Wind Tunnel Testing - 818

[Dave Smith]

https://www.factoryfive.com/wp-content/uploads/2013/07/IMG_20130717_130541_858.jpg

The crew is down in Charlotte today with the 818R and the 818S for a full day of wind tunnel testing. The goal is to qualify the aero performance of the front splitter, optimize rear diffuser angle, and validate combinations (rear spoiler and rear wing). Both cars are running carbon side skirts (although it looks like the aero benefit is next to zero - but they do look really cool). The number of variables to be tested merits a full day, but when we're done, we'll have drag and down force numbers complete for the street car at street ride height and the race car focusing on down force. More news later, but thought you guys would like the pics.

https://www.factoryfive.com/wp-content/uploads/2013/07/IMG_20130717_100840_571.jpg

The aero package is really important to the 818 program since down force and drag in this design can render a tremendous performance difference and we also want to make sure the aero parts we are selling are validated to produce balanced (safe) down force. We'll publish the optimized data early next week.

[Frank818]

Nice!!! :)

Thanks Dave!

[longislandwrx]

Talk about signing on at the right time! Looks awesome, looking forward to looking at the rear diffuser. Has it been decided yet whether the diffuser will be CF or aluminum yet?

[Mechie3]

My order form says "#80496: 818 Carbon Fiber rear diffuser -- $275"

:D


Dave,
If you optimize for the S and the R, does that mean the diffuser/splitter are different from the S to R, or just the angles of attack. Obviously if you optimize for either one, and just swap to the other, you lose balance with/without the wing (and windshield).

Nice pics too. It's cool to see a company actually validate things instead of pushing marketing speak "OMG this diffuser looks so hot it totally has to work and therefore you need it!!". ha!

[doofoo]

Woot! Looks great!

[Frank818]

Now if they optimize the rear diffuser with the front splitter, that makes it less advantageous to order only one of the 2. It's a pair.

Plus, it makes it harder to use a different rear diffuser (like Difflow.com) if it's not optimized, you may lose balance.
Something to think about...

[longislandwrx]

My order form says "#80496: 818 Carbon Fiber rear diffuser -- $275"


Yeah mine too, but I know they have had issues with CF production, and a lip and side skirts are a cakewalk compared to making a diffuser.
I'll believe it when I hear it from Dave or see a production part.

[Dave Smith]

The new front splitter is the same on both S and R models. Until the guys are done testing the different variations of rear spoiler/rear wing combinations (the rear spoiler is a new part that we haven't run where as the wing is known), I won't be able to answer your question on the rear diffuser angle and part, but it looks like it will be the same part. Until I have data, there is not much else I can tell you other than showing these cool pictures, but make no mistake, the wind tunnel testing is part of a larger program and commitment to making sure this car is done right. The cool thing is that on Friday we're running Ultimate Track Car Challenge at VIR, and we will be the first guys of many to benefit from the data.

[gwader]

So cool!

[Mike N]

Way cool and a significant $ investment by FFR, the Aerodyn A2 tunnel is not cheap. Of course it's just around the corner from my house :D

[Mechie3]

Way cool and a significant $ investment by FFR, the Aerodyn A2 tunnel is not cheap. Of course it's just around the corner from my house :D

What are you doing sitting at your computer then? ;)

[BipDBo]

What wind speeds were you able to test at?

Regarding the wing for the 818s, here's my 2 cents (which is probably more than it's worth).
If you're putting a wing on an 818S you're probably doing so for one of two reasons:
* It's for show. Unless you're really speeding, it won't make much difference.
* You plan to also track the car. In this case, you may want to consider removing the windshield, at least on track day. In this case, the overall aerodynamics of the car, and therefore, optimal wing angle should be practically identical to the 818R. You'll also have an 818 that's probably a little but less than 818kg.

[THE ITALIAN]

Pretty interesting.
Now, how about some aero parts that totally screw up the air BEHIND the car to slow down the better driver trying to pass?

[Frank818]

What are you doing sitting at your computer then? ;)

That's from where he controls the fans.

