My S1 Elige S Build...hopefully 480bhp/ton.....assembly mode

General Owners Cars
121

You’re getting there then.

Out of interest, if your wing end plates are strong enough, you could try them as they are without bracing them up in any way. A couple of weeks ago I was discussing end plates with Simon McBeath, as I’m thinking about perhaps designing some new ones for mine with some vortex generators. And one interesting thing I found out, was that that slightly flexible but still strong end plates can have an advantage over rigid ones as they create an additional aero effect. Don’t ask me what or how, as I only touched the surface of this idea, but I thought it was quite interesting.

Have you got data for you wing by the way, as close to 400kg at 100mph sounds like a hell of a lot!!! In free air, my SM183 with 120mm 2nd element at 100mph generates about 2300 Newtons and even the SM203 with 170mm 2nd element only generates about 3200 Newtons, and that is a seriously, seriously high downforce wing. I can’t accurately judge from your pictures, but your wing doesn’t look like it has a very exaggerated camber line or a great deal of thickness, which would imply that it isn’t a mega ‘high’ downforce wing. If you want, send me a good, up-close side view picture and I can probably get a fairly accurate idea on what it’s characteristcs might be from Simon. It might give you a better idea on what you’re dealing with.

122

well adding the upper element will add another 2 bolts each side which should help with twist, the bottom section could in theory flex inwards or outwards depending on how the air interacts with them, they are carbon so fairly stiff, its just more the length of them that causes any movement.

To be honest ive just done some very basic calculations on bits on info I can find.

The upper and lower element are moulded off a 2006 Honda f1 wings, with the lower element being a 250mm cord and have a max thickness of 30mm, if I get chance later ill get you the camber line for it. The upper element being a 150mm with a 15mm max thickness

my wing total length is 1750mm but with it having two pylons i have assumed 1700mm due to some stalling around the moutn points(it will probably be more than that thinking about it more)

For the moment I didnt have any data on the wing itself so I stole some from the simons wings, yes the dimensions are different but I though it would at least give me a bit of an idea of what downforce it might make.

Using Mulsannes Corner for calculations I came up with these figures

A 225/150 in free air at 1700mm with 29.5 AofA produces 2403N

AR= 175/25
= 7

Effective AR =7*(1+1.9*(60/175)
= 11.56
(170/7)*11.56 =280.74

(280.74/170)*2403 = 3968N or 405KG

Now as we know thats making a hell of alot of assumptions…one that the wing is identical to simons which we know it wont be and also that the wing will get the equvalent of completely free air, which again we know it wont.

So im making the assumption worse case scenerio it has the ability of creating that much downforce, I would imagine reality it will be about 75% effecient with 300kg and to be fair unless there is a massive amount more work to the front end we wont run it that strong anyway.

Do my maths make sense?

123

Does your maths make sense? eerrrrrr, I wouldn’t have a bloody clue actually!! I wouldn’t know how to calculate a wings downforce as you have to do simulations to get accurate figures and then back them up with wind tunnel data. All the wing data I need has already been done for me.

Just to give you an idea, my wing has a 300mm chord and is about 60mm thick. The rear flap is 120mm chord and about 25mm thick. Both have fairly tame camber lines. The high downforce version is visually a lot more aggressive.

As I said, email me a side on picture with a ruler laid on top of it and I’ll try and get it appraised for you.

124

405KG at 100mph from just a simple 2 element rear wing… ??? I too would be surprised :confused:

(as a comparison, the Cessna ‘Skycatcher’ weighs approx 380KG and has a 30 ft wingspan with an area of 120 sq ft. It stalls at circa 50mph…)

Have you considered what effect this downforce will have on your tyres and dampers for balanced handling at all expected track speeds???

I am curious mate… what is the target use for the car? :question:

125

… ‘A 225/150 in free air at 1700mm with 29.5 AofA produces 2403N’

… the max LD ratio normally is circa 15 deg AOA… I am curious to see how a wing operating at 29.5 AOA is producing a lot more downforce… certainly drag will be significant at this angle…

Discuss! :confused:

126

Im running a twin element wing, the lower element is run at 12 deg, the second smaller element is run 35 deg from the lower element, or 47 deg total giving 28.8 when it measured it.

