Landracing Forum
Tech Information => Technical Discussion => Topic started by: JackD on May 08, 2006, 10:21:47 PM
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to read
http://dragracingonline.com/burksblast/viii_5-1.html
and follow the progress of the problem that is plaguing them also.
Same subject, different day.
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good one jack!!!!
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Wish I could see it, whatever it is. This steam-powered Mac ain't what it's been cracked up to be.
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Wish I could see it, whatever it is. This steam-powered Mac ain't what it's been cracked up to be.
So you moved up to steam with the MAC ? When did the horse die ?
I gotta go. JD was nice to me so I need to check my pockets. LOL
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Jack,
Thanks for posting that link, I don't usually go to the drag racing sites but I do watch the fuel shows on ESPN2 and they did show Cory Mac's frame failure at least 100 times!!! also Branden's tire failure. If you make some fairly basic assumptions, i.e. the wing makes 6000 lbs of down force, the wing lift/drag ratio is approx 3:1 and the engine makes about 6000 lb-ft torque you can find that the bending moment being put into a dragster chassis is around 30,000+ lb-ft! I am sure that if you did a quick stress check it is probably more than 50-75% of the material yield strength and this equals low fatigue life. Throw in the additional flexing from a rough track and maybe scrape .010 off the bottom rails by hitting the track and you are inviting failure. One thing that the guy was wrong about is that as the chassis flexes the angle of attack of the rear wing actually decreases and the front wing's increases, which is probably a good thing. Just to keep the front wheels planted and resist the engine and rear wing forces it needs to make about 1800 lbs of down force!
It seems obvious that NHRA could fix this problem with a hack saw! just keep cutting an inch of each side if the rear wing until they can only go 300! Down force is proportional to the square of the speed so going from 330 to 300 should reduce the wing down force by about 20%. Sure the crew chiefs would have to learn an new tune up put they wouldn't have to change big parts. Maybe they wouldn't need those 130 gpm fuel pumps!
Just my two cents worth.
Rex
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not a good long term objective.
As long as they insist on learning the hard way it is going to be really tough on everybody.
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I've listened to the NHRA TV forecasters for the last 4 years and watched them move the HP rating of the engines from 5 to now this year 8000 HP. (I always wondered how they do that)...With in 2 years I expect to hear 10,000HP out of their collective pie holes. Ray Alley tries to do something but I personally feel his hands are tied too. O Well!!!
Don't look for your wallet Jack...I've already got it and it's for sale on e-bay, :<)
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I was at one of the Performance Racing Industry shows several years ago when they still had them in Sacramento and was talking to one of the guys from the company that makes the onboard data logging system that all of the fuel cars run (for the life of me I cannot think of their name! sucks to get old!!!) anyway they have a torque sensor that runs on the drive shaft so I asked him what was the absolute biggest horse power number that they had ever seen. 13,000 HP!!!! now he did qualify this as the torque sensor, which samples data at some set rate, 1000 time per second or something like that, picked up the torque spike at the exact instant that the clutch welded itself solid! of course this caused a big torque spike from the inertia of the engine, flywheel and clutch was instantenously locked to the tires. The maximum "real" maximum horse power was around 9000 and that was a couple of seconds into the run with the tire hooked and the clutch nearly locked up. That was also in the days of 98%. So the 8000 hp number that gets bantered about is probably close.
Makes you wonder what Lindsey and Leggitt make on 70%.
Rex
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Race Pak is the name you are hunting for.
Fuel type and rate of consumption is used to measure power output. In a TF application, some of it goes out the pipe as an unburned liquid for cooling so it is not an exact science. If you want to increase the margin of safety by slowing them down, a smaller fuel pump would limit the power but the penalty for broken part delays would have to remain.
50% or 90% is 1 measure. How much you use efficiently is the real measure.
What ever works the best is just right.
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Going 1320 ft in 4.4 seconds is 4.26 G's (16 x 4.26 x 4.4 x 4.4 = 1319.58') . 2025# x 4.26 x 1320 = 11,368,980 ft # divided by 550 divided by 4.4 sec = 4705 average HP after big aero drag . 7000 HP at the crankshaft is believable .
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Doing the correct math can arrive at the correct answer but often the answer gets there first.
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is that american or tiawaneese horsepower? remember when an 100 watt home stereo hurt your ears? then the import stereos showed up with 300 watts you could talk louder than! 5000hp on a dyno is probably the same as 13000hp on a tiawan load cell the size of your thumb. remember those cooooks on tv are still cooooks
kr
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HP, Watts, and lots of other stuff will always be factored by the difference between buying and selling.
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Scott, you young whipper snapper, prior to the 200 MPH theoretical maximum, 160 MPH was predicted to be unachievable. Barrett can probably remember when it was "established" at 135 MPH. He can also remember when the first dirt was made.
FREUD
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Freud, you are at least 5 years older then I am, and you still have dirt in your old rolex.'
Glen
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Make the run only one mag.. They can 't run the fuel volume with one it will slow them down!!!
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Scott, you young whipper snapper, prior to the 200 MPH theoretical maximum, 160 MPH was predicted to be unachievable. Barrett can probably remember when it was "established" at 135 MPH. He can also remember when the first dirt was made.
FREUD
Breathing was said to be the first problem encountered by the Speed Racer.
I guess that is part of why they are going faster now to hurry and get it over with.
Did you ever notice that Nolan always drove with a water soaked rag in his mouth ?
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I washed my Elgin pocket watch in the ditch by the dike but never have had a premier piece like a Roll-ex.
Dolan told everyone the drag race max speed was 100 when he knew he could run 110 and be sensational.
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Now remember boys, before you start biting each other, neither one of you still have real teeth................... :wink:
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Bob speak for yourself on the teeth, I have mine and freud has fang replacements. Oh, I forgot that Freuds time piece was a wind up Timex he biught at garage sale. :twisted:
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Slow down Top Fuel? No problem!
Have you seen somebody run with the chute out? Good luck running 300 dragging the laundry!
Old! Heck I think I saw Scott Guthrie checking times with a calendar!