20 replies to this topic

[Jhope]

here we go
http://retro2.vsni.net/81usw11.htm

[desmo]

jhope, I think this is the image you were trying to post. I remember thinking at the time that this car, which had it's ground effects skirts and wings suspended seperately from the chassis, was a clever but untenable reading of the rules at that time.
I did admire ACBC's cheek for trying it, though.



This should be an image showing how the concept worked, if the site isn't afflicted with javascript (see above).



[This message has been edited by desmo (edited 03-07-2000).]

[Jhope]

OH, thank you

[Art]

If it was like the pictures just posted they couldn't see it to approve it or not.

Art NX3L

[Jhope]

i'll post something written in a now defunct formula one magazine I have at home. It writes many interesting article on weird f1 inventions. It came out after the Tyrell x-wings were introduced in argentina in 1997. I'll type up the little piece, and then post it here for you all to read. It's quite a bizzare scinerio once you read it and understand it.

[CVAndrw]

As a new member, I hope I’m not already acquiring a reputation as a single issue crank, but I’m gonna risk it anyway:

It was a movable aerodynamic device! Just like suspension mounted wings (the instigator of the regulation), the fan car, sliding skirts and exhaust blown diffusers. Why the FIA always decides to selectively enforce and interpret their own regulations according to whomever is currently in the doghouse is something I’ve never understood.

[desmo]

CVAndrew,
I don't see how exhaust blown diffusers could be considered a movable aero device.

[Art]

Desmo.

How does an exhaust blown diffuser work?

Art NX3L

[desmo]

It is my understanding that it uses the velocity of the outgoing exhaust stream to amplify the airflow through the diffuser to get lower pressure, courtesy of Ing. Bernoulli's principle, and thus create downforce in the rear of the car without alot of drag penalty.

If anyone has a more accurate or clearer description please feel free to correct me.

"that really sucks, man"

Kurt

P.S. Why does the Lotus 88 pic I posted sometimes show up and sometimes not???

[This message has been edited by desmo (edited 03-07-2000).]

[Art]

Isn't this more or less what Ferrari has been doing for the last few years?

Art NX3L

[Art]

Or are you refering to the exhaust exiting throughe tht tunnels on the high down force cars?

Art NX3L

[BRG]

I thought at the time, and still do, that the Lotus 88 broke the spirit of the regulations, as did the Brabham fancar, even if both could be argued to comply with the letter of the rules. These were blind alleys and the FIA, however much we may dislike them at other times, were absoutely right to stop these trends from the outset. Perhaps it would have been nice if Lotus had been allowed to have one race, like the fancar got, just to prove it worked technically.

Personally, I hated the whole skirts and ground effect concept - it may have worked, but it was ugly and was not elegant engineering. It took F1 just TOO far away from the reality of road cars.

------------------
BRG

"all the time, maximum attack"

[CVAndrw]

Re: diffusers

Well, I know I'm not Charlie Whiting (although I of course think we'd all be happier if I were- I bet a lot of us would say the same thing about themselves) but my reasoning is thus: when exhaust blows through the diffuser to accelerate airflow, the amount of downforce generated varies- sometimes dramatically- according to throttle opening.

Therefore, I say the movable device is not the diffuser per se, but the throttle itself. When it changes position, the amount of downforce goes up or down. Get it? Makes sense to me. Thank you, thank you.

[CVAndrw]

P.S.:

I believe John Barnard introduced the concept in his original MP/4- six exhaust pipes (three per side) exiting the sidepods right where the diffuser begins to sweep up. This was part of the advantage the TAG-Porsche V6 eventually demonstrated over the more powerful but more bulky BMW 4.

[Ray Bell]

Gave the drivers a good excuse to keep the power on in a long sweeper - but what about when it was time to brake?
I wonder how much downforce was actually generated?
I wonder how much better F1 would have been if wings and other aerodynamic devices had been banned altogether from the beginning?
I do know, however, if I had been there and had a say, the Lotus 88 would never have wasted the fabricators' time.

