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Technical paper on development of Eagle 997 Champcar


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#1 MattPete

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Posted 02 May 2022 - 00:31

I was searching for something earlier today, and one of my hits was this technical paper on the development of the AAR 997 and 998 CART Champcars. I was hoping that there was more discussion about the design of the undertray, but I found it interesting that they had to modify the rolling floor of their wind tunnel so that the undertray didn't suck up the belt of the moving floor.  I was also surprised to find that Eagle was a Reynard chasis with different bodywork.

 

 

https://www.research...7-Champ-Car.pdf



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#2 Greg Locock

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Posted 02 May 2022 - 03:34

In Newey's book he described one disappointing car that didn't work as expected. Turns out the floor in the windtunnel would bend during a test and so gave bad results. 



#3 Magoo

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Posted 08 May 2022 - 23:24

Back when, there was a certain wind tunnel in the UK frequented by F1 constructors that, by leaving a cellar door open or shut, could produce two sets of numbers: one suitable for sponsors and media, the other for team engineering. 


Edited by Magoo, 08 May 2022 - 23:24.


#4 Greg Locock

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Posted 09 May 2022 - 06:04

Back in the day Germany's DIN would send inspectors over to witness the power curve test for an engine. Engineers were encourage to stand in the hallway against the exhaust vent (room ventilation) from the dyno room.


Edited by Greg Locock, 09 May 2022 - 06:20.


#5 Fat Boy

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Posted 09 May 2022 - 22:21

Back when, there was a certain wind tunnel in the UK frequented by F1 constructors that, by leaving a cellar door open or shut, could produce two sets of numbers: one suitable for sponsors and media, the other for team engineering. 

 

My God, are you making the accusation that someone might have their thumb on the scale when making a scientific measurement which happens to correspond with their personal compensation? How could one ever even contemplate such an injustice?



#6 desmo

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Posted 10 May 2022 - 13:57

I didn't even know F1 made public claims about aero data. Wouldn't it be simpler just to lie? Production cars would be another story.



#7 Ross Stonefeld

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Posted 10 May 2022 - 16:43

Exactly. Despite the media's love affair with the tech term du jour, I doubt they could tell you which end of the wind tunnel is which. 



#8 Fat Boy

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Posted 10 May 2022 - 16:48

I didn't even know F1 made public claims about aero data. Wouldn't it be simpler just to lie? Production cars would be another story.

...And refuse Bill the opportunity of yet another of his obviously bull**** stories? That's a bit unsporting, don't you think?



#9 Greg Locock

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Posted 10 May 2022 - 18:56

A consortium of car manufacturers did a round robin test, taking a variety of cars to all their different windtunnels (two of the American companies participated). Interesting findings were that some tunnels read low, and different procedures used by different manufacturers in the same tunnel (in Germany) led to different estimates of Cd and Cl. One of the interesting things was that effectiveness of the front air dam (as a mod) varied widely depending on whether the floor was moving or they used a BL slot ahead of the car, or some other means of dealing with floor interactions. The worst case Cd I have seen was for a truck 0.37 claimed, vs 0.47 measured, and the worst I've seen for a car is 0.27 claimed, 0.32 measured. Some of the differences in test procedure are reasonable in context but increase the difficulty of making comparisons - for example blanking the grill, or closing the interior vents. Others such as removing windscreen wipers and taping panel gaps and fairing the exhaust - not so much.

 

Sadly that report is not published publicly.



#10 Magoo

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Posted 10 May 2022 - 18:58

I don't believe the Eagle was built on a Reynard chassis, and I don't think the paper actually says that. 



#11 Magoo

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Posted 10 May 2022 - 19:51

...And refuse Bill the opportunity of yet another of his obviously bull**** stories? That's a bit unsporting, don't you think?

 

Oh, it's true. This tunnel and its special property was well-known in Champ Car circles when there were still multiple chassis suppliers. 



