Do Rear Wings Work on Convertible Race Cars?

[@TurboSunShine]

There is a missed opportunity here also exploring how the pop-up headlights affect the rear wing xD. Jk. Great video!

[@autumnrain7626]

Didnt think I'd see you here mate. Love your work on thingiverse!

[@TurboSunShine]

@@autumnrain7626 haha, thanks!

[@danielskrskr]

That's actually a thing! Confirmed added drag at highway speeds when the lights are up. Just might possibly affect the wing's downforce but I think it would be negligible if at all.

[@PersonManManManMan]

That is interesting question to research

[@shadow105720]

@@danielskrskr they could create a vortex that runs along the top edge and flows into the wing. I would actually like to see the fluid dynamic effects beyond "adds some drag" and also how it interacts with a convertible up and down and with a wing and without just because.

[@User10111993]

I used to have a Miata and this confirms what everyone told me about wings. if you're gonna do it go big or go home they say make it higher than the roof

[@s.lacasse8337]

Go big cut de windshield!

[@boobrowsky]

@@s.lacasse8337 and ur head so it's not in the flow

[@s.lacasse8337]

@@boobrowsky Im a bit cocky but my head still fit in a helmet. A roll loop and a helmet as a small frontal area.

[@allorfh2495]

just transform the miata into a speedster with a huge wing

[@lamborghinitestarossa2133]

Don’t make the wing too big. Once your wing is in space you will lose downforce.

[@JLewisRacing927]

"Much more than any sane person would put on an MX-5" *Cries in Jimmy Broadbent*

[@KYLEENGINEERS]

Hey Guys, sorry for the mic in shot and the somewhat questionable audio, I just moved and the echo level in my new room is absolutely insane! Will be doing some acoustic work on it in the new year for sure. Hope everyone has a great Christmas and New Year and I'll see you all in 2022!

[@DogZy9]

Commenting even before watching the video. Have a great Festive season you too, Kyle!

[@something7992]

Good too see your back

[@boobrowsky]

Hi just hang some rugs or blankets on big flat surfaces of wall and put some stuff in corners. May be it's bit ghetto style studio solution but takes only about an hour to set and reduces echo significantly. I done some Internet radioing doe years ago and it was may be not pro lvl but far better than nothing

[@flamingronin]

Microphone being in shot ruined the immersion for me

[@matmay]

Didn't notice even

[@Mr16bit]

Do you think vortex generators like on the roof of an evo would help the factory top keep the airflow attached down the rear window better?

[@SomeTenth]

There's definitely potential for that!

[@BrokeWrench]

Yes, I've seen a comparison of the airflow to the rear wing for an evo with vortex generators and an sti without, and the evo configuration works much better

[@Kett_22]

A hardtopspoiler would be interesting too.

[@Kalimerakis]

It might make a slight difference, but the separation bubble is so big and the angle on the roof so steep with relatively sharp edges. I doubt it will do a lot.

[@boykorolyuk]

If you watch Hartman aero videos he's tries lots of stuff in the wind tunnel. And they were a disappointment

[@khalifaskho4223]

still from 2020 and till now you look tired no joke, but the content and the detail of the information on every videos are worth it. Absolutely love your video man

[@jubuttib]

Really interesting video! This definitely covers the most common case of traditionally shaped roadsters/convertibles that people can actually afford, but also raises the question of whether the more "purpose built for speed" convertibles behave. Stuff like the convertible versions of many Ferrari and McLaren cars, or an even more extreme case in the Pagani Zonda Cinque Roadster. Cars which have significant structures and most of the shaping still there behind the drivers, instead of this classic design with essentially nothing past the A-pillar, except maybe the quarter window. Basically getting into the territory of "can you make the aero on a convertible work without going all out to something like an LMP900 car", with a normal windshield and a wing that's not lifted high up in the sky and twice the width of the car. =)

[@paddyneill1964]

I watch your video on removing the bumper in order to use the rear end as a diffuser. Along with this video they have answered a lot of questions I've had since I started working at the local track. I've seen top up/down, no top at all just roll cage. One had no windscreen and an active aero rear wing. Rear bumper on or just a couple bars welded on. I guess it boils down to the series you're racing in and personal preferences. Bravo Zulu sir.

