Door windows

[fritzponds]

Aptera said they were going to make the windows roll down. That is going to be a major redesign of the doors. They don't look big enough for the window to roll down all the way, the way they are designed now.

[MegaAutoBit]

I have been thinking about this myself. Not only do the bottoms of the doors look to small to store the windows, but the curvature of the doors and windows look like it would present some serious problems. If I remember correctly, the windows have more of a curve into the cockpit, and the bottoms of the doors are more flat.

[fritzponds]

Yea, either the window won't roll down all the way, which is fine for me, or they will have to make the window smaller. I like the windows the size they are now. I guess they will have to change the structure of the door as well, to make room for the window pocket.

[futura]

Well, now I'm just procrastinating on other work but check the attached image (from PM video).
I agree it's an interesting problem.
The curvature is noticeably altered from lower door to window.
The method of sealing a roll-able window seems to require the window can no longer be flush with the body. Altering both things would corrupt the drag coefficient (it seems).
That would be a fun problem to work on.

Cheers.
13

[Dubito]

Was thinking I never ride with windows open, scrubbed air easier on allergies and at freeway speed a/c is more efficient than open windows. So I thought I wouldn’t care if the windows didn’t roll down, except for emergency escape. Or drive-thru. Or toll booth. Or law enforcement that wants license but thinks opening a door signifies a greater threat. Steve, get on that window.

[fritzponds]

Maybe it could pop out and slide back along the outside of the body

[palmer_md]

Thats funny because that is what I was thinking and I sent this to Aptera a few months ago. Not a great photoshop...actually just a quick sketch with Paint, but you get the idea. I suggested that the window go outward first and then slide back as far as it could and still have some strength in case someone decides to drive down the freeway with it open.

I hope they figure out some way to make the windows open without hurting the aerodynamics of the vehicle. It only needs to be opened for paying tolls and drive thru windows and such. A traditional window is recessed into the door and will kill the fuel economy. The window needs to be flush with the body when closed just like the prototype.

Michael

[fritzponds]

Thats a good drawing. It could also pivot down after moving out, with the hinge at the front corner.

[c0mp13x]

Steve Fambro says the windows will roll down and they are considering 2 possible ways to make it happen. My guess is that they will roll partially down inside the doors, enough to pay a toll or grab a Big Mac. See "Windows" paragraph about half way through this post:

Fambro comments on roll-down windows (http://www.apteraforum.com/showthread.php?p=1023#post1023)

:)

[LQUAN]

Or Aptera can have rolldown windows similar to the Lamboghini Countach

http://en.wikipedia.org/wiki/Image:Countachgold.jpg

But then I would miss having nice breeze blowing into my face while driving

[palmer_md]

The problem I have with those windows (on the lambo), and all the windows that drop down into the door (almost all cars) is that it will probably double the drag on the car. One of the key features of the car is the low drag. Having windows that roll down could have a real negative effect on the efficiency of the vehicle.

I would rather have the windows not roll down and just open the door to pay tolls and communicate at a drive-thru and such than have the EV go from 120 mile range to 80 mile range.

I'm hopefull that the engineers will come up with something creative to keep the low drag and have the window crack open.

Michael

[LeeW]

Could the windows be hinged, maybe from the front diagonal edge and open like those on the Go-One, pictures at http://www.go-one.us/Pictures_of_go-one3.html

[butter]

As someone who knows nothing about materials, I wonder aloud, perhaps lamely (but why not): could they use something flexible like Plexiglas?

[LQUAN]

I think the prototype is currently has preformed plexiglass to cut cost and weight. Problem with plexiglass is that it scratch very easily. If it sits out in the sun for a year or so, plexiglass will turn yellow and dull out. I think we want to have standard safety atutomotive temperred glass for our cars. ;)

[butter]

If it seats out in the sun for a year or so, plexiglass will turn yellow and dull out. I think we want to have standard safety atutomotive temperred glass for our cars. ;)

oh whoops. heh. hmm. is there anything else that's flexible and clear? what about clear carbon fiber whatever (the stuff the actual body will be made of)? or is that dumb because it's impossible or extremely difficult/expensive?

ok, i guess not.

silicone?

[LQUAN]

Plexiglass is a brandname for acrylic. Acrylic is a synthetic polymer or plastic. It is somewhat flexible if the sheet is thin. If you notice the rear windows of some convertible vehicles manufactured back in the 80's, you see that they are all dull and yellowish - they are made out acrylic. All motocycles have acrylic windshields, and yes, they can get scratch easily if you used the wrong material for cleaning.

Acrylic cannot be used in passenger vehicles because in case of accident it does not break up into little peices like temperred glass. It will crack and cut the occupants. If you are trapped inside and need to get out quickly, you or emergency personel cannot safely break acrylic glass.

In case you are wondering what is temperred glass...Temperred glass is regular silicon base glass (like your home windows). It may be coated with anti-UV solution. The glass is molded in the form of a car window. While it is still red hot from the mold, they quickly blow or pass a breeze of cold air to both sides of the red hot glass and let the whole thing cool down at room temperature. This process will make uneven crytallization of the glass - cold air makes the two sides crytallize faster than the middle part. This process will create built-in stress onto the glass. Cold air makes the glass surface want to contract. Hot glass in the middle wants to expand. Therefore, when you break the tension on one side of the surface, equilibrium is breached, and the entire glass pull and push itself to destruction. ;)

[KarenRei]

LQUAN: Sure you're thinking of plexiglass (acryllic) when you talk about yellowing in one year? Acryllic is generally considered one of the more UV-stable transparent polymers, like polycarbonate. Sure you weren't looking at some polyethylene or clear PVC? For it to yellow in just one year, it'd also have to have no UV treatment (UV absorbers, free radical scavengers, etc) at all, either, and not be rated for outdoor use.

I've been involved in greenhouse design/construction before as a hobby, and the six main materials used in greenhouse construction are (from memory):

Glass: Traditional. Good IR absorber, virtually immune to UV damage, reasonably good transparency, brittle.
Fiberglass: Good IR absorber, low UV damage, fair transparency, scratches.
Polyethylene film: Most common material in commercial greenhouses these days due to low cost. Poor IR absorber, very prone to UV damage, excellent transparency. Often only good for a year, two at most.
PVC film: Popular in Japan. Fair IR absorber, somewhat prone to UV damage, good to excellent transparency. Often only good for 1-3 years.
Polycarbonate: Increasingly popular in quality home/kit greenhouses. Excellent IR absorber, blocks UV, low UV damage, excellent transparency.
Acryllic: Excellent IR absorber, transmits UV, low UV damage, superb transparency.

Note that the better of an IR absorber it is, the more of a greenhouse effect you'll get. In a greenhouse, that's what you want; in a car, not so much (certainly not in the summer).

[Matthijs]

I think the prototype is currently has preformed plexiglass to cut cost and weight. Problem with plexiglass is that it scratch very easily. If it sits out in the sun for a year or so, plexiglass will turn yellow and dull out. I think we want to have standard safety atutomotive temperred glass for our cars. ;)

"As an aside, all of the glass on the Aptera typ-1 prototype is laminated automotive safety glass, even the glass covering the solar cells on the roof! It was easier (though heavier) for the prototypes to have all laminated glass rather than some tempered and some laminated."

Steve Fambro at AutoblogGreen

[G-Jet]

Automotive wise, you would use laminated safety glass. You could use treated polycarbonate as some cars are already doing this, as well as many race cars.
So my guess is a mix of the two.

Acrylic can be good and is used in the aviation industry. Scratches can be removed with alot of elbow grease.

G

[davidrools]

I don't see a problem with opening the door for fast food. The fact that it opens upward makes it particularly convenient for this situation. For tolls, I imagine most Californian Aptera drivers probably use FasTrak (http://www.bayareafastrak.org/) already. And when you cross a bridge toll is free during commute hours for carpools and "motorcycles" ;) This would be a significant cost savings and incentive for people who frequently (or daily) cross a bridge (not uncommon in the bay area).

[KarenRei]

Up here in the cold, upper midwest, I don't want to have to open my whole door and let all the warm air out. Especially in an EV, where warm air doesn't come virtually free from a wasteful gasoline engine.

[Chupacabra]

I'd want windows that rolled down also. If they roll down into the body of the door it doesn't look like they'd roll down all the way unless there's some curvature of the door and window that we can't see from pics that might allow it to slide farther inside...

Or maybe the production model will be different enough it'll be able to roll down. Its a definite safety issue if the windows can't roll down all the way.

[panamericans]

I noticed in the pictures of the proto type Aptera that the side widows are fixed. In fact Mr. Fambro in his video makes a positive point of the flush clean fit nature of the vehicle’s design, which incorporates sealed flush fit windows… This flush finish is unique and quite different then what one would expect to see on the road. There is less wind resistance, less noise and the overall appearance of the body is enhanced.

There are also additional advantages... The Aptera has a climate control feature that takes the ‘sting’ out of parking in the hot sun, negating the need for open windows. The gull wing doors do not operate like the standard car doors. They swing up and NOT outward as one would find with a typical car door. This is an important feature, as when one approaches a ticket booth or parking ticket machine, the door would have to be opened in any regard due to the extended front wheel wells increasing the distance to the ticketing machine or attendant...But most importantly the gull wing doors do not take additional space as with standard car door designs. (They don't swing beyond the front wheel wells).

Come to think of it, side windows are rarely opened anyway. It would be uncomfortable and noisy to drive on the highway with open windows. Think about it, how many times is it necessary to open the side windows in the first place…especially with gull wind doors? If one has to reach uncomfortably through an open window to pay at a toll booth, the driver’s door would have to be opened anyway with the Aptera. To have opening windows would also mean accommodating flat glass sections and losing the curved form fitting glass as seen in the Aptera proto type. I suspect fixed curved windows should prove cheaper, cleaner and functionally a better alternative in the long run....

