do but a top fueler makes around 7000 to 8000hp. Would have thort a jumbo will make more just to get it up in the air!
What I would like to see is even biger engines say a 16000cc truck engine done to the same spec as a fueler. But could it be used to win a race?
What I would like to see is even biger engines say a 16000cc truck engine done to the same spec as a fueler. But could it be used to win a race?
Edited by drags06 on Saturday 13th January 01:38
Gazboy said:
northernboy said:
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? ...
Exactly that- a gallon of nitro methane gives four times the energy than a gallon of kerosene in this context.
So it should be putting out something like four times the power? Maybe a bit less, as it is probably burning it less efficiently.
This does not seem right. 4 engines each putting out 57,000lb of thrust = 228,000lb of thrust, or about 1 million newtons.
1 million newtons times 200m/s (I am guessing this bit slightly, at 400mph) is 200 million joules/second, or 200 kilowatts. 200 kilowatts = 270,000 BHP.
If 57,000 is the total for all 4 engines, you still get over 60,000 Bhp.
So, impressive as the dragster is, the figures comparing its power to a 747 just look wrong.
northernboy said:
Gazboy said:
northernboy said:
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? ...
Exactly that- a gallon of nitro methane gives four times the energy than a gallon of kerosene in this context.
So it should be putting out something like four times the power? Maybe a bit less, as it is probably burning it less efficiently.
This does not seem right. 4 engines each putting out 57,000lb of thrust = 228,000lb of thrust, or about 1 million newtons.
1 million newtons times 200m/s (I am guessing this bit slightly, at 400mph) is 200 million joules/second, or 200 kilowatts. 200 kilowatts = 270,000 BHP.
If 57,000 is the total for all 4 engines, you still get over 60,000 Bhp.
So, impressive as the dragster is, the figures comparing its power to a 747 just look wrong.
I think it means the power of the fuel not the engin!
Trooper2 said:
One fact that was not on the list, during a run there is so much pressure inside the cylinders that you could slip a peice of paper between the block deck and the heads.
Needless to say the head bolts get pitched after every run.
Needless to say the head bolts get pitched after every run.
I would let you do that mate. I love these engines but going near one on full song!!!!!!!!!
northernboy said:
Gazboy said:
northernboy said:
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? ...
Exactly that- a gallon of nitro methane gives four times the energy than a gallon of kerosene in this context.
So it should be putting out something like four times the power? Maybe a bit less, as it is probably burning it less efficiently.
This does not seem right. 4 engines each putting out 57,000lb of thrust = 228,000lb of thrust, or about 1 million newtons.
1 million newtons times 200m/s (I am guessing this bit slightly, at 400mph) is 200 million joules/second, or 200 kilowatts. 200 kilowatts = 270,000 BHP.
If 57,000 is the total for all 4 engines, you still get over 60,000 Bhp.
So, impressive as the dragster is, the figures comparing its power to a 747 just look wrong.
Close, very close,
said:
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).
Edited by beyond rational on Saturday 6th January 02:39
northernboy said:
Gazboy said:
northernboy said:
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? ...
Exactly that- a gallon of nitro methane gives four times the energy than a gallon of kerosene in this context.
So it should be putting out something like four times the power? Maybe a bit less, as it is probably burning it less efficiently.
This does not seem right. 4 engines each putting out 57,000lb of thrust = 228,000lb of thrust, or about 1 million newtons.
1 million newtons times 200m/s (I am guessing this bit slightly, at 400mph) is 200 million joules/second, or 200 kilowatts. 200 kilowatts = 270,000 BHP.
If 57,000 is the total for all 4 engines, you still get over 60,000 Bhp.
So, impressive as the dragster is, the figures comparing its power to a 747 just look wrong.
You aren't including the effects of thrust lapse, the published values for civil aircraft engines are the static thrust of the engine. As you go faster you have to subtract the momentum term from the incoming gasses hence thrust is proportional to Vjet/Vplane.
The maximum power case for an engine tends to be at the end of runway once you start going faster you have to throttle the engine back anyway to stop them melting. A single RB211 on a 747 is putting out about 30,000bhp at this point. It weighs considerably more than an dragster engine, however as an RB211 weights in at 4300kg.
