britishtrident
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| posted on 5/3/07 at 02:41 PM |
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quote:
Originally posted by smart51
A well designed lip spoiler will reduce lift at the rear no matter how much drag the front wheels create.
Actually it won't do anything it is sitting in a massive area of chaotic turbulent back flow.
Small lip spoilers are are intended to reattach and break airflow off cleanly thus tidy up the flow making the best of a bad job and reduce drag but
they can't work where the airflow is totally chaotic.
On 60s Le Mans racers like the GT40 and Lola T70 which were a lot better fron the airflow point of view than a Locost shaped car the spoilers had to
rise to about 8 inches in height before they got into the airflow they were intended to break off and higher still to get any down force..
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britishtrident
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| posted on 5/3/07 at 02:46 PM |
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Simple way to get a little free high speed down force and a drag reduction is to setup the car so the bottom of the chassis is 25mm lower at the
front than the rear.
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smart51
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| posted on 5/3/07 at 02:51 PM |
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quote:
Originally posted by britishtrident
quote:
Originally posted by smart51
A well designed lip spoiler will reduce lift at the rear no matter how much drag the front wheels create.
Actually it won't do anything it is sitting in a massive area of chaotic turbulent back flow.
Hence my "well designed" caveat. The main thrust of my point is that just because drag is high, doesn't mean you can't
improve it.
If a seven has a lot of lift at the rear, at speed; a suitable rear spoiler, of the right dimensions, with the right angle of attack, at a suitable
location can and will reduce that lift.
It seems idiotic to me that people say "sevens are aerodynamically bad. You can do nothing about it and you are stupid if you think you
can."
It is entirely possible to improve certain aspects of a seven's aerodynamics by a useful amount. Just because you can't make it perfect
doesn't mean you can't make any improvements.
[Edited on 5-3-2007 by smart51]
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britishtrident
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| posted on 5/3/07 at 04:34 PM |
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To get a rear spoiler or rear wing to work it has to be in clean airflow, even if the windscreen is left off and the driver lowered as far into the
car as possible the airflow at that point on a Locost as brocken down into turbulence.
The only way to clean airflow on to a rear aerodynamic device on a seven style car is increase the height greatly -- just look at how Clubmans racers
developed from the original Lotus 7 and Mallock U2.
Chapman of course did build a much aerodynamic version of the Seven --- the Eleven.
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smart51
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| posted on 5/3/07 at 06:13 PM |
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The caterham 21 was an aerodynamic 7 too. I really liked the 21, but not for the money.
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chriscook
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| posted on 5/3/07 at 07:10 PM |
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Have a search for some of Rob Palin's posts on aerodynamics - he does aerodynamics for a living.
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smart51
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| posted on 5/3/07 at 10:51 PM |
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http://www.locostbuilders.co.uk/viewthread.php?tid=58197&page=2
Similar topic with some interesting views
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Tralfaz
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| posted on 24/3/07 at 01:16 PM |
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Simon
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| posted on 24/3/07 at 04:21 PM |
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You're just being silly
I was going to point out the obvious - that lift is generated by air travelling (faster, therefore thinner) over a longer distance (ie over top of
car), trying to catch up with with the air going underneath.
Easy to fix. Don't let any air go under car. I'm probably going to go diffuser route ar rear of mine, and (because of the turbos) have
under engine bay "scoops" that remove air from under car and chuck it through side panels.
ATB
Simon
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C10CoryM
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| posted on 25/3/07 at 02:03 AM |
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Need I say more? 
"Our watchword evermore shall be: The Maple Leaf Forever!"
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MikeRJ
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| posted on 25/3/07 at 01:17 PM |
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quote:
Originally posted by smart51
It seems idiotic to me that people say "sevens are aerodynamically bad. You can do nothing about it and you are stupid if you think you
can."
If makes more sense when you add on "without totally ruining it's looks". The appeal of the 7 to many is the acceleration, handling
and classic styling, not the ability to cruise at 100+mph. All IMO obvioulsy.
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C10CoryM
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| posted on 26/3/07 at 01:22 AM |
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quote:
Originally posted by MikeRJ
quote:
Originally posted by smart51
It seems idiotic to me that people say "sevens are aerodynamically bad. You can do nothing about it and you are stupid if you think you
can."
If makes more sense when you add on "without totally ruining it's looks".
If men thought like that we would still be riding donkeys. Everyone here has picked the Locost for a reason. Probably not for its high speed
abilities, but to just say it sucks, and there is nothing to be done about it is a BS answer to me.
Things like: vented wings/arches, ducted radiator, full floor, diffusers and vents probably make a substantial difference to the lift of a locost with
little to no damage to the locosts look. I am planning these things, and plan to spend some time with a manometer to figure out what is actually
going on.
If those dont work, then Ill go like the 2J and mount a fan to suck the car to the ground
Cheers.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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G.Man
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| posted on 26/3/07 at 04:20 AM |
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A caterham with an aeroscreen has a drag coefficient of 0.29
Aerodynamics of a brick my backside...
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
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dilley
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| posted on 26/3/07 at 05:41 PM |
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I can hit 156mph and hit the rev limiter in top gear,running 240bhp at the wheels, I was allways told that I'd never get it over 135!!!
aerodynamics
on a track of course
[Edited on 26/3/07 by dilley]
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TangoMan
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| posted on 26/3/07 at 06:42 PM |
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156!! 
Now that must feel 'Interesting' in a 7.
Summer's here!!!!
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dilley
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| posted on 26/3/07 at 06:57 PM |
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its ok as long the car is setup properly.
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tweek
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| posted on 26/3/07 at 11:47 PM |
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you could always do something with the rollbar possibly?? its at the height to make a difference and tubes as far as i'm aware aren't very
aerodynamic.
I'm not talking anything outlandish, just make it less like a tube and more like a spoiler, shouldn't be that difficult with some grp?
Don't know how much effect it would have but its something.
cheers
Tweek
ps. feel free to correct me as my knowledge is sketchy at best. Just tryin that whole thinkin outside the box thingy
"oh dear..." said god,
"I hadn't thought of that"
and promptly vanishes in a puff of logic
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