MPK 1456

[3-4-me]

panamericans:
That's a pretty good arguement. Perhaps the reason so many of us want roll down windows, is the same for ordering the hybrid.
It's familiar and we're used to it.
If the car stays cool, quiet, and if opening the door solves the drive thru problem, I could forgo them opening.
One problem with opening the door is: if it's cold or raining, you expose the whole cab to the elements.
Not a huge problem if the heater works good, and the door has decent rain gutters.
Nice 1st post:cool:

[panamericans]

One of the most fascinating thoughts about the Aptera is she is a new and refreshing concept in many different ways… too many to list here. Her design and inclusions are not just to ‘impress’, but are original expressions of excellent engineering. I suspect it would be very difficult to argue otherwise.

It is also nice to read on the Internet the many positive market reactions to the Aptera... especially considering the beating the US public has experienced with foreign cars dominating public perceptions that when it comes to the value of 'originality and quality' it has to be 'imported’. It would give us great satisfaction if Aptera Motors can deliver what we believe it can (and soon)....with flush windows of course.

MPK 1456

[fritzponds]

of course.

[garygid]

With the windows open, it would seem that the Aptera's
performance would suffer greatly. So, we will mostly drive
with them up (also to keep out traffic noise, and fumes).

Also, if operable windows cause any significant performance hit,
I vote for fixed glass windows if good airflow through the
vehicle can be provided by the vent/fan system.

[LQUAN]

Here in Southern California, temperature can go up 110F or more for a couple months at a time in the summer. Without a regular AC that uses Freon to cool down the cabin, it would be hell with fixed closed windows. Sometimes when charge is runing low, you may not want to use the AC. And then there are people who like to leave their pets inside the car with windows partially open. With fixed closed windows, I hope you are not a smoker or ride with a smoker. There are many inconveniences with fixed closed windows. I would never buy a car with fixed closed windows.

Doors on Aptera is not gull-wing type. Gull-wing doors slide up on horizonal pivot. Aptera's door open up instead of open out. They have to open up because there is no room for them to open out like most cars. It will interesting to see how well the door counter-balance mechanism work years after years. Because if it failed to hold its own weight, it will slam down hard and fast if the car moved forward just a little bit while the door is open...I hope nobody has their arm or leg sticking out when that happen.

[Chupacabra]

Your CD will go down if you roll down the windows, but...


Static windows are a safety concern as far as escaping from the vehicle in bad crashes/fires.

SERIOUS safety issue if you have to open your door for every unknown person (Police impersonators, carjacking mug rape kidnapping.....). I'm sure women who buy Aptera would be ecstatic not to be easily dragged out of their car by a mugger/rapist posing as a newspaper guy or someone else just because they were "forced" to open the door on a vehicle with static windows.

I'm social and just want to be able to talk to people without having to open my door. Many times I'll pull up to a light and see a friend. Also, people are gonna ask you about your car, or a myriad of other reasons.

I like the feeling of the sunshine and wind on my face when in town. The outdoors in socal is nice. Its why I choose to pay higher $ and put up with traffic.


For those of you who want to drive in a hyperberic sensory deprivation chamber 24/7, feel free not to roll down your windows and enjoy that .11 CD. Personally I'd like to see the windows have the ability to be rolled down.

Chupa

[panamericans]

Yes, I must agree, it is true that when in a serious accident the door (or doors) might not open. Then again it is also equally true in such situations the impact force will cause these same windows to shatter, as tempered glass is designed to do. Side impact and frontal crash tests have repeatedly demonstrated this reality . The real danger in experiencing such traumatic accidents is getting impaled or crushed inside the vehicle.

When it comes to ‘police impersonators’, rapist and such other nefarious ilk, the ‘roll down window’ will give a false illusion of security… Once rolled down, the occupant’s safety is seriously compromised…. Road safety is about being aware… be it with vehicular traffic, pedestrians or being approached by ‘strangers’. One must judge each situation accordingly…as if one’s life depends on it.… It is one’s discretion that is the critical safety 'design feature’ in such situations.

What has been expressed on this subject so far are hypothetical projections and no more. Does it really matter if the windows are ‘flush fitted’ or ‘roll down’, as both have their merits and driver preferences?… However, it would be nice for a purchaser to have the option to select either format.... Why can’t it be so? In my opinion, it only enhances the attraction of the flexibility of Aptera’s many design merits, which helps make it stand out from the ordinary.

I also noticed in a short video where Chris Anthony of Aptera Motors mentioned that the car’s climate control will handle 120 degree outside temperatures to bring a parked car down to 75 degrees internally. Considering this is based on a heat pump system …it certainly could be possible… If one is comfortable on the inside, the windows are not critical to have in an opened position…but again, this is a matter of personal preferences…. “via de la Différence”.

MPK 1456

[panamericans]

Yes, I must agree, it is true that when in a serious accident the door (or doors) might not open. Then again it is also equally true in such situations the impact force will cause these same windows to shatter, as tempered glass is designed to do. Side impact and frontal crash tests have already demonstrated this reality repeatedly. The real danger in experiencing such traumatic accidents is getting impaled or crushed inside the vehicle.

When it comes to ‘police impersonators’, rapist and such other nefarious ilk, the ‘roll down window’ will give a false illusion of security… Once rolled down, the occupant’s safety is seriously compromised…. That is precisely what the ‘impersonator’ wants to achieve in the first place. Road safety is about being aware… be it with vehicular traffic, pedestrians or being approached by ‘strangers’. One must judge each situation accordingly…as if one’s life depends on it.… It is one’s discretion that is the critical safety design ‘feature’ in such situations.

What has been expressed on this subject so far are hypothetical projections and no more. Does it really matter if the windows are ‘flush fitted’ or ‘roll down’, as both have their merits and driver preferences?… However, it would be nice for a purchaser to have the option to select either format.... Why can’t it be so? In my opinion, it only enhances the attraction of the flexibility of Aptera’s many design merits, which helps make it stand out from the ordinary.

I also noticed in a short video where Chris Anthony of Aptera Motors mentioned that the car’s climate control will handle 120 degree outside temperatures to bring a parked car down to 75 degrees internally. Considering this is based on a heat pump system …it certainly could be possible… If one is comfortable on the inside, the windows are not critical to have in an opened position…but again, this is a matter of personal preferences…. “via de la Différence”.

MPK 1456

[panamericans]

Yes, I must agree, it is true that when in a serious accident the door (or doors) might not open. Then again it is also equally true in such situations the impact force will cause these same windows to shatter, as tempered glass is designed to do. Side impact and frontal crash tests have already demonstrated this reality repeatedly. The real danger in experiencing such traumatic accidents is getting impaled or crushed inside the vehicle.

When it comes to ‘police impersonators’, rapist and such other nefarious ilk, the ‘roll down window’ will give a false illusion of security… Once rolled down, the occupant’s safety is seriously compromised…. That is precisely what the ‘impersonator’ wants to achieve in the first place. Road safety is about being aware… be it with vehicular traffic, pedestrians or being approached by ‘strangers’. One must judge each situation accordingly…as if one’s life depends on it.… It is one’s discretion that is the critical safety design ‘feature’ in such situations.

What has been expressed on this subject so far are hypothetical projections and no more. Does it really matter if the windows are ‘flush fitted’ or ‘roll down’, as both have their merits and driver preferences?… However, it would be nice for a purchaser to have the option to select either format.... Why can’t it be so? In my opinion, it only enhances the attraction of the flexibility of Aptera’s many design merits, which helps make it stand out from the ordinary.

I also noticed in a short video where Chris Anthony of Aptera Motors mentioned that the car’s climate control will handle 120 degree outside temperatures to bring a parked car down to 75 degrees internally. Considering this is based on a heat pump system …it certainly could be possible… If one is comfortable on the inside, the windows are not critical to have in an opened position…but again, this is a matter of personal preferences…. “via de la Différence”.

MPK 1456

[panamericans]

Yes, I must agree, it is true that when in a serious accident the door (or doors) might not open. Then again it is also equally true in such situations the impact force will cause these same windows to shatter, as tempered glass is designed to do. Side impact and frontal crash tests have already demonstrated this reality repeatedly. The real danger in experiencing such traumatic accidents is getting impaled or crushed inside the vehicle.

When it comes to ‘police impersonators’, rapist and such other nefarious ilk, the ‘roll down window’ will give a false illusion of security… Once rolled down, the occupant’s safety is seriously compromised…. That is precisely what the ‘impersonator’ wants to achieve in the first place. Road safety is about being aware… be it with vehicular traffic, pedestrians or being approached by ‘strangers’. One must judge each situation accordingly…as if one’s life depends on it.… It is one’s discretion that is the critical safety design ‘feature’ in such situations.

What has been expressed on this subject so far are hypothetical projections and no more. Does it really matter if the windows are ‘flush fitted’ or ‘roll down’, as both have their merits and driver preferences?… However, it would be nice for a purchaser to have the option to select either format.... Why can’t it be so? In my opinion, it only enhances the attraction of the flexibility of Aptera’s many design merits, which helps make it stand out from the ordinary.

I also noticed in a short video where Chris Anthony of Aptera Motors mentioned that the car’s climate control will handle 120 degree outside temperatures to bring a parked car down to 75 degrees internally. Considering this is based on a heat pump system …it certainly could be possible… If one is comfortable on the inside, the windows are not critical to have in an opened position…but again, this is a matter of personal preferences…. “via de la Différence”.

MPK 1456

[panamericans]

Yes, I must agree, it is true that when in a serious accident the door (or doors) might not open. Then again it is also equally true in such situations the impact force will cause these same windows to shatter, as tempered glass is designed to do. Side impact and frontal crash tests have already demonstrated this reality repeatedly. The real danger in experiencing such traumatic accidents is getting impaled or crushed inside the vehicle.

When it comes to ‘police impersonators’, rapist and such other nefarious ilk, the ‘roll down window’ will give a false illusion of security… Once rolled down, the occupant’s safety is seriously compromised…. That is precisely what the ‘impersonator’ wants to achieve in the first place. Road safety is about being aware… be it with vehicular traffic, pedestrians or being approached by ‘strangers’. One must judge each situation accordingly…as if one’s life depends on it.… It is one’s discretion that is the critical safety design ‘feature’ in such situations.