[Frank818]

What wind speeds were you able to test at?

Regarding the wing for the 818s, here's my 2 cents (which is probably more than it's worth).
If you're putting a wing on an 818S you're probably doing so for one of two reasons:
* It's for show. Unless you're really speeding, it won't make much difference.
* You plan to also track the car. In this case, you may want to consider removing the windshield, at least on track day. In this case, the overall aerodynamics of the car, and therefore, optimal wing angle should be practically identical to the 818R. You'll also have an 818 that's probably a little but less than 818kg.

How about a third reason that would be

* To improve overall aerodynamics by reducing drag while adding downforce?

[skullandbones]

That's too bad that the CF side panels didn't make a difference but that could also be good if that indicates the basic design was already optimized at those locations. So you will have the data to optimize your wings and diffuser before VIR. That's fantastic! Can't wait to see the results of that. Thanks, WEK.

[blueoval_bowtie_guy]

Pretty interesting.
Now, how about some aero parts that totally screw up the air BEHIND the car to slow down the better driver trying to pass?

Good one!

[BipDBo]

That's too bad that the CF side panels didn't make a difference

To me, it's a great thing. It just means not to order them. It might not make much of a difference, but that makes the car a little bit cheaper and a little bit lighter.

[Mike N]

What are you doing sitting at your computer then? ;)

Some of us have to work for a living. ;)

The A2 is their small tunnel, their larger one has a moving floor and would likely be more accurate for evaluating things like the splitter and side skirts. But of course it's even more $$.

I'm just hugely impressed that FFR is spending this kind of money to build a truly well sorted car out of the box. Kudos to Dave and the team.

[Mechie3]

Some of us have to work for a living. ;)


Yeah...I'm one of those people. Thus, why I post all day. ;)

[Frank818]

Yeah...I'm one of those people. Thus, why I post all day. ;)

Well count me in then. :D

[Silvertop]

The new front splitter is the same on both S and R models. Until the guys are done testing the different variations of rear spoiler/rear wing combinations (the rear spoiler is a new part that we haven't run where as the wing is known), I won't be able to answer your question on the rear diffuser angle and part, but it looks like it will be the same part. Until I have data, there is not much else I can tell you other than showing these cool pictures, but make no mistake, the wind tunnel testing is part of a larger program and commitment to making sure this car is done right. The cool thing is that on Friday we're running Ultimate Track Car Challenge at VIR, and we will be the first guys of many to benefit from the data.

Is the new spoiler mounted to the rear of the 818S in the wind tunnel picture above? I think I see SOMETHING back there....... And that might be something I'd be interested in -- especially if it actually DOES something!

[Dave Smith]

Yes, the street car was tested with a new rear spoiler design that looks pretty good (you can sorta see a tad of it on the white 818S, its carbon, full width and mounts to the top of the rear lip). The guys reported that the testing all went very well and we should have final photos, specs, data and details on the CF aero parts in a few days.

This is a big week for the 818 development team as we wanted to qualify the final aero parts (done), next the team is headed to VIR for the Friday UTCC races where the downforce optimization data will be put to good use on the track against DP cars, ACR Vipers, Vettes, and a tremendously fast field of top race cars in a truly "David vs. Goliath" endeavor. The 818R now has 340 rwhp and weighs in a good amount under 2000 lbs. We are also running full slicks and putting go-fast FFR Nats Champ driver J. George behind the wheel.

The week of 818 fun concludes with the 818S, which is still the same weight as from Open House reveal (1826 lbs I think) and will be driven/tested on Friday and Saturday by another major Automobile magazine, rounding out both cars tested by major press. Out back, the crew is doing a FANTASTIC job of production ramp-up. We are currently at 3 per week and will be building the first 818R this week (tomorrow and Friday) for customer B. Stuke. Wayne Presley at VCP's and Erik Treves are going fast on their builds and giving hugely valuable feedback to the engineering team for immediate updates to the production cars in a way I've never seen at FFR where the engineers, guys in production, and office tech crew are hyper-attentive to any build issues.

