Polycarbonate for windows ?

I would like an all-polycarbonate window system. Plus, I would add a front window glass-polyfilm overlay (much like you apply a screen protector to a mobile phone) that is adhesively applied, yet replaceable. It only needs to be ~1.2mm thick. That would improve scratch resistance where it matters the most. Of course for this to work, the front windshield shape's curvature would have to be primary only (not compound curvature); OR it could be a multi-segmented (glass & adhesive film) overlay, with a special, glare-reducing clear polymer at the segment unions.

In today's webinar Steve and Chris confirmed that the Aptera is getting regular auto glass. However, they have people investigating polycarbonate to see if future Apterae could benefit from this.

More thoughts on the pros and cons of Polycarbonate (PC) windows:

I am wary of a PC windshield and other glass around the driver and passenger (i.e. windshield and side windows, as it is strong, yes, but it just does not last like glass, nor is it as hard (different than strong), which means replacements (or lots of polishing and coatings over time) will be needed needed just due to UV degradation over time, let alone scratching and such like a wiper would deal out (dragging dust, dirt, sand, etc. across the windshield. Is it worth the weight savings, better insulation, etc.? That is in the mind of the beholder. It certainly makes the off-the-lot experience better, with the trade-off of problems over time.

The cars on the road could look cheap after a few years going around with perhaps yellowed, scratched-up, sandblasted, pitted, warped, scratched, etc. windows, and the car could get a bad rap for just being like a motorcycle-class vehicle, which I would feel bad about. This would hurt resale value, I would think. One can buff out the surface damage some, like with plastic headlights, but that gets really old. It is not fun to maintain plastic that is exposed to the elements, especially when you need to have perfect vision through it (and it is a vehicle that is supposed to be parked in the sun whenever possible, so max UV exposure). Other disadvantages may be safety in circumstances where the PC's strength is overwhelmed, as unless it is engineered for safe failure like auto-glass is, shards may stab occupants in accidents, or the entire window getting pushed in with sharp edges going into the cabin could be a problem. In a rear-end collision, the entire rear window could become a deadly blade being pushed in or flying free as a unit, if not designed-around, but this kind of safety comes for "free" with auto glass (tempered and safety glass), at the expense of weight, of course. PC generally can't be made as optically-perfect in large windows, either... PC is better at overall strength (at the expense of hardness), so it would shrug off rock hits and such that could crack glass.

This manufacturer here makes PC windshields; it is not used for freeway-class vehicles or where there is a wiper involved: Polycarbonate Windshield, Custom Lexan Window Manufacturer (weprofab.com)

The PC manufacturers talk about hardness and other coatings, but coatings are coatings, and they wear off or de-bond over time... see the pic; these are my PC eyeglasses that I need to get replaced because one of the coatings on the PC lenses (probably the hardness coating), is failing after some time, and this is a common issue.

Anyway, those are just thoughts; we don't know the details of the engineering pros and cons being considered for this vehicle design, or newer tech, etc.

Point very well taken.

I've just had heated windshields on my mind for winter, wondering if eGolf's saves power with direct conduction instead of cabin-heat defrost. In the same manner which direct-conducting seat heaters save power over cabin heat.

Either way, I bet that it at least saves TIME compared to cabin-heat defrost, & the latter is DEFINITELY much faster with any EV than awaiting gas engine heat in cold weather! Many new gas cars also do that remotely, but as noted it takes them much longer to warm.

All EVs offer the ability to heat or cool the interior before driving - using a remote fob or phone app or even a home voice assistant. Unless it's an emergency and you must use the vehicle in the middle of a snow or ice storm with no time to prepare, there's really no reason to worry about scraping windows. Besides, if it's that much of an emergency that you can't spend a few minutes defrosting, what about the minutes you'd spend scraping?

Many plane owners get their polycarbonate windshields polished on a regular basis. Film sounds good too.

I like the idea of "limited life" exterior film, IF it isn't too expensive to replace, withstands wipers okay, & the polycarbonate is well electrically heated to make ice slide off without scraping.

Replace the film after a few years of sun, or a few decades with shaded parking (like home garage to work parking structure). Then you get a nice fresh, new surface periodically.

https://www.youtube.com/watch?v=gLIwwGSddiM at 3:02

phoenix, az here. every car i buy gets wiper DELETE and i apply Rain-x if there is rain forecast. i hate wipers. Lived in Mi for 44 yrs. before that. +1 for GLASS ALSO

I have flown many helicopters with polycarbonate windscreens. Rule number one was... NEVER use the wind screen wipers!!! Rule number two was...NEVER use the wind screen wipers!! Rule three was always clean with Mirror Glaze by hand and wipe with residue off with a non scratching cloth. I say go with the glass!

