Air blades.

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Bluezone

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I've been reading up on air blades/curtains and how theywork. It's kind of cool of how they reduce drag and if formed properly produce thrust.


I'm thinking the fog light pockets on the MKS would make perfect scoops to use this effect. I'd have to move the fog lights to the inner lower lower grill.Screenshot 20240226 164553 Photos
 

shaldaya

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Give it a try and let us know how it goes
Anything to help me at the track
 

Bluezone

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I haven't had good weather to try installing the air blades yet. I did get a chance to try a test of another idea, over a section of road that I know well. It's roughly three miles long with 2 very small hills and predominantly level or slightly downhill grade.
The test was done checking fuel consumed over the distance. Cruise control was used to maintain speed. Fuel consumption meter was set right after cruise control hit predetermined speed at same point. With photo taken at the run finish at same finish point. First two runs with the modification. Third run with the modification removed.
All runs done over a period of around 30 minutes. No traffic in front of me while doing the runs.
The first run average consumption was 27.5.
Second run consumption was 27.5.
Last run consumption was 26.3.
Sorry about the messed up first picture. Flash was accidentally left on.
The airflow mod was simple and stupid easy. I may have to look into trying to implement this in practical use. Don't expect this to increase mileage by a mile a gallon. It was a level and mainly downhill coast. The route chosen, was purposely used to amplify aerodynamic effects and done within limited time, to limit speed and windshift change.
Screenshot 20240326 193853 Photos2Screenshot 20240326 193926 PhotosScreenshot 20240326 193937 Photos
 

rubydist

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3 miles does not use enough fuel to get anything statistically significant for results.
 

Bluezone

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Quite possible and very true. But it was repeatable. Third Run was very similar to my normal Driving Experience over the road over the same distance.
It is 36% of the distance that the EPA uses to determine mpg. They use 11 miles. Is that statistically significant. There can be statistics and dam statistics, to paraphrase a quote.
The test isn't to see how much gas you use going uphill it's to check how much power is necessary, fuel usage, to maintain speed over a distance. Thus a predominantly flat or slightly downhill grade. The two small Hills eliminate any overzealous mileage reporting which can indeed skew results. The time limit helps eliminate and minimize any wind variation. Lack of traffic ahead removes any influence by drafting or passing cars causing influence on the results. Feel free to try this yourself to see how this works. Remember you need satisfy me with repeatable test conditions, not you. Since you have doubts please execute the necessary tests and record it and provide detailed recordings on everything dealing with test conditions. Me I'm quite satisfied with my results. So if you have doubts and need to inequivocally disprove. I suggest you perform a hundred mile run utilizing two exactly the same vehicles with one modified, one not modified. Plus a necessary gap between the two with no traffic on the same day using cruise control under identical barometric and wind conditions. Also Baseline runs of the two vehicles over the same distance without modification to show there's no variation between the two as well. Otherwise I will go by my own findings. Because in the end I'm not interested in statistics, I'm interested in findings. I've taken statistical analysis. They are very manipulable and malleable. Just like politics.
Nonetheless, for myself, there was over one MPG difference with the for the test conditions, traveling over level road plus slightly downhill. Nothing more wild than putting tape over the Gap at the top of the windshield and the roof. And providing a 45° angle between the Chrome stripping on on my MKS and the windshield. This is a known high pressure area on pretty much all vehicles with a hood.
Wind noise, although that's my opinion. Was much reduced. This is just an old speedrun trick that I was testing for validity. Clear packing tape can provide some interesting answers. Your mileage May vary. LOL
 
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You achieved a repeatable 1.2mpg increase over a 3 mile controlled route by just filling in the gap at the top of the windshield with tape? not in disbelief but unless I missed something I just wanted to verify thats what I read. I feel like the right strip of rubber molding could be glued into that gap and lay over the windshield to provide a more permanent and aesthetically pleasing final product and it would be relatively simple. for the wind noise alone this would be something to look in to.
 

Bluezone

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You achieved a repeatable 1.2mpg increase over a 3 mile controlled route by just filling in the gap at the top of the windshield with tape? not in disbelief but unless I missed something I just wanted to verify thats what I read. I feel like the right strip of rubber molding could be glued into that gap and lay over the windshield to provide a more permanent and aesthetically pleasing final product and it would be relatively simple. for the wind noise alone this would be something to look in to.
Just to be clear I wasn't expecting quite so definitive of a outcome from my small spate of testing. Normally if you're running tests series, you have allowances for data noise. Usually this is in the 2% to 5% range. It's also why I chose this piece of road because it shows noticeable effect when things are going even slightly wrong my cars state of tune.
As it is, we are sitting at a 4.563% differentiation in run to run data. So verging on just being data noise @ 5%. That depending on using data noise compensation @ 5%. It might even be a case of this mod being useful only at the speed I was traveling. It might make things worse at higher speed. Aerodynamics can do that.

"by just filling in the gap at the top of the windshield with tape?"