The next months will see the soft top design, further rapid integration of build ideas and refinements to the manuf process and especially chassis assembly area that takes a lot of time currently.

Tons of debate and work on the production schedule, hot list and longer term production plan that is focused on quality and on making sure the 818 hits the streets the right way. Hopefully you guys can appreciate the tremendous focus on this effort that the whole team has committed to. Ive never seen the company work so well together, overcome challenges so easily, and communicate internally so clearly and efficiently. It is a fun and exciting time and I trust you all can cut me and the team some slack for not having as much time as we'd like to communicate everything! More to come shortly.

[Frank818]

That is some nice updates, Dave. :)

Opens up the path for so many other questions, but I will keep them inside me for now while you focus on your current challenges. :)

[bstuke]

Please don't wreck my 818R....:p

Off to Cozumel to video Whale Sharks, Manta Rays and such. Looking forward to the following week..

[AZPete]

TGIFFFR ............Thank God I Found Factory Five Racing

(otherwise I'd be watching Big Brother and feeling worthless)

[bbjones121]

Thanks Dave. Awesome updates.

I am trying to find my donor for my 30th birthday coming up at the end of the year.

[Darkpiggy's dad]

I'm hoping the data you release will show either wing or spoiler on each version, but I'll be really happy with any data you publish from the wind tunnel. This project is so cool. Thanks.

[shinn497]

Dave,

Have you guys done and CFD modeling of the chassis before testing it or is it all empirical? I think I saw something akin to that on one of your promo vids.

With that said I can't wait to hear more about both testing and application off the chassis. Personally, I would rather have a street version without a rear wing. I've always been in the camp of modesty + performance. I really like that this car, despite its affordable price tag, has some serious tech behind it. That is 'murican ingenuity at its finest!

[Xusia]

Thanks for the updates Dave - they are appreciated! VERY much!! I can't wait to see & read more. :)

And of course, take delivery of my kit!

[NicksPapaw]

Thie commitment to excellence is why Factory Five Racing is the best. For some of the newer guys on here they have been bent out of shape about lack of wipers and such, you can now see the bigger picture. Remember, this was a drawing on a bar napkin just a couple of years ago. Look how far they have come since then. And at an affordable price point. Dave, thanks for the update and keep up the great work.

[THE ITALIAN]

"FFR Nats Champ driver J. George behind the wheel."
I hope John Kicks their butts all over the road, that will raise some eyebrows.

[WIS89]

"FFR Nats Champ driver J. George behind the wheel."
I hope John Kicks their butts all over the road, that will raise some eyebrows.

I too hope that FFR shows really well and raises some eyebrows! It would be great to prove what most of us already know--- FFR is an outstanding company producing kits to exceed our dreams while also having a blast and turning heads wherever they go! I hope the trip to VIR exceeds all of our expectations as well, and some folks get their eyes opened to what FFR is capable of bringing to market. Go get 'em guys!

Regards,

Steve

[UpstateCobraGuy]

Thanks Dave!

[Dave Smith]

I know that Jeremy and the engineering guys did flow analysis on the body with Solidworks software and as good as Solidworks is (exceptional!), there is absolutely nothing that can replace the honest, qualified feedback from a guy like John George as he removes his helmet and starts to speak about the last 12 laps at speed. The windtunnel helps tremendously and the cost is very much worth it. Wipers will happen of course, but what you pointed out is so true, the scope of the project and the timing of each and every item is akin to playing chess where there are a TON of moves and each one important, but, for those student of classic "Project Management" the pert chart is massive and all of the individual tasks needed are along a planned path, some items, like the optional rear spoiler or the full spread of optional seats (each one installed and tested) were not part of the critical path up front... Others like say the testing of the chassis in the very early days of the project or the suspension geometry and parts, well those things had to be addressed along a critical path. Every item is important in their own contribution to the satisfaction of the design goals. Even something as seemingly small as outsourcing the fastener packaging into assemblies (new for us) matters. The car and plan naturally evolves thru the development process. My particular skill set here at FFR is in coordinating the project against the backdrop of ALL the things we have to do each day. If that isnt done right you end up making promises that dont happen and failing on timetables as a habit, rather than an exception.