What has been expressed on this subject so far are hypothetical projections and no more. Does it really matter if the windows are ‘flush fitted’ or ‘roll down’, as both have their merits and driver preferences?… However, it would be nice for a purchaser to have the option to select either format.... Why can’t it be so? In my opinion, it only enhances the attraction of the flexibility of Aptera’s many design merits, which helps make it stand out from the ordinary.

I also noticed in a short video where Chris Anthony of Aptera Motors mentioned that the car’s climate control will handle 120 degree outside temperatures to bring a parked car down to 75 degrees internally. Considering this is based on a heat pump system …it certainly could be possible… If one is comfortable on the inside, the windows are not critical to have in an opened position…but again, this is a matter of personal preferences…. “via de la Différence”.

MPK 1456

[futura]

Sorry if this posted twice...can't see it.
So, awhile ago I posted my "druthers" list http://www.apteraforum.com/showthread.php?t=488 and one of the areas of concern was the roll-down window design. Well I noticed in the BusinessWire post...http://www.businesswire.com/portal/site/google/?ndmViewId=news_view&newsId=20080423005330&newsLang=en there's a high-res photo of the "new-hire" at Aptera. He's standing next to the proto and it appears the door-window is taped off in a "suggestive way"....uh you know suggesting how the "roll-down" window will be implemented...maybe. See expanded view here: 78
76
Cheers.

[gg222]

Maybe if you want the window rolled down you take the tape off. When you want it back up, you tape the window back on. :D But honestly Futura, good eyes.

[LQUAN]

Just as I suspected and mentioned earlier on this post. They probably have to make the roll down windows similar to the Lamborghini Countach or Subaru SVX.

http://en.wikipedia.org/wiki/Image:Alcyone_SVX.jpg

Just enough for you to stick your arm out to pay toll road and get drive-thru meals.

[c0mp13x]

Wow futura that is a awesome catch you made. Very subtle, but obviously gray tape on the window and probably the outline of a roll-down window idea.

I like the shape, and LQUAN I saw a Subaru SVX on the road just last week after not seeing one for years. Those "segmented" windows were a real eye-catcher on that 1991 Giugiaro design. I've always admired his company's automotive design.

Also- this whole window design problem may indicate that there is still more design and engineering for new VP Hannemann to help figure out than was speculated over in the "ApteraForum company" New VP (http://www.apteraforum.com/showthread.php?t=666) thread. We'll see...

:)

[KarenRei]

Huh, clever. I've never seen a window like that before (or at least noticed one). At first my reaction was, "Aww, only part of the window goes down?" But after thinking about it some more, it's a great solution; you still get to see out of a huge window, but you don't have to find a place to cram the whole thing into. The part that rolls down should still be at least 2/3rds the size of the entire window on the Volt, possibly more ;)

The bigger they make it, the better in my opinion, but at least this one is solved. Great catch!

[jenkins_pete]

Given the production schedule I don't understand how there can be no information on the windows at this time!? Doesn't this already need to be solved to make the production schedule?

It seems people are debating having opening windows or not but that is a moot point, the windows _will_ open. The question is how will they open. There is no possible way given the current design for them to full open. Does anyone know when the design is to be actually locked down?

There is frustratingly little information out of Aptera and their newsletters are a complete joke. I mean there is basically no new information each time for anyone that follows EVs in the news.

[evolutionmovement]

I wonder why they don't just have them flip upwards. They could be kept flush that way and it's a simple, light solution.

[panamericans]

Yes I agree there is very little information released…

Aptera Motors is receiving millions of dollars (read: many millions) of free advertising, that spans this planet thanks to the (recent) marketing benefits of the computer age. It has already attracted thousands of potential purchasers willing to plunk down deposits for a car they will have to wait a year or more for… and yet these same customers don’t even know its dimensions…amazing.

Not faulting the company, but this is a vehicle heavy with (refreshing) technical concepts that are in the process of being implemented. One doesn’t have to look past battery developments to understand this… I also suspect the dimensions aren’t being finalized until an acceptable turning radius can be worked out.

One thing is for certain, this car has caught the undivided attention if not loyalty of its customers… even if… (I hate to write this) it is still a ‘vapourmobile’ until the tangible details are finally released and perused

[c0mp13x]

Given the production schedule I don't understand how there can be no information on the windows at this time!? Doesn't this already need to be solved to make the production schedule?

...Does anyone know when the design is to be actually locked down?

There is frustratingly little information out of Aptera and their newsletters are a complete joke. I mean there is basically no new information each time for anyone that follows EVs in the news.
Gosh Pete, I thought Aptera has actually been better than the average automotive company at getting information out. I don't know what field you work in, but at the engineering firm where I work they are highly secretive of proprietary design. The current EV and "green" vehicle market is extremely competitive and it doesn't benefit Aptera to give away design secrets to their competition. Even about how it's windows will roll down...

Releasing early information (and promises) about your product only serves to spur the interest of the consumer. It may create excitement, but it also holds the potential to disappoint. Design ideas that are considered sound sometimes work, and sometimes they don't. Why release untested speculation about a feature when prototyping and testing prove that another direction must be taken? Even the deep pocket EV manufacturers like Tesla, ZENN and Phoenix have found that this is a very difficult business; it's very tough to meet the high expectations of customers... and press releases.

The manufacturing of automobiles is a highly complex engineering problem that holds the ultimate responsibility. Just like aircraft, you are dealing with not only people's safety, but ultimately their lives.

Give Aptera time, most of us here believe that they are making the right decisions to actually bring this crazy idea to market. The list of failed automotive ventures is a long one; this one actually has a chance...

;)

[LQUAN]

As I mentioned in another thread. Sales and marketing can only speculate the production release date, the engineers are the ones know the actual production release date. This is the reality of any engineering company. If you are an engineer or a marketting personel, you will agree with me. I expect to get my Type1e (#1893) in about 1.5 years from now. I also expect price to change after the first 2500 vehicles are shipped. At the increasing rate of gas price, I see the demand for EVs to pickup. As more and more Apteras start to show up on public streets, I expect the public to accept its looks and like the vehicles more. Prius, too, had the same problem with its looks before when the first model came out (eg center instrument consol, trapezoid body style, small, etc). Look at the demand for Prius now. 2 years from now Aptera will have other EV manufacturers on the theater to compete with. But I still expect the demand for EVs will out pace the number of EVs that all EV manufacturers can crank out. $27K to $30K is cheap for a car that is mostly hand made. Don't expect the price to stay the same after the first 2500 is delivered. I hope Aptera will honor their price at reservation - even when the car will be delivered 1.5 years from now.

Aptera is reluctant to publish a lot of details and specifications about their vehicles because of people like us on this forum, especially people like KarenRei, me, and a few others who love to publicly disect every little details about their new product. We have been putting a lot of pressure on Aptera with our expectations. We have to realize that this is new product for a small company. It is impossible for a new small company to match up people's expectations with what the big old boys at GM, Toyota, etc. can deliver. Any unattainable premature specifications that they disclosed can be desasterous when all eyes are on them. I like to see Aptera become successful. That is why I am very careful and be as accurate as possible to answer any technical questions regarding automobile in general.

[KarenRei]

Given the production schedule I don't understand how there can be no information on the windows at this time!? Doesn't this already need to be solved to make the production schedule?

Jenkins, this is a low volume car (for the time being, at least). The time from prototype to production is much lower. There can't be any guarantees about when they'll ship, but don't expect the schedule to look like the Volt's. And it looks like the window is solved, judging from the picture; I can't picture any other reason for that tape to be on there. Just because Aptera doesn't give out every detail of the car doesn't mean that they're not working on them. Quite to the contrary, most (not all, certainly, but most) car development projects are rather quiet. If you announce you're going with one thing, and then the final version ends up being different for technical reasons, you can end up disappointing customers. Or even getting lawsuits, in the case that people put down money in advance.

I suspect that what they're planning to offer for test drives in a month or two will be a roughly final design. So just wait for that.

[evolutionmovement]

Good point. Look at the Jaguar XJ220 - it was originally slated to have a V12, but eventually went to market with a turbo V6 (but didn't suffer a performance loss for it). People abandoned the car in droves and Jaguar actually sued people to try to make them keep their orders. I believe you could still get a new, untitled one 7 years after production ended.

Besides, the tease makes it all the more exciting.

[aptera1213]

well i understand keeping some stuff secret...all companies keep stuff close to the vest on a new product...

the one aspect that "pisses" me off though is the freaking dimensions...keeping that close to the vest is just strange...

A) how is that protecting trade secrets from rivals?
B) many of us need to know if this vehicle will fit in our darn garage (i have a two car garage, but with two single doors...will the wheel wells fit through my garage door? easily, with great care, or no freakin' way am i squeezing that puppy in my garage with an inch on either side as the only margin of error)

so fine, don't tell us yet what tires are being used, what batteries, the final engine choice for the hybrid...

but width and length are very important items to know...

do i remodel my garage or cancel my order or is the size fine for my single door garage?

[SpyderMike]

Back to the windows/doors in case of accident. Light airplanes have fixed plastic side windows. If the door jams in an accident, the manufacturer of my plane states to use the small hammer they provide to break up the plastic and then to place the heels of your feet at one corner and kick the window out. It has very similar doors to the Aptera.

[panamericans]

Nice plane good taste…

Yes, I agree with you. I believe that having the option for fixed windows would be a benefit and not an obstacle from a manufacturing point of view. From the photo that Futura’s keen eyes picked up, shows a pronounced concave or bow in the side windows which has functional advantages for the occupant, as well as adding to the aerodynamics and design esthetics of the car. A roll down window will subtract from this…

[c0mp13x]

Back to the windows/doors in case of accident. Light airplanes have fixed plastic side windows. If the door jams in an accident, the manufacturer of my plane states to use the small hammer they provide to break up the plastic and then to place the heels of your feet at one corner and kick the window out. It has very similar doors to the Aptera.
Mike- The windows must open in some convenient way (beyond breakage) to pay tolls.

And, more importantly, in Southern California we must be able to drive thru In-N-Out Burger to get our Double-Doubles :D

http://www.urbanmonarch.com/wp-content/uploads/2007/02/innoutb.jpg

[SpyderMike]

Mike- The windows must open in some convenient way (beyond breakage) to pay tolls.

