Ep50 Willem Toet on Applying F1 Aero To Your Car (1 of 2)

Willem Toet Introduction

Willem Toet, the former head of aerodynamics at the Benetton, Ferrari and Sauber Formula 1 teams, joins me for a very special two part show. Aero is one of those subjects that gets a lot of air time on TV but its often hard to relate that back to what you can do yourself. Willem Toet has some great insights and very practical tips. This is honestly an amazing chat with one of the best in the business. Be sure to check out the links in the show notes for some really good followup videos and articles. As ever, grab a pen, grab a coffee, sit back and lets listen to what Willem has to say.

[01:34] Meet aero guru Willem Toet

[06:53] How Willem got into motorsports (missing and Eng degree..)

[09:00] The epitome of a motorsports mindset

[19:17] Breaking the clock (then fixing it) at 7 years old.

[27:35] What is the most efficient way to generate downforce?

Links mentioned in the Willem Toet show:

– How do diffusers work?

a) https://www.linkedin.com/pulse/how-do-motorsport-ground-effect-diffusers-work-willem-toet/

b) https://www.racetechmag.com/2017/08/willem-toet-explains-motorsport-diffusers/

– How wind tunnels work? https://www.youtube.com/watch?v=KC0E0wU6inU&t=4s

– CFD post processing explained. https://www.racetechmag.com/2019/02/willem-toet-explains-cfd-post-processing/

– Willem Toet on Linkedin https://www.linkedin.com/in/willemtoet1/

Learn to Drive Faster and Set Up Your Track Car with Confidence @ https://www.yourdatadriven.com

FULL Transcript


Willem Toet: And I’ve tried really hard to be open and honest and give straight advice that where you say, look, if you had the budget you’d go carbon fibre and all this rubbish.

But with what tools do you have, what can you do?

And there’s always something you can do.


Samir Abid: Welcome to the Your data-driven Podcast.

If you like this podcast, be sure to visit our website at your Data driven.com for more useful help and advice on setting up your race car mastering, data analysis and driving faster.


Welcome to Episode 5050 Shows.

Can you believe it?

Absolutely amazing.

And thank you for listening.

So onwards we go to today’s show and I couldn’t be more pleased to celebrate this mini milestone by welcoming William Tote, the former head of Aerodynamics for Benetton, Ferrari, Sauber and BAR Formula One teams.


He joins me for a very special two parts podcast.

Aero is one of those subjects that gets a lot of airtime on the TV, but it’s often hard to relate that back to what you can do yourself in the paddock.

William has some great insights and some very practical tips.


This is honestly an amazing chat with one of the best in the business.

Be sure to check out all the links in the show notes for some really good follow up videos and articles.

OK, enough for me.

So as over grab a pen, grab a coffee, sit back and let’s listen to what William has to say.


So welcome, William.

Thank you.

It’s absolutely fantastic to have you here.

I’ve been dying to get you on the show for for quite some time now.


Taken a while?

Yeah, sorry about that.


I’m absolutely fine.

You’re here and I’m.

I’m really excited to hear about you and your background.

For those who are listening, I’m I’m sure they will find it absolutely fascinating to have that insight from the world of Formula One and aerodynamics, that hot topic that we always hear so much about the media.


But maybe I don’t always quite know.

Well, certainly from my point of view, how to translate that back to what I can do in the paddock as an amateur.

And So what I do with all of these shows is lay the Gordon down.

And the challenge is, you know, can we work towards one or two takeaways that maybe people listening could think about?


They can go and try and apply, They can look at all of these subjects.

I’m going to, you know, think about aerodynamics, but you know, whatever from your experience will be absolutely fascinating to hear.

So yeah, so that’s, that’s it.

So we have a little bit about you and then and then some of that.

How does that sound?



Yep, happy to talk about that.

Happy to, happy to go there.

So your audience is mainly amateur races or or largely do you think?

Largely yes, although you know most of the Formula One grids do listen now because.

You never know.


You never.

Know there’s always something you can learn, and I think that’s one of.

The oh, there is one of the things that’s always.

I mean, yes, one of the things that we’ve, well, I’ve certainly discovered having done shows like this, I often, you know, just to say a bit on that is that when I started it was very much like you know what can we learn from the pros.


I race as a hobby that I’m a professional, but interestingly it’s the people who almost take it the most seriously or the people who are, you know, more professional who actually always looking to learn.