At the most basic level I have to be responsible for every single part, person, decision and action of the company... While at the same time, I have to keep the big goals in mind and make sure we are making progress every day on those and recognize when we are and when we are not.

I have some very simple rules that are in my head every minute of every day and they form the foundation of every decision I make.

Are we doing something better every day?

Does every person in the company understand that the person/(s) who walks in the front door or calls on the phone, or emails is our boss and everythuing we do is ONLY because of their consent and support?

Is the tactical plan always supporting our strategic plan?

Is our strategic plan always always always is guided by our philosophy?

Is our philosophy understood in all of our actions? Are we making a difference in peoples lives? Are we contributing to our community? Is our work a perfect mirror of our love. Are our personal lives in concert with our professional lives?

A customer Erik Treves sent me a TED video link on companies and three circles of What (what a company makes), How (the unique ways the company makes these things to survive and flourish) and the WHY. I watched with wonder how the speaker so perfectly described Factory Five Racing... We start with the WHY. We definitely have to master the How and the What of our products and business, but undertsanding that we build something that carries a human soul. Understanding that we build things beyond physical parts... understanding that we build relationships with our cars. That we build community with our parts. That we build careers with our company and partnerships with our suppliers. Understanding that while PROFIT is important, it is NOT THE GOAL, rather the result of reaching our goals if they are right and well considered.

I remember when I graduated with my degree in Philosophy, wondering how it would ever help me in life. I did not, at the time, ever think that it would be absolutely central to building cars...

Too much caffeine this morning!

[flytosail]

Thanks again for all of your hard work in making the 818 into what it is today and what it will be for all of us. Someone here has a signature line about the fact that you never see a motorcycle outside a psychiatrist's office. I don't think you will see any 818s there either.

[Frank818]

That is some nice speech Dave!
I do understand the challenges or project management as I am in every day!
I have a better understanding of your future goals to come with the 818 and pleased to hear (read) all that!

Keep it up! :)

[THE ITALIAN]

I think the Philosophy that FFR has continued is that you have not lost that idea, that each and every frame that goes out the door is one project for that one person and most importantly, that one person's focus as a hobby and that could actually be his/hers one and only EVER large project.
Once a company loses that idea, it is no longer the FFR community.

I wish our country was run like FFR

[Martin]

Looking at the work that has gone into the 818 suspension tuning, the wind tunnel testing, the engine upgrades and the driver (John George) and slick tyres, I have a funny feeling that eye brows won't be raised, they'll be scorched off.

Dave talks about community all the time and I for one feel like I am part of it (albeit a very, very long way away from it).

Next time I have a beer, I'll raise a toast to FFR.

Good luck John - hope you post up another video with all of your telemetry data and video overlays. I watch every one of them that you post up.

Martin

[Xusia]

Dave, VERY good stuff. I love your outlook on running the company, goals, philosophy, etc. I wish I could work at FFR (seriously), but our family is committed to the area we live in. Keep up the good work. :)

[Frank818]

Good luck John - hope you post up another video with all of your telemetry data and video overlays. I watch every one of them that you post up.

Are these vids on youtube? I'd like to watch them too.

[Frank818]

Dave, VERY good stuff. I love your outlook on running the company, goals, philosophy, etc. I wish I could work at FFR (seriously), but our family is committed to the area we live in. Keep up the good work. :)

I am not committed! So if there's a place I'm in! :)

[shinn497]

I love how Dave always answers questions 3 times longer than I expect, and in meaningful detail. :D

Also it is nice to know that solidworks has CFD capability. Of course I wouldn't expect it to be perfect. It is an unsolved problem in physics and real world conditions are always going to be much different than simulations or even wind tunnel testing. I think each has its merits to point out different engineering challenges.

[JAubin]

Awesome stuff! Really interested in hearing how all the parts fared in this testing.


