Prawn and BigAls A3 Track Car

While you are knocking up brakets for wings do you fancy throwing some our way? Looking awesome. If you look at it on a small screen eg phone it looks like it's floating
 
im dying to see it with the proper ally brackets.
all sprayed up
great work!!
 
Looking good Nick

a9ed842f739e930dc8e9340bafbbaeaf77994c50c74fc6a86b046b54cb9b2c59.jpg
 
Thanks guys.
I'm pretty sure this wing will divide opinion, just like the last one did! I'm certainly more keen on this one than the last one. Hopefully when it's all finished it'll look spot on. If a little over the top still! Haha

I started today by making anther par of brackets, this time wth a few changes and a better fit.

I got these to a point I was happy with the outer profile, then cut out the middles to get to what I want to end up with:



I offered that up to the car, and was happy with it. So I made another:





Time for another test fit!



Hmmmmmmm. That's not quite as I imagined it.

This is more like it!





That's about where I left it for today. I've taken a few different pics at various angles, but with mdf brackets and no end plates it's very hard to see the end vision at this point. I can picture it, but you lot will have to wait until it actually exists to make final judgement :laugh:
 
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I've just caught up on this again and very impressed as always!
Car looks awesome m, garage looks awesome, just everything is awesome haha
Jealous as always!
Looking forward to seeing the finished product of the spoiler and it's looking great!
 
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Correct Karl :)

This is down to regulations though, not aero efficiency. Regs almost always limit wing position to below the roof line or similar to stop people going mad to gain an unfair advantage.

If you look at relatively unregulated stuff like Time Attack and SuperLapScottland you'll notice wings get higher and higher and further and further away from the cars. Like the gobstopper 2 I posted yesterday.

The higher up and further back the cleaner the airflow is, and therefore the better the wing will work.
In an ideal world the wing would be well above the roof height and the leading edge of the wing actually behind the rearmost edge of the car. There comes a point where it looks (even more) rediculous though :laugh:

Race series have strict regs in place to stop people going bonkers :racer:
 
Hard to see from your pictures. But the brackets look very close to the glass. Is there any risk of flex and movement when loaded with air flow and making contact with your rear window.
 
Looks like quite an extreme profile... I wonder if you'll see a dramatic increase in aerodynamic drag at high speeds.

ps. check your pm's, again :p
 
that's a definite aerial bender when the boots open!
Would look better with a matching diffuser ;)
 
g60leigh said:
Hard to see from your pictures. But the brackets look very close to the glass. Is there any risk of flex and movement when loaded with air flow and making contact with your rear window.
Click to expand...

Good question mate. I wanted it all to be a pretty close fit on purpose, to keep hardware out of the air flow as much as possible really. The brackets sit 4mm from the glass at the top, and a good 10mm+ clear at the bottom. In the way it's going to get loaded up I'm confident it won't hit the glass at all. It is close though.

Erikn89nl said:
Looks like quite an extreme profile... I wonder if you'll see a dramatic increase in aerodynamic drag at high speeds.

ps. check your pm's, again :p
Click to expand...

It is fairly aggressive Erik yes. As always it's hard to know exactly what you're buying when you buy online, and we took a gamble on this, not wanting to shell out the 3-4x more money for something of a 'pedigree' so to speak.

I've made a template of the profile of the wing, which I'm going to draw up and send to a friend who has the software to run CFD on the profile to see how it'll behave at different angles. Hopefully from that we can work out roughly where the optimum angle is going to be.

Dubster5 said:
that's a definite aerial bender when the boots open!
Would look better with a matching diffuser ;)
Click to expand...

It may even clear the aerial totally :laugh: I've not tested that yet!

Diffuser will come in time :)
 
Excellent article Karl :) I've read it before when researching prior to starting this :)

Hopefully it goes some way to explain why I've mounted it there I have:

In the case of closed saloons/sedans and GT cars that apply maximum height and maximum rearward positions (often related to maximum roof height and the rearmost extent of the vehicle), generally speaking put the wing as high and as far back as you can. This will enable it to work as well as it can by putting it in the ‘cleanest’ air available.
Click to expand...