And so it’s very difficult to define the audience now, but like, we’re all Motorsports enthusiasts.

Because I started, I started preparing a car for a girlfriend at university in the 70s.


I’m old and a little bit preparing cars and motorbikes for myself.

That’s where I started, with absolutely no knowledge or training whatsoever.

And there it’s a place where I was helped by people with knowledge and now being in the lucky position of working in top end motorsport for a long time.


And also in the lucky position that I continue to do some, let’s say, amateur motorsport, some hill climbing.

That you’re in touch with people who don’t have the resources you have in Formula One.

Well then you’ve got to give advice that takes into account the resources that they have and I’ve tried really hard to be open and honest and give straight advice that where you say, look, if you had the budget you’d go carbon fibre and all this rubbish, but with what tools do you have, what can you do?


And there’s always something you can do.

Always, yeah.

I think that’s such a refreshing approach in this it must help actually in the day job having that, always having that sort of resource constrained idea because.

I think it.


I think it does so.

It’s what what do they say?

It’s like you can’t because you do some work with universities as well.

I think and I I I think to to be able to explain anything you really have to sort of know it from from from the the foundation level as it were.


And then, if you’re almost spoiled a bit with the tools and technology you have with a lot of resources, maybe you don’t quite always understand it.

Quite as well, yeah.

So I’ve got one, a little example of Formula One gone mad and being careful with resources.


I’ve always thought a lot about using, let’s say, the most precious time.

I’ve never considered my time to be the most precious thing, although the truth is you only have so much time on the planet, if you know what I mean.

You We haven’t invented the Live Forever pill, and thank goodness we haven’t, because we’ve got a big enough population problem as it is without the Live Forever pill, and so you have a limited amount of time on the planet.


So it is the most precious resource.

But I’ve always thought, OK, what is the thing that’s limiting?

Let’s say the development of this project we’re working on and quite for many, many years it was time in the wind tunnel.

So when I started, my first aero project was actually without a wind tunnel at all, was in Australia working on a formula, an English formula three car or you, let’s say European, but it was English formula three car taken to Australia and to be converted to race in Australian Formula Two.


They had different powertrain requirements.

You had bigger tires you had to use or could use, you had different aerodynamic regulations.

And the first thing I actually learned about was the suspension didn’t work.

It just didn’t work with the much bigger diameter tyres we had for the Australian regulations.


But it was a March, it was a March 793 and March came with different pickup points because they sold these cars around the world.

So with no engineering knowledge at all, my first degree, my degree at university was in biochemistry and genetics.


Wow, nothing motorsport related.


I fell in love with motorsport through my first wife, a girlfriend at university who wanted to go racing.

Who’s going to prepare the car?


That’ll be me then.


Young, enthusiastic man.

Well, I think a lot of parents listening maybe over that situation is, oh, that’ll be rebid.

I’ll be the sponsor as well.

Go on.


Let’s go for it.

And she was at least as quick as I was.

I’m, I’m a very enthusiastic human in everything I do.


And she was at least as quick as I was driving a car.

More, let’s say, refined.

I’m very step beyond the limit.

Then take a tiny step back and see if you are then on the limit.


And she would approach the limit instead of sticking beyond it, instead of leaping beyond it, and very, very quick.



But who’s going to prepare the car?

Well that’s me.

So I learnt about motorsport and the benefits if you like, or the fun that it gives you.

I learnt from doing and then there were various experienced engineers and drivers who helped with advice.


I’m sure it didn’t hurt that having a girl driving, being able to compete with the boys at that time in the in the 70s would have been mid 70s.

It was before the March 793 and the mid 70s.


Having a girl driving against the boys and being completely competitive, like winning races in one make touring car series, winning races in Formula Ford’s really competitive against the best of the boys.

That taught me if you like a lot about motorsport and how and how difficult it is to be competitive and so I’ve learnt a great deal.


For example, you have a one make touring car series and you’re not allowed to change much at all.

For example you had to use in the first series you had to use the standard springs and standard dampers and so an old an old hand an old racing hand said OK well you’ve got to use standard springs but there’s nothing say that the springs have to be really really new and people had tried going to taking the springs to in Melbourne it would be Melbourne, Australia where I grew up it would be central springs in Melbourne and they would take your standard springs and reset them for you.


But that was illegal and you could and all the standard part paint markings were gone and things like this.