Also it is nice to know that solidworks has CFD capability. Of course I wouldn't expect it to be perfect. It is an unsolved problem in physics and real world conditions are always going to be much different than simulations or even wind tunnel testing. I think each has its merits to point out different engineering challenges. Solidworks Flow Simulation is actually what used to be COSMOS CFD, it's really well integrated and it makes it super easy to roll changes into a new study. As you said, definitely never something you can get a good result and assume it's ready to go, but I'm sure FFR saved a lot of time and money getting their airflow to 90% and then making adjustments based on real world results.

[RM1SepEx]

Sounds like the timing is perfect... wind tunnel results out next week... I show up Saturday with my trailer to pickup my S kit and some extra cash for CF pieces...

[metros]

This is a really exciting time for FFR and enthusiasts alike. Really looking forward to seeing how the 818R does at UTCC.

[longislandwrx]

Thanks for the answers.

At the open house Dave talked about having a responsibility to every employee and their families. He said when he signed an employment contract he was making a promise to be there for years to come for that person. It gave me shivers. If every boss/owner was like Dave there's no telling how strong this country could be.

[Matty_STi]

So do we get to see the wind tunnel results? I know it's proprietary but there are some of us who may be wanting to push the boundaries with an 818 (myself included) and having access to that information (perhaps by signing off on a NDA) would be greatly beneficial.

Just sayin.

-Matt

[wleehendrick]

So do we get to see the wind tunnel results?

Yesterday, Dave said: "The guys reported that the testing all went very well and we should have final photos, specs, data and details on the CF aero parts in a few days. "

Patience, young Padawan.

[Matty_STi]

Yesterday, Dave said: "The guys reported that the testing all went very well and we should have final photos, specs, data and details on the CF aero parts in a few days. "

Patience, young Padawan.

Not what I was looking for..

I am looking for the detailed wind tunnel results, i.e. something I can plug into ansys, openfoam, or autodesk FFS sim. In order to engineer bits and pieces for some more intense uses of the 818..

ya know..

[wleehendrick]

Ah... it sounds like for you want, you'll need not only wind tunnel results, but solid models of the body geometry, CFD modeling, etc... good luck!

[Matty_STi]

Ah... it sounds like for you want, you'll need not only wind tunnel results, but solid models of the body geometry, CFD modeling, etc... good luck!

Well cfd modeling I can do myself with what I have access too, body geometry can come from various places plus I can just take the images of what is out there and assemble a wire frame or full construct (which I will be doing anyways). Really it's the wind tunnel testing data which is so exciting. I don't have a wind tunnel, and live no where near one. CFD only goes so far and despite the large compute resources I have at my disposal still doesn't come close to real world data.

Real world data also means that I can use real numbers in my sims to gauge the effects of my aero package. Which means when it comes to track testing I have a far better idea of what I am walking into.

*here's hopin at least*

-Matt

[Dave Smith]

The crew went from the wind tunnel on Wednesday to the track today (at VIR). They are quite busy and I can't imagine having numbers to you before next week as they dont even get back til mon-tues. We can probably help a lot of people with the data and will be very forthcoming.

[Flamshackle]

The crew went from the wind tunnel on Wednesday to the track today (at VIR). They are quite busy and I can't imagine having numbers to you before next week as they dont even get back til mon-tues. We can probably help a lot of people with the data and will be very forthcoming.

So great, thanks for staying in touch Dave. Very excited to see how the car performs over the next few days and hearing all about it.

I am gathering interest here in New Zealand for a group of us that are interested in this car and think I could get an order of three-five within twelve months.

[bstuke]

19836

[Matty_STi]

The crew went from the wind tunnel on Wednesday to the track today (at VIR). They are quite busy and I can't imagine having numbers to you before next week as they dont even get back til mon-tues. We can probably help a lot of people with the data and will be very forthcoming.

You the man Dave. Much thanks

-Matt

[Mechie3]

So...free solid works cad models for all? ;)

[FFR-ADV]

The crew went from the wind tunnel on Wednesday to the track today (at VIR). They are quite busy and I can't imagine having numbers to you before next week as they dont even get back til mon-tues. We can probably help a lot of people with the data and will be very forthcoming.

