Hasse
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| posted on 3/1/06 at 11:17 AM |
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Aerodynamic cycle wings?
What do you think, is there any Gain/improvement to "copy" the front wings with a "spoiler" like on the new Caterham, to
reduce front end lift?
And also, would it have any effect at all to have the underside of the car covered and flat?
/Hasse
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tadltd
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| posted on 3/1/06 at 11:41 AM |
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Yes. Gains will be made in both areas - if you can measure it, you will be surprised on how much the lift is reduced.
If you can introduce a slot IN THE NOSECONE behind the radiator and duct the air through it (and not into the engine bay) you will get further
improvements...
[Edited on 3/1/06 by tadltd]
Best Regards,
Steve.
www.turnerautosport.com
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tiffshaw
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| posted on 3/1/06 at 11:42 AM |
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A flat bottom on the car is a definite aerodynamic advantage.
By having a totally flat floor and running the car in rake ie. nose lower than tail. The air passing under the car will expand as it flows to the
rear sucking the car to the floor.
This effect can be improved by adding a diffuser at the rear of the car.
The effect can be quite impressive infact F1 cars can get more downforce from the undertray than from their rear wings hence the FIA introducing
barge boards etc to limit this.
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smart51
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| posted on 3/1/06 at 12:00 PM |
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Reduced drag = less power needed at all speeds (but much more at the top end).
There are 100 things you could do to improve a seven but then it wouldn't look much like a seven anymore.
A tear drop shaped bubble instead of a cycle wing would be best. Think of a down hill skier's aero crash helmet. It would look a bit odd
though.
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Genesis
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| posted on 3/1/06 at 12:11 PM |
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quote:
Originally posted by tadltd
Yes. Gains will be made in both areas - if you can measure it, you will be surprised on how much the lift is reduced.
If you can introduce a slot behind the radiator and duct the air through it (and not into the engine bay) you will get further improvements...
U2U and email sent
[Edited on 3/1/06 by Genesis]
Going fishin'
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Guinness
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| posted on 3/1/06 at 12:38 PM |
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Apart from changing the engine, from a C to a D, aerodynamics are this years project for the Indy.
Looking at panelling underneath of the engine bay with ali, with removable panels for access, vents at the back of the engine bay to let the air out,
a rear diffuser in ali like the one from Fisher and other trial and error bits.
Mike
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andylancaster3000
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| posted on 3/1/06 at 12:39 PM |
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A guy at uni did a year at Caterham last year. He had quite a bit of input on the new CSR caterham (with aero cycle wings)
He was saying that back to back wind tunnel tests showed that the old wings created lift in suprisingly high 10's of kilos and that the new
wings actually were giving slight downforce! This was mainly achieved getting the wings to run a lot closer the wheel and rolling them forward a lot,
so things can be greatly improved even with normal wings.
Having said that, i wouldn't really want too much downforce on the wheels and suspension!
Flat bottom is a nice idea too. What about a some sideskirts and maybe even a big fan at the back! 
Andy
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rusty nuts
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| posted on 3/1/06 at 12:53 PM |
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A problem with creating downforce on the front wings will be even more broken wing stays . Remember reading an article years ago about a 7 with
clamshell wings that had vents in the wing to reduce lift /drag
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smart51
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| posted on 3/1/06 at 01:17 PM |
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quote:
Originally posted by rusty nutsA problem with creating downforce on the front wings will be even more broken wing stays.
A significant upforce / lift on the fron wings may also damage the stays. For least drag, neutral list is preferable.
slight downforce is better for grip than lift.
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emsfactory
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| posted on 3/1/06 at 03:04 PM |
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How come all these yank tanks get away with having bare tyres all round?
Also, will rotating the wings forward round the wheels not help to decrease lift?
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andylancaster3000
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| posted on 3/1/06 at 04:38 PM |
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emsfactory: Yes, if the arch is rotated forward it should 'scoop' less air. As I mentioned above, caterham found this to be the case with
running it closer to the tyre. Apparently it was also found that the air that was being thrown up by the back of the tyre into the arch was also part
of the problem, as when it met the air coming in from the top and it had nowhere to go but force the arch up!
Andy
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emsfactory
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| posted on 3/1/06 at 05:50 PM |
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Ok. So is there any regs as to how much of the tyre has to be covered by the wing?
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Avoneer
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| posted on 3/1/06 at 07:13 PM |
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Why can't someone make a stick on aerodynamic wing for all our normal arches?
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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emsfactory
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| posted on 3/1/06 at 08:03 PM |
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Like a mini version of the billet jobbies you see on corsas?
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Simon
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| posted on 3/1/06 at 09:08 PM |
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quote:
Originally posted by emsfactory
Ok. So is there any regs as to how much of the tyre has to be covered by the wing?
It you are referring to SVA, then yes. The arch has to cover from in front of the wheel (but not the tyre) to (being safe) a point below a horizontal
line drawn from the wheel centre to the rear.
HTH
ATB
Simon
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Rob Palin
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 posted on 4/1/06 at 07:50 PM |
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Y'know just the mention of these cycle wings makes me twitch like Dustin Hoffman in Rain Man. The cycle wings on the Caterham CSR bear a
striking resemblance to those which I designed for Caterham several years ago as part of an agreement between them and the company I work for whereby
we would produce a 'zero lift' car and they would produce the associated parts as a special edition upgrade kit with our logo embossed
into them.
We did an 8 hour wind tunnel test which some of you may remember was covered in Autocar magazine (complete with a picture of a younger but chubbier
version of me). We managed to reduce the lift of the car from around 40kg at 100mph to almost 30kg of downforce at the same speed. With a decent
reduction in drag too.