So you just I I I found a breaker’s yard now in English in England it’s a Breakers, In Australia they call them wreckers.

So I found a wreckers yard and there was, this was for Renault Twelves going back a bit and this Renault do us a Renault 12 at the bottom of a big pile of cars.


And I said I’d like the springs from that 1972 Renault 12 and the mechanic in charge, Oh no, we don’t need to go there.

So we’ve got a nice set, a nice use set in the office, ready to go.

And no, no, no, no, I want those.


Well, that’s $20 extra then, you bastard.

Excuse my friend, that’s $20 extra UB because we have to take all those cars up and and that takes anyway, I waited, I got the springs and they’re like an inch lower than standard springs.

So then I’ve got completely standard springs for this car that are an inch lower.


You’re not allowed to lower the cars.

You’ve got to use standard springs.

And so you learn with a road car going racing, OK, you have to use a standard springs where you want to get your centre of gravity lower, so then inch lower and brand new dampers because they’re going to be as good as you’re going to get.


Or used dampers not not much damping, not what you want.

So that was my first lesson and then the next lesson was, OK, you’re not allowed to blueprint the engine.

Well, you’re allowed to blueprint the engine, as in you can select parts, but you’re not allowed to take any weight off.


So to balance a set of Pistons, you couldn’t you.

You weren’t allowed to even grivble anything.

Nothing was illegal.

But you could go to the main importer for Renault and weigh the 400 Pistons they had in stock at the main importer at Renault.


And the reason they had 400 Pistons in stock is this was the days when things were not that reliable.

And two things, one, they weren’t quite as reliable, but also it was we had the ethos back then of you make it last 25 years and you have therefore you have to rebuild it and we don’t have the same ethos and maybe some of that we have to go back on.


But that is another subject altogether.

So then I’m.

Waiting 400 days today that things are still a little bit we we had an example in our race series where we have a standard Cam, it’s a printed Cam.

You have to use this Cam and the manufacturer of said Cam is, you know, it’s not an industrial global giant.


They’re variable.

So it’s reasonably common.

Well, again, we, you know, we bought five of them and measured them all, chose the one we like the best and sent the other four back.


Well, so I did that with a Pistons.


So you then select four that have the same weight and other there’s maybe one that was lower but you said four the same weight, minimum weight.

And I did the same.

The engine builder I I spoke to suggested weigh the big ends and small ends of all the con rods you can get.


So I did weighed all the big ends, all the small of the con rods and you have a set that are 4 the same and he told me what the target should be but basically the lightest and balanced and then measure all the camshafts and they probably had 50 camshafts.

I measured the lobe and measure the the maximum.


Effectively you’re looking for the maximum lift.

Yeah, so we did that.

That may have helped my girlfriend at the time to be doing well in races, but she was also a very good driver.

And when you get when you get side to a Formula Ford, any advantage you may have in the vehicle is gone.


The that’s incredibly competitive.

And then we split up and I thought, OK, was it only her?

Or really, is motorsport something special?

Wouldn’t it be?

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And for me, what was really special is I could make a difference today, race it tomorrow, or even make a difference with the set up of the car and see it race and you get this instant feedback.


You’ve done a good job or a bad job instant.

And that hooked me completely.

And then with the with the March, I didn’t have any clue back then about suspension kinematics, but I’d had some advice for some from some really sensible or so a guy called Frank Gardner, an engineer, race driver, Australian, but also raced in the UK in tin tops against it.


In the era of Jim Clark, that sort of era, he was a better engineer.

He was a really great driver, but not Jim Clark.

He was fantastic.

But who do you, how do you beat a senner or a Jim Clark or?

Yeah, it’s hard, but he gave me some really good advice just just to open your eyes and look.


And with this March, I literally took some strips.


I measured up the car, looked at the potential pickup points and looked at what you could adjust.

Got a bit of cardboard on a table, some strips of cardboard for the suspension legs in front view and literally move the upright up and down.


The pretend upright up and down with no spring or no damper just to see what happens to the camber.

Where does the contact patch go?

Does it go sideways?

Does it just go up and down?

And then that, for me, was an absolute revelation.

Amazing, isn’t that?


Yeah, that cardboard.

Can we call it I?

I used to work.

With it exactly.

Cardboard CAD.


I I took that later when I came to England.

Later I took that, put it into a little computer program and that and I’m I’m remembered to draw things like the effective swing axle length and to draw the suspension moving.