[@philpunxsutawney9411]

Thanks Kyle ! very interesting. Would you test a no windshield condition for a race Miata. I know the frontal area would be reduced by 50% ish but I would like to see the effect on the rear wing.. probably less wing will provide more or same downforce with less drag. You're the one who can answer that for sure !!

[@quinvarela1050]

I second this.

[@davereynolds8209]

I am thinking the same!

[@shaggyshaggadellic1955]

Yes! I use my pop ups as flaps to help slow me down. Do a video on the pop up drag! It has such a drag they made specific wiper holders for the mx5.

[@Azulevo]

There are several hundred of us that have converted a Miata into an exocet. While saving huge weight, the aero is horrible. There are some things that could be helpful though. Obvious ones are no windscreen, cover over passenger side (no passenger seat) and probably large wheel fenders. But your take on what could possibly be done to improve aero on an exocet would be fantastic, considering the majority of Exocets are built to drive on track.

[@stephenhawkingMLG]

Okay but this is only for the NA, the NB has significantly redesigned aerodynamics. Could you do this for the NB and also include ducklip spoilers bc they stick up a bit higher than the lower lying spoilers?

[@nehok]

Super interesting! Thanks Kyle, I have often wondered about this myself. I Think a fair few miata people will be watching this one. Definitely curious about how effective vortex generators are on the air down the back of the hard top also. Would also be interested to see what if any benefit on the rear wing swapping the mirrors to so a small race mirror type there is.

[@flipflop7577]

Watched it🙋 miata owner....with a ducktail spoiler....🤫😅

[@nehok]

@@flipflop7577 Same here! I have a hard top tho, so extra interested in vortex generators. Good 3d printing project.

[@kriswashburn7945]

Thanks Kyle, this is wonderful information as always. Roofless miata owner here, I'd love to know if there's anything I could do to improve air flow without a roof with a ducktail. Would a Gurney Flap on the top of the windshield help or hurt? Would vortex generators on the top corners of the windshield help? Or at the bottom near triangle windows? Would covering the passenger area with a tonneau cover make a difference? Would a bikini top wrapped over the roll bar help? I'd be happy to toss some money towards this type of testing info on Miata's and I would think and hope other's would too. Do I hear a gofundme? or similar option for this? Thanks again Kyle!

[@danielskrskr]

@@kriswashburn7945 I think you meant to make your own comment. You replied to someone's comment^

[@Jordan-jx5xg]

I just discovered your channel a day or two ago and I have watched all of your videos since you came back to KZbin one year ago! Being interested in cars, tuning and aero myself, I am absolutely enjoying the hell out of your videos! Cheers to you and all your wonderful knowledge

[@ValentineC137]

Putting the roof down is the Miata’s secret budget DRS

[@EliteSniperTV]

Gotta hit 60 at some point 😅

[@Toadatx]

I was wondering if you could expand on this with a popular race configuration of a convertible in which the windshield is removed? Perhaps one with the cockpit open and another test with a tonneau that encloses the passenger area with the exception of the driver? I know the necessary roll cage and the drivers body would disturb airflow to the wing to some degree but it would be interesting to see if it is worse or better than either of these two configurations.

[@DingoZed]

I've been waiting a long time for this video to pop. Thank you so much!

[@zzzz1192]

I was so stoked to see you post, you videos are so informative and quite interesting, especially when you use common cars that a TON of people modify. I bet if you tackled the most common cars and modifications, you not only would have a bunch of "material" but i can only imagine the algorithms/the amount of clicks/connections would be wild because people are already searching those cars and mods. Could even "mock" items/brands and run them side by side in test.

[@torrb3n]

This video gave me great insight in what to do when I will finally track my s2k, thank you for the upload!

[@olivid3]

Great video as always! Would be interesting to see the effect of a bumper cut on a MX-5. There are a lot of arguments about it on the forums but no clear data.

[@Pocket4ce]

Already done, check out his video list.

