Anyone else thought it is strange that the front spoiler does not go the full width of the front but has a huge gap in the middle?
[image]http://www.fastdrive.org/lotus/exige_gt3_4.jpg[/image]
![http://www.fastdrive.org/lotus/exige_gt3_4.jpg[/image]](http://www.fastdrive.org/lotus/exige_gt3_4.jpg%5B/image%5D){kind=link}
I would imagine that they’re trying to get air under the car so that the flat floor and little diffuser have something to work with. It’s a more efficient way of gaining downforce than a great big airdam at the front.
I would imagine that they’re trying to get air under the car…
Or perhaps through the mouth and over the screen? Could a full splitter may hamper that?
Ian
There are several aerodynamic theories, but on the downforce generated by a flat underside they all rely on the Bernoulli Effect
So, you need to speed up the airflow underneath the car. One of the ways is to make it closer to the ground, and another would be to direct more air through one point.
So, on one hand you’ll want less air on the sides of the car so that it creates a dynamic barrier to the atmospheric pressure and on the other hand you want air to flow really fast underneath.
Solution: leave a gap in the splitter, but it is not to be done “by hand”, lots of work is involved into getting the right shae, otherwise the resut can be less downforce.
Or, you could revert to the basic theory and have a fixed flat splitter all across.
HTH, somehow it all makes sense today (just waking up from a night out, lots of Tequila!)
Check these out:
http://www.mountwashington.org/discovery/arcade/bernoulli/
http://hyperphysics.phy-astr.gsu.edu/hbase/pber.html
http://www.iit.edu/~zwicker/lesson2.htm
http://hendrix.uoregon.edu/~demo/Demo/Fluid_Mechanics/Dynamics/Spool.html
We asked Gav about the front splitter last night. Azrael was spot on Apparantly the wind tunnel tests showed that the “gap” would aid the airflow enabling the rear diffuser to work more efficiently. However, the overall balance of the downforce is now not to their liking, so a full splitter will probably be utilised on the race car.
Isn’t the splitter called a splitter because that’s what it does ?? ie ‘splits’ the air ?
Its not actually there for downforce is it ? (well not in the same way you put a wing on for downforce anyway) BTW I realise that its all about increasing grip but you know what i mean…
I understand that its there to interfere with the so called laminer flow and mess with the boundary air which causes drag, rather than actually directly introduce downforce?
The rear diffuser does the same at the back of the car… I think.
Not that I would have thought of this on my own of course, but now that I see this gap being introduced in a few sports/race car splitters, it kinda makes sense to me that the gap in the middle allows better control of flow under the car (i imagine what water would do if it were flowing there) and thus reduce drag ? and permit the rear diffuser to do more work, as confirmed by Pesky and Azreal
I guess what Gavan might be saying is that they will be happy to sacrifice some top speed for better balance (more?) downforce at the front and rear at the expense of increased drag ?
Anyway, I think it looks mean with the gap, especially when its so sticky-outy
I thought it built up pressure above it, causing downforce? As seen in Eau Rogue pic of MarkA’s - clicky
Ian
ps. To their credit, the Edwards have now improved the fixings
I thought it built up pressure above it, causing downforce?
nah… Uldis’ Bernoulli links above tell us that to do that the splitter will have to slow the air movement down above the splitter.
I suppose it might do a bit of that, but it’s not its real job which I believe is to…‘split’ the air (or ‘spoil’ the air ), interrupt the boundary air, reduce lift under the car by speeding the air up under there, but i’m not sure how much slowing down of the airflow it could do above it.
At least that’s how I understand it at the mo’
Isn’t it a case of an upside down wing principle as IDG is (sort of) suggesting. By making the air travel faster underneath (vacuum effect) the slower air travelling over the car will be heavier & therefore pushing the front of the car down
Tim.
tim
i think we are all saying almost the same thing… its prolly getting a bit pedanic now but the point is that we are reducing lift by speeding up the airflow beneath the car… not by slowing it down over the top… subtly different methinks.
also the splitter tries to reduce drag i think via interfering with the slow moving air at the boundary of the cars envelope… i think this is where they talk about laminer flow ?
Isn’t it a case of an upside down wing principle as IDG is (sort of) suggesting. By making the air travel faster underneath (vacuum effect) the slower air travelling over the car will be heavier & therefore pushing the front of the car down
Yes, that is a better explanation (thank you), although instead of speeding air up by making it travel faster (plane wing), the air above the spliter is slowed by reducing its options to escape (ie. down). Twas my thinking.
Ian
also the splitter tries to reduce drag i think via interfering with the slow moving air at the boundary of the cars envelope…
A splitter will always add drag Mike.
Ad Ian, Tim, I already felt that my post was transparent to Pesky.
May be the fact that (as pointed out before) I don’t actually say anything.
Check this other link out
I think it’s very well explained there, especially where on pages 2 and 3 the mentione the two different approaches.
This looks like a slightly crude attempt at an anhedral splitter. The idea being that a conventional full length splitter can stall the airflow under the car during heavy braking or cornering a lead to unpredictable handling traits. Splitters like these are actually mandatory within the latest LMP regs as sported by the new R10 http://www.mulsannescorner.com/news.html
On LMP cars they have been used with some success as a way of trading predictable handling against outright downforce. I have seen them used plenty of times on GT cars too but usually these cars revert to a conventional splitter because most gt cars have little scope to generate frontal downforce using underfloor venturis so it comes at a premium. So no surprise that Lotus are changing this already.
On the subject of splitters… all they do is give the high pressure air at the front of the car a surface to act on and are, as such, very efficient.
Aerodynamics man. It properly blows my mind. I understand the whole upside down wing theroy and stuff, but all of the downforce against drag stuff blows my mind. Plus surely there is nothing we can really do without testing it and I personally don’t have my own wind tunnel. Plus if I did, i doubt i would have a clue what to do with it.
Sean…
Well my simple thinking is along the lines of Gav lapped quicker with an Edwards rear diffuser, and Mark has pictorial evidence of the front doing something, PLUS they look good - so sold!
Ian
Ian, that seems like sound judgement!!! I’m sold too!!
Plus surely there is nothing we can really do without testing it and I personally don’t have my own wind tunnel.
Sean…
This GT3 car is going into the wind tunnel (possibly the 1st Exige to do so?) so it will be interesting to see how many mods are produced following the sessions. Maybe not applicable at all to us S1 drivers but I’m looking forward to seeing what happens.