Supercar kit for IPRA

[choppo]

Thought i'd post up what ive been working on for the last few weeks. Almost cost me a finger too!
Anyway, IPRA has rules about how big/long/wide etc etc you can have any body kit. Inspired by Listy's thread and his recent plans, i thought id post up some pics.
Step 1. Buy a Rick Kelly VY V8SC copy - fibreglass. First thing you notice, the quality of fit is rather duboius. Like the angle of the fixing points is all a bit bunged up - its the edge of the mould so i assume they dont take great care with this bit. Even more so, the first trick is the front bar ISNT made to fit road car front guards. The V8SC of the day had massively wider front guards. So after finding a guy who has a front bar that he modified to suit standard car width guards, ive now got a spare front which i already modified ...
Step 2. Get out the jigsaw, Dremel (the BEST tool!!) and everything else and cut it to bits. Needs to be 100mm off GL. Not exceed your standard front bar profile looking from above. Sounds easy but it aint.....
Step 3. Draw a profile on the ground of the original bumper and make sure what-ever you do, the new bumper must stay inside this line.
Some pics of the last few weeks
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1716.jpg
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1717.jpg
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1712.jpg
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1713.jpg
V8SC bumper profile on the outer, got to stick to the original profile of the car though
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1720.jpg
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1721.jpg
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1722.jpg
Back on without any 'guts' though.
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1723.jpg
Skip a few processes and...
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1736.jpg
Skip a few more processes and fibreglass the bastard back up
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1735.jpg
Several weeks later. Almost back together (brake duct inners still not done)
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1736.jpg


It doesnt stop with the front bar - now lets look at the side skirts. Again must be 100mm off the ground. Make up a jig, cut the skirt, support it with gussets
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1743.jpg
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1744.jpg

Then there is the rear wing :doh:
http://i474.photobucket.com/albums/rr107/choppo21/IMG_1745.jpg
Chop chop chop.... only 1/2 done, but getting there.
Even worse, im yet to tackle the rear bar :lol:
After all this effort, i think im gonna make a mould of everything so when some prick slams me at the track, i can re-create the pieces WAY easier :teach:
Sorry for the many pics guys, but its been a LONG process, and still got a few more weeks to go :lol:

[NickS]

Is all this actually going to provide any benefit Chop ? ... or just look cool ?

You have way more patience (or is it time ?) than me, good luck mate, can't wait to see how it looks finished.

[35R]

wow, can't wait to see how this goes :breakdance:

[choppo]

Is all this actually going to provide any benefit Chop ? ... or just look cool ?

You have way more patience (or is it time ?) than me, good luck mate, can't wait to see how it looks finished.

Now that is the BIG question and one ive gone over and over and over again before i did this. Believe me, ive toiled over this in bed, on the toilet, in the shower, at work..... Infact, just after i spent my first 8hrs on this a few weeks ago, im thinking "Holden racing teams, spent a billion on the aero to get this front bumper to work properly, now im chopping it and compromising the billion they spent to get it to work properly, all in my back yard shed :lol: :lol: :lol: :lol:". Almost canned it there and then, BUT... What i cant say is it doesn't work... yet. The temptation to get more front and rear grip via 'legal' means is attractive, very attractive actually.
In the challenge to 'get to the front' of IPRA, you do some extra-ordinary things. This is another of those 'things'. Having said that, i love it, keeps me broke and occupied :lol:

And yes, it is very important for the car to look the goods and sound the goods :devil: (not ashamed to say), so much so that the amount of time designing the new front bar is huge as it must keep as best possible the 'original VY V8SC' lines. There are one or two guys who have done custom kits that don't follow the original lines, which im not a fan of.

So it could be all pointless in other words, because if it doesnt look ok, ill put the 'ol Clubsport kit back on.

[.charged.]

Ive lodged my protest for PI already chop :)...... it looks good mate, we have a guy we use SA Fibreglass plug plug, he is bloody good he has taken moulds for all our splitters, flares etc and he only charges a carton of beer for a replacement splitter :)........ so if you bust a splitter or rip off a flare the cost is cheap. You wont have to lift at turn 1 at PI with all that downforce mate ;).

P.S Have you sent your EOI deposit off yet for the Nats yet ?

[GTS Listy]

Looks good chop. Mine is all fibro and has been modified by monkey warehouse to raise it a bit and fit the different lights. No idea about the following the orginal car shape and all that as it was not a consideration at the time. I will check it out though but seriously doubt it.

Lots of work on those side skirts too.

Best of luck with it and hopefully you can achieve what you are after.

[choppo]

Ive lodged my protest for PI already chop :).
P.S Have you sent your EOI deposit off yet for the Nats yet ?
It cost's ya. I cant wait for a few NSW guys to spend their cash protesting :lmao:
As a design feature, it has a lower lip that will protude from the bumper. All legal but it will cause a stir. :lmao:

[Benson]

Love your work! Backyard Style!!