Because I was a little bit worried about my ability to program the maths correctly, and I figured if I drew it, I’d see when I’d made a mathematical error.



So and it’s so easy.

These these.

Error like you get assigned the one really easy geometry really.


Easy to make mistakes and and having a way of checking and then we also had different aerodynamic rules with this March that we could use in Australia.

Things like you could have wider body work, wider wings, you the rear wing could go further back.


So we made a few one steps at a time and for example we made it had a almost like a sports car nose on this open Wheeler and we were able to go wider.

So we made a wider sports car nose and the thing then oversteered like a pig.

It was like, wow, much more front grip but really dangerous to drive.


So then we just made a wider rear wing and moved it further back.

And then we had a car with much more downforce if we needed downforce.

Or you could just wind it off if you didn’t.

So I’ve got a question for you on that one.

So you’ve experimented there.

So I have this thing where I’ve got a little sailing.

You know, you don’t learn from experience, you learn from experiments.


And the reason that I find that empowering is because a lot of the time in the paddock, certainly when I’ve in there, you know you you go out and you try something, you come back and it’s not quite what you expected.

And a lot of good advice Paddock folklore, I call it, you know, from people who are all around, you know, and they’re they’re throwing ideas and solutions at you And all of them sound credible And it’s like and and you end up but some can be completely opposite.


Like one could be like, oh, you go this way and then the other could be that way.

And they’re both completely credible.

And you’re like, they’re all great.

Thank you.

But I’m not.

It’s not helping me work this out.

And one of the things with the experiment is you have to kind of predict what you’re going to do beforehand.

You have to sort of lay it on the line.

So I’m going to change this and I expect this happen.


But if it doesn’t, it’s probably going to be because of the XY and Z reason or whatever.

But but also it doesn’t get you down.

You just sort of go, OK, that that happened and let’s just try and work out exactly what did actually happen, not what we assume happened.

And then once like it’s spend a little bit more time on working out what happened then jumping to a solution but then not get down about it.


And just so it’s OK well, how do, what do I do?

Do I reverse out of that or in your case what you just said like I will keep that but then I will compensate at the back of the car do.

So I mean the reason it was oversteering or whatever is because I’ve now got more grip at the front than I had before, which is a good thing, you know.


So you’re like I want to put some of the back to to balance the whole thing out.

Say how did you deal with that?

Like, were you, Did you have that thought process or were you?

Were you thinking, Oh no, we should take it off?

Precisely that.

So there was a switch in my head about.


I was about 7 years old.

My dad had died when I was six.

I had a really tough early life.

I will not go into it all, but I had a really tough early life.

Dad died when I was 6.

Mum’s on a widow’s pension.

She had five kids, one on the way, so six kids.


We had no money and between us we had one cheap alarm clock and it would be taken from the from mum’s bedroom into the lounge room.

That would be our clock.

And on my way one day I dropped the clock and it broke and my mum was very upset and as a 7 year old I thought well yeah, that’s my fault, I broke it.


What do I do?

And with my younger brother, one of the things we used to do.

On the way to preschool and school, which we’d go wandering, we’d take the long way, we’d go via the tip and have a rummage and just see what was there.

That was interesting And we found an old clock and I went to a watchmaker jeweler with my broken clock and asked could you fix it?


And he said, look, it’s a Woolworth’s clock, you go, you pay you 2 Aussie dollars and you buy another one.

Well, we’re $2.00.

I’ve saved up a penny.

Can you fix it?

No, but someone gave me a couple of broken clocks and I think it was one of these watchmakers.


Look, here’s a couple of broken clocks.

One’s got the same thing wrong as yours.

Leave that one alone.

Here’s one with something different.

Maybe take that one apart and have a have a little bit of a look at it and see maybe what’s wrong.

Take the back off and have a look.

So I took the back off and two main things go wrong.


If the clock’s not like worn out completely, you over wind the mainspring and you break where where the mainspring?

Right in the root of the mainspring where you where where you wind it.

You break it.

That’s one thing that goes wrong and the other you have a little lightweight spring that does the timing.

It’s like with a mass that does the timing and it has two little pins that go on on onto a gear that allowed the gear to turn, not turn, turn, not turn, and and one of those pins will break.


That’s what was wrong with mine.

And by looking at the clock with the broken spring, all I needed to do was replace the spring from one of the two clocks that didn’t have a broken spring.