Well there was also the packing tape run from the sides of the "windshield Chrome", on my mks, to the windshield face, at about a 45° angle as well. The Chrome strip running beside the windshield on the MKS sits proud of the windshield from a quarter of an inch at the top of the windshield . To a maximum of 2 in at the base of the windshiel. Think of the sides of a pan holding water in. I think that this is big chunk of it.
Adding an incline to this 90° surface change/air fence, should likely help ease the airflow around the side and closer to the greenhouse area of the car. So it would be adhering a little better to the side glass. Not to mention possible reduction in air pressure buildup on the windshield.
I didn't test both areas individually. I do have a sneaking suspicion that that Gap at the top causes rather turbulent airflow. So possibly non-laminer flow. I'm not 100% sure if that's a detriment or not. If that Gap works the right way it reduces lift. If it works the wrong way, the airflow becomes detached.
The point is it should reduce the size of the hole the car is punching through the air. The smaller the hole the lower the drag at the rear. It's the pressure difference between the front and the rear of the car that causes drag. Just like a wing produces lift because of pressure differential between the top and the bottom of the wing.
The air curtain, if I ever get that completed. Should reduce drag by making the air stream adhere more closely to the sides of the car. Smaller hole in the Airstream for the car. Plus and a increase likelihood of the Airstream better filling in the low pressure area at the back of the car.
The tires in the air blade mod case, produce a lot of turbulent air flow that pushes the airstream away from the car side and that increases drag because of the bigger disturbance in the air. So dead air. What I'm trying to say is the energy imparted by moving through the air, should be used to help guide it as opposed to trying to coax dead air into moving into the low pressure area behind the car.

As for the wind noise it doesn't completely disappear. It does seem to be reduced to my old ears. I'd also say the noise produced is also a slightly higher frequency. At my age higher frequencies are not something I hear quite as well is when I was in my 20s and 30s. Younger ears might perceive it as more annoying or more noticeable. To me it sounded less noisy.

I would suggest thinking about your frame of reference in all of this as well. Short of hurricane winds, the air around us is motionless or should be considered relatively motionless. On the highway, air is not moving past us at 60 miles an hour. We are moving past the air at 60 miles an hour. It's our motion through the air, displacing and compressing it, out of the the way of our cars that causes problems. That movement through the air, produces the low pressure void behind us.
That is what mainly creates the drag/pressure differential. The faster we move, the larger and more energetic the air/fluid displacement becomes (x^(3)). Which is why drag load increases with speed.
 
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shaldaya

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Mind uploading a couple pictures, I'm having trouble visualizing what you did to your car to get these effects
 

Bluezone

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Mind uploading a couple pictures, I'm having trouble visualizing what you did to your car to get these effects
Okay I took some pics just showing short pieces of duct tape, instead of clear packing tape. I wasn't going to duct tape the whole car so just imagine it top to bottom along the sides of the windshield and a full strip across the Gap at the top. As it is I'm going to be removing packing tape for quite some time. It doesn't come off easy LOL20240328 19125520240328 19124520240328 191239
 

Bluezone

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Well I installed the permanent version of the airflow mods and one other, early MKS specific mod.
Not sure if it made any Improvement or not. Different day different wind patterns.Screenshot 20240401 205220 Photos
 

kryptto

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Keep reporting in nothing shocks me when dealing with looks vs mpg compromise.
 

yaycandy

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Keep reporting in nothing shocks me when dealing with looks vs mpg compromise.
I don't think we purchased the sho for mpg so i usually don't bother with anything to improve drag coefficient as my degrees are in aerodynamics. No changes can be seen until highway speeds or greater and then most improvements create high pressure zones that increase downforce at higher speeds, making you slower and making high speed mpg worse. Thats what canards on the front bumper will do. Taping the windshield will have nearly no effect on our cars because of the windshield angle. The gen 4 sho actually has a great aerodynamic design.
Best to do is keep the under pan on, seal up as much as you can under the car. Make it flat under the rear bumper and add a diffuser. Add lowering spring. Take the side mirrors off. Remove as much weight as possible and unsprung weight. Our heavy rims dont help. Dws06 + is the lightest tire for our rims without sacrificing actual performance
 
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Bluezone

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I have to say yes and no.
Not that improving airflow beneath the car doesn't cause big improvements in drag coefficient.
At around 40 or 50 miles per hour aerodynamic drag does not have a lot of effect and performance. You're forgetting three things though.

Aerodynamic drag goes up cubed to speed increases. You need to devote more horsepower to overcoming aerodynamic drag in the quarter mile.

Once you're in 4th gear (maybe third gear because you definitely are over 60 mph) the effect of mechanical advantage of gearing drastically drops torque multiplication. Airplanes in their efficiency range don't have to so much with this because altitude reduces air density. As a recall they generally have a fixed ratio drivetrain. Be it a propeller or a jet engine. Not to say they don't see drivetrain efficiency changes +/- with speed.