[@nehok]

@@Pocket4ce The last time he covered cuts it was a little simplistic, (fair enough too). One of the main elements of the rear bumper that miata people discuss is how from the inside it looks like a scoop or parachute. Some people will cut a few holes in it with for this reason. (totally ineffective I would think). So the cut is thought to be sort of doubly effective on a miata. In the model on Kyles sim there is a bit of a cavtity on the stock bumper but not as much as there is in real life. Though saying all that I imagine that everything he says in that video still holds true despite this.

[@Pocket4ce]

​@@nehok Small world, ex-spec Miata mechanic here. We've never cut the bumpers in our spec cars, but our SCCA STL cars had the bumper bar "relocated" to make room for a cut even with the trunk floor. We didn't bother with cutting holes or anything like that. I've actually consulted with Kyle on the aero package of my autocross/track day car a few months back and left with a really novel solution to rear aero. I am more than satisfied! JKF Aero's standard fees are super reasonable (more than you would imagine) and honestly, a huge value. I suggest shooting Kyle an e-mail! He is a busy guy, but I'm sure he will respond.

[@nehok]

@@Pocket4ce Cheers! Sounds like you have far more experience than I! I just track my miata atm, though I'd like to do some sprint racing in the future. I find aero tuning a really interesting avenue to get faster. Especially as there are very little reliability downsides as aposed to adding turbos etc which i'm lothed to do. When i dirve my car to the track and you think about the amount of money each day costs.

[@philb8437]

An analysis of a targa top like the RF with center portion removed would also be nice to see. I wonder how much the open portion would change both the drag and downforce

[@JerGol]

A quality write up, very informative and well researched. Could I briefly note my appreciation for the rear spoiler on the back of your head? 11/10 on commitment to the subject!

[@rolandotillit2867]

I would love to hear your thoughts on the 2022 F1 cars and their pitch sensitivity. The Indy car guys have more experience with ground effects than F1 guys. Honda is powering enough Indy teams, if I were Red Bull and or Honda I'd be on the phone to HPD powered Indy teams and get as much data on car setup as possible. McLaren already has an Indy team, probably gonna help them tons with the new car. If nothing else they have a setup direction.

[@mr.kroket]

How are the next 2years in formula1 looking to you..?

[@rolandotillit2867]

@@mr.kroket Next year they may give the 2020 cars a run for their money, 2026 will be disappointing if they keep things as they are.

[@xavierrodriguez2463]

I have a question that might make for an interesting video. On modern passenger aircraft the wingtips have upwards pointing wingtip devices, designed to act as fences that reduce the high pressure air flowing from under the wing to over the wing reducing lift and creating a vortex that increases drag. I know that the endplates on modern race car wings serve functionally the same purpose. A consideration of aircraft design is wing sweep, which turns a portion of the flow over the wing from running along the chord, to running along the span of the wing, this reduce the speed of the air going over the top of the wing and reduces shockwave formation at transonic flight. This span-wise flow has an effect on how much air is forced towards the wingtips and can add to the vortices generated at the wing tip. There have been some aircraft (such as the HFB 320 Hansa Jet) designed with forward swept wings, where the span-wise flow flows inward towards the fuselage. (among other potential advantages and disadvantages of forward swept wings) I heard that an advantage of this, is that it reduces the intensity of wing tip vortices, as there is way less air flowing towards the tip, and way more flowing towards the fuselage, where the fuselage acts like a giant fence. My question is, would a rear wing on a race car, if it was swept forward, reduce vortex drag in a similar way? I know that the rear wings of some sports cars and super cars are curved inwards (Such as the Koenigsegg Jesko), but I'm not sure if it's a stylistic choice or an intentional design choice that takes advantage of this effect.

[@marcobrancorsini2479]

How would a rollcage affect the aero? I'm really curious to see

[@gummostump4217]

Furthermore, I'd like to know how a rollbar would affect aero on old convertibles with cut/removed windshields

[@ChrispyNut]

Well that was almost what I predicted, however I didn't predict the use of a wing that was almost 50% wider than the vehicle, which is basically what through off my prediction 😀

[@jonahmingo]

Is it more aerodynamic to have a fender flares/wide body or a wider car with smoother sides if the width was the same?

[@engineer1692]

Smooth side is more efficient.

[@herlegz6969]

What about with wind deflectors many convertibles have that can be raised and lowered while driving, usually in the rear seat or just behind the front seats.

