Aerodynamic Shape Optimization - Improving the Efficiency of the Aptera EV

[@nutzeeer]

I hope it will actually look like that!

[@AirShaper]

First cars they made actually do look like this!

[@anoopster]

Would be super cool if you used the music from the video as the audio the Aptera has to pump out when driving at low speeds in parking lots.

[@AirShaper]

That would be pretty impressive :):)

[@younesmekraldi9438]

I’m gonna try this airshaper ,i did master thesis last week and i designed a SUV in SolidWorks and i also used flow simulation SolidWorks and the results weren’t so accurate

[@AirShaper]

It's indeed not easy to get accurate flow results (even in the most capable CFD packages - quite a lot of settings need to be right). Feel free to get in touch at [e-mail] !

[@younesmekraldi9438]

@@AirShaper thank you

[@flymypg]

I'm here after seeing Aptera's recent video containing clips from this video. Is AirShaper also able to support optimizing wheels, rims, covers, and particularly the internal volume of a fully or partially enclosed wheel? That is, can AirShaper optimize across what are essentially 3 semi-isolated domains (exterior, semi-enclosed wheel well with rotating wheel, and under-vehicle)? Looking at the Aptera design, the wheels are either in pods far out to the sides, or are fully enclosed in the center of the under-vehicle flow. Basically eliminating the complications of conventional wheel wells, and even the need for a flat floor under the vehicle. Just how difficult is it to optimize an overall design using conventional wheels placed near the corners of the vehicle body? Is it better to take Aptera's approach and avoid the issue?

[@AirShaper]

We've optimized wheels & rims before (can't name the supplier). There, we mainly look at the ventilation drag (aerodynamic torque on the wheel & rim translated into an equivalent drag penalty). Those simulations included either a full vehicle or a part of it. We can optimize in multiple locations, but only of the optimization goal (e.g. drag reduction, ...) is the same, although it becomes complex after a while. Feel free to drop me more details at [e-mail]. Indeed, most conventional wheel well issues are avoided in the Aptera design, as well as the underfloor challenges. New challenges came in, with a "naked" supension crossing the air gap between the car and the front wheels. Optimizing conventional wheels is still possible, including tricks like air curtains, closed wheel covers, narrower wheels, ... It depends on your target market!

[@jurepecar9092]

Go Airshaper! Go Aptera! :)

[@AirShaper]

Thanks Jure!!

[@bunnyonabunwithagunnicepun5689]

Very impressive, indeed! I have a question - when a vehicle turns, is drag somehow applied to the side of the vehicle at a slight angle, or is that just the G-force? If drag IS applied, what can we do to help alleviate that, specifically? (I think this can be simulated by slightly changing the angle of the subject in relation to the direction of drag itself). Sorry if it's a dumb question, I'm just spitballing random ideas here.

[@mraeropriteshrai404]

Yes drag will be there, assume if you fire a bullet and and it starting curving ( here it will be same but at a low level )

[@bunnyonabunwithagunnicepun5689]

@@mraeropriteshrai404 ah, I see! Thank you!

[@AirShaper]

Not a dumb question at all - on the contrary. There are two forms of "extra drag" related to this: - Sidewind: if you're going straight but there is a sidewind, then the resulting wind vector is not coming in straight at the nose anymore, but at an angle. That means that the front wheel covers for example, can start to block the flow (as the wind approaches them partially from the sides, seeing there large surface area). Shapes which are streamlined in a forward direction can then become less streamlined. In case of the Aptera though, this effect should be limited. - Corners: when taking a corner, the vehicle follows a curved trajectory. Seen the other way around, the wind around the vehicle is taking a bend. In Formula One, this is a very important aspect, as things like drag and especially lift can change by a large amount when cornering, just because of this effect. They actually sometimes run simulations with "curved virtual wind tunnels" to take this effect into account.

[@joeycad]

Wonder if the back wheel could pivot to "crab" point in the direction towards a wind blowing in a perpindicular direction to travel. Aptera having the slimmer tail already, this could be possible for increasing range in a side wind traveling situation.

