stand in miniature esprit almost finished

stand in miniature esprit almost finished

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Discussion

teigan

Original Poster:

866 posts

192 months

Wednesday 8th November 2006
quotequote all
i had a 3D computational model of the espritS3, left over from the navier stokes fluid simulations i did last year to diagnose the aerodynamics. those tests showed no consideration for car performance was involved in the body design. any wind tunnel tests done by lotus were for marketing photo opportunities only. it can be argued that computer wind tunnel simulations are imperfect, so i made a miniature esprit to stick in a real wind tunnel at a local airframe technology center. it still needs a chassis, powertrain, and wheels. when i get around to finishing it, i can prove once and for all that the esprits fare worse than most blocky sedans at high speeds because of a lack of basic understanding of flow dynamics on part of their engineers. this wastes fuel and adversely affects steering even at moderate speeds. here's a few snapshots of the miniature if anyone is curious:

http://pg.photos.yahoo.com/ph/i_teiga

kylie

4,391 posts

215 months

Wednesday 8th November 2006
quotequote all
So what parts of the car are you referring to that are bad...? I would have thought that the flying wedge would have been OK. The pics you took are a bit dark, hard to see the model.

teigan

Original Poster:

866 posts

192 months

Thursday 9th November 2006
quotequote all
i'd have thought a wedge was a great shape too, but not any random wedge is going to work. a lot of stochastic factors are involved which can cause turbulence and unintended lift. you also want a shape that that doesn't change resistance rapidly when rotated through a steering maneouver. sorry about the dark pictures. they were taken with a motorola V3 indoors. better photos at a later time then.

lotusse89

314 posts

238 months

Thursday 9th November 2006
quotequote all

5 USA

8,531 posts

203 months

Friday 10th November 2006
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There's no new information here! Lotus didn't put a thumping great tail spoiler on the back of the turbo for nothing. It's also well known there were related problems filming the submarine Lotus in The Spy Who Loved Me.

green_meanie

34 posts

195 months

Friday 10th November 2006
quotequote all
So!
Lets get this straight.
Your Lotus Esprit is a...

Fuel wasting
Badly designed
Poorly constructed
unstable (at any speed)
parts bin kit car

FFS why did you buy it??????????????????????????????????????

I've said it before and I'll say it again.
Teigan you're a tit !

And you want to prove your theory that the Lotus designers didn't use a wind tunnel.

TO WHO EXACTLY? Does anybody really care?

My Esprit feels rock steady at speeds I'd not care to mention,
I don't care if I use a few thimbles full of fuel more getting there, if I did I'd by a Toyota Prius.
I don't care if it's difficult to work on, if I can't do a job on it I'll give it to a man who can
I don't care that some of the parts came from Toyota or wherever, I'm not trying to disguise the fact by sticking stupid bits of plastic in the rear lights etc....

My car costs me a fortune, it's let me down a few times and it's got a few quirks.
But then again so have previous girlfriends...........
But I still love them.

teigan

Original Poster:

866 posts

192 months

Saturday 11th November 2006
quotequote all
a simple machine like the esprit shouldn't cost a fortune to run. maybe you got cheated by dishonest mechanics who persuaded you into unnecessary repairs and upgrades. why vent your frustration on others who didn't fall into that trap? the wind tunnel miniature is going to help determine the exact shape of my lower engine tray. it'll henceforth be used each time i make a new part for the car. seems an efficient workflow strategy; and debunking the critics of my initial computer based simulation will be a bonus.

GKP

15,099 posts

199 months

Saturday 11th November 2006
quotequote all
The basic Esprit shape for the S3 was decided by the S1 of a few years earlier. Lotus bolted a few extra well thought out bits onto the 1976 shape to help with stability at higher speeds.
Bear in mind that at that time Lotus was at the forefront of F1 aerodynamics and was capable of exploiting airflow to a much greater degree than it's competitors and Chapman was more than happy to have a crossover of skills between departments.

If you think that you've a better understanding of airflow dynamics than F1 engineers then fair play to you. I think it's a shame that you're wasting your time playing on the internet.