Thanks Dave,

I am looking forward to learning what works best from the testing, both in the wind tunnel and on the track.

Cheers!

[Slatt]

19836

I'd say 3rd place is pretty good for a debut appearance.

[AMW1011]

I'd say 3rd place is pretty good for a debut appearance.

3rd gear went on the warm up run, so that's the 3rd+ go down a gear. Pretty good considering, just not a very good show of what the car can do.

[Slatt]

Ya, I replied here then saw the other thread. I'm quite happy with the results. Not to hijack an aero thread, but nobody there has said "NA" yet! :rolleyes:

[metalmaker12]

I figured the car would be first or second, I knew something went down

[tcoon]

I love it Dave! Good on ya! Rock on and best of luck to John at the Challenge! Maybe next year we'll book a really fast coyote powered coupe for that event!

[Rx007CYM]

What a great debut. Anything under 2:10 is flying around VIR. That 7 that got 2nd is well prepared. Way to go FFR! Sucks third got cooked otherwise sub 2:07 sounds very attainable.

On a side note it must have been sad going around Oak Tree Turn. RIP Mighty Oak.

[FFR-ADV]

Nice looking rear diffuser. I like the aggressive stance. (Gotta add that to my order....)

A spoiler or wing is likely in the cards. Lotus ran into a similar challenge with getting rear lift before they added an integral spoiler lip in the Elise. The Exige then used a wing to further increase aerodynamic induced grip. You don't have to watch the whole video of project M1-11, but 38 minutes and 56 seconds into the video is the portion when they got their first feedback from scale wind tunnel testing of the Elise:


https://www.youtube.com/watch?feature=player_detailpage&v=TZ5lxms9xuw#t=2307s

I will probably go with a wing eventually once the removable hardtop is available.

Cheers!

[Ironhydroxide]

I know that Jeremy and the engineering guys did flow analysis on the body with Solidworks software and as good as Solidworks is (exceptional!), there is absolutely nothing that can replace the honest, qualified feedback from a guy like John George as he removes his helmet and starts to speak about the last 12 laps at speed. The windtunnel helps tremendously and the cost is very much worth it. Wipers will happen of course, but what you pointed out is so true, the scope of the project and the timing of each and every item is akin to playing chess where there are a TON of moves and each one important, but, for those student of classic "Project Management" the pert chart is massive and all of the individual tasks needed are along a planned path, some items, like the optional rear spoiler or the full spread of optional seats (each one installed and tested) were not part of the critical path up front... Others like say the testing of the chassis in the very early days of the project or the suspension geometry and parts, well those things had to be addressed along a critical path. Every item is important in their own contribution to the satisfaction of the design goals. Even something as seemingly small as outsourcing the fastener packaging into assemblies (new for us) matters. The car and plan naturally evolves thru the development process. My particular skill set here at FFR is in coordinating the project against the backdrop of ALL the things we have to do each day. If that isnt done right you end up making promises that dont happen and failing on timetables as a habit, rather than an exception.

At the most basic level I have to be responsible for every single part, person, decision and action of the company... While at the same time, I have to keep the big goals in mind and make sure we are making progress every day on those and recognize when we are and when we are not.

I have some very simple rules that are in my head every minute of every day and they form the foundation of every decision I make.

Are we doing something better every day?

Does every person in the company understand that the person/(s) who walks in the front door or calls on the phone, or emails is our boss and everythuing we do is ONLY because of their consent and support?

Is the tactical plan always supporting our strategic plan?

Is our strategic plan always always always is guided by our philosophy?

Is our philosophy understood in all of our actions? Are we making a difference in peoples lives? Are we contributing to our community? Is our work a perfect mirror of our love. Are our personal lives in concert with our professional lives?