Already know what the plan is with the springs, we will be turning up to testing with a box full of springs to find the correct balance, I think we will end up about 800/1000 but it maybe more depending on how much grip the kumhos generate and how much downforce we actually produce.

Tyres wont be an issue, if we magically produce 600kg of downforce at 150mph then the total weight of the car will only be 1400kg which for 225/255 tyres wont be any concern.

The target use for the car is to produce as much downforce as possible to allow for later braking and high apex speeds, obviously I need to be mindful of drag, hence im trying to make my setup as effecient as possible, hence the twin element, big end plates, big splitter and diffuser, and canards.

i can explain the thoughts behind each part if you like and see what you think?

overall I want the car to have the ability to run 1.13 around donnington park, if we can achieve that I will be very happy.


Did a little bit of work this afternoon on the car.

To help my front end create a bit of downforce I went hunting through my carbon fibre bits and found 2 pieces of 2mm carbon angle that were the correct length.

Drilled and bolted them through, ill shorten the bolts when I get chance.

Next ill bolt some 50mm strips of carbon to them to keep the high pressure air on top of the splitter, I was reading a wind tunnel test with a shape similar to ours and they gained 4% total downforce from doing it so I hope to gain similar amount(mine wont be as high but will be much longer)

Then fitted my EP crank pulley,

the original was 1820g and the EP one is 350g, was a bit of a pain to fit as its really hard to feel if its in the groove, but I think its on correctly as it felt like it was but ill turn the engine and check its perfectly centred.

So 1.5kg plus another 3.5kg from the flywheel will make a nice 5kg weigh saving of rotational mass and helps offset the weight of the turbo manifold and atb diff


And just to make sure noone has missed it…ive fitted a big wing!!

127

Also my ATB arrived, its alot smaller than I expected, for some reason in my head they are alot bigger, my god its heavy so something so small…i really hope its as good as people say and allow me to get on the power much earlier in the corners

Including my favourite book that started all the madness as a size reference

128

Not much of an update as I have to go and fetch some parts on saturday and im going to a concert sunday night so I dont know if ill have time to fit the kelvar doors and upper wing element.

Also mocked up all my downpipe and exhaust system and welded it all together.

The turbo is v-banded with a 2.5" outlet, that then turns into a 90* bend, straight over the gearbox, through a flexi down to another 90* into the backbox then a 90* exiting where the fog lamp would normally go(bit like an s2 gt3 box), I did think about directing it vertically down into the outer element of my diffuser(set at 100mm as a sacrificial barrier to let the inner elements work without any high pressure air interference) as the sound would bounce down the strakes cancelling the sound, but in the end decided that the risk of potentially upsetting my underfloor ground effects and the fact that a turbo should quieten the engine down a bit made me keeping it point out the back for the moment.

Ordered some m10 stainless bar to make the back box hangers and also make a bracket from the gearbox to help stop and snag when its hot.

Got some 15mm ID stainless tube aswell for making the oil drain

Finally I wanted the turbo core running vertical to help oil evacuation to hopefully not blow an oil seal and the outlet of the turbo comp housing running horizontal, that way when I sort out a chargecooler there it should look a nicer that having to twist silcone pipe to weird angles.

But when I had finished the actuator was in the wrong position and moving it around didnt get it as straight as I liked, so the bracket was bend to get everything lined up, but to make sure it didnt flex when used a little brace was added.

Also the wastegate outlet has been massively ported out so allow maximum flow to help control boost and creep, this should hopefully allow us to run really low boost, ie about 6-7psi, which means we can spend time testing doing the suspension and aero rather than worrying about the engine.

129

Picked up my kevlar doors and upper element wing yesterday,

Fitting the upper element was fairly easy and I followed simons suggestion about spacing between the elements.