But there isn’t really any need to go much over the maximum height of any vehicle to get a wing to work well.
Click to expand...

It'd be nice to have it slightly further back, but it's getting into the realms of looking ****** silly then :laugh:

Depending on how the price comes back for these brackets, I may well look into trying to get more done in the future to experiment with different positions. we will see how much a single set cost first though before getting too carried away!
 
Prawn said:
It is fairly aggressive Erik yes. As always it's hard to know exactly what you're buying when you buy online, and we took a gamble on this, not wanting to shell out the 3-4x more money for something of a 'pedigree' so to speak.

I've made a template of the profile of the wing, which I'm going to draw up and send to a friend who has the software to run CFD on the profile to see how it'll behave at different angles. Hopefully from that we can work out roughly where the optimum angle is going to be.
Click to expand...
Have you also captured the profile of the car, to determine boundary layer influence and flow vectors? This could help determine the optimal offset from the roofline vs the angle of attack, for max downforce at minimal drag ;)
 
audi upgrades
I Hadnt actually considered including the car profile in the CFD Erik. I can't confess to knowing the first thing about it myself, but Ash is incredibly good at that sort of analysis and wrote his whole dissertation on Mercedes F1 aero. It was him who offered to do the CFD in the first place.

My plan had been to have Ash work out the wings optimal AoA in free air, then relate this to the direction of air flow in the position the wing is to be mounted.

I've started to work out the direction of air flow off the tailgate using some highly specialist equipment bought partly on eBay, and partly in Pound Land :laugh:





 
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Haha, brilliant! and with that perfectly flat floor in your back yard, you can work out the angles pretty accurately too.

Speaking of that floor, when are you giving it walls and a roof?
 
:lmfao:

Even the aerial is trying to become more aero.
 
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CFD= Cornish Fluid Dynamics, a new take on this science and engineering nonsense.
 
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Thanks Bill. Hopefully that's not the case :laugh: a bit of testing will be required for sure.

Hopefully adding more aero to the rear will allow me to reduce rear toe in without making the rear unstable at higher speeds, with the toe change helping it rotate better on the slow - mid speed stuff.

Obviously I'll find all this out when it's next on track and I can have a proper mess about with various settings and angles.
 
Robin works fast!

Initial drawing of the bracket Robin has drawn from my template:



We spoke about it at length last night. Robin is going to make one or two tiny changes to it, then get some quotes to have a pair made :)

Happy days! Won't be too long with any luck :)
 
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What area would you like to improve the car the most, power, handling or braking? (I'm sure weight reduction would be up there as that improves everything).

I think I saw somewhere you would like larger brakes but are limited by 17" wheels.

Which area do you think you will be targeting next? (excluding all this work on the rear wing).
 
That's a pretty good question!

I tend to look at mods in 2 categories: Those that take a lot of time and effort with relatively low spend. And those that cost a lot but don't take that long to action.

There are of course mods that cost a lot and take a lot of time, and they're a long way off :laugh:

Power - I really don't want any more to be honest, it's got plenty.

Handling is something that can always improve. I'd like to play around with rear geo a little more, and potentially triangulate a spare rear beam I have to see how it works. That's a way off yet though, as it falls into the time / effort list!

Braking - performance wise it's incredible at the moment. I really couldn't ask for more braking power, but they do run hot, and pads don't last long at all.

In an ideal world, I'd upgrade to 18'' wheels, which will allow bigger rubber and more grip, as well as larger brakes that'll run cooler and last longer. if I were going up in size I'd want to go up in width too though, which would mean body alterations to get wider wheels in, and it all gets a bit carried away!

It will happen one day, but it's a long way off.

Weight reduction is something I'm very keen on, and shouldn't be a costly one either. To do it properly though required pulling the car to bits, which means it being secure and inside a garage.