Of course an RB211 also has a life expectancy of over 20,000 hours between off wing maintainance, rather than 7 seconds. It you were to design a gas turbine to be light weight with a life expectancy of say 50, 15 second cycles you could probably get something that would generate more power with equal weight when compared to a dragster's engine without using anything more exotic than kerosene as fuel.
beyond rational said:
northernboy said:
Gazboy said:
northernboy said:
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? ...
Exactly that- a gallon of nitro methane gives four times the energy than a gallon of kerosene in this context.
So it should be putting out something like four times the power? Maybe a bit less, as it is probably burning it less efficiently.
This does not seem right. 4 engines each putting out 57,000lb of thrust = 228,000lb of thrust, or about 1 million newtons.
1 million newtons times 200m/s (I am guessing this bit slightly, at 400mph) is 200 million joules/second, or 200 kilowatts. 200 kilowatts = 270,000 BHP.
If 57,000 is the total for all 4 engines, you still get over 60,000 Bhp.
So, impressive as the dragster is, the figures comparing its power to a 747 just look wrong.
Close, very close,
said:
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).
Edited by beyond rational on Saturday 6th January 02:39
It just says that the dragster uses ALOT of fuel to do what it does, even with the fuel having four times the energy per unit volume.
You could in essence say the dragster would use four times more fuel than the 747 in energetic terms at full throttle. Clearly the dragster engine is not very efficient, wheras the turbofan is.
Dave
this is whats said-
Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume.
So reading into this it looks like it is the fuels energy that its on about not what the engine is doing with the fuel!
Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume.
So reading into this it looks like it is the fuels energy that its on about not what the engine is doing with the fuel!
Talksteer said:
northernboy said:
Gazboy said:
northernboy said:
drags06 said:
...the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume...
Amazing facts, but, can I ask, what do you mean by 4 times the energy volume? ...
Exactly that- a gallon of nitro methane gives four times the energy than a gallon of kerosene in this context.
So it should be putting out something like four times the power? Maybe a bit less, as it is probably burning it less efficiently.
This does not seem right. 4 engines each putting out 57,000lb of thrust = 228,000lb of thrust, or about 1 million newtons.
1 million newtons times 200m/s (I am guessing this bit slightly, at 400mph) is 200 million joules/second, or 200 kilowatts. 200 kilowatts = 270,000 BHP.
If 57,000 is the total for all 4 engines, you still get over 60,000 Bhp.
So, impressive as the dragster is, the figures comparing its power to a 747 just look wrong.
You aren't including the effects of thrust lapse, the published values for civil aircraft engines are the static thrust of the engine. As you go faster you have to subtract the momentum term from the incoming gasses hence thrust is proportional to Vjet/Vplane.
The maximum power case for an engine tends to be at the end of runway once you start going faster you have to throttle the engine back anyway to stop them melting. A single RB211 on a 747 is putting out about 30,000bhp at this point. It weighs considerably more than an dragster engine, however as an RB211 weights in at 4300kg.
Of course an RB211 also has a life expectancy of over 20,000 hours between off wing maintainance, rather than 7 seconds. It you were to design a gas turbine to be light weight with a life expectancy of say 50, 15 second cycles you could probably get something that would generate more power with equal weight when compared to a dragster's engine without using anything more exotic than kerosene as fuel.
the jet cars are brill but not as quick from the tree (standing start) to finish line!
drags06 said:
the jet cars are brill but not as quick from the tree (standing start) to finish line!
The jet cars tend to use 1950/60's jet engines and not particularly aggressive designs from those period anyway. In the 1960/70's R-R designed lift engines that had a thrust to weight of 20-1. Today we could probably do significantly better, I suspect in the region of 30-1. That would be for an engine that would last a season or two not just a few runs. A 500lb engine producing 15,000 of thrust in a 2000lb car could in theory produce ~ 7.5g acceleration from standing and because such an engine is likely to have a fairly high V-jet the thrust won't tail off that much by the end of the run.
Of course if you were to run the engine up against the brakes of the car and then release the brakes and throttle the engine up you wouldn't go as fast because you would have to wait while the engine accelerates to maximum power. It would be far more effective to tether the car on a cable with the engine at full power before firing and explosive bolt and cutting the car loose.
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