#12 Magoo

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Posted 10 May 2022 - 19:57

My God, are you making the accusation that someone might have their thumb on the scale when making a scientific measurement which happens to correspond with their personal compensation? How could one ever even contemplate such an injustice?

 

While that certainly happens at times, it is absurd in the extreme to claim therefore that science doesn't work or is not reliable. 

 

Science is the closest thing humanity has to objective truth.

 

I have never encountered a critic of science with one-thousandth the credibility of science itself. But go ahead, keep following the televangelists and AM talk radio hosts. 



#13 Fat Boy

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Posted 10 May 2022 - 21:12

While that certainly happens at times, it is absurd in the extreme to claim therefore that science doesn't work or is not reliable. 

 

Science is the closest thing humanity has to objective truth.

 

I have never encountered a critic of science with one-thousandth the credibility of science itself. But go ahead, keep following the televangelists and AM talk radio hosts. 

 

 

You can let go of your pearls, Dear, no one is criticizing "Science". I am criticizing its misuse. Your anecdote, while clearly a fabrication, does exactly the same thing.

 

One of the fundamental tenets of the scientific method is to never stop questioning one's observations. Since you seem to already know all the answers, I can see how this would run counter to your preferences.

And your parting shot was just pure foolishness. Honestly, Bill, is that the best you can do? Because it was F-ing pathetic. To Beckett with you... Try again. Fail again. Fail better.

 



#14 Magoo

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Posted 10 May 2022 - 22:15

You can let go of your pearls, Dear, no one is criticizing "Science". I am criticizing its misuse. Your anecdote, while clearly a fabrication, does exactly the same thing.

 

 

 

 

Imperial College. Ask around. 



#15 Magoo

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Posted 10 May 2022 - 22:34

Exactly. Despite the media's love affair with the tech term du jour, I doubt they could tell you which end of the wind tunnel is which. 

 

In the early '80s when high downforce became news, the numbers were all over the race magazines. 



#16 Fat Boy

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Posted 10 May 2022 - 22:36

IDGAF, because I've actually done a bunch of tunnel testing. No 'sponsors' or media come to watch. There's no one to impress with your parlor trick. It's boring as crap. You change a part, sit for a while, change a part, etc. It doesn't surprise me that leaving a door open or closed elsewhere in the building might influence readings, but your convoluted story is meaningless. If anyone on the team side of things wanted to show a 'good' number, they'd simply nudge the ambient correction factor and be done with it.

Here's the problem with your 'stories.' They're not yours; so they lose a bit in the re-telling. If you wanted to share your experiences writing 350 articles about how to make 350 horsepower from 350 cubic inches; I bet you could tell that story with razor sharp clarity. The problem is, no one really cares about that story, so you're stuck telling the ones told to you.



#17 Magoo

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Posted 10 May 2022 - 23:11

IDGAF, because I've actually done a bunch of tunnel testing. No 'sponsors' or media come to watch. There's no one to impress with your parlor trick. It's boring as crap. You change a part, sit for a while, change a part, etc. It doesn't surprise me that leaving a door open or closed elsewhere in the building might influence readings, but your convoluted story is meaningless. If anyone on the team side of things wanted to show a 'good' number, they'd simply nudge the ambient correction factor and be done with it.

Here's the problem with your 'stories.' They're not yours; so they lose a bit in the re-telling. If you wanted to share your experiences writing 350 articles about how to make 350 horsepower from 350 cubic inches; I bet you could tell that story with razor sharp clarity. The problem is, no one really cares about that story, so you're stuck telling the ones told to you.

 

Blah blah blah blah.

 

Imperial College. Ask around. 



#18 Fat Boy

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Posted 10 May 2022 - 23:47

LEARN TO REBUILD YOUR CARTER AFB, page 47



#19 Magoo

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Posted 11 May 2022 - 00:50

LEARN TO REBUILD YOUR CARTER AFB, page 47

 

Ever been in the Imperial College wind tunnels in London? 