I had a working clock and presented it to my mother, and I was the smartest man on the planet at the age of seven years old.


After that it’s it gets harder.


But and.

That that feeling.

But what that did is it told me in my take was if you understand how things work, you can fix things.

If you can fix things, you can make people happy.


So I’ve from that moment I started a little mini clock repair business, earning a penny, which that was a big deal for us, yeah.

And so started repairing clocks and just got me into loving the idea of understanding mechanisms.


And so that applied then to suspension on the race card, applied to the aerodynamics on the race.

So I do have this philosophy as what can you open up without doing any damage?

You know, something stopped working.

Can you take the back off carefully without doing any damage where you can certainly take the back off and have a look.


Now there are some things that are quite dangerous.

You let’s say AT VS broken and and an old style TV and you take the back off and it’s got some big capacitors.

They can retain quite a powerful charge that’ll give you a shock months after you’ve disconnected them.

So you have to be careful.


But what can I do?

Opening something up and having a look.

And for me the same applies to tuning.

Yeah, well I’ve I’ve electrocuted myself when I shouldn’t have.

Doing something silly.

Yeah, yeah.


Anyway, that’s.

It’s a philosophy though, isn’t it?

That’s a philosophy.

It is something that.

Lots of that.

Take the first step, see what you can understand.

And so, and I did the same.

So there are a few things happened that that allowed me to make steps in life.


So I’ve got the wrong degree for motorsport, but I’ve got this attitude of investigating and I’ve got a certain amount of experience than preparing cars and while at university.

So I left home young at 16, needed to finish school.


Two years of school I needed to finish, had to figure out how to effectively put myself through.

So I was very lucky that a young couple who was starting a family took me on as a foster son for a couple of years.

But in the end, then, you’re still trying to look after yourself.


And then once I got to university, I’m then an independent human being.

I have a scholarship to pay my university fees, which was fantastic, but I needed to live.

So I had a job working in the university union, washing dishes, serving tables.


I had a job on mowing lawns for a school that had extensive sports fields.

I’d had a job as a kid anyway, as a paper rounds and things like that.

I was used to working and then I got a job night shift while I was at university Thursday night, Friday night, Saturday night, pumping petrol at A at a petrol station.


So then Friday lectures were hard, you understand?

Yeah, because you’ve done Thursday night shift all night and then we can’t really go to bed, can you?

What do you do?


And so yeah, Friday lectures were a bit dozy for me.


And then you lose every Saturday because you do Friday night, you know Thursday night, Friday lectures Friday night, then Saturday you go Saturday morning you go to bed, you just completely cream cracker.

Then you just sleep through and the boss bring the boss learnt 1130.


Ring me up so that I’m there for midnight just for the proper start of their right but it was really a late night shift and.

But that when in those days cars were less reliable, a car would come in or be towed in with a problem.


You open the bonnet and you have a look.

What it’s not going to hurt to open the bonnet.

You might see some and you would see things like it’s got a terrible misfire and it’s night time.

So you open the bonnet with this terrible misfire and you literally see a spark coming through the distributor cap because you today’s engines you would see nothing because it’s all completely hidden.


It’s all undercover.

It’s all tightly packaged.

But in those days the engine was well exposed.

There’s plenty of hand room to get around and and we used to keep distributor caps in the office.

So you just oh what make and model.

Look up the distributor cap, replace the distributor cap.


Make sure you remember the order of the leads.

Put the leads on carefully and you’ve solved the customer’s problem.

And again, you feel very I love it when you can solve someone’s problems, yeah.

You may know that at the end of season one I read the Motorsports Playbook, a summary distilling the 1st 20 shows into Nuggets of wisdom.


I made the notes so that you don’t have to you’re not got it yet.

Go and grab yourself a copy from the website.

So that got me more knowledge if you like about cars and what goes wrong and and so same sort of attitude and then the same applied with the aerodynamics on this Mark 793 that a wider nose gave you you you didn’t get any drag change really at all.


You took drag off the front wheels and put it on the bodywork that was generating downforce and and then the rear wing by moving the rear wings further back and reducing its angle you were able to balance that that nose have the same drag as you had before but have a car with more downforce and it was like Eureka like wow.


And we we so much so we almost didn’t believe it and we did a back-to-back test because you just changed the nose cone and put the old rear wing back on and how did we met we had a new wing so.

If someone is listening, thinking, yeah, I’ve got like something, you know, that I want to explore with my arrow or whatever.