Get Fastrak and get a salad at Irvine Ranch Market!

Seriously, I have a car with plastic side windows and I haven't had problems yet...the again, The little windows on this car are worthless for anything but yelling at people. I must say that a good airconditioner is a must! The interior heats up real fast. Aptera's will as well with all the window.

[panamericans]

What is the main concern is the extended distance of the front wheel wells from the main body which will not allow one to approach close enough to the curb to reach through to a toll booth, or sadly the ‘In N Out’ attendant. The door will have to be opened in any case.

The ‘up side’ to this situation is that the gull wing doors don’t open past the front wheel wells….i.e. they don’t take up anywhere near the swing room of a standard car door… bon appetite

[garygid]

If the windows are indeed to be split, I certainly hope that
the "dividing line" between the movable and fixed parts
of the window does not detract from the sleek, unspoiled
look of the Aptera prototype.

I think the "split" in the Subaru SVX (http://en.wikipedia.org/wiki/Image:Alcyone_SVX.jpg) ... is very UGLY.

If necessary, I would rather see them cut off the front 6 (or so)
inches of the prototype side window, If that will help it roll down
into the door.

If that fails to work, I think that a full hinge-up, outward-opening
window is a good idea that at least should be considered for
the initial deliveries.

Many vans have this sort of arrangement on some of their
windows (although they usually open only a little way).

[panamericans]

Gary,

I agree with you. A split window is bloody ugly!

I hate to see Aptera lose her clean lines for a less than perfect window ‘fix’. Let's hope they give us options in this department.

mpk 1456

[Don]

A lot of good reasons here, pro and con, for roll down windows. Here is mine. On occasion, I will roll down a window and lean out to look rearward when backing a vehicle. The reason for doing so would be even more evident with the Aptera. Those three rear facing cameras might not be adequate under some circumstances, say at night, unless there is a very strong back up light system. Rain might also limit what the cameras can do. It is still questionable if the cameras can show anything close to ground level - a large rock or even a small child. When one hears a sickening crunch, it is too late to ask these kinds of questions.

[KarenRei]

Those three rear facing cameras might not be adequate under some circumstances, say at night, unless there is a very strong back up light system

Watch the nighttime walkaround video on YouTube; the cameras seem to work very well in low-light conditions. Your point still stands, though :)

Anyways, I did a quick mockup of what the split windows might look like under different styles of split. The first image is unmodified, and the other three have the lines drawn in as well as I could from the pic Futura posted earlier. I think it looks okay if they keep it as close to they can as "glass touching glass". Obviously, they'll need some sort of seal, but the fainter, the better, IMHO:

http://www.daughtersoftiresias.org/images/aptera_windows.jpg

They're really sloppy and lazy, but they should give you an idea.

[SpyderMike]

I tell ya, from some angles thething just doesn't excite me...I think it needs some chrome side pipes.

[Aptera #1159]

I tell ya, from some angles thething just doesn't excite me...I think it needs some chrome side pipes.

O god, No.:p

[G-Jet]

nice job Karen. no chrome pipes. wonder if there will be a choice of windows?

G

[appyfan]

So I've been reading about these various window designs and I've noticed that most of our concerns, stem from things like being able to speak to a cop and making sure we can get our In 'N Out without a hitch.

I think at this point the best option would be for them to design the window so that it would go down as a single unit but obviously not all the way down because there isn't enough space. Kind of like the rear windows on most sedans.

I mean from the sounds of everyone including myself, having the window rolled down at a max of 2/3rds is really all you need to get your lunch or pay a toll. Also, it would probably save alot on production costs and probably save time in terms of an overall design timeframe...

[garygid]

I agree, window part way down is enough, if that helps
get the Aptera into production.

I suspect that one will rarely drive this vehicle with
the windows down, due to the extra drag.

However. some slow speed driving on a country road, with
the arm resting on the window ... seems like a nice memory.
Back when the air was clean, and ... yep, I am an not
quite "older than dirt".

Now, one would probably get "blasted" off the road
by folks wanting to pass and "Get There".
What ever happened to "Enjoying the Journey"?

[evolutionmovement]

A roll down window requires the window to no longer sit flush, if just at the base of the window unless you had a somewhat complicated mechanism that would retract the window inwards towards the passenger compartment and then dropped it down into a pocket in the door. The mechanism would also have to apply outward pressure on the window when the window is up. Flip up windows, like a small Cessna, solves most problems.

[gg222]

Do flip up windows have a way to be locked? I not sure I know what you mean by flip up.

[garygid]

Flip up would have a hinge along most of one edge, and
one or two latches inside to "lock" the window in its shut
(and quite flush) position.

As an alternative, the window could flip down, hinged
along the long bottom edge.

It will be interesting to see what Aptera does.
I just hope that it does not spoil the beautiful look.
And, a split window will have a visual block that
will be at just the wrong height for some folks.

Another alternative fro roll-down (to keep the window
in one piece) is to not roll all the way down.
That would seem to satisfactory, and save the
Aptera's good looks.

[appyfan]

Okay, how about this...

How about they have the window pop out of the frame as a unit and roll backwards towards the rear of the car? Like the side door of a dodge ram van or something

I have absolutley no idea how this would work but it just sounds really cool.

[n_dawg]

*sigh* Roll-down windows are such a hassle. It’s a shame so many activities require them.

Or maybe not…


Park in the lot and walk through the drive-thru! You're getting a double-cheeseburger, you might as well get some exercise.
Use Ez-Pass, or just step out of your car. Ignore the people honking behind you.
The police are just pulling you over to ask about your car. Open the door. He’ll think it's adorable.
The Aptera has a great ventilation system. Why even use the windows? Besides, ZEV drivers all know the air around highways is amazing.
Don’t litter. That's like installing solar panels on the roof of your Hummer. Big ones. It’s embarrassing.


Come on guys! Who’s with me?!

[LQUAN]

No rolldown windows? Well let's see...

Have you guys seen the cooling system on the Tesla? The cooling condensor and the two cooling fans take up almost the entire front trunk. I didn't see where they put the compressor. I would assume in the front too with its own electric motor. If the compressor is in the back and doesn't have its own motor, it probably uses the drive motor for operation. Basically, the front trunk is dedicated to cooling 2 people inside. To me, that is an effective AC system. Let's not concern about current draw just yet. Where do think Aptera is going store a similar effective AC system? Not in the front trunk, because that where the battery is going be. In the rear? So we are talking about a tiny AC system for 2 in Southern California heat with no rolldown windows! Back in the old days when we didn't care about CFC; cars used R120 Freon and can get away with small AC systems and can still have very chilling effect. In the last decade or more, R120 has been banned and replaced with less effective Freon, R134a. For R134a to be effective, the condensor must be larger to have similar chilling effect. Where Aptera is going tuck away all that AC equipments to get away for not having rolldown windows?

Bottom line, I got to have rolldown windows -- even if they are going to be ugly partial rolldown windows like Subaru SVX. Partially rolldown windows are only good for air. To pay tolls or receive meals at drive-thrus, you still have to open the doors (let's hope it doesn't rain like dogs and cats at the tolls), because you cannot extend your entire left arm out that window - only as far as your elbow. Remember, you must extend your arm past the wheelpant to reach anything. And even if you can reach out to receive your meals with the help of the nice attendant who almost fell out her window to hand you the tray, you are going to have a hard time manuevering a couple of large size gulps into your car.:D

[Chupacabra]

My thoughts

Partial rolldowns seem like a cool idea. They would help maintain the aerodynamics of the vehicle, having a smaller hole (though it'll undoubtedly screw up the CD while down). But, the implementation at least on that Subaru posted is F U G L Y ! So if they did this, like Karen said... as much as possible it should be glass to glass. Maybe even have small clear rubber seals. Subaru went with fugly thick black ones!

The bowing of the window seems huge.. kinda cool but from the perspective I'm not able to take it all in. Future, could you post the entire photo?

[KarenRei]

Have you guys seen the cooling system on the Tesla?

Tesla's cooling needs are so huge because they're using LiCoO2 batteries (runaway decomposition fire risk if they get too hot), because they use so many of them, and because they subject them to such extreme conditions. Not applicable to the Aptera.

If a little window unit box can cool an entire apartment while only running a fraction of the time, I don't see why the Aptera's heat pump has to be sizable at all.

So we are talking about a tiny AC system for 2 in Southern California heat with no rolldown windows

I love the talk of southern California heat. What's next, complaints about your frigid winters? (kidding! :) )

[G-Jet]

I like the window solution they came up with. Looks like it will work well for the needs of those who absolutely want a window, and those who like the fixed window.

G

[Chupacabra]

I love the talk of southern California heat. What's next, complaints about your frigid winters? (kidding! :) )

Hey now, it did get up to 75 degrees one time...

Just kidding, usually the summers can be in the 90s, and sometimes (rarely) 100s. Not Phoenix Arizona heat, but we have our days. Mostly those 80s days are just super sweet. I'm looking forward to one of those allegedly coming this weekend...

[KarenRei]

Yeah, 90 degrees, occasionally over a hundred, and low humidity.. in upper midwest, it's the same in the summer, but with moderate humidity. I once had my AC go out for a few days, and the candles in my house melted. Not pool-of-wax melted, but a number of them are bent as much as 30 degrees to this day. And in Houston, where I grew up (after I moved there from CA, where I was born)? Summer temperatures get up to the hundreds with *high* humidity. My father once flew from Houston to Cairo, and said that Cairo, at 120 degrees, felt a lot more comfortable. Houston is miserable in the summer. Even at night. Try this out:

http://www.srh.noaa.gov/elp/wxcalc/heatindex.html

Here's typical Houston summer conditions:

http://en.wikipedia.org/wiki/Climate_of_Houston

The summer months in Houston are hot and humid, with occasional afternoon thunderstorms. The average daily high temperature peaks at 94 °F (34 °C) at the end of July,[3] with an average of 99 days per year above 90 °F (32 °C).[4] The average relative humidity ranges from over 90 percent in the morning to around 60 percent in the afternoon.[5] These values of relative humidity results in a heat index higher than the actual temperature.[6] The hottest temperature ever recorded in Houston was 109 °F (43 °C) on September 4, 2000.[7] Heat stroke can strike people who stay out of doors for long periods of time during the summer.[8] Houston's heat and humidity made air-conditioning an essential element in Houston's early survival, and it continues to be important in day-to-day life.[9] Air conditioning is considered the stimulus for the growth of Houston in 1950 when it became the most air-conditioned city in the world.[10] Tropical cyclones can move into the area anytime during the summer months, bringing heavy rainfall.[11]

Punch in "100" for the temperature and 80% for the humidity -- I've been in conditions like that many times. That's right: a heat index of 158.2F. And it feels it. You can't escape it by going into the shade, either, like you can with dry heat. Utterly miserable.