Caterham then went away and refined the parts to make them more production and sales-friendly. The version they came back with is very close to what
has become the CSR. I have their original styling sketch of it on my wall at work in fact - complete with our company's logo.
Unfortunately they decided that tooling costs were too high and that they couldn't go through with it. Around 3 years later there was an
article in Evo magazine where they were wind tunnel testing a new car. It was very similar to what we had done for them. I approached Jez Coates
(Caterham's Tech Director) at the wind tunnel and made that point but he said that their truckie had designed it having been inspired by formula
1...
I've always been unhealthily bitter about this because the tie-up with them was my idea in the first place and I had to push quite hard at work
to get the thing set up. Now something that bears the fruits of our labours (and a free wind tunnel shift) is being sold without the accreditation we
originally agreed.
Yes the wheelarches do work. Very well in fact. Shame though that every time i see them i don't feel pride but instead just disappointment.
Sorry to rant like this but the therapy just ain't shifting this cloud of bitterness 
Cheers
Rob
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Deckman001
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| posted on 4/1/06 at 09:04 PM |
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Rob, don't you hold original drawings,that are dated that you could use against them, surely you could do a 'caterham' on them for a
change !!
Jason
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Triton
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| posted on 4/1/06 at 09:26 PM |
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House bricks just aint aero dynamic though, if you want less drag a full body is the best option
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Mix
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| posted on 5/1/06 at 07:22 AM |
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Rob
Don't suppose you would like to post some drawings would you ??
Mick
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Mark18
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| posted on 5/1/06 at 05:46 PM |
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I remember that article in Autocar, that's before building a car ever crossed my mind, it was that good.
Mark
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Rob Palin
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| posted on 5/1/06 at 10:15 PM |
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Unfortunately there were no 'official' drawings at the time as the whole thing had to be done at minimum cost so we just worked with
hand-drawn sketches. Equally there was never a written version of the agreement, just the gentleman's handshake variety. Needless to say we
don't do that anymore.
I've talked to numerous people since then about the various ways to improve the aero of 7-type cars but, as Triton says, you're fighting a
hopeless battle and are better off with a closed body. That said, it's still possible to have the same awful lift balance in a closed car f you
don't sort out your front wheels or cooling system properly.
Sorting the front arches on a 7 can make up to 65% reduction in front lift from the normal arrangement (about 20kg less lift at 100mph). It's
not that they generate downforce but they just eliminate the mechanisms which would otherwise generate lift. This means you could get away with
weaker mounts, not stronger ones.
Andy Lancaster's right about the description of those mechanisms. It's all about preventing a build up in pressure underneath the cycle
wing. Those wings were designed to prevent air getting in and venting any that did get in along with whatever was dragged up from the rear.
You'll see something very similar around the front wheels of Le Mans prototypes and it's taken to the extreme on DTM cars.
You can get almost half the benefit just from having your normal-shaped wings as close to the tyre as possible and running with them rotated forwards
around the wheel so their front edge is about half way up the front of the tyre. That's 10kg less lift at 100mph for no extra cost. Bargain!
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Deckman001
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| posted on 5/1/06 at 10:54 PM |
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quote:
Originally posted by Rob Palin
You can get almost half the benefit just from having your normal-shaped wings as close to the tyre as possible and running with them rotated forwards
around the wheel so their front edge is about half way up the front of the tyre. That's 10kg less lift at 100mph for no extra cost. Bargain!
Dam, Ive just bolted mine in the normal place !! Oh well another change after sva !!
Jason
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andyps
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| posted on 6/1/06 at 12:24 PM |
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quote:
Originally posted by Rob Palin
I approached Jez Coates (Caterham's Tech Director) at the wind tunnel and made that point but he said that their truckie had designed it having
been inspired by formula 1...
Interesting - you see lots of wheel arches in Formula 1.
Maybe you should let us have drawings of your design - maybe if someone started making them to your design and Caterham were to file a complaint
things would get sorted....
Andy
An expert is someone who knows more and more about less and less
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iank
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| posted on 6/1/06 at 02:34 PM |
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quote:
Originally posted by andyps
quote:
Originally posted by Rob Palin
I approached Jez Coates (Caterham's Tech Director) at the wind tunnel and made that point but he said that their truckie had designed it having
been inspired by formula 1...
Interesting - you see lots of wheel arches in Formula 1.
Maybe you should let us have drawings of your design - maybe if someone started making them to your design and Caterham were to file a complaint
things would get sorted....
smirk, yes lots of wheel arches in that sport
I'm not a lawyer, but I don't think Caterham would have any grounds to sue (not that they might not try anyway). Since they are shaped
that way for a technical reason (needs to be covered by a patent) not to look attractive (covered by a design tradmark IIRC).
I remember Ferrari sued some testerossa copy based on the distinctive side air intakes but lost since in some advertising bumph they claimed the shape
improved the airflow.
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Cita
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| posted on 6/1/06 at 08:32 PM |
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quote:
Originally posted by Deckman001
quote:
Originally posted by Rob Palin
You can get almost half the benefit just from having your normal-shaped wings as close to the tyre as possible and running with them rotated forwards
around the wheel so their front edge is about half way up the front of the tyre. That's 10kg less lift at 100mph for no extra cost. Bargain!
Dam, Ive just bolted mine in the normal place !! Oh well another change after sva !!
Jason
I thought that for the SVA the wheel arches had to extend to somewhere halfway the back of the tire.
What about a stiff sort of brush which is mounted inside the arch and just touching the tire.It will at least disrupt the airflow and not create a
lower pressure zone.Dont know what it will do when raining though.
The mounting nuts-bolts-screws-whatever at the leading edge of the arch wing will also prevent the perfect splitting of the airflow.....me thinks
Cheers Cita
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