37 Wind Tunnel Runs Part 2! Vortex generators, canards, and wings.
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- Опубліковано 7 лют 2020
- Part 1: • 37 Wind Tunnel Runs- L...
Audi Wind Tunnel video: • We Go To The Wind Tunn...
M2 Wind Tunnel Video: • Wind Tunnel Testing Ro...
Race Louvers: racelouvers.com/content/Race-...
Facebook: / ajhartmanaero
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Recorded on GoPro 7 Black: amzn.to/2YW7B5N
Edited with Pinnacle Studio: amzn.to/30NWm11
I attended a talk by some aeronautical engineers with the subject being boundary layers. They used synthetic oil mixed with a dye which they applied to an aircraft wing especially at the wing root and to the fuselage fore and aft of the attach point. This was used instead of the tufting. They dye held in suspension by the oil would concentrate or not showing the boundary layer separation. Of course this was very messy and the aircraft owner got a very extensive wash job afterwards. Goos video very interesting. I’m jealous
I'm just here to say how much I love that you've got Kyle Gass helping out in the windtunnel.
Vortex generators have a somewhat hidden physics called Entrainment; creating an effect similar to how a Dyson fan blows air beyond the hoop. This may be part of the additional drag. This stabilizes the airflow behind the vehicle, creating greater stability at speeds starting around 70mph. I have also placed them at the front of my front wheels on the fender, and can feel the tire pass out of the air-flow when turning.
The rear wing is mounted high so the air flow generated by the VG have no effect on it. If there was a duck bill on the trunk or low mounted wing then the VG may provide better airflow and allow the wing to work for more downforce
@@2be1withU I've seen VG's placed at your top line of tape/string on the rear window with reports that it connects the airflow cleanly to the car, which might clean the flow over the rear wing.
Who gave this thumbs down?!? He doesn’t have to share this info with anyone, yet here it is. Lots of info here and I’m going with larger end plates now!!
I am in agreement. Share knowledge is exciting to do. Shared knowledge educates us all. Some unfortunately see kept knowledge as power. No reason the “Thumbs down” this video.
Nice! Shots with the smoke were very interesting to see👌
Doing God's work! Real cool to see videos like this.
That aluminum foil @14:30 looks awfully familiar ;)
Man - awesome that you shared these learnings. We endurance-race an e36 and I was wondering: have you ever tested e36M3 mirrors vs the stock ones? Would love to hear what you found if you're willing to share.
The issue I see with the AirTabs vortex generators was more one-off placement or even actual need for them than their effectiveness. We know they work, but they're not for every application.
Alex NutCasio agree. Would have been nice to try different locations but that was where air tab recommended putting them but tunnel time is expensive and had more important runs to do.
@@ajhartmanaero If you follow Aussie Julian Edgar on YT, he had an Acura with a similar rear windshield and put the tabs on the glass about 1/3 down and they worked great. However, you can partially test your BMW by using the 3inch tufts on the rear windscreen and see how the air is flowing off the roof and if its detaching or not.
I love the wind tunnel testing, but why don't you show the data results?
It's in the description race louvers
Great video and thank you for posting it. Would love to see these tests done with an actual splitter with tunnels.
Me too. I want to take my car this summer.
Thanks for sharing all this AJ. Those VGs are what they sell for semi trucks to help smooth the airflow between the tractor and trailer and trying to close up the wake behind the end of the trailer. I think they're probably more appropriate there, but too big for a race car.
yup.
😳 That quote is from an operation📎 paperclip scientist. Let’s not forget history or we shall repeat it 😁👍🏿
Some good info and work I shall apply to my GR Toyota. Thanks 👍🏿
Kickass video, I don’t really know what any of that means but that wind tunnel is awesome 🤣🤣
We can test the stability of Tecoblock pavers and decorators boards in hurricane force winds in there.
That would be hilarious lol
@@ajhartmanaero why was the kidney grill partially covered?
That car rings a bell.
Hi! How much downforce can produce the canards in your test?
super infteresting. was the splitter a plain plate or did it have any of your diffusers?
flat alumalite with a mangled up front edge and no rake.
Those roof vortex generators look strange with the wider part forward, it makes sense that they would add extra drag and barely improve downforce on the rear wing. When you guys were doing the smoke testing it was really bouncing around over the back of the roof area! The shark fin style vortex generators on my Mitsubishi Evolution X are much more streamlined but who knows if they keep the air attached to the rear window any better so that the wing gains downforce from having cleaner air.
The Df gain usually comes from less lift on the rear glass. But these in this case didn’t work.
@@ajhartmanaero Another place to try is the upper rear window, this will also add less drag.
What is the purpose for the cutout of the rear upper corner of the wing end plates? I see them fairly often.