I'm really against polycarbonate for the windshield. Even with coatings it will not be durable (remaining transparent for long). Take a look at all the cars with cloudy headlights. Guess what? They're coated polycarbonate or plastic. I have problems with coatings on my eyeglasses after 2-3 years and I can't imagine a more pampered existence than that. Sure, polycarbonate is light, impact resistant, and cheap, but it is not going to hold up to windshield wipers, ice scrapers and sand blasting behind trucks.

Everyone has scratch resistant coating on their glasses, and I bet everyone has scratched glasses.

"A replacement of auto safety glass would probably be easier found than one of polycarbonate. "

Not in the size and shape of the Aptera.

He spoke about polycarbonate with a UV/Scratch protecting film over it. IMHO using PC for the fixed windows on the doors and for the non-solar hatch would seem to be a good compromise.

I can also speak to the use of laminated glass in car door windows: It does wonders for noise reduction - but it's as thick and as heavy as laminated windshield glazing.

Most of the rock and stone damage I encounter comes from debris flying off or out of trucks. Two cars ago had just reclaimed the vehicle from the body shop after significant hail damage (including ALL new windows) and, as I waited to pull out of the shop's parking lot onto the 4-lane highway, a flatbed hauling a front-end loader zoomed past and a 1 pound rock flew off the digger's treads and smashed my brand spanking new windshield. I have luck like that...

@pistonboy @Harley Barber I put a 5.0 Ford V8/5-spd./Torsen in a '72 240Z*, & then switched to a $6k Fiat 500e with a 1-moving-part motor & no gas now for 5.5 years.

* Back on topic, I replaced the big, heavy hatch glass with an easily-sourced, reasonably-priced local custom polycarbonate upgrade

Maybe an aircraft windshield supplier would step in.

As long as Aptera is in business and we can get polycarbonate replacement windows, everything is fine. But lets be realistic. Startup companies, regardless how much we love them, do often go out of business. Aftermarket automotive glass companies step in and provide replacement windows. But how common is polycarbonate.

I am not aware of any vehicles using polycarbonate windows. Are there any?

I would think that whatever Aptera put in its windows and windshield you could get from Aptera or they could refer you to where you could get it

Interesting material and concept. There are many different types of polycarbonate as seen in eyeglasses. I wonder if they could build my eyeglass prescription into the windshield?...at least my half of it. Just joking, before you all start responding.

maybe polycarbonate as a transparent more efficient effective structural support, with minimally existing glass layer on the the top for scratch resistance. this may also help allow more thermally insulating windows/windshields for efficient heater and AirConditioning. want to ventilate? maybe open window a little and have some sort of optional device to minimize the aerodynamic penalty of such (3d printer can do the trick) although this is probably not worth doing in terms of efficiency even though some may want this anyway to breathe in fresher outdoor air.

the glass layer on top of polycarbonate is also non toxic, in case polycarbonate is smelly, dont know if is it just that i remember a transparent stiff plastic that smelt weird

With such a low angled aerodynamic shape, rock hits should have less effect.

@pistonboy IF the OEM windows are polycarbonate, it will likely be much easier to find replacements in polycarbonate, than in glass.

Polycarbonate should be much cheaper than glass, once they are set up for the shape. In Colorado, our glass windshields have only lasted 2-3 years on average due to rock hits, so polycarbonate would probably last longer than glass for us. Aircraft usually use polycarbonate or acrylic windows.

I have had eye glasses made of glass and made of polycarbonate.

The polycarbonate is much thinner and lighter. The rollup mechanism and window grooves for holding polycarbonate would be more narrow. Would they still be able to accommodate a thicker window made of glass.

And my third concern would be scratch resistance, especially over the long term. After some online research, polycarbonate appears to be improving in that regard though is highly dependent upon special coatings for its scratch resistance. I would be concerned that the front window would need to be replaced after X number of years of regular use or such creating surface scratches, in comparison to glass generally lasting for the much longer haul unless it is directly impacted / cracked. Polycarbonate appears to be more resistant to significant impact than glass, though less resistant to smaller scratches.