Aero on Drag racing cars

Please discuss here all your remarks and pose your questions about all racing series, except Formula One. Both technical and other questions about GP2, Touring cars, IRL, LMS, ...
VARIANT | one
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Re: Aero on Drag racing cars

Post by VARIANT | one » Wed Feb 22, 2017 4:36 pm

biker_ev wrote:Yeah, 3.x seconds at 300+ mph is boring as hell!

Sent from my MotoE2(4G-LTE) using Tapatalk
As a spectator, in which it's looked the same for decades now, indeed, yes it is.

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Re: Aero on Drag racing cars

Post by strad » Thu Feb 23, 2017 8:33 pm

VARIANT | one wrote:
roon wrote:If they were any longer they would begin to resemble F1 cars.
Top Fuel is pretty much a technologically stunted form of motorsport... for safety reasons. What they should do it ditch the nitromethane nonsense, mandate pump gas, and open up the rulebook on just about everything, and let them work their way back up to the current speeds through different tech. Vacuum traction would be awesome to see in drag racing, maybe six drive wheels. It's just --- boring the way it is right now.
Don't watch!!!!!
Motorsport without danger is like cooking without salt
Sir Stirling Moss

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Re: Aero on Drag racing cars

Post by strad » Thu Feb 23, 2017 8:40 pm

Brian, You didn't mention that you have to anticipate what happens when you put out a cylinder.
As it is if you lose even one it starts pushing you toward the wall. What happens when you are depending on it for downforce or traction?
The only problem I have with modern NHRA T/F is that they need to go back to 1320ft.
Motorsport without danger is like cooking without salt
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Re: Aero on Drag racing cars

Post by donskar » Fri Feb 24, 2017 2:48 am

Some scattered points for the technically more astute than me to chew on:

Top fuelers generate 10K - 11K HP (verified by a Rockwell device attached to the putput shaft of one of the best of the top fuelers.)
The supercharger requires 1K HP to spin it (!)
The ETs and MPH mentioned here are accurate and are achieved in 1,000 feet, not 1320. Strips were shortened to try to reduce speeds. Didn't work.
NHRA (Nat Hot Rod Assoc) is very safety conscious (or maybe it's just PR). Years ago, a very technically advanced drag racer named Pete Robinson ("Sneaky Pete") experimented with ground effects on his fueler. It killed him.
I dislike the current NHRA setup, which is basically a traveling circus of a small group of racers (small because of the very high co$t of racing at the top level). The NHRA would have you believe, for example, that only the 16 fastest cars in each premier group qualify. In fact, sometime LESS than 16 cars even show up -- again, too expensive.
Next week I am traveling to Bakersfield, California for the "March Meet." Every year since 1959, drag racers from around the USA travel to this meet. Not 16, but often 20-30 cars show up in each class, including some very wild ones that the NHRA will not sanction (imagine, if you can, a 10K HP hemi fuel engine in a 90-100 inch wheelbase fiberglass-bodied Model T) . Further, "nostalgia drag races," featuring retro cars, such as front-engined fuelers are growing at a very refreshing rate.

Hope this adds something to this thread, BTW, I worked as a "gopher" on a top fuel dragster back in the late 1960's. It was more fun then; a few guys with $3k or $4k could qualify at a national meet. We did.
Enzo Ferrari was a great man. But he was not a good man. -- Phil Hill

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Re: Aero on Drag racing cars

Post by donskar » Fri Feb 24, 2017 2:58 am

Apologies for going off topic in my previous post. On topic:
I hope some of you with much more aero knowledge than me will consider the aero effect of the rear tires growing several inches taller at top speed than at rest (and, of course, narrower).
Also consider that the overall aero of a top fueler is horrible, but it took several years for the aero advantage of the fully enclosed body to exceed its weight disadvantage.
Finally, off topic (mea culpa) but I hope some of you with a strong mech engineering background will consider that top fuelers (and cars in several other top classes) spin their tires throughout the 1000 feet. "Tire shake" is the bete noire of top drag racers. Ironically, it is caused by the tires spinning too much -- or too little.
Another factoid: top fuelers use two sets of injectors, one above and one below the supercharger.
Enzo Ferrari was a great man. But he was not a good man. -- Phil Hill

hpras
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Re: Aero on Drag racing cars

Post by hpras » Fri Feb 24, 2017 6:30 am

I'll just leave this here....


VARIANT | one
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Re: Aero on Drag racing cars

Post by VARIANT | one » Fri Feb 24, 2017 2:49 pm

strad wrote:Don't watch!!!!!
I don't. I come by it every five years or so, give-or-take. Squint a little. Shrug. "Same sh1t" and change the channel.

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Re: Aero on Drag racing cars

Post by strad » Mon Feb 27, 2017 2:59 am

??? I saw no backfire.
What I saw was how few power strokes actually take place. They may snap to 8000 rpm but how many revolutions take place in a little over three seconds. :wink:
VARIANT , I take it you didn't watch Phoenix. If you do not watch, how can you comment with such a strong opinion?
Motorsport without danger is like cooking without salt
Sir Stirling Moss

roon
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Re: Aero on Drag racing cars

Post by roon » Mon Feb 27, 2017 3:11 am

About 400.

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Re: Aero on Drag racing cars

Post by MadMatt » Wed Mar 01, 2017 10:35 am

strad wrote:Brian, You didn't mention that you have to anticipate what happens when you put out a cylinder.
As it is if you lose even one it starts pushing you toward the wall. What happens when you are depending on it for downforce or traction?
The only problem I have with modern NHRA T/F is that they need to go back to 1320ft.
Agree, top fuel should use the 1/4 distance. Nowadays it is too similar in performance with funny cars, which is a shame.

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Re: Aero on Drag racing cars

Post by strad » Thu Mar 02, 2017 6:38 am

rear wing down force?
6000lbs at speed.
Grabbed this from Phoenix first round.
http://www.stradsplace.com/public_html/ ... nforce.mp4
Motorsport without danger is like cooking without salt
Sir Stirling Moss

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Re: Aero on Drag racing cars

Post by gruntguru » Fri Aug 11, 2017 5:14 am

Brian Coat wrote:
Tue Feb 21, 2017 6:54 pm
Exhaust thrust: This is a very live topic in fuel racing at the moment, the key is to get the right balance between thrust off the line and downforce, which is influence by the header 'lay down' angle.
I believe the thrust is of the order of 1000 lbs. Pointing straight back that gives the car an extra 1000 lbs of accelerating thrust. Pointing straight up (and assuming unlimited power and a coefficient of friction of 3) gives the car an extra 3000 lbs of thrust. Somewhere in between (close to vertical) is optimum but this changes further down the track as the car becomes less traction limited.
je suis charlie

MadMatt
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Re: Aero on Drag racing cars

Post by MadMatt » Fri Aug 11, 2017 9:09 am

How did you come up with 1000lbs?



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