Face it; when it comes to weather in the US, it's hard to beat California ;) There's this one Lewis Black routine where he's talking about the best job in the world: a weatherman in San Diego.

(anchor voice): "Gee, Lou, how's the weather going to be today?"
(weatherman voice): (shrugs shoulders) "Nice?"

[butter]

I live in southern California but was born in Pennsylvania and have visited the east coast and midwest and east Asia during the summers -- we here in LA have NOTHING to complain about -- NOTHING.

So as someone who lives here in hot but *dry* SoCal, I say to my very fortunate brethren -- stop your whining! (I say that with love, of course.)

[evolutionmovement]

I was in Aswan in November and it was over 100, but very manageable because of the lack of humidity and the breeze coming off the Nile. The same temperature or less here in Massachusetts is terrible, especially if we get several of those days in a row and the heat seems to build up. It's very difficult to sleep without A/C.

[LQUAN]

I live in southern California but was born in Pennsylvania and have visited the east coast and midwest and east Asia during the summers -- we here in LA have NOTHING to complain about -- NOTHING.

So as someone who lives here in hot but *dry* SoCal, I say to my very fortunate brethren -- stop your whining! (I say that with love, of course.)

I have been living in Wilkes Berry PA for many years before moving to Los Angeles CA. I must say that I absolutely love SoCal weather. Just don't put me in a car with weak AC and no rolldown windows during the summer.

[evolutionmovement]

Slide back van-style windows would be difficult and expensive to engineer so that the mechanism was entirely contained within the door, yet strong enough to support the weight, potentially over rough roads while open over years of use, without rolling forward when slowing down. I've looked into all these ideas for my own car and decided the best is just a flip up, almost gullwing style.

[Aptera #1159]

Aptera,

I do not want roll-down windows. This car is already different, why conform to the status quo.

No windows if efficiency is affected. I will learn to and can live without roll-down windows.

Thanks.

Just my thoughts.:cool:

[gistmarrs]

Punch in "100" for the temperature and 80% for the humidity -- I've been in conditions like that many times. That's right: a heat index of 158.2F. And it feels it. You can't escape it by going into the shade, either, like you can with dry heat. Utterly miserable.


I hear this all of the time, but I've never seen it. In most cases, the people are talking about the high temp and the peak RH for the day, which happen at exact opposite times of the day. An extreme hot day in Houston can be seen here http://www.wunderground.com/history/airport/KHOU/2007/8/12/DailyHistory.html This is a day where the record was set at 102F. The high RH was 79%, but the RH during the time that it was 102 was only 35%. That comes up with a heat index of 109F.

The hottest place in North America is in Southern California, Death Valley. Since, the inside of that car doesn't care what the humidity level is, this is the worst case scenario that you can put on the cooling system.

[appyfan]

Park in the lot and walk through the drive-thru!



Actually man, I tried this a few times at a few different drive throughs and they refuse service. Apparently you need to have a car there in order to be served. It's total BS.

[G-Jet]

Most in-n-out burgers have a walk up window.
:)

G

[appyfan]

Oh... Yeah I forgot. I'm more of a taco bell dude.

[n_dawg]

Actually man, I tried this a few times at a few different drive throughs and they refuse service. Apparently you need to have a car there in order to be served. It's total BS.

If they require you to be in a road-worthy vehicle, just bring an A-bike (http://www.a-bike.co.uk/) along with you.I've gone through drive-throughs on a bike no problem.

[appyfan]

That... Thing... Is amazing. I so want one!


But getting back to windows....

[KarenRei]

I hear this all of the time, but I've never seen it. In most cases, the people are talking about the high temp and the peak RH for the day, which happen at exact opposite times of the day. An extreme hot day in Houston can be seen here http://www.wunderground.com/history/...lyHistory.html This is a day where the record was set at 102F. The high RH was 79%, but the RH during the time that it was 102 was only 35%. That comes up with a heat index of 109F.

The hottest place in North America is in Southern California, Death Valley. Since, the inside of that car doesn't care what the humidity level is, this is the worst case scenario that you can put on the cooling system.

I just wrote a script to gather all of the heat indices from summer of 2000 in Houston (actually, it was to gather all from 2000 to 2008, but it's only completed 2000 so far). Note that all of these numbers assume that you're in the shade; sun adds about 15F to the heat index (note that this means that mornings and evenings show up as hotter here). Some statistics for you:

Update: Re-running to correct a mathematical precision error

[garygid]

In my Opinion:
Opening: OK
Partial roll-down, opens at top: OK
Hinge-Out: OK
Not-Opening at all: not as OK (but needs really good fresh-Air system flow)
Performance Loss: almost not OK
Really Ugly: not OK at all!

All solutions still need a Climate-Control system sufficient for a quite Hot day.

[futura]

* Over the same timespan, the following hours have heat indices over 150F (format: Heat index, date, time, temperature, humidity%):

150.511831 2000-9-2 5:53 79.2 92
150.996498 2000-5-27 20:27 82.4 84
150.996498 2000-6-18 9:02 82.4 84


Again, note that all of those while the sun is out, if you weren't in the shade, would be about 15F hotter -- and many time more hours that didn't make the cut would have if you counted that.

* The median heat index for all hours, night and day, not counting being in the sun, is 133F.
Death Valley has nothing on Houston, heat-index wise. Any CA car designer who wants to go national needs to realize how much nicer even the worst parts of CA are in the summer than the Gulf Coast.

I'm not gonna dispute the weather in SoCal vs Houston. KarenRei, when I plug in the simpler Steadman coefficients (8 parameter not 16) I get a HI value of 90 not 150 as in your table. Might want to recheck your script.
Cheers.

[KarenRei]

I'm not gonna dispute the weather in SoCal vs Houston. KarenRei, when I plug in the simpler Steadman coefficients (8 parameter not 16) I get a HI value of 90 not 150 as in your table

Yes, I use the 16 coefficient formula, copy-pasted from here:

http://www.srh.noaa.gov/ewx/html/heatindex.htm

Perhaps I'm not using enough precision; I'll re-run it with more.

(update: looks like there was a precision problem; I'll correct the above post when it finishes)
(update2: I'll give it a long run, and have it compare with Needles, also having a long run; it'll be a few hours)

[SpyderMike]

Houston is miserable.

[gistmarrs]

I'm not trying to say that Texas isn't hot, just that it gets just as hot in California as anywhere else. If you want proof, look at Neeldes, CA in July, 2006. Everyday got over 104F that month, with one day having an overnight low of 100F.
http://www.wunderground.com/history/airport/KEED/2006/7/25/MonthlyHistory.html?req_city=NA&req_state=NA&req_statename=NA

Most days had a HI over 110 and many around 120, substantially higher than any of the days on your chart.

[garygid]

So others can better understand what you are talking about,
here is the chart, apparently derived from the 16-factor formula:
(sorry about the formatting, multiple spaces get displayed as one space)

------------------------------------------------------------------
HEAT INDEX CHART

AIR TEMPERATURE (degrees F)
--- | 70 75 80 85 90 95 100 105 110 115 120 125 130

% 0 | 64 69 73 78 83 87 91 95 99 103 107 111 117
- 5 | 64 69 74 79 84 88 93 97 102 107 111 116 122
R 10 | 65 70 75 80 85 90 95 100 105 111 116 123 131
E 15 | 65 71 76 81 86 91 97 102 108 115 123 131
L 20 | 66 72 77 82 87 93 99 105 112 120 130 141
A 25 | 66 72 77 83 88 94 101 109 117 127 139
T 30 | 67 73 78 84 90 96 104 113 123 135 148
I 35 | 67 73 79 85 91 98 107 118 130 143
V 40 | 68 74 79 86 93 101 110 123 137 151
E 45 | 68 74 80 87 95 104 115 129 143
- 50 | 69 75 81 88 96 107 120 135 150
H 55 | 69 75 81 89 98 110 126 142
U 60 | 70 76 82 90 100 114 132 149
M 65 | 70 76 83 91 102 119 138
I 70 | 70 77 85 93 106 124 144
D 75 | 70 77 86 95 109 130
I 80 | 71 78 86 97 113 136
T 85 | 71 78 87 99 117
Y 90 | 71 79 88 102 122
- 95 | 71 79 89 105
100 | 72 80 91 108

Note: Exposure to the Full Sun can increase the
Heat Index by up to 15 Degrees Fahrenheit.
------------------------------------------------------------------

Well, you get the idea.

[butter]

I'm not trying to say that Texas isn't hot, just that it gets just as hot in California as anywhere else. If you want proof, look at Neeldes, CA in July, 2006. Everyday got over 104F that month, with one day having an overnight low of 100F.
http://www.wunderground.com/history/airport/KEED/2006/7/25/MonthlyHistory.html?req_city=NA&req_state=NA&req_statename=NA

Most days had a HI over 110 and many around 120, substantially higher than any of the days on your chart.

It doesn't matter. In layperson's terms (my favorite, since I'm a layperson), when it's 100 degrees and very humid (like it is in most parts of the country east of the West Coast), it feels god-awful and you want to rip your own skin off, you're suffocating so bad. When it's 100 degrees and *dry* like it almost ALWAYS is in Southern California, it simply doesn't *feel* as bad.

When the air is wet with moisture, the sweat on your skin won't evaporate as much (if at all, in some super-humid places) -- thus your body doesn't get to be cooled. In a hot, *dry* place, you sweat like crazy *but* the lack of humidity in the air makes it easy for sweat on your skin to evaporate, which drives the cooling process for the human body.