Edited by Magoo, 11 May 2022 - 01:15.


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#20 Fat Boy

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Posted 11 May 2022 - 01:16

No, nor do I care about your story concerning it.



#21 desmo

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Posted 11 May 2022 - 02:11

Imperial College

That was what I'd assumed anyway.



#22 Magoo

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Posted 11 May 2022 - 04:41

IDGAF, because I've actually done a bunch of tunnel testing. No 'sponsors' or media come to watch. 

 

That's weird. I've been party at wind tunnel sessions many times where media and sponsors etc were invited to attend.

 

And conversely, I've also been invited to attend many times as a member of the media. 

 

One media visit that comes to mind here was at Imperial College for the opening of the 5x10 tunnel aka Honda tunnel in the 1980s. 

 

More recently and closer to home, the two GM tunnels in Warren and the Ford tunnel in Allen Park are commonly used for media demos. 



#23 Magoo

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Posted 11 May 2022 - 05:11

That was what I'd assumed anyway.

 

It's a well-known story. It's bizarre to be told I made it up. 


Edited by Magoo, 11 May 2022 - 06:40.


#24 Catalina Park

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Posted 11 May 2022 - 10:46

The other flaw at the Imperial College was that the tunnel was located under a lecture hall and the strut that supported the models would move according the the capacity of the hall upstairs. It would play havoc with the ride heights.



#25 Fat Boy

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Posted 11 May 2022 - 17:58

That's weird. I've been party at wind tunnel sessions many times where media and sponsors etc were invited to attend.

 

And conversely, I've also been invited to attend many times as a member of the media. 

 

One media visit that comes to mind here was at Imperial College for the opening of the 5x10 tunnel aka Honda tunnel in the 1980s. 

 

More recently and closer to home, the two GM tunnels in Warren and the Ford tunnel in Allen Park are commonly used for media demos. 

 

It doesn't surprise me that you went to tunnels during media parties. We've all been to those types of wine & cheese deals at unconventional venues. Is this what you're presenting as some sort of 'proof' of your ridiculous Rube Goldberg "Let's trick the sponsors and media" scenario? For real? Well, I stand corrected. The fact that there are public opportunities to visit wind tunnels completely validates the story. I don't know how I ever doubted.

 

Most of your stories have massive holes in them. I've just ignored the inconsistencies for the last 15 years to be nice.

 

When I've gone to tunnels, it's with the operator and a couple other members of the team. There's never been any wine, cheese, media, sponsors or black-tie gala's. Something tells me our visits have had entirely different goals.



#26 Fat Boy

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Posted 11 May 2022 - 18:13

On the actual topic of the Eagle, I had a little insight to it at the time, but I wasn't involved. They really felt as if they were stronger aerodynamically than the Reynard, which was what they were running previously. I'm not sure if the Eagle 997 was a Reynard tub or whether they produced it in-house. Regardless, if their own, it was very similar to a Reynard tub. The advantage Lola eventually found was not the very high downforce numbers of the Reynard, but consistently good numbers over a much wider ride height window. They reduced their ultimate potential, but they did so by making the effective window of operation much wider. It was much easier to get a 'good' setup on a Lola than a Reynard, especially on street circuits, but, at places which everyone runs low and stiff (Laguna, Mid-Ohio, etc), the Reynards were always very competitive.

AAR's real problem was Goodyear tires. Trying to race against Firestone at that point was an exercise in futility.



#27 desmo

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Posted 11 May 2022 - 18:51

I'm a little torn on spec tires in high-level racing, but they are probably for the best.



#28 Fat Boy

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Posted 11 May 2022 - 20:59

I'm a little torn on spec tires in high-level racing, but they are probably for the best.