You'll easily chop 1 sec with your aero mods

[taztassio]

looking good.

what airfoil are you using and what coefficient of lift are you hoping to see.

you might be better off choosing a naca or nasa based symmetrical airfoil, that way an angle of attack of zero will be no lift, and a negative angle of attack will provide negative lift (downforce).

this will also keep your drag lower when not in use .

adding camber to the wing will create more down force for a given angle of attack but also more drag. best looking up some common drag profiles for this.

I am not to sure on that abrupt bit on the trailing edge of your wing. unless its a high lift device (not needed on a rear wing) you need to make sure the airfoil comes to an apex at the trailing edge.

generally for a low velocity wing, you want it thick for more down force if thats what you require. there are also equations for Leading Edge radius to help with this.


btw, I study aerospace engineering, im not some knob who wants to talk shit, just wanna help you out with your wing design, especially noting the camber and thickness of it.

[ghz28]

The trailing edge flap is called a "Gurney Flap", invented by the late and great racer Dan Gurney. It is an element of almost all race car rear wings, and many front ones in high downforce race cars.

All the V8 Supercar wings have them as a feature as they increase downforce for a given angle of attack at the relatively low airspeeds of race cars, and can even reduce drag coefficient at the same time.

Not the world's greatest source of the truth, but a convenient one in this case, here is a Wikipedia reference....

http://en.wikipedia.org/wiki/Gurney_flap

My only other comment would be that the flaps I have seen on race cars all seem
to be very thin, ie made of a sheet of metal or in the case of the VT Supercar wing
on the back of my car, a 1.5mm thick raised edge of carbon fibre.

Cheers,

Garry

ps Choppo, I am sure you can get access to one down there but if you want
me to measure the dimensions of mine I can do that and let you know.

I have my rear wing set to the median position, about 11 degrees AOA, but others
tell me that for the shorter tracks I should increase it to the maximum available angle
of 17 degrees. And with my real front splitter, which was 38mm off the ground in my case,
I noticed an increase in corner speed through turn 2 at QR of around 8 km/h, with about the
same increase in turn 1 with the rear wing. I was told that for QR those were the places
where the aero package would make most difference.

[taztassio]

depending on airfoil, any larger than 15-20deg angle of attack is stall worthy.

btw thanks for the info on the 'flap' at the rear, it should stil be an apex tho, (as you said, thin).

not really a new invention, however good and cheap way to modify a static airfoil cheaply, however too much angle without boundary layer energizing will cause separation

[OZY 260]

Looking the goods chop. I am very interested to see the end result and what results you come up with

[hsvredsled]

This should help your calculations.

F = 0.5 * A * coeff * ro * v^2.

[taztassio]

still needs the coefficient of lift to make that one work.

also, you should look at drag polars, give you a rough idea of the drag vs Cl. (rough because its a finite wing)

[choppo]

Wow interesting....hadn't got that technical about it. Just as a note, our rules say the rear spoiler can only be;

The entire spoiler, including brackets must be wholly contained within a 200mm x 200mm box when viewed from the side of the car. Similarly, when viewed from ontop, it must be completely within the outline of the car.

That spoiler is meant to be a replica of Rick Kelly's i.e. is suppost to be a mould of his.

Now ive had to chop the width of the wing, the length and the height to fit the above. Not being able to use VG's above the rear windscreen, ill be interested to see if it does anything at all! LOL

[choppo]

Very interesting - would you have a photo and dimensions at all? I'd like to have a perve - also, you mentioned your was adjsutable? Mines jsut a fixed bit of FG :shock:

The trailing edge flap is called a "Gurney Flap", invented by the late and great racer Dan Gurney. It is an element of almost all race car rear wings, and many front ones in high downforce race cars.

All the V8 Supercar wings have them as a feature as they increase downforce for a given angle of attack at the relatively low airspeeds of race cars, and can even reduce drag coefficient at the same time.

Not the world's greatest source of the truth, but a convenient one in this case, here is a Wikipedia reference....

http://en.wikipedia.org/wiki/Gurney_flap

My only other comment would be that the flaps I have seen on race cars all seem
to be very thin, ie made of a sheet of metal or in the case of the VT Supercar wing
on the back of my car, a 1.5mm thick raised edge of carbon fibre.

Cheers,

Garry

ps Choppo, I am sure you can get access to one down there but if you want
me to measure the dimensions of mine I can do that and let you know.

I have my rear wing set to the median position, about 11 degrees AOA, but others
tell me that for the shorter tracks I should increase it to the maximum available angle
of 17 degrees. And with my real front splitter, which was 38mm off the ground in my case,
I noticed an increase in corner speed through turn 2 at QR of around 8 km/h, with about the
same increase in turn 1 with the rear wing. I was told that for QR those were the places
where the aero package would make most difference.

[ghz28]

Hi Choppo,

will take some photos with scale tomorrow for you and either post here or send them to an email address if you prefer.