So it's not just about the plain numbers. Humidity plays a hugely key role in how wretched the human body feels in hot weather.

[KarenRei]

Yeah. Just from a subjective standpoint, at least, I've been to Phoenix in the middle of summer. It *feels* nothing like Houston, despite the temps being hotter. And when the sun goes down in Phoenix, you're fine. In Houston, the misery carries on. And the summer lasts and lasts; September is similar to June. Winter is colder than CA, but not by a great margin. Spring and fall -- blink and you miss them.

I've also backpacked in Japan in the summer, and it's similar to Houston. Not as bad, but still hot and humid. To make matters worse, I was carrying a heavy pack that didn't let air get to my backside, and to top it all off, they're inexplicably averse to air conditioning in many public places. I don't think Aptera would be a good car for Japan, though -- too wide. They like tiny little clown cars :) Loremo, I could picture that there better than anywhere else. VentureOne? Sure. And Smart? I *did* see one there, and this was a few years ago. ;)

[Chupacabra]

Are you guys really arguing about the weather? Let's have a weather-off.... I'll award the worlds' tiniest violin to the saddest story i read. :rolleyes:

[panamericans]

Yes, I agree…. The weather subject should be thrown out the window… Hey, wasn’t this section to be about ‘windows’ in the first place? Opening or fixed of course….

[c0mp13x]

Gots to agree Chupacabra... let's try to keep posts on-topic if possible.

We have a "off-topic" forum for whatever you want to say. Keeping posts on-topic makes it nice for new folks coming to this forum looking for relevant information and for those of us searching the forum for info on the Aptera.

Thanks- :)

[KarenRei]

Back to the basic point: if the vehicle gets too hot inside, nobody's going to be able to use it. :)

[garygid]

I agree, too hot inside, and the Aptera will only be used by
the "apteraholics", and not by the main stream (or my wife).

[garygid]

Another way to save the sleek look of the windows is
to reduce the actual window size, and at the same time
increase the width of the black "frame", keeping the
total area roughly the same size and shape.

Actually, the bottom edge of the window's black "frame"
is probably an inch or so lower than it needs to be.
Likewise, the upper dimensions of the frame can probably
be reduced by one half to one inch and still preserve the
strikingly good style.

So, shrinking the frame about an inch all around, and
widening the frame an inch would make the window
2 inches smaller on all edges, and perhaps allow it to
"roll" down "normally" (completely) into the door.

Comments?

[garygid]

Does anybody have any further information on Aptera's
solution to this "opening-the-window" problem?
Hopefully, not an ugly split-window solution.

Maybe somebody will call them and report here?

[appyfan]

You know I had some sort of premonition about Aptera coming with no opening windows; just as you see in the pictures. I couldn't tell if I was dreaming or not.

Could be nothing, however.


And as a side note, I am the 100th poster of this thread! Go me.

[daddio]

They appear sealed. Will the production :aptera: s have rolldown windows or will the climatic control system always keep th car comfortable?
If sealed... I suppose only Aptera can only replace to orginal spec of low drag with proper fit

[garygid]

Aptera said that the production windows will open in some
manner, although the prototype windows did not.

We suspect a split-window configuration where
the lower "half' of the window rolls / goes down.
But, like most else, we do not know.

[daddio]

Thank you...
If a split window is NOT going to offer a safe way to exit in an emergency and the climate control can keep the inside temperature resonable most of the time without giving up much efficiency.... Keep it sealed for minimal drag. I can keep a window break / sealbelt cutting tool in the glovebox!
http://spectrumadvertising.com/item_information.cfm?SupplierItemGUID=B3BA98C7-0833-42D6-9DE7-7CE6156147D5 <-- Just add APTERA on the handle

Ever since my niece was paralyzed in a car rollover.. we keep this type of tool on our family cars.

Cheers!

[evolutionmovement]

Are the side windows even glass? They'd probably kick out in any event. I think they may just hinge at the top like a Cessna 152/172 window. Probably the easiest solution to engineer and manufacture while allowing the flush fitting.

[deanwvu]

Some people need easy outside access in some manner.

There is always the drive through issue.

But, if I could get an Aptera, I would need a roll-down window, as I drive through security every day at work which requires me to present my ID.

Solid, sealed windows just won't do...

[daddio]

Oh.. All our toll roads and bridges use EZ pass so you are just scanned as you drive through the old collection booths and now there are high speed scan lanes, installed when roads are upgraded/widened. You are billed monthly.
Sure they still have one or two toll collectors (depends on road/bridge) for the people that refuse to move forward with EZ pass
Stopping a car, even a hybrid (when your gas engine kicks in) then accelerate again... 1) pollutes 2) you have some loss economy.

We use a driveby scan system for our badge ID at our plants

So we don't open our windows much

This may be a future trend?

[garygid]

And, the tourists could always swing the door up, if really needed.
But, a good fresh-air system for the cabin would be essential.

I would rather have a fixed window, or even a window that just hinges
at the top and swings upward, rather than an "ugly" split window.

[G-Jet]

Gary,
Define "ugly". what if the window system looks really good?

G

[garygid]

If you do not know "ugly" when you see it ... I fear that there
is little hope for you ... just joking. But, here we do not have
"wunp" it with a stick to see if it is "ugly".

If it looks really good, it is not "ugly" ... unless maybe you been drinkin'!

So, here is a car that was "uglified" with split windows.

In my eyes only ... other opinions may vary ...
the "split" in the Subaru SVX (http://en.wikipedia.org/wiki/Image:Alcyone_SVX.jpg) ... is ... "ugly".

Also, windows were discussed extensively here in the topic "Door windows":
http://www.apteraforum.com/showthread.php?t=339

[G-Jet]

Check out the Pininfarina Sintesi and Nardo concepts. Also, the SVX was designed by Guigaro and he has used the split window on many concepts. Even Mercedes has used it.

"ugly" is only an opinion, sometimes shared by one, sometimes by all.

G

[KarenRei]

The aforementioned cars:

http://www.sweetauto.net/gallery/files/1/2008-Edo-Competition-Lamborghini-Murcielago-LP640-Versione-Nardo-Driver-Side-1280x960.jpg
http://www.cars.justelite.net/wp-content/uploads/2008/03/nuvera-fuel-cells-sintesi.jpg

[garygid]

Yes, "ugly" is all in the eye (and mind) of the beholder.

The Sintesi (http://www.sintesi.pininfarina.com/)and Nardo appear to try and lessen the visual impact
of the "broken" window by using heavily tinted glass in their concept
cars, but such heavy tinting would likely have trouble passing the
CA Vehicle Code regulations that limit tinting (http://www.dmv.ca.gov/pubs/vctop/d12/vc26708.htm) in vehicles.

Dark tinting tends to "absorb" energy, and the interior can get hotter.
On the other hand, a reflective layer (like silvered sunglasses) would
cut down the transmitted light and tend to reflect the heat energy,
but is generally not allowed.

[evolutionmovement]

The first picture is of a Lamborghini Murcielago and it has standard windows. The Countach, two generations earlier, employed a split window concept with the very small lower portion rolling down, but too uselessly small to be of any practical use. There have been many concepts, but the Subaru SVX is the only practical application of the window-within-a-window idea that I've seen. The idea with the SVX was to evoke the image of an aircraft canopy, probably an earlier attempt to tie in to Subaru's (Fuji Heavy Industries) aviation heritage, though the SVX also replaced the XT, which was a pretty aerodynamically efficient car, so perhaps it was a continuance of that theme as well.

[Raiyn]

I can't tell you how much I despise the window in window idea. I has an opportunity to drive the SVX several years ago and invariably the seam would end up as a distracting blind spot.

[daddio]

Leave it to the Italians to keep it sexy..... Even my Italian-made Robotic (all electric) lawnbot cuts my grass is style: "Green and (attractively) Mean"
http://www.robotlawnmower.ca/lb3500.cfm

Believe me, a split window will not make a present deposit holder of an Aptera walk away!

[garygid]

I believe that many people are wanting the Aptera not just for its
mileage or range. If they wanted just that, there are other choices.

I believe that they see in the design a wonderfully different
style that is beautifully functional, they are expecting attention
to technical details (like the 3 TV cameras that deal with a classic
vehicle problem, the "blind spot"), and they see the Aptera as a symbol
that people will accept change, and that "change" does not mean
giving up what one really wants.

So, if things are done well, they will be proud to display the Aptera
as a vehicle that they do not have to make excuses for.

Sure, some people still want 450 horsepower.
And, my friend said that his current / recent Corvette
got 27 mpg on a recent long freeway trip.

A split window can create an annoying visual blockage of the driver's view.
The Vehicle Code goes to great lengths to keep one from adding
things that can "block" the driver's view. However, it apparently does
not require a "big" or "useful" side window, and probably does not prohibit
fixed areas of glass (even tinted) as part of the "body" or door, even for
a car (less for a motorcycle, of course).

[esmith]

I think the current / recent Corvette gets 35 mpg.

No, it doesn't. Corvette is remarkably economical for its horsepower, but it gets 28 mpg highway max. Even that with a special electronic interlock that forces it to go from the 1st directly to the 4th in city driving.

Today, when you buy a car, you have to make a choice, either 1) get something that gets 30+ mpg (highway driving), or 2) get something that has 200 horsepower. You can't do both at the same time. Looks like an inherent limitation of present day gasoline ICE designs. There is a couple of borderline cases from Honda/Acura stables (Honda Civic Si, Acura TSX), they basically design engines with very high redline and use different valve timings below 5000 rpm and above 5000 rpm. This way you get good mileage below the threshold and good acceleration above the threshold.

[evolutionmovement]

Most cars have variable valve timing now (Honda's VTEC), though there are different systems with various levels of effectiveness. The reason is to get good performance out of a small engine. The higher rpm the engine can breathe to, the higher the horsepower (horsepower is just a multiplication of the torque. Small engines make little torque, so in order to move the car quickly, they have to generate their torque at a faster rate. This generally requires lower gearing that can be detrimental to fuel efficiency, but that's a whole other thing).