A customer Erik Treves sent me a TED video link on companies and three circles of What (what a company makes), How (the unique ways the company makes these things to survive and flourish) and the WHY. I watched with wonder how the speaker so perfectly described Factory Five Racing... We start with the WHY. We definitely have to master the How and the What of our products and business, but undertsanding that we build something that carries a human soul. Understanding that we build things beyond physical parts... understanding that we build relationships with our cars. That we build community with our parts. That we build careers with our company and partnerships with our suppliers. Understanding that while PROFIT is important, it is NOT THE GOAL, rather the result of reaching our goals if they are right and well considered.

I remember when I graduated with my degree in Philosophy, wondering how it would ever help me in life. I did not, at the time, ever think that it would be absolutely central to building cars...

Too much caffeine this morning!



This right here is why I would take a pay cut, move on my own dime, and still BRAG to EVERYONE at the chance to work at FFR. I love cars, work on them daily as a hobby, though i've always had the plan to keep it a hobby so I can retain the love. But working in a company with these ideals..... Priceless.

[Scargo]

This is the closest I can find to being a thread relevant to my questions so I will revive this...
When testing was done was a higher placed wing tried? What is the mounting height of the wing? Why was the twisted shape of the APR GTC-300 chosen?
I am considering the G-Stream, which is straight, and wondering if I might benefit from it being a little higher? Is there a significant relationship between the roll bar, clean air and the height of the wing?
I haven't a clue what I'm doing! I will have a splitter and canards or other front aero to complement the wing.

[Santiago]

I'd also like to know from the horses mouth why they initially went with the twisted element APR wing. I have my suspicion that this was used simply because it was available to them (or there was a business relation they were nursing, or something other than pure performance).

A twisted element is great for maximizing airflow that is not approaching the wing at a common angle across the wing's entire span. So if you've got a forward body shell that invites airflow down (as you do w/a fastback), then your wing is "seeing" a greater angle of attack (AOA) relative to the air that is working it. That is, the portion of the wing behind that part of the bodywork is seeing that increased AOA and thus is being worked harder. So you'd usually back off the wing's AOA (for a given downforce and/or drag goal) relative to horizontal since it's already at a higher AOA once the air is flowing. Cool, but this leaves the tips of the wingspan that are not seeing this greater AOA; they're seeing plain ole horizontal airflow in a free stream. So if you twist the wing in the center, you've got a more of the span acting in an efficient range.

All that goes out the window if you don't have that fastback profile. Thus, FFR's red-and-now-grey mule is running a straight wing element.

As for height, I'd also like to hear from the horse's mouth why they are using such a low mount. In theory you want the wing high up in free air (unless you've got a body profile and rear diffuser that can work in tandem with the wing, and we don't). As they've got it now, it's directly in-line with the roll-bar tube, and that's not good. A round tube in open airflow creates drag and LOTS of turbulence. So look at the old wind-tunnel test videos they posted (particularly the time from 0:58-1:03) and keep an eye out behind the bar. You'll see plenty of turbulence. So you're feeding the wing dirty air, and that means you need to work it harder in order to get X-amount of downforce. Working the air harder also means you're seeing more drag - not just from the round tube but now from the wing which is likely pitched more than it needs to be to get X-amount of downforce.

Now throw all of that out the window again, because it doesn't matter if you want X-amount of downforce out of that rear if you can't get the front to keep up with it. Reports I heard were that they backed out of the rear wing's AOA because the car just pushed and pushed at speed no matter what they did to the front (early Blue mule reports). So they can "get away with" feeding the rear dirty air because the front is just not keeping up with the rear even in its inefficient state. So the mantra I've carried is that if you want more out of the rear, start with the front.

Of course, a higher & more-efficient rear wing would still deliver a "less-than-X" amount of downforce with less drag than one being fed dirty air. So that's something. But keep in mind that the higher your stanchions get, the more robust they need to be. A big wing can see lots of buffeting at speed, and I've seen some scary rear-camera video of questionably robust mounts. Something to think about.

Best,
-j

[Hobby Racer]

I would like to throw my request behind this as well. Some more detail from FFR on the rear wing choices they have made and some insight on how testing has changed their direction would help the community figure out the best direction to go.

Thanks!