Cheers,

Garry

[choppo]

Much appreciated Gaz!
email to stevencook@nitroxgroup.com.au if they are too big for the forum.....

As an aside, as mine is 'fixed' and will work at a minimum i reckon (because of the restrictions i have), what is the MAX angle of attack you guys reckon without it stalling????
And is this angle taken from putting a straight edge over the whole wing and measuring the angle or is it just the first or last bit of the wing you measure the angle????? Tas, id be interested in your view here too

tks

Hi Choppo,

will take some photos with scale tomorrow for you and either post here or send them to an email address if you prefer.

Cheers,

Garry

[GTS Listy]

Chop this is only for information but the front spoiler I got the panel guys said it is quite flimsy. They have had to add a couple of brackets to make sure it stays put. Also they had to trim and clean up some bits to make everything fit right. It was a good thought but if I ever go racing with it I would have to get the proper VT supercar stlye race one. They do sell them and are much thicker fibro but I liked the VY look supercar spoiler. It will be finished Friday arvo so I will post some photos up.

Looking good and some great DIY work there. Wish i had the skills to do something like that.

[Aeron]

I kind of blacked out when you guys started getting all tech'o :nutbag: :D

But it looks great so far Chop. I love it!!!!! :dance:

[taztassio]

Angle of attack varies for each airfoil, as does drag.

the drag polar is a parabola shaped curve of drag and lift, and gives you an idea of how much lift to drag you get.

the cl max will be at some angle of attack, usually at 15-20deg, but i wouldnt run more than 15deg. you could give me the NACA, NASA etc code of the air foil and Ill tell you.

Ok guys, i found what I was looking for.

This is fukn rough, as it is for an infinite wing etc, and even its finite wing calculations wont be exact, you will need some fine tuning on the track etc, and it doesnt include HIGH lift devices (multiple wings, boundary layer energizing, boundary layer sucking/blowing).

http://www.mh-aerotools.de/airfoils/jf_applet.htm

This java app will allow you to create and modify airfoils based on thickness etc, and you can export the coordinates to excel, and scale them to your size. you can even input your own airfoil design and see how it goes (just remember, you want lift, but that just acts down, so remember that!)

if you need any help with nomenclature, settings etc I can help. some of the functions you wont use but some will give you a good idea.

Cheers guys, hope this helps, perhaps this link should be a sticky if it already isnt :)

btw, make everything dimensionless, as in thickness a function of chord, that way you just need to scale to your dimensions easily!

Nick

[choppo]

FFS Tas :bravo: Ive got a cut down bodgie cut up rear wing half the size it should be in the dirtiest air it could be in the worst position on the boot.. So what angle you reckon this shitter should be? Not my preference, but thems the rules :sigh:

Angle of attack varies for each airfoil, as does drag.

the drag polar is a parabola shaped curve of drag and lift, and gives you an idea of how much lift to drag you get.

the cl max will be at some angle of attack, usually at 15-20deg, but i wouldnt run more than 15deg. you could give me the NACA, NASA etc code of the air foil and Ill tell you.

Ok guys, i found what I was looking for.

This is fukn rough, as it is for an infinite wing etc, and even its finite wing calculations wont be exact, you will need some fine tuning on the track etc, and it doesnt include HIGH lift devices (multiple wings, boundary layer energizing, boundary layer sucking/blowing).

http://www.mh-aerotools.de/airfoils/jf_applet.htm

This java app will allow you to create and modify airfoils based on thickness etc, and you can export the coordinates to excel, and scale them to your size. you can even input your own airfoil design and see how it goes (just remember, you want lift, but that just acts down, so remember that!)

if you need any help with nomenclature, settings etc I can help. some of the functions you wont use but some will give you a good idea.

Cheers guys, hope this helps, perhaps this link should be a sticky if it already isnt :)

btw, make everything dimensionless, as in thickness a function of chord, that way you just need to scale to your dimensions easily!

Nick

[taztassio]

well, here are your options.

measure the profile and plot it on the program... (including the 'gerney flap')

or run it at -10deg angle of attack. due to the flap at the back, you wont need 15deg I dont think. start at 10, and work your way up or down if need be. but I would be smoothing it to an apex (ie a point)< with a radius off the back. that should make the flap more effective.

as you have large camber and thickness on that foil (good traits for low speed which cars are...) you will need to sort that flap out a bit otherwise it will be drag central!

[2 cylinders shy]

Any updates choppo?

[choppo]

Nope LOL. Lack of time and keeping my business alive ATM has got the better of the project. Plus, next round of the State Champoinship is approaching fast, so ive put it all back together (as a clubsport) and started the race prep.... ill be back onto it soon i hope - ill let you know when more progress is made :cheers:

[.charged.]

Chop I can send you mine faux carbon fibre, constantly variable and designed to break air at the rear screen, geez you late model guys have it easy :)

http://i98.photobucket.com/albums/l269/toyocharged/stateoftheartrearspoiler.jpg