These cars are infamous for their brick-like aerodynamcs... has anyone gone attempted to fix that problem? I was thinking something along the lines of
this:
- Duct radiator inlet and exhaust (vent out of hood... I'm planning a middy)
- Flat bottom with rear diffuser
- good aeroscreen (no near-vertical windshield)
- Inboard shocks with pushrods
Anyone have any input? Would this help at all or would it all be for the wind (no pun intended 
) ?
Do you mean something like this.jpg)
or this.jpg)
or this more a road going version.jpg)
Wow, those are pretty extreme.
The second one looks more like a Morgan than a Lotus.
A lot of the "locost" kits are going inboard suspension now as well MNR sportscars,the new MK Indy that I am building has inboard,and not so locost but the original 7 the caterham csr 260 has inboard suspension,I supose you can make a seven a lot more les brick like,but then as the pictures above they then become less like a true 7
quote:
Originally posted by Middy Tim
Wow, those are pretty extreme.
This is the MK inboard.jpg)
and the csr,high cost compared to locost.jpg)
Wow that blue & red car is truly awesome!
just love the style
though the doors a tad small!
[Edited on 11/1/07 by macnab]
A while ago we did a more aerodynamic 7. It wasn't just the drag that needed attention as the standard-spec car has over 40kg of lift at the
front at 100mph.
Moving the suspension inboard had not as much effect as you would have thought, since the widest part of the car is still the rear and pretty much
anything you do to tidy up the flow at the front just means that the air is in better condition when it smacks into the rear arches.
The standard windscreen is horrendous so an aeroscreen is a fair improvement.
Getting a diffuser to work is very tricky, again because of the backward shape of the car (it's like an aerofoil in reverse with the ends chopped
off). It's important to control the flow inwards from the side edges of the car - which unfortunately means having endplates / sideskirts much
of the way along the underside. It's also important not to go too steep with the diffuser itself and have it made from one bent piece of ally or
whatever, rather than two straights ones which meet at the apex - any mismatch or gap here will render the whole thing useless.
The most critical areas for lift are the front wheelarches. You can reduce lift by nearly 70% just by treating them properly. Have long ones that
cover from at least 3 o'clock to 9 o'clock (viewing the wheel from the side as a clock face) and have them as close to the tyre as you dare.
Cutting louvres in them also wirks a treat but you'll have to put some wire mesh/gauze in them to stop stones etc coming out. A wire gauze
would limit dirt/water whilst still retaining part of the aero benefit.
Hope this helps.
all very usefull stuff
there's an idea, just make the front wings out of mesh...
The importance of having a roof and windows etc for aerodynamics is also often underestimated.
Each to their own but personally I think trying to make a Se7en aerodynamic is missing the point. They have truly brick-like drag coefficients. Even
fairly substantial % improvements in drag are going to have small effects due to the massively disadvantaged starting point.
You'd need to rake back the screen, put a roof and windows on, get rid of the Jaws like opening at the front, cover the wheels completely, get
rid of the sticky-outy headlights
Ooh hang on, someones done it
(okay it needs a roof!!!)
oh but look at those headlights missing the plastic windows...
You can buy vented wings like the ones I have on my car, which will help.
Description
If you put an aeroscreen on, put half doors on also, as these will help smooth the airflow down the side. I got mine from Fluke Motorsport.
Description
[Edited on 11/1/07 by Phil. S]
Blimey. Fluke sure aren't Locost!!! How much for a rear diffuser!!! Shamoan!
quote:
Originally posted by PAUL FISHER
quote:
Originally posted by Middy Tim
Wow, those are pretty extreme.
I agree,the top one is a westfield,pictured back in 1990 I belive,if I recal correctly did over a 170mph,the other two are donkervorts.
[Edited on 19/05/04 by PAUL FISHER]
Did you get the nosecone from Fluke as well? I'm keen to get one of those with a lower intake aperture. Does yours fit a book chassis?
I think I'm going for the mesh vents in the wings, after the SVA test off course.
quote:
Originally posted by Rob Palin
Did you get the nosecone from Fluke as well? I'm keen to get one of those with a lower intake aperture. Does yours fit a book chassis?
Where'd my posts go???
[Edited to say:] They've reappeared and now I can't delete this one.
[Edited on 11/1/07 by Phil. S]
Ehem, whys the post at the top duplicated now?
quote:
Originally posted by Phil. S
The nose is standard Westfield. I don't know whether it will fit a book chassis.
Wouldnt it be easier to compensate for the poor aerodynamics with a bit more power?
Wasn't that Enzo Ferrari's opinion? "Only incompetent engine builders need worry about aerodynamics!".
Then someone pointed out that it can help you go round corners faster, too...