Before the days of variable valve timing, an engine designer would have to pick a cam profile that worked best for the application. Race cars would have cams (and heads) optimized for the air flow profiles of high rpm, but they'd run terrible at low speeds. Lumpy, loping idles that sound like the engine is about to die on old muscle cars are a familiar example - they run too much overlap (intake and exhaust valves open at the same time) and duration for low rpm air flow characteristics. Conversely, a street optimized cam profile (and head design) would not allow enough air to enter the combustion chambers fast enough at high rpm, so the engine would effectively run out of breath. Variable systems can have two cam profiles to optimize both rpm ranges, simply valve timing changes to achieve the same goal (but not as well), or a combination of the two so that you get good drivability, performance, and mileage at normal rpms, but also allowing the engine to run high rpm when acceleration is needed. So, really it's more for performance/marketing (since horsepower numbers sell cars) reasons than mileage as without variable valve timing, the default profiles would be much closer to the low rpm profiles of the variable system than the high rpm profiles to keep an economy car economical and the emissions clean. A better solution would be rotary valves controlled by step motors or the infinitely variable (within their range of operation, of course) solenoid-controlled poppet valves similar to the pneumatic systems on F1 cars. Solenoid-controlled valves require much higher voltage electrical systems than current cars use (the talk is of 48 VDC systems). But, I digress...

I agree that there's a limitation to current vehicles, but much of it resides with design. The weight, unfortunately, can only be reduced so much with all the safety requirements, but the aerodynamics are terrible and that's a big wall blocking efficiency. Even the ugly Prius isn't nearly as efficient as it should be (especially not enough to justify how ugly it is), being just a hair better than a 1980's Subaru XT, it's only good in comparison with all the bricks out there. I don't know why they only went half-way towards efficient aerodynamics and then stopped, but the car should have covered wheel wells, better flat underbody cladding, and a more tapered tail at least. Perhaps they feel they have to ease customers into the looks more efficient aero requires and maybe the next generation will be more radical. Either way, I think the Aptera is probably the only intelligent vehicle being made (hopefully, at least) and I'd buy one, split windows or no (hopefully no).

[garygid]

Yes, the Corvette mileage was 27, not 35 mpg.
I guess I must have had a brain fart.

[greenerist]

I think it's definitely convenient for drive-thrus, toll roalds, etc. Also i'm wondering since the doors swing upwards would they have to wire from the roof into the frames of the doors? Also with such a rounded shape and short door they look like they can only slide down half way?

[deanwvu]

Short way works for me.


I just need to get my arm plus my ID through a hole, and back again.



Honestly, though, I would like, some days, to have the windows down and the wind in my hair (actually, the wind over my bald scalp...)


I took a nice drive yesterday through the West Virginia countryside in beautiful low humidity, about 78 degrees... had all the windows down--it was gorgeous!

I'm just saying, it would be nice. If I were taking a short, low speed trip in the 1e, for which I knew I had more than enough battery range, I would like the windows open on a beautiful day!

[KarenRei]

Don't worry, they will -- they've said that they will :)

Yeah, it'd probably cut your range 2 or 3-fold, but if you just want to enjoy a nice drive, by all means.

[thecoook]

I hope this is not a repeat subject, but I think the Aptera as shown on the company site has two different doors on it, the Driver's side is a tri-lobal design whereas the Passenger side is much more squared off at the bottom, as if to anticipate a roll-down window design.

[n_dawg]

Those images are pretty old. I doubt those are anything other than the prototype.

[GunnyD]

don't know if anyone else noticed this but I point your attention to the split door window behind Neil.


http://www.aptera.com/images/neil.jpg

[Apt3448]

Good eyes, GunnyD. It was noted on other images as well. In this image - and another one, somewhere - it just appears to be a piece of grey tape, and it's main function seems to be that it works as a Rohrsach test for all of us so hungry for details, as you can see in this tread and others (just search split window).

[Reellucky]

I have a mint condition 1982 Delorean DMC-12 in my garage and they resolved the window issue with a small electric power opening window at the bottom center of the fixed window. They nicknamed it a "toll booth window." It works for fresh air, toll booths, and fast food drive-up unless you get the large drink. For that you have to pop open the gull-wing door which is half the fun of owning a Delorean anyway.

Cant wait till I have my type 1-H parked in the garage next to my Delorean......definitely a DREAM GARAGE..... :)

[gkra]

don't know if anyone else noticed this but I point your attention to the split door window behind Neil.

Honestly, it almost looks like scotch tape put on the window, possibly to evaluate where they would put the split for the openable window.

[daddio]

Remember "wing windows". Simple and manual....
http://www.irememberjfk.com/mt/2007/09/wing_vent_windows.php
...It will not let wind blow through your hair.... but it will ventilate.
Sorry I don't use drive up service or manned-toll booths (EZ pass nowadays)... so I don't have much use for operable windows these days ( Carry a window break tool though.. for emergency exit!)

[Ardie3301]

I believe that Steve Fambro's FAQ states that the windows will "open," not explicitly "roll down." This leaves several methods available to Aptera.

If the window remains one piece, it may be a simple hinge at the top and it would swing up -- the actual geometry to be determined to effectively get out of the way, and not to damage itself if you open the door while the window is open, and not to get torn off by the wind should it accidentally open while the car is going down the freeway.

If Aptera adds swing arms, the entire window may more pleasingly swing up sort of parallel to the curvature of the car's body. (Please refer to my horrible ascii art below)

. . . . . . . . |_ . . . |\
|| . . |/| . . |_| . . |\|
|| . . |/| . . . .| . . . |


If the window is split into two pieces (an aesthetic tragedy), only a small portion will be able to roll down into the door body, and I don't think the opening would be tall enough to accept a large drink from the McDonald's drive-thru. (Be careful of that outrigger wheel!)

I suppose Aptera could run the split vertically (another aesthetic disaster), and the forward portion could slide rearward to allow access to a toll booth, parking attendant, drive-up ATM, or kid in a paper hat.

-- Ardie

[n_dawg]

A force field would solve all these problems.

*ZAP* "Oh, sorry, forgot to disengage the energy beams…"

[aptera1213]

how about this as a solution...

watch the video (http://www.disappearing-car-door.com/)

crazy...but cool

i wonder how expensive it is?

[Matthijs]

That reminds me about the BMW Z1 doors.

MkoTZVKT7wg
Link (http://www.youtube.com/watch?v=MkoTZVKT7wg)

[Apt3448]

how about this as a solution...

watch the video (http://www.disappearing-car-door.com/)

crazy...but cool

i wonder how expensive it is?
Now that would be really cool!! Loved watching that one. I'm guessing expensive, heavy. The next best thing after our winged :aptera:

[apterapilot1551]

I seriously hope it's roll down windows so I can enjoy the SoCal weather while driving.

[garygid]

However, if you drive with the windows down,
it is likely to hurt your "e" range noticeably - more drag.

[Eyelawdoc]

I was examining the roll down windows on my Honda Insight this evening while washing it. While not completly flush with the body, they are pretty darn close.

Although it adds weight and complexity to the door design, it shouldn't be an insurmountable problem to fashion something siimilar for the Aptera.

[apterapilot1551]

However, if you drive with the windows down,
it is likely to hurt your "e" range noticeably - more drag.

I'm definitely willing to sacrifice drag to fully enjoy my aptera on warm sunny days...

[Ardie3301]

As far as a roll-down window, I don't think that the door has enough room to hold a rolled-down window to allow for a large enough gap to fill the usual needs of "outside world interaction," namely, a toll both, a drive-up ATM, and a fast food drive-thru window.

I seem to remember that Audi had an almost-flush window in one of their models from the late 80's when they were experimenting with aerodynamics again. The window had little pegs mounted on the inside of the glass, oriented sideways, and the pegs ran in a track that could be mounted more inboard than otherwise. The glass was very nearly flush to the rest of the car body. Of course, this only works with rectangular-shaped windows, and it requires a framework fore and aft of the window. Not very adaptable to the Aptera.

There is another possibility I'm thinking of:
If you lurk at small airports, you will see that almost every little airplane has some kind of tiny window (often called a "storm window" or "storm vent") on the pilot's side. A number of them are simply curved plates of Plexiglass that fit into similar cutouts of the left window. The window edges are rabbeted (L-shaped treatment on the edging of the storm vent, and a reverse L-shape on the window cutout). The storm vent has a latch on the top and a couple of acrylic hinges on the bottom, and it opens inward and downward, into the cabin area.

Now, *this* may be do-able in the Aptera.
This solution, although not nearly as sleek as a 1-piece window, would still retain the slippery drag coefficient while closed, would not be too expensive for Aptera to implement, and would allow folks to interact with the outside world when it becomes necessary. It would even let you drive with the window open and smell the ocean as you hum along Highway 1.

If the window is hinged at the bottom, like the ones in little airplanes, it would have to be positioned forward enough so it doesn't interfere with the driver or the steering wheel while it is open. The hinge could be a low profile piano hinge and hopefully not be a detraction from Aptera's tasteful interior.

If the window takes a triangular shape, such as a really big "smoker's window wing," it could be hinged along the leading edge so it would naturally open inward and upward out of the way. Hopefully. A coil spring on the hinge could keep it open, or some mechanism could allow a number of settings between "open" and "closed."

True, it won't be as nice as a fully roll-down-able window, but it will work, and it won't be too costly in materials or weight for Aptera to implement.

-- Ardie

[JimmyDreams]

I'm definitely willing to sacrifice drag to fully enjoy my aptera on warm sunny days...

Me too...to an extent. My daily commute is 75 miles round trip. If I cannot charge at work (unknown at this time) then reserve power is going to be my friend.

I'm not worried about Aptera not getting me there and back (at 55mph). I would LIKE to get there and back at 70mph. If opening a window means driving 55mph, they'll stay closed.

