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Where does NASCAR Radio get them?
Nascar NASCAR and other professional stock car racing (rec.autos.sport.nascar)
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#21
 
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Re: Where does NASCAR Radio get them? -
11-06-2009
, 12:08 PM
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Interesting that Cup cars (then Grand National) were running nearly 200 without spoilers in the early 70's. |
draggy rectangular boxes tend to generate much less aerodynamic
force (in any direction) than aerodynamically clean shapes.
It's interesting that that you pick 1970, too, since that was the
year of the winged Mopars, and the time when 2" decklid spoilers
and under bumper "chin" spoilers first started to appear.
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I find it hard to believe that a car body could generate nearly 2000 lbs. of lift at the rear. |
800000lbs of lift at 180mph too. Yet that also happens
John
#22
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"armpit" <armarmpitpit (AT) yahoo (DOT) com> wrote in news:ZJGdnWfIYc8Bs2nXnZ2dnUVZ_oudnZ2d (AT) giganews (DOT) com: Interesting that Cup cars (then Grand National) were running nearly 200 without spoilers in the early 70's. Not really. Those cars had a very different body shape, and big draggy rectangular boxes tend to generate much less aerodynamic force (in any direction) than aerodynamically clean shapes. It's interesting that that you pick 1970, too, since that was the year of the winged Mopars, and the time when 2" decklid spoilers and under bumper "chin" spoilers first started to appear. I find it hard to believe that a car body could generate nearly 2000 lbs. of lift at the rear. I'm guessing you have problems with the idea of a 747 generating 800000lbs of lift at 180mph too. Yet that also happens |
I'd just like to see some data on it. 2000 lbs. net lift on surfaces that
weren't designed for it just seems like a lot to me.
#23
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I'd just like to see some data on it. 2000 lbs. net lift on surfaces that weren't designed for it just seems like a lot to me. |
what car model he used (or if his results are a composite of more
than one) but he gives:
60 mph - 165 lbs lift
90 mph - 372 lbs
120 mph - 662 lbs
150 mph - 1035 lbs
Note that with a car going forward the lift is primarily acting
on the after portion of the car - lift at the very front tends
to be cancelled out by net downforce on the hood and windshield.
(note also that 2000lbs of lift on surfaces not designed for it
would probably break something - but the cars in question can't
go fast enough to generate that lift, so it doesn't matter).
I will see if I can scare up some numbers specific to a Camry
or Taurus or similar.
John
#24
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Apparently, a number of callers (okay, only two that I know of, but I only listen about 45 minutes a day) have come up with the solution to the "Talladega problem": Instead of restrictor plates, make them race V6s. (Say - what DID happen when they tried this, apparently with the early Busch/Nationwide cars?) -- Don A few years ago when they used V6's in Busch cars, they were |
speed is to use a RPM limiter or reduce the engine size to about 190
Cubic inches.
#25
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"armpit" <armarmpitpit (AT) yahoo (DOT) com> wrote in news:QMCdnRBuaqKB_mnXnZ2dnUVZ_r6dnZ2d (AT) giganews (DOT) com: I'd just like to see some data on it. 2000 lbs. net lift on surfaces that weren't designed for it just seems like a lot to me. Try "The Isaac Newton School of Driving" by Parker. I'm not sure what car model he used (or if his results are a composite of more than one) but he gives: 60 mph - 165 lbs lift 90 mph - 372 lbs 120 mph - 662 lbs 150 mph - 1035 lbs Note that with a car going forward the lift is primarily acting on the after portion of the car - lift at the very front tends to be cancelled out by net downforce on the hood and windshield. (note also that 2000lbs of lift on surfaces not designed for it would probably break something - but the cars in question can't go fast enough to generate that lift, so it doesn't matter). I will see if I can scare up some numbers specific to a Camry or Taurus or similar. |
at Daytona or "Dega from the pre-roof-flap era to know that the cars do
indeed produce enough lift to leave the ground. Once they turn sideways and
lose the downforce from the spoiler, up they'd go.
I think it would be really interesting to put a Cup car in a wind tunnel and
rotate it to various angles and see what kind of downforce/lift was
generated, and then try some different methods/devices to see how those
numbers changed.
#26
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I think it would be really interesting to put a Cup car in a wind tunnel and rotate it to various angles and see what kind of downforce/lift was generated, and then try some different methods/devices to see how those numbers changed. |
The problem with that is you need a really big wind tunnel to
do it in, wide enough that you can put the car crosswise and
still have enough space at either side that the walls of the
tunnel don't affect the flow. I think the only tunnel that's
big enough to do that (that's available to Cup teams) is the
Lockheed tunnel, which is expensive, inconvenient, and not well
instrumented for race car testing.
Teams do do testing at small angles of yaw (which fit in a
"normal" wind tunnel), but that's more to optimize downforce
& minimize drag in the corners than to address the issue of
preventing lift in a spin.
John
#27
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"armpit" <armarmpitpit (AT) yahoo (DOT) com> wrote in news:ZZWdnX6FhpV_82jXnZ2dnUVZ_uqdnZ2d (AT) giganews (DOT) com: I think it would be really interesting to put a Cup car in a wind tunnel and rotate it to various angles and see what kind of downforce/lift was generated, and then try some different methods/devices to see how those numbers changed. (you think like I do) The problem with that is you need a really big wind tunnel to do it in, wide enough that you can put the car crosswise and still have enough space at either side that the walls of the tunnel don't affect the flow. I think the only tunnel that's big enough to do that (that's available to Cup teams) is the Lockheed tunnel, which is expensive, inconvenient, and not well instrumented for race car testing. Teams do do testing at small angles of yaw (which fit in a "normal" wind tunnel), but that's more to optimize downforce & minimize drag in the corners than to address the issue of preventing lift in a spin. John |
#28
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I think it would be really interesting to put a Cup car in a wind tunnel and rotate it to various angles and see what kind of downforce/lift was generated, and then try some different methods/devices to see how those numbers changed. |
I seem to remember seeing footage on TV during a race or
one of the racing news programs.
#29
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John McCoy wrote: The problem with that is you need a really big wind tunnel to do it in, wide enough that you can put the car crosswise and still have enough space at either side that the walls of the tunnel don't affect the flow. I think the only tunnel that's big enough to do that (that's available to Cup teams) is the Lockheed tunnel, which is expensive, inconvenient, and not well instrumented for race car testing. Teams do do testing at small angles of yaw (which fit in a "normal" wind tunnel), but that's more to optimize downforce & minimize drag in the corners than to address the issue of preventing lift in a spin. Then how did they test the roof flaps? |
That was rather imprecise, but it told them they were on the
right track.
I would assume the final testing was done in the Lockheed tunnel.
John
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