I did my 60k word dissertation o this very topic - i found the biggest factor was the outboard wheels - by enclosing them, you can cut Cd by approx
25%. other mods, diffusers, spoilers, aeroscreens, flat bottoms, rear end breakaway, wakes atc...were looked at too....pretty interesting stuff if
you're a geek like me!
Tom
Rob - Thought you were busy working to make someone else's race car better...
[Edited on 11/1/07 by chriscook]
Yes, i am, but currently the computer's doing all the hard work and i'm just waiting for it to finish. Tick tock, tick tock...
dont forget skin friction , all ferraris are painted red because the paint is smoother
the body is so bluff that to do it right would involve a full body, thats why im doing it - i need to reach 200mph.
Is the 'MK inboard' top wishbone bent or "pre-failed" as The Blessed Colin
would say? 
bent but no a big deal IMHO, it doesnt see as much force as the lower one, mainly braking etc. Plus theres always the argument that you want the bones to bend before the chassis!
Hi having built the first westfield with the full body kit on i can tell you for definate it take 10 mph of your top end at 135 mph .
[img]http://www.locostbuilder.co.uk
[/img]
cheers matt
quote:
Originally posted by DarrenW
Wouldnt it be easier to compensate for the poor aerodynamics with a bit more power?
Worth pointing out though that the power requirement for a given (high) speed increases by the cube of the speed.
If you want to go 10% faster you need 33% more power, then 33% more cooling which means even more drag and probably a reduction in that
10%benefit...
OR you could just reduce your drag in the first place.
If i was after good aerodynamics i wouldnt have even given a sevenesque a second glance. For me thats not what these cars are about. i can see why
someone might want a few % edge on the next man on a track but for most people its just down to the look you want and adding a little driver
comfort.
At the end of the day they are what they are - a quirky fun 60's styled sports car. Discussing how to make them aerodynamic is a bit like
discussing how to make a Pinto weigh 50Kg less - a waste of time.
quote:
Originally posted by DarrenW
... discussing how to make a Pinto weigh 50Kg less
But it wouldn't be a pinto any more and still not as good as many more modern engine, which kind of
agrees with you point.
quote:
Originally posted by DarrenW
If i was after good aerodynamics i wouldnt have even given a sevenesque a second glance. For me thats not what these cars are about. i can see why someone might want a few % edge on the next man on a track but for most people its just down to the look you want and adding a little driver comfort.
At the end of the day they are what they are - a quirky fun 60's styled sports car. Discussing how to make them aerodynamic is a bit like discussing how to make a Pinto weigh 50Kg less - a waste of time.
I take your point, but also people spend a lot of time & effort making the cars lighter to improve handling and performance - both of which are
also improved by aerodynamics.
Is it any coincidence that Colin Chapman's motto was "add lightness" but he was also one of the great aerodynamic innovators in F1?
aerodynamic forces increase by the square of the speed - indicated by the term V squared in the equation for drag force .
If you are referring to Rob's: "Worth pointing out though that the power requirement for a given (high) speed increases by the cube of the
speed."
Notice he says power not force. Cue power vs torque debate
quote:
Originally posted by Volvorsport
aerodynamic forces increase by the square of the speed - indicated by the term V squared in the equation for drag force .
if the aerodynamic force raises by the square of the speed then so does the power requirement to overcome them .
im sure if you did the maths you would realise that most cars would need quite a large amount of power just to get to 100mph .
Ta for the help Chris.
Volvosport - Aerodynamics is my day job so i do actually do that maths on a regular basis. Well, kind of, a while back i wrote a little macro for
Excel to do it for me.
Power = force x speed
and the drag force = 1/2 x density x speed squared x drag coefficient x frontal area
So Power ~ speed^3
Solving a cubic equation isn't that simple and an iterative approach is the easiest way, hence the macro. It takes in engine power, CD, frontal
area, mass, and drivetrain efficiency and allows you to calculate an estimate of your top speed OR to put in a target speed and then work backwards to
calculate either the CD or power required to achieve that, whichever one you don't already know.
[Edited on 13/1/07 by Rob Palin]
quote:
Originally posted by Rob Palin
Ta for the help Chris.
[Edited on 13/1/07 by Rob Palin]
Yeah, am back into work shortly. Would have been there already but the garden fence has blown over and i've been sorting that out.
With the work thing i have to report my progress back to TD at the autosport show tomorrow. Late one tonight then...
yes and perhaps i should stop talking nutsack . i should know better having studied it properly too .
its always easy to say somert without thinking . im sure theres a thread somewhere where i agreed in the first place .
this one cool
Rescued attachment e2_1.jpg
and the back with wide arches
Rescued attachment e3_1.jpg
Hi from actual testing i will confirm that that rear wing dose nothing but take top speed of the car.
At 130 mph it reduced the mph by as much as 5 mph using 200 bhp to drive the car.
cheers matt
Ugly stick.
The Vertigo????????