[@jake10386]

You should add something about having a hardtop or a fastback that can really tell you about the air seperation issues with different configurations

[@saienide9301]

good god... during the flow analysis i noticed that when you have a wing not only does taking the roof off reduce the effective area of the wing but it creates huge low pressure zones right behind the supports due to how the air moves. note to self, keep the roof on

[@turdferguson1021]

Love this channel. Please do an MR2 Spyder.

[@juanpablocorreiaecheverria2857]

Hey Kyle, could you make a simulation to show why the back of some SUVs are so squared (like the Chevy Equinox or Honda CR-V) yet, they are very aerodynamic vehicles.

[@sqmotorsports9230]

All these studies assume essentially "flat" oncoming air / level ground, but what happens if the front of the car is pitched up or down? I run an ND Miata with the Balckbird Fabworx lexan spoiler, which is primarily designed for autocross. However, last month at Road Atlanta I was doing about 115-117 on the back straight and as the car changed pitch all hell broke loose - the rear end flew up off the ground for what felt like an eternity. I took the spoiler off and it was fine for the rest of the event (top down at all times) but I'd love to see what that rear airflow looked like

[@ninelivesracing]

I would like to say we are the insane Miata wing people. :) thanks for the video kyle.

[@ProjectDuckHQ]

Very good video, great analysis. I do wonder though, what would your take be on the soft tops? They typically have the same general shape as the hard tops (well, with the humps of the supports) but probably have higher drag due to the texture of the fabric. I would assume that they would be somewhere in the middle, but my guess would be the higher end since it resembles the shape of the hard top. Would be great if you could make an analysis on it!

[@yo_its_devo]

My basic understanding of fluid dynamics leads me to guess that the texture has a negligible effect on drag when there are much larger forces at play from the pressure distribution. If anything, the slightly textured and non-uniform surface of the soft top may behave like a golf ball and create a slight layer of turbulent air around the top. And in principle, just like a golf ball, that turbulent layer would help to reduce the wake produced by the top as the flow "bends" back down towards the trunk. That's all highly speculative though and now I'm curious to see an actual analysis haha. Not sure how easy it'll be to simulate a soft top in CFD though.

[@stevesloan6775]

Good to see your content come up🎅🏻🤜🏼🤛🏼🍀🇦🇺😎

[@Scotracer1987]

What flow velocity are these cases done at? How sensitive is the wing performance to speed?

[@blakeandrew5058]

Could you do a video on space frame vs monocoque chassis and how they compare in rigidity, weight, etc.?

[@leokaravasili9649]

I havnt seen any proper videos regarding WRC aero, they have a massive rear wing which would indicate that they have pretty decent downforce at the front but they only really have a small splitter, no venturies, wheel arches and pressure cut outs at the front so im struggling to see how they have so much front end downforce that they need such a large rear wing for. Can you make a cfd video on this pleaseeee

[@Calicarver]

I bet a properly shaped rear diffuser would probably work best regardless of top up or down - or headlights up or down?

[@acefighterpilot]

Could you put something like a Fowler flap vertically on the A-pillars to bring in clean flow from the side of the car with the top down?

[@IhsanMujdeci]

Would be cool to see the fastback results and a wing.

[@blowenfuse]

So, I drift, obviously, we are sideways, or at least moving through the air at a none direct angle. I would love to see some tips and tricks based around that. I assume a flat underbody will be a massive help, but you can often feel a car's aero fighting against you, rather than helping.

[@sijonda]

Did I miss what the velocity was? I think that's very important here and at what speed does the spoiler do nothing even with the roof up.

[@M-PASTA]

2:25 how dare you bring my sanity in to this!

[@o_Shockwave]

So when I go to autocross in my nearly stock MX5 I need to put the soft top up. Got it!

[@andrewtang2602]

Awesome video! Please do a video on splitters!

[@ДимитърГенев-ш4и]

I have question about "flat" wings like Audi a7 first generation and many others , what is the benefit of these profile ? I think they generate low down force and lots of drag.

