Downforce throughout the years?

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Potto
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Joined: 31 May 2019, 03:03

Downforce throughout the years?

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Does anyone have knowledge of the downforce levels throughout the years? Especially in the 1970's and 1980's. How the downforce grew throughout the 1970's, and I'm very interested how the ground-effect cars of the late 1970's and very early 1980's compare to later 1980's cars, 1990's cars, or just newer cars in general. I've heard that the ground-effect cars and particularly the Brabham BT46B (Which proved that it could dominate compared to the already dominant Lotus 79) had some of the highest downforce levels in F1 until the early 2010's. Actual track times are probably difficult to compare since they were restricted by the lower horsepower compared to the massive power engines of the 1980's, and other factors.

Here's a quote I found interesting on Wikipedia:

''Brabham's lead driver, Niki Lauda, realised he had to adjust his driving style, mostly for cornering. He found that if he accelerated around corners, the car would "stick" to the road as if it were on rails. This had the side effect of exposing the driver to very high lateral acceleration, which would become a major problem in the ground effect era. In his autobiography, Lauda described the car as being unpleasant to drive due to the lateral loads and reliance on aerodynamics over driver skill. He realised early on that the rate of ground effect development meant that in the future, every driver would be exposed to such g-loading while behind the wheel of such a car, and the physical effort needed to drive the cars would leave the drivers exhausted by the end of the races.''

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jjn9128
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Joined: 02 May 2017, 23:53

Re: Downforce throughout the years?

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It doesn't have any numbers, but you may find this interesting. It's some CFD studies of basic geometries through the ages.
Image

The early ground effect cars did not produce that much downforce by modern standards, even with skirts and tunnels. You'll find it difficult to find numbers for old cars but this from Katz would be relatively representative. These days downforce exceeds Cl = 3.6 and lateral load in excess of 5g is possible.
Image
Image
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

Potto
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Joined: 31 May 2019, 03:03

Re: Downforce throughout the years?

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So if my tiny brain understands this correctly that means the 1980's saw the biggest boost in downforce? That surprises me, I always assumed the 1970's saw the biggest change, and that late 1970's and early 1980's cars had more downforce potential than the later years in the 1980's. The skirts should allow the car to have more constant downforce since it blocks out air?

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jjn9128
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Joined: 02 May 2017, 23:53

Re: Downforce throughout the years?

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Potto wrote:
01 Jun 2019, 19:38
So if my tiny brain understands this correctly that means the 1980's saw the biggest boost in downforce? That surprises me, I always assumed the 1970's saw the biggest change, and that late 1970's and early 1980's cars had more downforce potential than the later years in the 1980's. The skirts should allow the car to have more constant downforce since it blocks out air?
The first wings in the 1960's were essentially symmetrical aerofoils at incidence. The high wings were then banned in '69 and the aerofoils started to develop more camber, but through most of the 70's the bottom of the cars was flat and all the work was being done by the wings, at points in the 70's the front aero was more like a splitter. Until the Lotus 79 and Brabham BT46 appeared in '78 which were the first cars to make use of underbody downforce (the fan car obviously in an active way). But the skirts were really an 80's development up to '84 when the floor was mandated as flat between the axles. That's were you see the sharp jump on that graph, but by then they'd learned the benefit of the diffuser which is still a region of intense development.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

JJR
JJR
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Joined: 12 Jul 2013, 20:02

Re: Downforce throughout the years?

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Hi Potto,

I have some numbers from Peter Wright,. He made plot of downforce levels from 1965 to 2000 :

1968: 1000lbs@150mph - high wings
1976: 800lbs@150mph
1978: 2000lbs@150mph
1980: 3000lbs@150mph
1981: 2300lbs@150mph - skirts banned
1982: 2500lbs@150mph
1983: 2000lbs@150mph - flat bottom
1986: 2500lbs@150mph
1992: 3500lbs@150mph - peak downforce
1995: 1800lbs@150mph - stepped floor, smaller wings
2000: 2600lbs@150mph

For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne) :

1989: 2200lbs@150mph
1990: 2300lbs@150mph
1991: 2450lbs@150mph
1992: 2750lbs@150mph
1993: 2450lbs@150mph
1994: 2350lbs@150mph
1995: 2050lbs@150mph
1996: 2350lbs@150mph
1997: 2500lbs@150mph

timbo
111
Joined: 22 Oct 2007, 10:14

Re: Downforce throughout the years?

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JJR wrote:
17 Jun 2019, 09:24
1992: 2750lbs@150mph
1993: 2450lbs@150mph
Why such a change between 1992 and 1993? I thought the aero regulations were pretty much the same, no?

JJR
JJR
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Joined: 12 Jul 2013, 20:02

Re: Downforce throughout the years?

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timbo wrote:
17 Jun 2019, 13:19
JJR wrote:
17 Jun 2019, 09:24
1992: 2750lbs@150mph
1993: 2450lbs@150mph
Why such a change between 1992 and 1993? I thought the aero regulations were pretty much the same, no?
In 1993 aero rules have been changed, smaller rear wing (950mm above ground) and mainly overall width from 2150mm to 2000mm , front wing overhang from 1000 to 900mm.
And yeas it varies from team to team. So it could be different for top runners like williams.

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SiLo
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Joined: 25 Jul 2010, 19:09

Re: Downforce throughout the years?

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JJR wrote:
17 Jun 2019, 09:24
Hi Potto,

I have some numbers from Peter Wright,. He made plot of downforce levels from 1965 to 2000 :

1968: 1000lbs@150mph - high wings
1976: 800lbs@150mph
1978: 2000lbs@150mph
1980: 3000lbs@150mph
1981: 2300lbs@150mph - skirts banned
1982: 2500lbs@150mph
1983: 2000lbs@150mph - flat bottom
1986: 2500lbs@150mph
1992: 3500lbs@150mph - peak downforce
1995: 1800lbs@150mph - stepped floor, smaller wings
2000: 2600lbs@150mph

For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne) :

1989: 2200lbs@150mph
1990: 2300lbs@150mph
1991: 2450lbs@150mph
1992: 2750lbs@150mph
1993: 2450lbs@150mph
1994: 2350lbs@150mph
1995: 2050lbs@150mph
1996: 2350lbs@150mph
1997: 2500lbs@150mph
What was special about 1992 to have such high numbers?
Felipe Baby!

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jjn9128
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Joined: 02 May 2017, 23:53

Re: Downforce throughout the years?

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SiLo wrote:
17 Jun 2019, 14:10
JJR wrote:
17 Jun 2019, 09:24
Hi Potto,

I have some numbers from Peter Wright,. He made plot of downforce levels from 1965 to 2000 :

1968: 1000lbs@150mph - high wings
1976: 800lbs@150mph
1978: 2000lbs@150mph
1980: 3000lbs@150mph
1981: 2300lbs@150mph - skirts banned
1982: 2500lbs@150mph
1983: 2000lbs@150mph - flat bottom
1986: 2500lbs@150mph
1992: 3500lbs@150mph - peak downforce
1995: 1800lbs@150mph - stepped floor, smaller wings
2000: 2600lbs@150mph

For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne) :

1989: 2200lbs@150mph
1990: 2300lbs@150mph
1991: 2450lbs@150mph
1992: 2750lbs@150mph
1993: 2450lbs@150mph
1994: 2350lbs@150mph
1995: 2050lbs@150mph
1996: 2350lbs@150mph
1997: 2500lbs@150mph
What was special about 1992 to have such high numbers?
Active suspension.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

OO7
OO7
171
Joined: 06 Apr 2010, 17:49

Re: Downforce throughout the years?

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JJR wrote:
17 Jun 2019, 13:56
timbo wrote:
17 Jun 2019, 13:19
JJR wrote:
17 Jun 2019, 09:24
1992: 2750lbs@150mph
1993: 2450lbs@150mph
Why such a change between 1992 and 1993? I thought the aero regulations were pretty much the same, no?
In 1993 aero rules have been changed, smaller rear wing (950mm above ground) and mainly overall width from 2150mm to 2000mm , front wing overhang from 1000 to 900mm.
And yeas it varies from team to team. So it could be different for top runners like williams.
Also in 1992, bodywork between the rearmost part of the front wheel and the front wheel centreline could rest on the reference plane (front wing end-plates that sometimes came into contact with the ground, to control tyre squirt), while bodywork ahead of the front wheel centreline was limited to a minimum height of 25mm above the reference plane. In 1993, bodywork ahead of the rearmost part of the front wheel, was limited to a minimum height of 40mm above the reference plane.

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DiogoBrand
73
Joined: 14 May 2015, 19:02
Location: Brazil

Re: Downforce throughout the years?

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jjn9128, I'm very enthusiastic about aerodynamics, wether it's open wheelers, race cars in general or even road cars, but I understand far less about the subject than I would like to, even though I don't work with anything related to that area nor do I have any plans to do so.

Where would you recommend I look for to learn more about car aerodynamics in general?

Maritimer
19
Joined: 06 Sep 2017, 21:45
Location: Canada

Re: Downforce throughout the years?

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jjn9128 wrote:
17 Jun 2019, 15:16
SiLo wrote:
17 Jun 2019, 14:10
JJR wrote:
17 Jun 2019, 09:24
Hi Potto,

I have some numbers from Peter Wright,. He made plot of downforce levels from 1965 to 2000 :

1968: 1000lbs@150mph - high wings
1976: 800lbs@150mph
1978: 2000lbs@150mph
1980: 3000lbs@150mph
1981: 2300lbs@150mph - skirts banned
1982: 2500lbs@150mph
1983: 2000lbs@150mph - flat bottom
1986: 2500lbs@150mph
1992: 3500lbs@150mph - peak downforce
1995: 1800lbs@150mph - stepped floor, smaller wings
2000: 2600lbs@150mph

For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne) :

1989: 2200lbs@150mph
1990: 2300lbs@150mph
1991: 2450lbs@150mph
1992: 2750lbs@150mph
1993: 2450lbs@150mph
1994: 2350lbs@150mph
1995: 2050lbs@150mph
1996: 2350lbs@150mph
1997: 2500lbs@150mph
What was special about 1992 to have such high numbers?
Active suspension.
Active suspension was around in 93 as well, they had lower bodywork and bigger wings in 92.

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jjn9128
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Joined: 02 May 2017, 23:53

Re: Downforce throughout the years?

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DiogoBrand wrote:
17 Jun 2019, 23:28
jjn9128, I'm very enthusiastic about aerodynamics, wether it's open wheelers, race cars in general or even road cars, but I understand far less about the subject than I would like to, even though I don't work with anything related to that area nor do I have any plans to do so.

Where would you recommend I look for to learn more about car aerodynamics in general?
Joe Katz books are a pretty good balance of not being too over-technical but imparting loads of detail. Willem Toet's articles on LinkedIn and racecar tech magazine are always brilliant for f1 aero. I'd avoid Motorsport or autosport as their "technical writer" is awful. That said piola's drawings are excellent. "Competition aerodynamics" by Simon McBeath (I think that's his name) is usually used by undergrads starting out, I wouldn't say it's that high level though.

You can also look for papers on different subjects on google scholar. Not many are free but there is a growing pressure for government funded research to be open access.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

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jjn9128
769
Joined: 02 May 2017, 23:53

Re: Downforce throughout the years?

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JJR wrote:
17 Jun 2019, 09:24
Hi Potto,

I have some numbers from Peter Wright,. He made plot of downforce levels from 1965 to 2000 :

1968: 1000lbs@150mph - high wings
1976: 800lbs@150mph
1978: 2000lbs@150mph
1980: 3000lbs@150mph
1981: 2300lbs@150mph - skirts banned
1982: 2500lbs@150mph
1983: 2000lbs@150mph - flat bottom
1986: 2500lbs@150mph
1992: 3500lbs@150mph - peak downforce
1995: 1800lbs@150mph - stepped floor, smaller wings
2000: 2600lbs@150mph

For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne) :

1989: 2200lbs@150mph
1990: 2300lbs@150mph
1991: 2450lbs@150mph
1992: 2750lbs@150mph
1993: 2450lbs@150mph
1994: 2350lbs@150mph
1995: 2050lbs@150mph
1996: 2350lbs@150mph
1997: 2500lbs@150mph
What are those in coefficients? Pounds are an unused measure outside the States.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

JJR
JJR
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Joined: 12 Jul 2013, 20:02

Re: Downforce throughout the years?

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For Tyrrell F1 cars (SAE paper from Ben Agathangelou and Mike Gascoyne), frontal area = 1,47m2, all values are for ballance conditions of 36% on the front

1989: CL = 2.47, L/D = 2.63
1990: CL = 2.58, L/D = 2.85
1991: CL = 2.72, L/D = 2.97
1992: CL = 3.04, L/D = 3.29
1993: CL = 2.70, L/D = 2.95
1994: CL = 2.63, L/D = 2.62
1995: CL = 2.29, L/D = 2.49
1996: CL = 2.62, L/D = 2.44
1997: CL = 2.75, L/D = 2.42