It's a mixed bag. When you have multiple companies, there are a lot of free tires, which is nice. The problem is, if you're not on the preferred tire; you're in real trouble. I've had it both ways. If you're on better tires than your competition, it's like shooting ducks in a barrel. If you're on the lesser tire, then good bloody luck. You'll need it.

If I can't have better tires than everyone else (after all, who doesn't want that?), then I like knowing that this particular variable is not a concern.



#29 Magoo

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Posted 11 May 2022 - 23:54

It doesn't surprise me that you went to tunnels during media parties. We've all been to those types of wine & cheese deals at unconventional venues. Is this what you're presenting as some sort of 'proof' of your ridiculous Rube Goldberg "Let's trick the sponsors and media" scenario? For real? Well, I stand corrected. The fact that there are public opportunities to visit wind tunnels completely validates the story. I don't know how I ever doubted.

 

Most of your stories have massive holes in them. I've just ignored the inconsistencies for the last 15 years to be nice.

 

When I've gone to tunnels, it's with the operator and a couple other members of the team. There's never been any wine, cheese, media, sponsors or black-tie gala's. Something tells me our visits have had entirely different goals.

 

 

I've spent most of my time in wind tunnels working. Honestly, I don't know where you gathered up your assumptions. 

 

You remind me of a favorite aunt. There were a great number of subjects she knew absolutely nothing about, but she refused to allow that to restrict her opinions in any way. 



#30 Magoo

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Posted 12 May 2022 - 06:25

Here's another interesting paper on wind tunnels and aero, a doctoral thesis. 

 

 

Monoposto racecar wheel aerodynamics: investigation of near-wake structure and support-sting interference

 

 

https://dspace.lib.c...andle/1826/2058



#31 Magoo

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Posted 12 May 2022 - 08:25

Back in the day Germany's DIN would send inspectors over to witness the power curve test for an engine. Engineers were encourage to stand in the hallway against the exhaust vent (room ventilation) from the dyno room.

 

 

Yes, there are nearly endless ways to manipulate dyno results. Often as anything, the dyno operators are inadvertently tricking themselves. 



#32 Ross Stonefeld

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Posted 12 May 2022 - 15:06

AAR's real problem was Goodyear tires. Trying to race against Firestone at that point was an exercise in futility.

 

I think we really missed out seeing the last Eagle run on Goodyears and the not-good-yet Toyota, and the final Penske on Goodyears and an interesting-but-complicated Mercedes. A Penske-Honda-Firestone in 2000 would have been fun. 

 

Your Lola/Reynard comparo, what years roughly was that? Lola was good, or at least popular through the mid 90s but then fell out of favor but then people started switching back again. Hogan/Castroneves had some decent runs(I think on ovals) in 99, Ganassi famously switched in 2000 and anecdotes from the team were that it was a better car than Reynard. Newman-Haas went back to Lola after the Swift foray and turned it into an absolute missile, and within a few years only the cheapo teams were running Reynards  :lol:

 

It's funny how quickly things could turn in that series. If you'd said 98/99ish that in a few seasons a Lola-Toyota would be hard to keep up with, people would be giving you the  :confused:  and  :smoking:  emojis all day long.



#33 PayasYouRace

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Posted 12 May 2022 - 17:39

1998 was the low point for Lola, was it not? With just Arnd Meier and Davis Racing running it. 2000 was the first season after Goodyear left too. Lola obviously did a great job of coming back at that point.



#34 Magoo

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Posted 12 May 2022 - 19:00

Once big aero arrived, the multiple chassis supplier system in CART/Champ Car became unsustainable. One supplier would develop an advantage, however small, and immediately dry up the orders for the others. One supplier would thrive and the other one or two would go broke. Happened time after time. 



#35 Risil

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Posted 12 May 2022 - 19:16

I swear we had something in one of the Indycar RC threads a few months ago where Nigel Beresford spoke a bit about Lola in that period. As best as I can remember they had some issues with wind tunnel correlation but the 1998 chassis was very good, not that you could tell because none of the good teams wanted to run it.