[@pawansoni-ib8pt]

Which is this software?

[@AirShaper]

Hi Pawan, in the background, this is the adjoint optimization module of OpenFOAM. We've heavliy automated this and integrated it into AirShaper so anyone can use it (see www.airshaper.com or drop me an email at [e-mail] for more info).

[@robertkirchner7981]

It would be very useful if some manufacturer of utility/cargo trailers would make a serious effort to build a truly aerodynamic trailer, which could be pulled by an EV with less range loss. The supposedly "aerodynamic" trailers you can buy now all look like they were penned by some designer who really doesn't know the science.

[@AirShaper]

Hi Robert, true, a lot of trailer designs are not very aerodynamic, despite some claims. Very often, the baseline shape looks like a drop shape, but there often are issues: - a rounded tail looks aerodynamic but often isn't, as the air sticks to the rear. A sharp cut-off is often better (to meet length constraints) - auxiliary geometry often disturbs the flow, offsetting the gains of the base shape - the underfloor is often neglected, with exposed chassis components disturbing the flow. We have trailer customers using AirShaper, like this one: cleantechnica.com/2021/08/12/new-teardrop-trailer-for-electric-vehicles/

[@TaylorPhase]

Can you guys help me aero mod my Hyundai Ioniq? I want to make the most fuel efficient production car on the planet

[@aaronfranklin324]

Sure. Take out the engine and batteries. Throw everything else away. Lash a few sticks together to hold together the engine, batteries, and some space saver high pressure tyres from the dump. Wrap it in a 20 buck dome tent. Congratulations! You have what you asked for.

[@AirShaper]

We've run simulations on the Ioniq before: www.autoevolution.com/news/hyundai-ioniq-5-really-needs-a-rear-wiper-aerodynamic-studies-reveal-170529.html To make the most efficient vehicle on the planet, you should probably not start off of the Ioniq - the base shape of a hatchback is just not aerodynamic enough.

[@Turksarama]

Best bang for your buck to do this is probably start with a Honda Insight, though you're unlikely to be able to optimise it much more.

[@aaronfranklin324]

@@Turksarama are you kidding? A formula 1 chassis weighs 15kg. The Honda insight, made of the lowest strength to weight material known to man, with the crudest and lowest performance joining tech known to man: Mild steel folded and spot-welded. Chassis weighs?? Over 100x less function to weight ratio. In toughness to weight Bamboo outperforms carbon fibre composite like the formula 1 car by at least 10x. So basically, if you want a high performance EV, you can build at least 10 of the best in the world from the batteries in any car on the street today. But any other part but the wires, is fit only for the scrap metal dealer. Particularly if you hope to keep it. Car construction of today, 10 years if you are lucky and less if you don't spend lots of time and money in preserving it. There's a bamboo suspension bridge in China built in 1100AD, still being used by trucks today.

[@AirShaper]

@@Turksarama The tapered rear is indeed quite good on the Honda. But for sure it could be further improved using air curtains, a smooth underfloor etc.

[@anotheryoutuber_]

love this vehicle, but currently modifying a minivan to be more slippery in the air cause the aptera just aint ride for all my needs

[@AirShaper]

Yeah cargo space is perhaps a bit limited on the Aptera! How are you modifying your minivan?

[@anotheryoutuber_]

@@AirShaper moderate undertray, mirror delete, rack removal, rear bumper cut outs. just a few small things but as we know small things can add up. might play with some vortex generators depending on what the data tells me.

[@AirShaper]

@@anotheryoutuber_ Yes, very valid input! It's more a matter of regulations and practicality preventing them from implementing most of those. Vortex generators are usually only useful ahead of separation areas, which we don't have too much on this car. See this video: airshaper.com/videos/diy-aerodynamics-2-vortex-generators/MC6woj6tsQY

[@cooper1507]

I appreciate aptera what I'm curious about is what happens when a Yukon side impacts it.

[@AirShaper]

Good point - although I think the reinforced safety cage is aimed at improving side impact safety. Curious to see the first test results.