Currently they are both set to maxmum downforce 29* AofA which is how ill run it for the first couple of laps and see how much out it is, then turn them down to get a better balance

Next i attempted to fit my drivers door, took some fiddling to get on and its not a perfect fit but for the cost if them and the weight saving I cant complain to much, total weight saving is 17kg, I was going to get them cleaned up at a bodyshop and polished but I may aswell wait until the full car needs painting after a few seasons of abuse
Also fitted the poly window but as you can see its no where it needs to be, so im going to get some ali plate to where the old cant rial used to bolt to with velcro on it, then attach velcro the window and see if it will hold

Next will be putting my lightweight mirrors on and getting the engine running

130

Front is getting there now, just need to put my canard end plates on and get the clam trimmed to let the high pressure air out of the back and top like jamies. That should mostly cover it.

It looks pretty mad from the front but its all functional so I hope it all comes out as planned, due to the size the splitter that should be effective no matter what happens.

Im looking forward to seeing what it looks like on track as all time attack cars look pretty mad in the confines of a garage.



I also added to the splitter end fences today, ive made them the same height as the lower canard so that if that does flex from the airflow then it pushes down onto the end fence and into the splitter which is transfered to the chassis, no point having aero if any downforce they create never gets to the chassis

I have thought about actually making them higher than the lower canard and then shrink as the get closer to the canard(which would help more against any washover of high pressure but I could really do with someone like Simon to tell me it that is ok or that the front edge of the end plate will cause issues with clean air getting to the canard…I could spend hours in a wind tunnel testing stuff if money was no object!!

Also added the mirrors, very easy to fit, weigh hardly anything and after checking adjustment I can see clearly behind me

131

I have a couple of questions if i may!

Do your neighbours stop and stare as they walk past. :open_mouth:

And is this you.

The picture above, front on, really reminds me of Mad max films from my youth.

I guess only time will tell us if you are genius or lunatic. I for one wish you all the best and hope it all works for you. :clap:

132

Car is Darth Vader in disguise. Best of luck, enjoyed reading about your progress.

133

Actually most people have mentioned it looks like the batmobile, so much so that my girlfriend has bought me a batman T shirt and has said I have to put a batman symbol on the front of the car.

As you say im either a genius or a lunatic, I will only know after the first test session at donny from the lap times whether it was all worth it.

134

You are a genius.

Any bloke that can spend that much time effort on a car and still have a girlfriend, let alone one that still talks to you MUST be a genius.

:angel:

135

Well if it does’nt work on track at least it would make a good hostess trolley for your girlfriend. :laughing:
On a serious note though looks like you have spent alot of time and effort on this project, and I hope it drives good on track :clap:

136

Put me down to come to Oulton to see this crazy man & his crazy machine :thumbup:

Look forward to seeing the Time Attack 2014 Calendar :sunglasses:

137

Everyone is welcome to come and watch, as you can see in this build, theres no secret squirrel here, its all bare, warts and all :slight_smile:

My competition all know whats coming, some will laugh and some will look at it seriously, as long as they enjoy reading about it then thats all that matters

Did a little bit more work on my car tonight.

Fitted my throttle body adapter plate, the easiest option would have been to fit a vvc inlet manifold but ive been told the turbotechnics inlet manifold has much better flow rating than the vvc one so I thought it was worth working a bit harder to keep it, you can just see it bolted to the red inlet manifold.

Also test fitted my downpipe and exhaust again to make sure that it had all been cut and angled correctly, then marked up all the hangers for box

You can see how its going to exit like an S2 elise/exige, we will see how it copes with the noise levels, its a 2.25" box hence the reducer, which ill use for the short term until we finally turn the boost up to full where ill change to a 2.5" and decide whether to go bigger if its noisy for all tracks

Oh yeh, also got a picture of the inside of my doors…mmmm kevlar, be useful to hide behind if my girlfriend gets mad for spending all my time in the garage and tries to shoot me

138

Fitted my other door and mirror today

reminds me something from Predator for some reason

Got my turbo feed oil line made up, was a bit of a pain as we spent ages trying to work out what fitting was in the turbo

139

Looking very smart. That’s a hell of a wing, though! Will it squeeze out and down the drive?

140




:laughing: Love it! :sunglasses: