Aero on Drag racing cars

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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!!!!!
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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.
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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

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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....


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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?
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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
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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

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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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Re: Aero on Drag racing cars

Post by e36jon » Thu Oct 04, 2018 10:33 pm

Greetings all

Apologies for reviving the long-dead-thread.

I'm an avid fan of Top Fuel racing and have been thinking about ways to improve the cars. Like the thread starter I went and found a rules package and most of what I had in mind survived. That said, as others have mentioned, the NHRA can and does swing the ban-hammer if they think something is a safety risk, or if they feel it will start a spending war.

So, just to put it all out there (And give up my one chance at becoming a zillionaire!):
  • "lenticular disc" front wheels: These are sorta like the classic 'Moon' discs, but actually stick out proud of the tire, and are curved. These have rocked the cycling world. Also fixing something aero this far up the food chain has to have benefits down the line. See World Superbike experiment, below.
Image
  • Reposition the main fuel feed to the injector hat, and move the throttle linkage inboard as well: All of that may not matter from an aero POV given all of the other mayhem happening locally, but it looks like a ton of junk in the airflow at 300 mph...
  • Try a 'swans neck' mounting of the rear wing: Sounds like they don't care about structure in terms of size / location, only where the wing ends up. Gotta think they could pick up some efficiency here. Again, may not matter given the stated angle of attack...
  • And lastly, a power adder, because 11,000 hp isn't enough: I've been looking at the injector hats / throttle bodies and they don't seem to have much of a radius to them (Around the throttle bodies.). You look at intakes anywhere else and there's a monster radius, often going around past horizontal on the outside edge. You all get it. Seems like they could improve airflow enough to take some RPM's out of the blower, or just make more power. I'm probably just missing something here...
Last one is for the Funny Car gang:
  • Everyone is running the hinged tail-ligt flaps to get high pressure air out fromn under the body. The flaps are regulated by the NHRA, but the lead-in inside the body is never mentioned. Like with the injector, above, getting some radiused 3D geometry on the intake side of those opening should increase airflow by 30% or more.
FWIW, even though I know everything is tightly controlled, I really enjoy the show. My brain still has a hard time comprehending what these fuel cars can do. Last time I went I ended up talking with Greg Anderson about his cars unique front suspension without even realizing who he was (I didn't follow Pro Stock at the time.)... I can't see that ever happening at an F1 race!

Cheers,

Jon

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Re: Aero on Drag racing cars

Post by strad » Fri Oct 05, 2018 12:25 am

Some interesting things to think about. I think, just my opinion, that mostly they think they have more than enough power and that the problem is trying to control what they have.
I don't know anything about those wheels but if they work it seems like it would be free MPH.
Motorsport without danger is like cooking without salt
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