Once I have a garage lots more will happen :)
 
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Brackets look sweet! Are they missing a hole on that cad model?

Sounds like there will be a few exciting developments once the garage is done!
 
There is one hole missing yes Ste.

Until I've worked out the angle I want to set the wing at, I won't know exactly where the hole wants to be.

In an ideal world, I'd like the turn buckles fully closed when the wing is in the flattest position I'll ever run it.

it became pretty apparent when I offered the wing up on the template that even a tiny change in position of the turn buckle resulted in a huge angle change. I think the angle changes are going to be measured in single turns of the buckle.

Due to all the angles involved, the turn buckle needs a cut out of the back leg like this to clear:



In light of this cut out, we decided to beef up the lower leg to retain strength, as this will be the main load path downwards into the tailgate.

I didn't want the cut out done at this stage until I've offered it all up and made absolutely certain what angle I'll be mounting at.

I'll drill the bracket for that single hole and make the cut out notch myself, then once I've tested the wing on the car and I know the mounting system as a whole works, I'll remove it and have it all powdercoated black :)
 
Ahh I see! That makes sense
Gonna take a few vids of the spoiler after? See if there is any flex?
Hopefully it will be sound
 
Definitely yea! Want to be sure its all working ok and it's solid enough at speed.

I'll be doing as much testing as possible with wool and a few other ideas too to try and get the best from it.

Robin finished the drawing today and it's been sent off to be cut :)



This seems to be going well so far!
 
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nice man!!!
not taking long at all!!
get that ****** thing on there!!
they look awesome
like some sort of ancient japanese weapon!!
 
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Bracket order confirmed :)

Being shipped to me next week, can't wait!

I'll get it all test fitted, and do the holes / notches for the turn buckle. Then I'll whip it all off for powdercoating before final fitment :)

Can't wait to get it all on finally!

With the new larger splitter, and the new massive wing, the car is looking pretty bare along the sides / middle.

I'm currently looking at ideas for some kind of side skirt. Nothing huge or silly, but something visual to lower the side line of the car, and also have the positive effect of stopping as much air from getting in under the sides of the car.

I've got a few ideas on how to do what I want and how to mount it, but currently I've got no ideas on a material to use.

I'll need something reasonably flexible, around 1.8m long, and 100-150mm deep. Somewhere 5-10mm thick.

Any ideas?
 
There are only 3 key dimensions on the bracket Karl as you say. the distance between the 2 car mounting points, and the distance from each of those to the wing front mounting point.

These create a triangle obviously. Then the rest is drawn around that. The 0.32mm is just the distance it happens to work out as the longest dimension in the plane. or at least that's how I understand it.

Nige has suggested I use insertion rubber for my side skirt plan, but I'm afraid to search for 'Insertion rubber' on google :laugh:
 
Bit of gutter on the sills, job done...

Could potentially get away with some kind of generic chav-branded aftermarket skirts perhaps? Must be something subtle about!

audi_a3_8l_linextras_warrior_bodykit_14a303_1323794026.jpg


AudiA38LFrontNEO2-720N_2.jpg


Almost as gangster as your old BMW...
 
Some strips of old rubber conveyer belt? Haha
Got plenty here at work!
 
Are you going to have any kind of left to right bracing for it ?? Whilst I appreciate all the load will be downwards it does look like it's going to be a little flimsy left to right... I wonder if it might start fluttering if it starts to resonate at certain speeds
 
Hi, Testing at speed , with the camera, will tell us. However we do envisage that there will be some lateral movement and are at present looking into a wire cross section within the four internal extremities at the top of the brackets.

We will also be applying a grease and diesel paste mixture to various points on the car and wing which will tell us what the airflow characteristics are.

We did look into testing in a wind tunnel, :rolleyes: but I don't want to sell the house so the old fashion way is being put to use.
 
"Long time no see, Big Al! "


Just been plodding along and letting Nicholas do the talking. I'm looking forward to seeing how good or not so good the BGWv 2 is going to be.
 
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