[@n.brucenelson5920]

Aptera has been continuously modelling their design for crash worthiness. Once there are production intent vehicles available to test, they will be physically crash tested to FMVSS Part 200 crash test standards by a third party and the ratings published.

[@benykla]

so cool

[@AirShaper]

Thanks Halfina!

[@ReflectionBreak]

Did they actually changed anything beside SoP date?

[@AirShaper]

The way it works is that our software automatically suggests shape modifications to reduce drag. This was done on the nose, the roof, the belly pan, the front wheel covers, the rear wheel skirt and the tail. The suggested changes are exported as modified 3D files, which Aptera then loaded into their own CAD geometry. They then balanced the aerodynamically modified shape with production, cost, safety, design, ... constraints to come up with a new shape. That new shape was then re-evaluated and a significant amount of the reduction in drag was kept.

[@ccibinel]

@@AirShaper Then they reluctantly add mirrors because NHTSA is dumb and undo a ton of the good work... I would love to know the current Cd value; I doubt it wont be 0.13 or better even with these recent tweaks.

[@AirShaper]

​@@ccibinel The mirrors are indeed unfortunate in terms of aerodynamic drag... Aptera mentioned they will take the car out on the road and log drive train data to get first insights on real coefficients (along with tuft testing) - so I'm curious for those results!

[@colinvanful]

total bollocks i can buy 20 cars for less than this usless [car ] costs i would not want to have a crash in this thing .

[@Thejenner1]

damn its ugly

[@n.brucenelson5920]

Many of us think that functional form is beautiful.

[@aaronfranklin324]

Not impressed. You are still 4x heavier and using electric systems of 1/4 the efficiency that you could be. Why? Obviously doing it right would result in something 100 times cheaper, 100x as reliable, and your not interested in your customers, only profit.🙄🥱

[@mitchkeller6548]

What systems would be 4x as efficient?

[@aaronfranklin324]

@@mitchkeller6548 no electronics

[@mitchkeller6548]

@@aaronfranklin324 so you are saying gasoline right?

[@aaronfranklin324]

@@mitchkeller6548 no. I am most certainly not saying gasoline. I am saying with a simple brushed DC motor, no electronic battery management, speed control systems, just decent high efficiency gears and relays to control how many battery cells are in series or parallel, with the appropriate weight reduction I suggested, it would be a useful, not at all slow, true unlimited range, solar powered car. Truly the school kids are doing better in the GT class of the Solar challenge in Australia. Even though they have all the power wasting electronics still.

[@aaronfranklin324]

@@Carl_in_AZ it qualifies as a motorcycle. If it didn't have the absurd high power motor it would even fit in to low registration cost classes worldwide. You don't need all the crash test safety certification in motor cycle classes. Look at the Chinese electric passenger trikes and cargo vehicles available for under $US 1000. On AliExpress Though, as usual you have American companies importing them and selling them for over $10 grand. Personally, having demonstrated that it's perfectly possible to build an amphibious mobile home 20 ft long, 8 feet wide, full standing height, powered by a 250W brushed DC motor, free junkyard carbatteries, and drive it at 5 to 20 mph over 40miles of hilly backcountry roads, and 20 miles down a lake in three days, only on solar power produced by 200W of solar panels, and most of the trip with over 500 kg of cargo on board, I have little patience for its impossible-ing and spurious belief that million+ component electronics systems that are unrepairable and stop working when they can't get their software update. Or do get one that doesn't work, for reasons that may or may not be intentional. Complexity doesn't increase safety. I started using electronic speed controllers, but on finding they seriously reduced torque speed and range. Were prone to failures such as suddenly jamming in full power output, built my own spade switch style 12-24-36 volt fwd/rev system. By doing this I also automatically installed recyclic braking, as if you change down to a lower voltage than the back end the motor is making, you are charging your batteries. As for gears. For most purposes a single planet gear set, clutch shifted to put out either 1:1 or 1:6 reduction is all that most people would ever need. Hub drive motors are just stupid. As is three driven wheels on something like the Aptera. Perhaps a low power crawler geared option on the front wheels for low traction off-road use would be warranted. No more than 500W per wheel.