Since the late Seventies technology has moved on, so I wouldn't be surprised if improvements can be made to a 30 year old design using ideas that are in today's public domain. Ask yourself why these ideas are available today. It's because of a group of highly intelligent, enthusiastic and dedicated engineers huddled together in an old aircraft hanger in sunny Norfolk bringing their ideas and theories to reality.

green_meanie

34 posts

195 months

Saturday 11th November 2006
quotequote all
The simple machine that I use every day and has lower service intervals than a normal car that need doing, wider tyres than a normal car that need replacing, thirstier than a normal car that needs filling up, faster than a normal car that demands higher insurance costs and if something does break, trust me! I don't get cheated. So yes it does cost a fortune to run, but that's a relative idea of fortune.
As for your wind tunnel testing, unless your model is perfectly to scale and of a reasonable size and you make the parts with perfect precision from the "scale" model all you're going to do is upset the flow of your car.

My suggestion is that you stand in the tunnel yourself, face the air flow, get your wang out and start peeing

teigan

Original Poster:

866 posts

192 months

Saturday 11th November 2006
quotequote all
i would do that on a bet, but it would probably void the warranty. i took laser level measurements off the actual car, with an autoart toy for cross reference. in most cases, the toy was misleadingly wrong.

lotustt

35 posts

203 months

Saturday 11th November 2006
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Pass me what you're smoking. Geez does it ever end with this one?

lotustt

35 posts

203 months

Saturday 11th November 2006
quotequote all
Pass me what you're smoking. Geez does it ever end with this one?

arium

101 posts

201 months

Monday 13th November 2006
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teigan said:
i would do that on a bet, but it would probably void the warranty. i took laser level measurements off the actual car, with an autoart toy for cross reference. in most cases, the toy was misleadingly wrong.


Peeing in the wind would void the warranty? On whom or what?

Can't you just buy a replacement tray for underneath the engine if you've lost yours? Even put a diffuser at the back if you must. Gosh this is one very old car for goodness sakes. It'll never run with what's current.

Steve

M Blur

59 posts

190 months

Tuesday 30th January 2007
quotequote all

I'm very interested to hear more about your study on airflow etc as it may help me change some of my plans for the better..

It's pretty commonly known that the wedge isn't a great aero form, or at least not in the 70s-80s incarnations. Mainy because it's neither smooth nor tapered like a teardrop. However it's what I have to start with so will work from there. My aim is to make a lot of downforce for track work and clean up the airflow under the car and try and establish some ground effects. In time I would then look to make the deisgn more efficient and cut out unneccessary drag where possible. Ultimate drag is of less consequence as the car will have surplus power to still push it up to a top end but then anythign over 160 in a track car probably isn't going to be realised and my new trans is geared for 170 on 17" rims. Proposed modifications to date being:



Interestingly I do know of one full body tub that was scuplted after testing at MIRA.. any thoughts on problem areas and reviions welcome - it wont be until after this season that we can make second undertray skin to properly link up front and rear diffusers.

Cheers
Jon

teigan

Original Poster:

866 posts

192 months

Wednesday 31st January 2007
quotequote all
looks great. the biggest problem we have is the turbulence behind the car. if the tail section were a little longer, things would improve noticably. handling would improve too.

with regard to my mini project, i got a little carried away, and am in the middle of welding myself a tiny chassis. on hindsight i should have made it out of wood. i'll keep you posted. i think i can at least verify your undertray theories for you.

968ant

126 posts

175 months

Friday 2nd February 2007
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You Really need to get out more!!!!!!!!

That fact that the esprit is so imperfect is what makes it so, well, perfect!! I don't for one second expect you to understand this in the cocooned little world you live in!!

Please accept my appologies if this is a wind up, and you are not infact a tit.

Ant.

Edited by ErnestM to fix the formatting

Edited by ErnestM on Monday 5th February 19:24

Kimbers34

164 posts

185 months

Saturday 3rd February 2007
quotequote all
Here's a pic of the original wind tunnell model, owned by a Collector in Cornwall England.



Maybe, just maybe Teigan will shut up now.

teigan

Original Poster:

866 posts

192 months

Sunday 4th February 2007
quotequote all
i didn't know the esprit began with a giant chair in place of wheels. lotus has come a long way since those early days.

Kimbers34

164 posts

185 months

Monday 5th February 2007
quotequote all
Trying to make light of it doesn't work. Admit you were wrong and get on with being Teigan.....


Edited by Kimbers34 on Monday 5th February 22:20

teigan

Original Poster:

866 posts

192 months

Tuesday 6th February 2007
quotequote all
wrong about what? i already stated that any wind tunnel tests done by lotus were for photo opportunities only. showing me a crude model is hardly the same as providing recreatable test data.