25% of all the drag produced in a car comes from the wheels. Improving airflow in and around the tires is low-hanging fruit for drag reduction. Again generally aircraft don't have to deal with it. They generally try to pull the wheel assemblies up into the airframe and wings. So as to reduce drag. Otherwise 747's would have their landing gear down all the times. Because looking at it that way, landing gear structures would be no big whoop in the airflow. So then, why pull them up into the aircraft?

None of the things I'm trying, are looking specifically for improvements in MPG. You'd be missing the plot if you thought that. I'd gladly take more gas mileage if that's the side effect though. The miles per gallon is simply a measure of aerodynamic drag and the amount of fuel it takes to maintain a particular speed . Screenshot 20220912 124030 Photos
Look at the time slip. Virtually everyone running on our platform finishes the last half of the quarter mile in the 4 to 4.6 second range. The speed is well above normal Highway speeds. That's pretty consistent. If you can get that part of the Run below 4 seconds, you're edging into the 10-second quarter mile range. That's mostly due to gearing and aerodynamics. You can get through that brick wall with huge horsepower. But why not help the run outcome and your cars Powertrain by improving the aerodynamics in other areas? Even thermally, reducing the load on the engine reduces the heat load. So, long way around, more horsepower to apply to accelerating the weight of the vehicle. Rather than fighting air drag.
Since you work with aerodynamics, maybe you can input some ideas. I'd assume that you have access to cfd or some other aerodynamic modeling software.
Horsepower is sexy. So is aerodynamics. Otherwise why add an air splitter or a wing to your car?
 

yaycandy

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Wow. You cant just make small changes and compare them to a 1/4 mile speed. There are many other factors when lined up at the tree. Even down to what vehicle previous left the surface before you and how much rubber and water was added or taken away. Along with many vehicle factors like launch rpm just to name 1 of many. What did you do to your negative results? Just throw them out and only post the 1 positive? Lol
 

Bluezone

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Wow. You cant just make small changes and compare them to a 1/4 mile speed. There are many other factors when lined up at the tree. Even down to what vehicle previous left the surface before you and how much rubber and water was added or taken away. Along with many vehicle factors like launch rpm just to name 1 of many. What did you do to your negative results? Just throw them out and only post the 1 positive? Lol
Where have I done that. Show me specific instances when I was talking generalities?
Yes there are many different factors that affect your launch at the lights. Where did I talk about launching the car other than right now? I talked about the improving the time of last last half of the quarter mile. When aerodynamics play a greater role. No where did I mention speed. I talked about time. Speed is more a measure of horsepower at the end of a quarter mile.
Heck wind changes are huge variables. But you're basically indicating not to bother. A aerodynamicist saying don't try to make any improvements.
Dan Gunter added a small tab to the end of his airfoil on his race car. He misled all the other Racers telling them it was just to help mechanics to push his car in the garage area. Very tiny change relatively speaking. It took a little while but the other Racers figured out that he was on to something.
And again I say you're missing the plot point. This is about making small changes to to make small improvements to your quarter mile run.
Show me where I'm throwing out data. Look at my earlier posts it shows three runs with the mileage on the car and timestamps. No thrown out data. Return trips were not included, too much traffic on the return portion. Maintaining a specific speed was impossible and the interference due to wind turbulence and drafting made them useless. Regardless those trips showed consistent improvements when the changes were applied. Using them would have been dishonest.
I've also stated there are many variables that can affect things. I've also stated I was surprised that it had as much effect as it did.
Where is your data to disprove?
Perhaps you should go back to designing doors at boeing.
 
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shaldaya

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Uhh.... why y'all arguing. Better aero is always a good thing
Better aero means better performance AND better mpg
More downforce means lowered top speed, sure, BUT it means way better cornering speed (I'm a track guy, not 1/4 mile guy)
Also, no DURR!!! Of course there are more factors, there are always more factors. Thats an absolute stupid argument.
I see data, that's ALL I care about, and I want to see more data and more tests, successful or not
 

Bluezone

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A few pictures from 9 years ago. After a snow storm. You can see how the wind sculpted the way the snow settled around the car due to air flow. Meaning faster moving air reduced the snow accumulation and slower moving air increased snow accumulation.
Look at how far away the snow settled away from the car.
Kind of cool .20150202 11345720150202 11350020150202 11345220150202 11334220150202 11332620150202 113518
 

shaldaya

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A few pictures from 9 years ago. After a snow storm. You can see how the wind sculpted the way the snow settled around the car due to air flow. Meaning faster moving air reduced the snow accumulation and slower moving air increased snow accumulation.
Look at how far away the snow settled away from the car.
Kind of cool .View attachment 90148View attachment 90147View attachment 90149View attachment 90150View attachment 90152View attachment 90151
that is the best visualization of aero I have EVER seen
 

Bluezone

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that is the best visualization of aero I have EVER seen
Thanks. I thought they were pretty cool pictures.
Yesterday I tore into the car to see about implementing air curtains. Unfortunately there's a large metal structure where the lower plastic bumper attaches to the fender. While air could be ducted out through that area it would lose all the velocity gained by tapering the air flow. So it's a no-go. Unless someone else wants to get out a Sawzall and try implementing it on their own car to see if it works.
 
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