Usually vortex shedding. It’s a drag reduction technique, but a very small one. Would have been cool to test multiple size endplates.
Maybe I'm not seeing this right but did he put 5 on one side and only 4 on the other? If it's not symmetrical, is it going to make a difference?
13:34 Just look at the vortex generated when you pause it frame by frame! I wonder if the shark fin VGs (turned 10 degrees) can generate better vortices with less drag? 🤔
The first wing on the car that got the clear endplates.. Was that a nrg innovations wing? Cause I have one on my s197 gt.
David Robinson not sure honestly. It was the worst of all of them tho.
Test with front wheels turned for a curve.
Is there a list of all the data available somewhere? Awesome videos btw!
It's in the description race louvers
About wheel area aero: I notice Ford did some aero trickery for the new F150 in the wheel area. They used ducts from the front to just in front of the front wheels. The ducts are narrow at the wheelwell and run nearly the height of the wheelwell. I assume they are using this to redirect incoming air away from the wheelwell. Do you think this has promise in a racing environment for reducing drag? Has it been done before in a racing environment?
They do the same thing on the Mustang. They use that duct to stream and smooth air around the wheel/wheel well area to reduce drag. Problem is, once you put wider wheels on (very common on race cars) all that factory stuff is useless as the duct then points at the tire which isn't good.
@@ajhartmanaero I figured it would have to be made to the application. I guess with racecars it's probably better to minimize the opening than to try to do this. Maybe if the tire didn't fill the wheelwell.
@@ajhartmanaero did you leave them on the Mustang or block them off?
@@Racer_Mike87 blocked on the gt350.
Is there any real difference between the swan neck mounts and normal mounts?
Yes
Very interesting videos, thanks for sharing! I also would really wish you could give some real general results with the wings like you were with the louvers. You mentioned the gurney flap on the ebay wing was surprising... but nothing of whether it was good or bad. I assume it was helpful as you didn't immediately rip it off? Since I have the exact same wing I'm really curious. Thanks!
knate240sx I think I mention the gurney flap numbers in a clip. I need to walk a line between giving out info and protecting info since it’s what I do for my business. I will eventually do a “lessons from the wind tunnel” recap video.
@@ajhartmanaero Thanks for the quick reply AJ, I'm still learning from being able to see most of this! This cheap wing has a very rounded trailing edge, not sharp at all, so I imagine it may behave a little differently from a properly built wing. You did mention "100 something lbs" at 100mph, which I assume is better than the baseline. Based on leaving the gurney on and then flattening the wing I assume that the L/D was pretty good with the gurney added. I already had added larger end plates to our wing, sounds like I may need to try adding a gurney and losing a bit of AoA.
knate240sx depends if you need the extra Df or not.
@@ajhartmanaero I don't need more Df in the rear, was just wondering if gurney + less AoA can give same Df with less drag?
Cool stuff. Like I said once, no one doest tests like this on UA-cam :)
Do you remember any data from the canards that you could share?
I do but am always cautious on sharing cause the addition of canards, on this car in this exact setup was about 44lbs at 100mph. But change the splitter, or tire width, or even radiator ducting will change the numbers.
@@ajhartmanaero yeah, its only true for that same car with that exact setup.
Thank you for your work.
Are you all going to publish the data?
no.
The way they synced up at 7:45
Reducing the costs of airtabs? Either you have a 3D printer or you don't. Never pay retail again. Lol. I'll get back to printing kazoo parts while designing some venturi nozzles for dust removal inside cnc vertical mills.
So, where are the numbers promised at 1:52-55? Am I missing something?
Yes. They are in there.
Tire blockers ... I have them on my car, but I have never known what they were called.
Tire blockers, dive plates, some might reference to them as canards, S flaps, wickers... I see them all used interchangeably despite being a little different. Tire blockers is about as easy as you can get.
AJ Hartman Aero ... 100%, I have called them ‘like a gurney flap on the wheel well’ ... which is cumbersome at best. So I like ‘tire blockers’, differentiates them from the more typical canards.
Where do you get those tire blockers?
We make the canards. Tire blockers were just a diy piece cut out of a sheet of aluminum
thought the vortex generators were the wrong way around.
Any data on the splitter rods? How bad are they really?
Not as good as an airfoil shape but if you need them you need them. We didn’t do a run without them.
@@ajhartmanaero Thanks buddy. I just sent you an email from your site.
Any data from wheel blocks or canard?
Yes.
@@ajhartmanaero where is that pdf? Your other pdf in the description was fantastic.
Where might I procure them canards😏
My website. Link is right in the description.
are the VG's backwards?
No. They were installed per the manufacturers directions.
What is the function of the carnard sir?
Make downforce.