#36 PayasYouRace

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Posted 13 May 2022 - 17:52

I wonder how much of Lola’s thin order book for 1998 was driven by the 1997 F1 disaster. I can believe that the car wasn’t that bad, but they didn’t have a representative team running it.

#37 Ross Stonefeld

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Posted 13 May 2022 - 19:29

True, but Newman-Haas had switched to Swift at the start of 1997 too. So you were relying on Tasman and errata. 



#38 Magoo

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Posted 13 May 2022 - 22:45

One more brutal aspect of the competition among chassis suppliers was in pricing. The less favored suppliers each season were often compelled to lower their prices on chassis, aero packages, and spares kits to keep their existing customer teams and attract new ones, further weakening their ability to compete. 



#39 Henri Greuter

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Posted 14 May 2022 - 09:54

The failure of Lola in the late 90's has often been related with the F1 disaster.

But I wonder, After 2K Reynard `lost it` gradually but at that time they were also spreading their wealth thin. Reynard was participating in some endurance projects.

 

Still there was a lot of potential in the basic Reynards of 2K and 01. But the best of them deserved to be renamed into either Renske or Peynard instead

 

 

But I agree, the `Changes of Fortunes` for the British based Customer car builders in the 80's, 90's and the first half of the 00s if we allow us to look onto the CART&successors series, that makes up for an interesting situation to look at.

 

Back to the late 90's and early '00s, apart from the factor `Goodyear` I could also nominate another one: Mercedes-Ilmor loosing the plot.

 

As I understand that situation, Ilmor-Mercedes had Team Penske as its primary outlet and/or partners and the late 90's engines being given designs specs as recomanded and requested by what Team Penske needed for their last PC## designs. Don't forget, the PC##'s were designed with the Ilmor-Mercedes engines an integral part of the entire design. Reynard, Lola and Swift had to design cars that at least allowed some compromises in order to accomodate different engines to be used in the cars

But with hindsight Penske was pursuing a wrong concept, in addition to their troubles due to being committed to Goodyear. But it also meant that the remaining Mercedes teams got stuck with an engine that was designed primarily for Penske chassis but because of that something of a compromise for the other CART chassis.



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#40 Magoo

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Posted 14 May 2022 - 16:47

Ilmor blamed Magnetti-Marelli for the various problems with the compact engine. I don't know if that was fair or not. 



#41 Henri Greuter

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Posted Yesterday, 12:05

That is new to me and I won't/can dismiss it.

But I have heard another reason.

Maybe others have heard that one too.


Edited by Henri Greuter, Yesterday, 12:05.


#42 Magoo

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Posted Yesterday, 14:27

The trend in Champ Car engines at that time was for ever-smaller packages to optimize chassis and aero, etc. Toyota developed an especially small engine but it was fraught with mechanical problems. Ilmor and Mercedes then adopted the approach (and hired the designer) in the belief that with their experience, they could overcome the problems Toyota had suffered.

 

It didn't work out, but according to Ilmor USA president Paul Ray, it wasn't due to any inherent problems with the engine itself, but with the Magnetti-Marelli engine management system. 

 

Fairly typical. There always seems to be plenty of blame to go around. 



#43 Magoo

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Posted Yesterday, 14:30

One more brutal aspect of the competition among chassis suppliers was in pricing. The less favored suppliers each season were often compelled to lower their prices on chassis, aero packages, and spares kits to keep their existing customer teams and attract new ones, further weakening their ability to compete. 

 

And there is a vicious cycle aspect to this. When a company is selling 18 chassis a year, there is room for a decent development budget. With only four or six chassis, not so much. 

 

Descending spiral. 



#44 Magoo

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Posted Yesterday, 14:32

I don't believe the Eagle was built on a Reynard chassis, and I don't think the paper actually says that. 

 

But it definitely did have a Reynard gearbox.