I do have a reader question actually for you, which is kind of we could we could throw it in now and it’s about like if of all the different parts of the car, you know, what’s kind of the most efficient to least efficient part of a car to change.

If you were changing something for exactly this kind of thing and you know and then how would you, how do you know if it’s making a difference?


And I might I might feel it as a driver, but I might not as well.

So is there something that I could do to help me determine or not?

You know, I’m getting less on.

On US sports car or an open wheel car.

So focus first on open wheel cars, the most efficient device.


If you’ve got any scope at all to do anything, there will be the floor.



So the bit you don’t see.

The bit you don’t see, a front wing will be the next and the rear one will be the least efficient.


And that is efficiency.


For aerodynamics, is the ratio between how much downforce it produces Compare more compared to how much drag it has, and so a floor.

So I’ll give you 1 crude way of estimating the form drag of an object.


So let’s take.

Form drag as in the shape like.

Yeah, the drag caused by the shape, so two types of drag.

There is skin friction.

So if you blow, if I blow over my phone, I have skin friction.

But if you put it at an angle and move it relative to the flow, so that skin friction is not going to be 10 times as much when you’re at an angle compared to when you’re on the flat, it’s it’s going to change but not dramatically.


But if you think so, let’s take our phone and we put at an angle and we’re pushing it through the air in this direction.

OK, we’re going then if you think I’ve got pressure acting on a surface, so I’m increasing the pressure there and I’m reducing the pressure there and I’ve got this angle, then that’s going to tell you the angle of the force.


That’s the angle of the pressure force that will have.

And let’s say the average angle is like that.

Then you’re going to have if you’ve got a difference in pressure between the top surface and the bottom surface, then the angle that that that force is acting is at 90° to your surface.

So let’s say like this, you’re going to have a downforce to drag ratio of [12:50].


Look at the rear wing, you’ve got a downforce to drag ratio of 1 to one or two to one, say, or one to one, OK, That’s why that’s your efficiency right there.

Now it’s not the whole picture because you’re missing skin, friction, drag, and they’re all sorts of you when you get into great detail.


There are lots of details it gets really.

That’s the lovely thing about we’re never short of complexity and detail and I think one of the big challenges to reverse out but one of the as often as possible.

But one of the things that I really love about the time I have in my life now being able to pass on what I’ve learnt is you can strip away some of that complexity and find the essence that let’s you make progress without needing the higher degree in mathematics and without needing all those layers.


Understand the complexity because it is complex, but look for where it could be relatively simple.

And so efficiency you can, If you just think how much air is going in the front of my device, how much air is coming out the back, What’s the average angle of attack of that device.


And that’s going to give you a clue about the efficiency.

It’s only a clue, but it works.

For say front wing, floor rear wing it works.

Yes, I almost like taking it as a black box and saying, well I’m I’m sort of pushing it at this end and I’m getting this output over here.


And if I sort of adjust the angle ever so slightly I’m going to get a different output for the same in in effect.

And then and in a way you could just design some experiments with your car with maybe ride hype or in your case different wing settings or whatever to try and like work out OK what difference has that made if if if any.


I had a guest on a little while ago and he is a aerodynamics expert as well and he he he suggested a couple of different tests that you could do practical tests looking at tough tough testing and wool and yarn and things which was all the big news for me.


But also this idea of a top speed test so or or at least a speed in a in a particular gear.

So you sort of go flat out in a particular gear and if you you know depending on the speed that you got to was was related you know that’s that sort of portion to the drag that you have so is.


That so that’s quite a good way How fast you accelerate given certain conditions.

Coast down is another equivalent thing.

You go to top speed, suddenly stop in a consistent way, everything consistent.


But suddenly just say if you’ve got a manual car, put it into neutral, decide you’re going to take the put the foot on the clutch or not on the clutch.

But everything should be consistent, so the higher the speed, the more accurate your measure of drag will be and you just compare the rate at which the car slows down one run to another.


If you’ve changed something on the car it’s pretty.

In the end good experiments are simple and bull Tufts, so if you want to make a lot of cotton or bull Tufts to put onto a car then I suggest you take a sheet.

So here I’ve got just a, let’s say an A4 ring binder.


Yeah, take your cotton and wind it round something.

It might be a sheet of aluminium or sheet of steel.

Take a cotton, wind it round and round and round, tape it, Tape it at the beginning and the end.

