Fascinating facts.

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alan s
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Fascinating facts.

Post by alan s » 13 Jan 2003, 15:06

Here's a copy of something posted on one of the lists today.
I'm posting it on here out of general interests sake as I personally found the figures & facts quoted almost beyond belief but according to the original poster, they are genuine & I have no reason to doubt him. I would say judging on the terminology they are Yankee sourced.
I'm sure everybody will be as fascinated a I have been with them.
Alan S
Some interesting Top Fuel facts
* One dragster's 500 cubic-inch (8,193cc) Hemi engine makes more horsepower than the first 8 rows at Daytona.
* Under full throttle, a dragster engine consumes 1.5 US-gallons (5.68 liters) 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 then a stock hemi makes.
* Even with nearly 3,000 cubic-feet-per-minute (1,415 liters-per-second) 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 7,050F (3,900C).
* 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 1400F (760C). The engine can only be shut down by cutting of it's 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 200mph (322km/h) well before half way down the track, therefore 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 300mph (482km/h) per hour before you have read this one sentence.
Fascinating stuff
Alan S

tomsheppard
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Post by tomsheppard » 13 Jan 2003, 19:51

Most of that rings true but I am sure that a 747 drinks more than 1.5 litres per second on takeoff

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vanny
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Post by vanny » 15 Jan 2003, 17:32

Yeah, but if it does only take 1.5 litres per second to move that, its got to be pretty economic!!
Of course that could be 1.5l/s for each engine??
Vanny
Merseyside, UK
Citroenbx19rd@bxproject.co.uk
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humpy
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Post by humpy » 15 Jan 2003, 19:50

As far as I remember the jet engine is extremely efficient, butmaybe someone else has some concrete figures. Internal combustion engines are extremely inefficent. The fact that a comparison can be made between these two vehicles only goes to emphasise the point.

Zummerman
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Post by Zummerman » 15 Jan 2003, 23:08

Hi guys,
If you check back you'll see that Tom misquoted. The figure is actually 1.5 US Gallons (5.68 Litres) per second, a big difference. Aviation fuel is normally measured by weight. It's basically paraffin with some anticing and antifungal additives with a specific gravity around 0.8. The Vulcan bomber I used to fly burned about 18,000 lbs of fuel in its first hour of flight which included take-off and a 20 minute fullish throttle climb to over 40,000 feet. That's about 10,500 litres or 2.92 Ltrs/sec. The 747 had similar performance to the Vulcan but weighed around 2.5 times as much. So its probably safe to assume that, despite more efficient engines, it uses just under twice as much fuel.
QANTAS - Quite A Nice Take-off, All Survived!
Ian <img src=icon_smile_cool.gif border=0 align=middle>

tomsheppard
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Joined: 19 Dec 2002, 15:46

Post by tomsheppard » 16 Jan 2003, 14:47

Thanks, Zummermann, got my imperial and metric muddled- Oh, well I could always work for NASA. Interesting figures which seem to tally.
What does it burn on takeoff? I'll bet you'd feel it in the wallet if you left the choke on!
I did once read that the fuel load of a 747 exceeded the all up weight of a 707. That is nearly enough paraffin to wash down a whole XUD engine!
Back to dragsters, though; How are they started up and what is the idling speed likely to be?