Good video. It would be a great video with some basic data presentation even if only % changes to obscure data you don't want to reveal.
It would but even percentages don't tell the whole story. If we got a 20% gain thats a way different number if the original part made 10 lbs, or 300 lbs. Same for if I gave exact numbers. Canards for example, would put out different numbers on different cars. Even another E36 if the splitter was different would produce different numbers. So thats why we kinda keep that stuff to ourselves. We know what is a step in the right direction or not depending on what we want to achieve.
@@ajhartmanaero I'm assuming you also don't want to disclose the whole story for various, understandable reasons.
Beyond the argument of trusting your audience, balance was a theme of your video and a goal with your changes. Disclosing what changes were made with resulting balance changes and a little data or few charts mixed in would really help your content imo.
As-is, while I enjoyed the video, this structure has hit a functional limit for me. I'm left feeling vaguely teased but ultimately unsatisfied with the payout.
Results, data, comparisons, etc would have me looking more carefully at your product, the vendor whose product is featured's product (Race Louvers), and eagerly awaiting the next video.
It seems to have worked well for Aerobytes in Racecar Engineering Magazine. Perhaps it would work well for you on UA-cam.
I mean, yeah we want to keep some stuff to ourselves. Wind tunnel time isnt cheap and one of our advantages as a company is the knowledge we gain from going there. In the video clips I do try and give quick recaps of if it was an improvement or not, but then again what is an improvement depends on what you are trying to achieve. I’m pretty confident we give out more info then any of our competitors. All our cfd is on our site. In the Audi wind tunnel video I did dive into numbers more. A lot of our parts were designed by a guy that now works for Mercedes F1. So if the parts and info we spent a lot of time and money on developing, and give to you for free isn’t enough to make you consider our parts, then I don’t know what to tell you. But if you do go to the wind tunnel I would volunteer my time to come help you and you can post any numbers you want.
@@ajhartmanaero , I'm aware of Kyle and his design contributions. I've looked at your website in the past but haven't in a while. I'm aware of the difficulties in laying this information out, operating a small Motorsports business, product development, and what you're providing. Thank you for your offer to work with me in the tunnel.
What I'm trying to offer here is constructive criticism outside of yourself and as a viewer who isn't aware of the above information. Someone coming into your channel fresh to watch this video as it stands on its own.
I didn't intend an attack or to put you on the defensive. We engineers aren't known for our social expertise ;) . imo if you only compare yourself to others out there you won't reach your own potential and what you can offer through this channel. With relatively minor tweaks I think you could be an aero analysis benchmark on UA-cam that generally raises the bar for our community. I don't think this will take more wind tunnel time (since you are already tracking changes and results), just more video post-processing and perhaps a conclusions or breakdown segment off site.
Hood vents already separate the flow
why the hell did you not share how much downforce got generated? i'm trying to find out how much downforce that NRG creates
Top secret stuff.
@@ajhartmanaero why is it top secret? It's not like someone is gonna steal your idea or anything since it's a widely available wing that anybody can buy. We're not looking to copy your entire aero setup, literally just want to know what speed that wing starts generating downforce
From what i read and watched on other videos (air shaper, kyle.engineers, etc.) roof vortex generators are to be placed very near the spots where airflow separation would occur. That would be as near as feasible to the sharp downturn "corner" of the roof and the rear window.
And the supposed primary reason for roof vortex generators was to reduce the drag from the rear window flow separation. Not sure if they are supposed to reduced lift but it would seem that having attached flow on the rear window might actually cause lift, unless that flow also affects the airflow to the rear wing which might then result in net downforce.
Wind tunnel time is expensive 😯 though you most probably already planned and prepared all the stuff that you were going to do in the wind tunnel ahead of time, to make the most of your time there.
That "Watch Your Head" warning label should be standard on all wings. It will prevent many wives from hitting their heads and many husbands sleeping on the couch.
BTW...I have that first wing. I bought with Hilton Honors points on Amazon...lol
i feel like they don't care about the paint or scratching things 😳
Not on this particular vehicle.
Vortex generators are mounted or designed the wrong way around. Pointy edge must face forward.
Not according to install guide of the company that made them.
@@ajhartmanaero did I miss how the vortex generators performed? I have the same ones on by E36, made a video of before and after, I think you'd enjoy it!
I also noticed how far forward you mounted the VG's. I didn't notice until after I mounted mine, but air flow separation didn't occur until ~6" off the back window, I have mine on the rear window upper mould line but they could've been mounted on the window itself.
LSX_M3 very end of the video I mention how they did.
Have mounted and used them on planes. Those are way over engineered. If you have more tunnel time. Try the aircraft design. Actually easy to make. And I would try them in the middle of roof and on the wing.
what the hell they doing