Trying to improve Aerodynamics on Aliner Ascape for EV TV

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Trying to improve Aerodynamics on Aliner Ascape for EV TV

Postby hwitten » Thu Apr 14, 2022 11:50 pm

Ioniq5Ascape.jpeg
Ioniq5Ascape.jpeg (450.19 KiB) Viewed 499 times


Hoping to use my Hyundai Ioniq 5 as my TV. At the moment I take about a 50% hit on range at 100 kmh.

Trying to improve on drag as much as possible and what comes to mind is the undercarriage being fully exposed.
Wondering if it it would be worthwhile to close that in to make for smother airflow on the underside.

For the boxy rear I'm planning to install Airtabs on sides and roof.

Hoping for some suggestions to add to the pot posting.php?mode=post&f=2#
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby MickinOz » Fri Apr 15, 2022 4:41 am

I hear that it is very common for EV to take a big range hit when towing.
Haven't put a lot of thought to it, I haven't got my head around it at all, but one thing just occurred to me.
I suppose your trailer has brakes? Does the Hyundai have regenerative braking?
How do the two interact?
Does the presence of brakes on the trailer take away some energy that might otherwise be utilised to put some oomph back into the battery? :thinking:
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby GTS225 » Fri Apr 15, 2022 7:45 am

I think I'd do the air tabs first. That flat rear is a huge airflow change and low pressure area, especially at speed. Truck fleets don't use them to be stylish.

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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby tony.latham » Fri Apr 15, 2022 9:43 am

That flat rear is a huge airflow change and low pressure area, especially at speed.


That's the issue with this trailer and I don't have any idea how to fix it. It's not the undercarriage. I've seen a few semi-trailers that have baffles in the rear but I have no idea how effective they are.

Image

Here's a page that shows what shapes produce what drag:
https://study.com/academy/lesson/aerodynamics-lesson-for-kids-definition-facts.html

You might take a look at Slim's video... but it won't rectify the flat back shape of course. It might help with the frontal mass that's exposed above your roofline. But Slim's deflector will also add some drag.



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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby Tom&Shelly » Fri Apr 15, 2022 10:30 am

In my career, I worked on a few aerodynamic studies, and suffice it to say, it's a very difficult problem to analyze in detail and make predictions about. That said, the general idea is that creating turbulent air is bad. It takes energy to make turbulence, which of course comes, ultimately, from your fuel. The square back on that trailer is particularly bad in that regard since the air tries to move into the (relative) vacuum created behind the trailer as it moves down the road. As the air moves in, it creates turbulence. The intent of the baffles is to help smooth the airflow in the back and reduce the volume of vacuum that the air tries to move into. But we all already know all of that.

There are three ways to study the problem, only one of which seems to be practical for us. The first would be to use a super computer* to try and figure out the best length, and angles for the baffles, and the second would be to build accurate scale models and test in a wind tunnel. The practical method is to make some reasonable looking baffles and experiment on the road. My guess is that your first attempt will produce the biggest improvement, and any tweeks thereafter will be minor, but I might be wrong about that.

Tom

* Be wary of web sites that claim to allow computer analysis and read the fine print. Turns out they implement the equations using 2 dimensions, which is fine for students studying the phenomena of turbulence, but the results will be entirely incorrect in the details, including our situation, which is fundamentally based on a 3D world!
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby flboy » Fri Apr 15, 2022 1:40 pm

I put Airtabs on my 7x18 and they had no impact on gas mileage, but I did notice a difference is sway and pull as large trucks approach from behind. Also, it seems more stable in crosswinds... however, this is all very subjective being there is no way to quantify.



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YouTube Video of Finished 6x12 Trailer:
https://youtu.be/6_-8cVdWUIA
YouTube Video of 7*18 with 2ft V-nose Trailer:
https://youtu.be/MUcMM86LA2g
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby Modstock » Fri Apr 15, 2022 7:52 pm

Um, aerodynamically it doesn't get much better than that and EV's aren't really designed to tow. Maybe try towing a different trailer just to see how bad it can get.

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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby tony.latham » Sat Apr 16, 2022 9:54 am

and experiment on the road.


Here's my wind tunnel. I just gotta set up a camera on a tripod and give it a good drive-by. :lol:

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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby gudmund » Sat Apr 16, 2022 3:12 pm

agree with everyone here..... what I see here looks about as 'aero' as you can do....Looks Good!!....... something you may want to research into would be building some kind of a fixed short (maybe a foot or two) awning 'rearward' off the your trailer roof edge backend (kind of what is on your own vehicle's rear deck lid hatch in horizontal level with your vehicle's roof line) the picture posted here of the 'Trailer Tail' kind of shows it also at it's trailing horizontal upper edge = it helps in getting the air off the roof and further away behind the trailer, so when it does drop = the turbulence being created happens away from the trailer as it falls off. I am thinking some kind of 'fixed' awning could be built that could also serve 'double duty' as a kind of a rain guard/overhead cover for the back galley area when camping also. Just a thought........
PS I spoke to a trucker last summer in the middle of ND when in a rest stop about the 'Trailer Tale' on his trailer = he said it does seem to help on long steady hauls, but the trouble with it is when backing up to some loading docks and 'forgetting' it is still extended = sometimes damaging it. :x
Last edited by gudmund on Sat Apr 16, 2022 8:02 pm, edited 1 time in total.
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby Squigie » Sat Apr 16, 2022 6:00 pm

Ooof.
That flat rear is the killer. Unless you can streamline the rear, I don't see much being gained via other means.

I doubt that it would be very effective, but perhaps a spoiler might help.
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby MickinOz » Sun Apr 17, 2022 6:04 am

With an petrol or diesel vehicle, by far the best way to improve fuel consumption (range) is to slow down.
I don't know if EV's are the same, but I believe the saving is because the slower you go the less drag you must contend with. Have you tried slowing down to 90 km/hr?
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby Philip » Sun Apr 17, 2022 9:37 am

To make any type of improvement you need to know where the drag is coming from. The cheapest and fastest way for a person without a wind tunnel is to use tape and 2" to 3" pieces of string. Do straight lines across the body or bodies to be tested. Make the rows about 12" apart. Go for a drive and video tape all tape strips to see what the strings are doing. Then experiment with air tab's to even the flow out as best as you can.

Something like this.

https://www.bing.com/images/search?view ... ajaxserp=0
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Re: Trying to improve Aerodynamics on Aliner Ascape for EV T

Postby hwitten » Sun Apr 17, 2022 9:41 pm

MickinOz wrote:I hear that it is very common for EV to take a big range hit when towing.
Haven't put a lot of thought to it, I haven't got my head around it at all, but one thing just occurred to me.
I suppose your trailer has brakes? Does the Hyundai have regenerative braking?
How do the two interact?
Does the presence of brakes on the trailer take away some energy that might otherwise be utilised to put some oomph back into the battery? :thinking:

The Hyundai has very good regen.
I have the trailer brakes set very low. Still have testing to do to confirm but allowing the trailer to push a little should assist/help the regen.
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