[@neoncarrotgaming1128]

it would be intriguing to see how much a vortex generator at the back the of roof section would effect the rear wings effectiveness ! if there's a way to model that it would make for some great additions

[@anidiotinaracingcar]

*Less* drag with the roof off, I hadn't seen that one coming

[@andrewp9954]

I think that was mostly the case with the large rear wing because removing the roof prevented the wing from receiving smooth air to cause drag/downforce.

[@larsmurdochkalsta8808]

Great information as always! Have you considered doing a video on reducing pitch stability in high ground effect cars? Edit: improving pitch stability

[@pedroaalmeida96]

As always a very good content!!! Thanks a lot! One question though, which software do you use to do these simulations?

[@GuzziHeroV50]

This is interesting, I just bought a Mini Roadster which has a retractable spoiler. If this data follows through, the spoiler gives drag with negligible downforce gain. So it is just a gimmick, essentially. Question: Does it make any different whether the driver / passenger windows are open or closed? I'm guessing it would cause negative pressure in the cabin and bring the over-body flow down earlier.

[@davereynolds8209]

Really enjoyed your analysis of aero on convertible. I have a couple of questions. I removed the roof and side windows primarily to save weight. Should I replace the side windows with plexiglas? If I fill in space behind seats will that improve aero? What is optimal angle for rear wing, we are currently running 10 degrees Thanks in advance for your help

[@KarlenBell]

Will adding vortex generators on top of the front windshield reduce the drag behind?

[@cmderkeen2338]

Another thing I'm curious about is the current trend of oem spoilers having the middle section scalloped out so that only the ends are raised. What does that do to the flow profile and is there any aero benefit?

[@TimothyChapman]

What CFD software are you using?

[@WheezyCyclist]

in a series that dictates no roof, im guessing an aero device along the top of the windscreen to try manage the wake would be beneficial?

[@rotorblade9508]

I’ve never seen any convertible racecars , do you have an example? :) I mean racecars have a roll cage and the top mechanism is either completely removed e.g. mx5 cup or a hardtop installed, most of the times they start from the coupe street version when developing a race chassis.

[@byronanderson-lister4750]

What if you removed the windscreen? I'd assume that would help. Obviously, the driver/seats would interfere but not as much as the windscreen?

[@honzastrnad]

What about vortex generators on the top of the windshield?

[@mitchellsteindler]

Can you please do a video on the Zenvo TSR-S wing? Some people claim it does absolutely nothing...I think it's time for you to assess it!

[@ralphstan8279]

Would a bikini top help this situation with the Convertible? I have a giant wing, no roof, no windows and am considering making a bikini top (or tonneau cover but favoring the bikini top). I was even considering having it taper further down towards the back like a fast back. I do only autocross with average speeds of about 50mph and have a NA Miata with front splitter as well. Very similar to your model. Love your videos by the way.

[@old_egg_shen19]

I would like to see the same analysis with the front windshield removed.

[@cmderkeen2338]

I'd like to see a comparison between the oem and TRD spoiler on an AE86 3 door hatch. I'm curious about which one does a better job at reducing drag (less recirculating wake at the rear for faster acceleration) and lift and if the TRD spoiler produces any added benefit of down force because of the longer surface and rake.

[@FullNelsonYT]

I'm curious how much of an affect a sunroof would have. Opened in various positions (closed, opened, and tilted up)

[@KomboAndy]

Would it be useful to put vortex generators on the Hard Top?

[@JUNKYARDGTO]

I wounder if my stock GTO spoiler works 🤣 Awesome video subscribed

[@ajprice]

Would the same apply to cars with a vertical back window like an Elise or MX-5 RF?

[@psprocket4126]

Thanks for the great video! In your opinion, if you are racing with a hardtop and open side windows, would holes in the rear window help the drag and downforce situation? IF they help, would you put them in the top or bottom of the window and what size would you make the holes? Thanks!

[@shawnshibu]

What if we delete the windshield and put a flat lid on most of the interior other than the driver's seat?

[@louis-marievigo4592]

and with a roof spoiler like the BMW 3.0 CSL Batmobile Roof Spoiler

[@coliimusic]

Hey Kyle! A bit of a wiggling question in my mind has been bugging me since trying group C in the sim. The Mazda 787B has this low wing aero philosophy and that downward sloping rear end, but right at that tail section, there's a small gurney flap across the bodywork. Whats it for? Positive pressure over the rear bodywork? Stopping downwash/lift from the sloping bodywork? To help the diffuser/rear wing? I need answers!