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Life and love are mixed with pain...

[Jhope]

desmo: on the picture you posted (layered one) where are the venturi tunnels. I always thought that in order to create downforce from the floor, you needed the profiled floor.

[Jhope]

found a wind tunnel image of the 88



AND A STORY
Description

This is the actual Team Lotus windtunnel model used to develop the radical "twin chassis" F1 car. The "twin chassis" concept is one of two major aerodynamic innovations pioneerd by Team Lotus, the other being ground effects in the Type 78. The "twin chassis" concept proved such a threat to current design practice that it was immediately banned by the FIA, never being allowed to race. This is the actual model that Team Lotus used to test the design in the windtunnel and later attempt to explain the workings of the design to the FIA.

History
The immense downforce of the new sliding skirt ground effect designs had forced the use of unprecedented wheel rates to restrict suspension movement. As a result the drivers had to endure brutally rough ride characteristics and skirt failure guaranteed a big accident. FISA introduced a ban on sliding skirts for the 1981 season.
The Type 86 prototype and Type 88 racecar were designed to circumvent the ban on sliding skirts and also isolate the driver from the aerodynamic download. Based on the Type 81, it's aluminum honeycomb monocoque with conventional suspension formed the primary chassis, carrying the driver, fuel tanks, and drivetrain, all relatively softly suspended. A secondary chassis was constructed in carbon composite and carried the bodywork, side pods, wings, and radiators. This transmitted the downforce directly to the unsprung portion of the primary chassis. The primary chassis could therefore be relatively softly sprung with the high downforce transmitted directly to the tire's contact patch.

A single prototype Type 86 was constructed and tested in 1980. Anticipating potential acceptability problems with the twin chassis concept, a fall-back Type 87 was concurrently designed, also based on the Type 81 chassis. Work then proceeded on the Type 88 race version of the twin chassis. Both the the primary and secondary chassis were constructed in carbon composite, with three carbon beams of the secondary chassis running through the primary chassis and all the aero downloads of the secondary chassis being fed directly into the uprights.

The car passed scrutineering at Long Beach but was banned from the race due to protest. A subsequent hearing by the American FIA signatory found the car approved. However, when Lotus attempted to race the car again at Rio it passed scrutineering but was again banned. At Argentina it failed to pass scrutineering and Chapman's outspoken press conference resulted in a $100,000 fine by FISA. An appeal before the FIA in Paris was conducted to attempt to overthrow the ban, a proceeding in which this model figured prominently, but the ban remained in effect.

Lotus then produced the revised Type 88B with bodywork differences. This revised car passed RAC scrutineering and again practiced, despite a threat from FISA that the British race would lose it's World Championship status. Further protests from other teams saw it removed for the fourth time, never to attempt to race again.

HOPE YOU ENJOY THIS




[This message has been edited by Jhope (edited 03-08-2000).]

[desmo]

The wind tunnel model of the Lotus 88 is for sale. The owner is asking $15K US. Here's the URL to find out more:
www.race-cars.com/carsales/lotus/88modl/88modlss.htm

[desmo]

jhope,

I see your point. It appears to me, and I'm just guessing here, that the increase in the area front to back in the area enclosed by the skirts is accomplished by necking down the cross section of the tub rather than raising the floor. I don't see why this wouldn't achieve the same end.

[Jhope]

I see your point as well. But one thing though, when you put the chassis on with the skirt, the outside air cannot get under the car, thus not interfearing with the air low. Now from what i see in the diagram, there is no room for clean air movement in the "tunnel" because the radiators and engine componets are in the way too. Plus, from what I read, in order to make it work properly, the venturi tunnels have to be there. Maybe Lotus was hiding soemthig with this diagram.

[f li]

I suspect that if anyone else (especially Ferrari - whose vocabulary does not include the word "innovation") had created the beast it would have been legal. Chapman pretty much scared the **** out of all the other constructors who could never make the "great leaps forward."