Then take some strips of tape and put them downwards and then cut beside one edge of the tape and then you’ve got lots of cotton stuffed made all at once.


That’s the matter.

That’s it.

I don’t know because I’m you’ve done that.

Before, I’ve done that a lot, because imagine one at a time sticking around.

Time is everything.

And so I was going to explain right at the beginning.

I was going to explain a Formula One, things gone mad, so we started wind tunnel testing.


My first was 2 shifts in a wind tunnel to design the bodywork of a car. 28 hour shifts.

That was all we had and you had to design the bodywork of the car and two eight hour shifts and that was done for the Bovis sponsored Aston Martin Nimrod that ran in 1983 and 1984.


We did the work in 1982, two eight hour shifts.

We doubled the downforce of the car with two 8 hour shifts.

You take the standard as produced 19811982 Aston Martin Nimrod and we doubled the downforce with new bodywork.



And that was another two hour hour shifts.

But then you get to Formula One, it gets harder and people have been working for years.

Yeah, but when I first got to Formula One it was an 8 hour shift, Five days in a wind tunnel, three weeks out.


Say it a weekend.

Three weeks out.

A week in, three weeks out.

It was an ex military facility still managed by the military.


You arrive at [9:00] and we stop work at [5:30] and you have an hour for lunch.

That was that was your day.


And if you wanted more, the boss would say Can you convince Alan in the wind tunnel to work on for another half hour, please?

Give him 20 bucks and I’ll give you the money back when you get back to work.

And what about us, boss?

Do we get any tip ourselves?


You’re dead.


You just get hold of you, the privilege.


You’re working here, yeah?


Well the the, the, the contract was you do whatever hours are required to get the job done.

Yeah and that was long hours.

And so anything like putting Tufts on would be part of even in Formula One at the end those days it was part of what we did you you looked at the airflow.


Especially for someone like me without the theoretical training that I should really have got myself early on in my days in Formula One, it was very helpful to get visual cues as to what the air was doing.

So a really useful thing will be a tuft of cotton on a wad.


So we would have just a metal rod with a just a little bit of of wall on the end of it and you could move that.

We had the advantage of working with an open working section wind tunnel.

So you could just take a long rod and poke it into the air flow from outside where there was very little flow and and just look at what the air did and move the the rod around to see, well, there’s nothing stopping you in say on a closed track doing that sort of thing or taking a few Gopros or a GoPro, point it up at a particular part of the car, plaster it with Tufts and have a look at what the flow is doing.


Yeah, it can.

Yeah, you can do that.

What do you look for in?

What do you look for in a tuft?

It’ll depend where, OK.

If you want all over there, all I know.

If you want low drag.

If you want low drag, you want the tuft to be pretty much stationary in a fixed position.



So it it it doesn’t move around like crazy.

Yeah, yeah.

And say on the upper surface of bodywork and wings, if you want clean flow and you’re in particular if you want load drag, it has to be nicely settled.

The air you if you if you create a shape that is too extreme, the air will separate.


That will cause turbulence.

And then you know just ahead of that point, if you want to smooth, you want to load drag body just ahead of that point where the air goes turbulent.

You want to add some material to make the shape change smoother so you can.

The best shape is a very very elongated teardrop is the best shape, very low drag and the difference is like [12:50] or more if you take a round bar.


The front of a round bar is good, The back of a round bar is a disaster.

And you you go to an elongated, like an elongated teardrop so that you have a ratio of say 5 width to to A5 length to 1 width.

A really elongated teardrop.


And it’s likely to have 110th of the aerodynamic drag of a round bar.

Sorry, a 10A. 10 a 10th.

Yeah, a 10th.

It’s staggering.

That’s what I asked.

What I think.

That’s where I think aerodynamics like wow, what?

No, that can’t be right.


Yep, that’s right.

And so for example, if you have round wishbones, you can you can put a teardrop like shape around the outside, make it a bit bigger and still have less track.

That’s very cool.

And that’s it for part one.


What a fascinating story so far, and a tough background that William has had.

Little did he know that he was fixing that clock at seven years old.

Possibly the rest of his whole life will be dominated by trying to beat the clock in future.

Hope you got as much out of this as I do.


Remember to check out all the links in the show notes and I look forward to having you join us again in Part 2.

If you liked this episode.

Be sure to subscribe to the podcast and visit us at your Data driven.com.