[@soupos1866]

Hi! Mechanical engineering student with a heavy interest in motorsport here. I'm just wondering out of curiosity, how do you develop your models for CFD analysis? I will begin to learn CFD in my coursework soon, but I would love to do some experiementation on my own so I was just wondering about sourcing the models you use in your videos. Thanks! Keep up the awesome content!

[@Kett_22]

Thank you for the great video. I wonder what impact a hardtopspoiler would make.

[@jsternberg]

I’d love to mess around in CFD on a car with a roll cage. Wonder what would be an effective way of managing airflow without adding a roof. Would I basically just be a Targa top…

[@GulliJ]

Very instructive video, thank you Could you explain or show how you modelize such detailed model of car ? Where did you get data from real car ? And eventually how do show the flow, but this point look more easy. Thank you again Cheers 🇲🇫

[@VikiJoker1924]

2 Questions: 1. Is this a full scale model? Like, was this Miata precisely designed to represent the actual vehicle, or has it been scaled down? (My guess is, it's a smaller scale 3D model) 2. How much does weight play a role in affecting aero? I know more weight will make the car more lower, hence it affects the drag and dforces. But, I want to know if it is true or I am incorrect?

[@JD-sm7dq]

Please comment on the McMurtry Spéirling, thanks.

[@Pocket4ce]

Another great video, Kyle. Thank you very much!

[@federicoferrari6895]

Hello Kyle! I would like to throw at you an idea you might find interesting for a video. The aerodynamic impact of louvers (i am talking about the rear window ones they put on old race and rally cars in the 70 and 80s). It would be very interesting to know how they work. Hope you are fine and thank you

[@Bbeavis]

I feel like this video is somehow directly talking to me.

[@Mi-Chis]

Well… how about loosing that windscreen and closing off the cockpit on the passenger side? can you run this mod through your computer?

[@juanrubin5997]

When are we going to see a part two for the yaw probe ?!!

[@daviddroescher]

Genuinely speaking, the canopy on the truck in my avatar ,being a fastback shape, would result in an improvement of function for a "Bonneville Spoiler" Vs a "flat" Tonto cover/tarpauline. Especially when exceeding 200mph( 320kph) ( current Target is 227.8mph)

[@AlexCoachPl]

Mr. Engineer, can you please advise on how the aero (spoiler/wing and diffuser) works on Miata Kart (or any other open-wheeler Atom-like car)? Many thanks

[@rolandotillit2867]

My s2k says they do. No aero at Sebring = 2:35, same car + aero = 2:29.

[@Mediarahan003]

I wonder what a wing like the Lancer Evo 9's WRC style wing would do on a roadster.

[@JSG1901]

Have you done any work with a convertible with the windshield removed?

[@TheCarpenterUnion]

Do with a T-top next please w/ and w/o windows. That's what I'm making my build eventually

[@dresdensvo]

Where is the most effective spoiler placement on my hatchback Pinto ?

[@haaseuros9789]

What software is this? I would love to see how my widebody kit does for my z4

[@NNFaNRacing]

Where did you find the models for an NA miata?

[@MarkSanders77A]

Excellent - Subscribed Thanks for adding some PROPER data (beats myths and hearsay everytime) ... This was super helpful for my #LotusElon project - ie maximising range.

[@The_BenboBaggins]

I always fancied the idea of 'breadvan-ing' a convertible such as the MX5/Miata - I often wonder what performance gains or losses would be seen from it?

[@petersizen3897]

The Peugeot 307 CC behaves differently. That car has lower drag with roof down (and windows up). The top speed is higher. I am curious what do you think about this, why is this possible.

[@arrindaley3714]

So I could use a convertible's soft top like a DRS on the straights! 🤣

[@User10111993]

But you need to be Hercules to pull it back up in the braking zone 😂

[@rotorblade9508]

normally the rules won’t let you install the wing higher than the roof plane. so the best position is right below

[@wibuwe]

Super cool. What velocity were these models simulated at?

[@mihirrayganga3479]

Which software do you use for post processing? Looks really good. Hope you can answer