70 mph I can handle all day long. If I have to slow down to 55mpg, I'll claw my eyeballs out.
:rolleye0003:

JimmyD

[esmith]

If Aptera adds swing arms, the entire window may more pleasingly swing up sort of parallel to the curvature of the car's body. (Please refer to my horrible ascii art below)


You may be onto something. There are four possibilities:
- Inside and up: open window could hit you on the head if you open the door
- Inside and down: open window could prevent you from opening the door
- Outside and up: open window could prevent you from opening the door
- Outside and down: extra drag, difficult to make the whole thing aerodynamic

It is a sophisticated solution and it will look futuristic, but it's definitely a way out.

[DonC]

However, if you drive with the windows down,
it is likely to hurt your "e" range noticeably - more drag.

I'm thinking it's not going to be a big deal. If the Force needed to overcome drag = Cd * A * V3, then opening the windows would affect drag in a linear way. Additionally at low speeds tire resistance is probably dominating, and if you have to go up and down hills, which is common where I live, wind drag may constitute only a third or less of the total resistance.

Then we get to the question: which would draw more power, the AC system or the additional power needed to overcome the increased drag.

On this board I've seen estimates that the range might drop from 120 to 80 miles or less. That's seems overstated.

The EV-1 engineers said that 55 mph was the cut-off for when having open windows would cut down on range more than the AC. Below that speed you'd get better range with the AC off and the windows down. I think the context of this was also important: they didn't want everyone thinking they needed to have the windows down when on the freeway so it was convenient to tell everyone to use the AC at freeway speeds, which most people find more comfortable. The real number might have been 60 mph or more.

I think Mythbusters (whatever the TV show is) did a test on this as well. Their computer model told them that having the AC on and the windows closed would get them better range but the actual test showed the opposite. Then there is this study, which didn't find much difference but did note that having the windows down mattered more the more aerodynamic the car.

http://www.sae.org/events/aars/presentations/2004-hill.pdf

Even if air drag increased by 40%, we're still talking about a very aerodynamic car with a very low CdA. Much like not saving many gallons of gas when going from a very fuel efficient car to a more fuel efficient car, I suspect going from an incredibly aerodynamic car to a less aerodynamic car will not have that big of an impact at speeds when you'd want the windows down rather than the AC on.

Do you have any estimates of at what speed, if any, opening the windows would extend range more than running the AC? Or would that depend on the time of day and how cloudy it was? :)

[KarenRei]

I can pretty much guarantee you that a car like the Aptera will get far better range with the AC on than the windows down at all but the slowest speeds. As you noted, the more aerodynamic the vehicle, the more pronounced the difference, and the Aptera has a tiny CdA. But there are reasons to go with windows down other than cooling; sometimes, a breeze just feels nice, and if you're only going a dozen miles or two, what does it matter? :)

As for the Mythbusters, that ep was widely criticized on the forum. They didn't rely on their insturmentation, which should be authoritative (as it was measuring combustion). Instead, they had two different vehicles, two different drivers, and a very awkward, almost certainly inaccurate fuel-measuring system, and declared its results to be authoritative.

[DonC]

I can pretty much guarantee you that a car like the Aptera will get far better range with the AC on than the windows down at all but the slowest speeds

What numbers do you think are realistic for "far better range"? Just curious.

[KarenRei]

Aptera uses a quarter to a third as much energy as a typical car, and perhaps a tenth that of a full-sized SUV. The Mythbusters, if I recall correctly, tested on full-sized SUVs, and got mixed results. The more streamlined the car, the bigger the difference between windows down and AC. Consequently, with a car like the Aptera, you'd expect a huge difference.

Fueleconomy.gov says the AC on max reduces fuel economy by 5-25%, while Edmunds says 1mpg (5% for a 20mpg car -- lower than Fueleconomy.gov's numbers). To its credit, the Aptera's cabin is fairly small, they're going for an efficient system, making use of solar assist, and there's no energy wasted in an alternator. Going against it, the Aptera is using much less energy per mile, so the AC will make up a proportionally larger percent. I think 15% reduction in range for AC on max the whole time in the Aptera sounds reasonable. For an AC cooling load similar to what you'd get from windows down, probably 5% or so.

From a window perspective, if the results on SUVs are mixed and you're losing 5% mileage or so from windows down, and the Aptera is using a tenth as much energy per mile, then you'd lose about a third of the Aptera's range from having the windows down.

These are *very* rough numbers, for a number of reasons, and I almost hesitate to post them. One, it's hard to get reliable data on the effect of AC and windows for any particular model. Two, the effect of having your windows down isn't necessarily going to correspond linearly to how aerodynamic the vehicle is, you'd need either real-world testing or CFD modeling. But I think it's about the best you could do right now, and it strongly suggests to me that windows will be much worse.

[3-4-me]

Another thing to keep in mind is:
A/C ON an ICE is run by a pulley off of the engine. The drag on the engine is what causes the drop in mileage.

The Aptera is using some type of heat pump that is electrical. I have no idea what the draw is to run it, but it is a different type of "drain" than a typical A/C setup.
It seems like apples to oranges to me.

[DonC]

From a window perspective, if the results on SUVs are mixed and you're losing 5% mileage or so from windows down, and the Aptera is using a tenth as much energy per mile, then you'd lose about a third of the Aptera's range from having the windows down.

These are *very* rough numbers, for a number of reasons, and I almost hesitate to post them. One, it's hard to get reliable data on the effect of AC and windows for any particular model. Two, the effect of having your windows down isn't necessarily going to correspond linearly to how aerodynamic the vehicle is, you'd need either real-world testing or CFD modeling. But I think it's about the best you could do right now, and it strongly suggests to me that windows will be much worse.
I sort of calculated backwards starting with your favorite shortcut -- that the Aptera went 70 miles at 80 mph. This means the Aptera was using 11,428W to overcome wind and tire drag. We know that the Cd is 1.1 (right?) and I guessed A to be 1.5m^2, which gave me 222N at 80 mph. Total N should be around 312, which means that 90N was due to rolling resistance. Assuming the weight of the Aptera is 900Kg suggests that the friction coefficient is 1% of body weight. That actually seems about right to a little low since I'd expect a small car to ordinarily have a coefficient of around 1.8% or maybe 1.6% if equipped with low RR tires. (I would have guessed 1.1% or 1.2% for the Aptera).

In any event, at 35 mph, which is more city driving, using the same number for CdA and .9% for the frictional coefficient I get 40N attributable to wind drag and 80N attributable to the tires. This means that if opening the windows increases wind drag by 50% that will only be 14% of total drag and 14% of the range.

That should if anything overstate the effect since if you start going up and down hills the force needed to overcome wind drag will become less of a percentage of the total force needed to propel the car. Plus if you need to run the AC then that would be a drain as well.

I'm coming out with a different number than you are -- less than 14% and maybe around 10% is a quite different than a third. Since you obviously know more about this stuff than I do, where am I going wrong?

[KarenRei]

I see no reason to assume that opening windows will merely increase aerodynamic drag by 50%, given that Steve has mentioned that merely having the windshield wipers exposed would double drag.

[DonC]

I see no reason to assume that opening windows will merely increase aerodynamic drag by 50%, given that Steve has mentioned that merely having the windshield wipers exposed would double drag.
The problem is that I agree with you on the AC draw. If you look at the EV1 experience we have a car with a CdA only 50% higher than a Twike and an interior smaller than the Aptera's. Basically it seems like a decent benchmark. If the GM engineers thought it was range efficient to open the windows rather than run the AC at speeds up to 55 mph, drag from open windows couldn't have been that great. This follows because, as you've pointed out, the AC draw wouldn't have been that great and the drag from opened windows was less.

Maybe poorly designed wipers are worse than open windows?

Hopefully by this time next year we'll have some actual driver experience.

[KarenRei]

Agreed; right now, without doing a CFD simulation and knowing the details of their AC, the best we can do is speculate. Although I will note that the EV1 used ~200Wh/mi, while the Aptera uses ~83Wh/mi, and it's AC has a solar climate assist to boot ;)

[rotus8]

The other question that goes along with this is how good is the ventilation without either the AC or the windows open? Properly designed NACA ducts and possibly some simple fan assist can actually do a better job than open windows, and with negligible effect on drag. Of course this is assuming it isn't boiling hot outside, but that's a problem with open windows too. I find a nicely controlled breeze of fresh (not conditioned) air from well placed and adjustable vents is more comfortable than the uncontrolled buffeting from open windows.

[esmith]

We know that the Cd is 1.1 (right?)

Cd is 0.11.

[KarenRei]

And, of course, what really matters is CdA. We have been told that the total drag is 1/5th that of a Prius and 1/25th that of a Hummer.

[DonC]

And, of course, what really matters is CdA. We have been told that the total drag is 1/5th that of a Prius and 1/25th that of a Hummer.
I actually saw that in the wiki you had a stated CdA of .93. What's interesting about this is that -- given the famous 70 miles at 80 mph -- the rolling resistance at 80 mph calculates out to be two percent of body weight. That's not crazy but it seems high. (It also BTW suggests that even if opening the windows doubled drag the range would only drop by 15%).

I'm wondering how confident you are that the DOD of the battery pack is actually 100%. Assuming the wiki CdA is roughly correct, and it should be, 8 kWh rather than 10kWh for the batter pack gives a lower coefficient more in line with what I'd expect.

[KarenRei]

All I have to go on is the numbers that Aptera releases, unfortunately. If you feel like posting your numbers on the wiki, by all means, go ahead; there's nothing wrong with speculation and calculation so long as it's noted as such.

[garygid]

When exiting in the rain, will water pour off the door and roof right onto the driver and seat?

[palmer_md]

The typ1 was not designed for use in foul weather states...you can only purchase if you live in an area with less than 3" yearly rainfall.

Just kidding, I'm assuming that there is a hidden gutter system under the seam of the door and body. When the door is closed water from the roof falls thru the gap and then flows down this gutter to the ground. When the door is open this gutter system will still be in effect and the door will actually aid in providing some shelter from the rain.

Of course this is all speculation, but it seems very logical.

[DonC]

All I have to go on is the numbers that Aptera releases, unfortunately. If you feel like posting your numbers on the wiki, by all means, go ahead; there's nothing wrong with speculation and calculation so long as it's noted as such.

Karen, I went ahead and did this in the battery section. Using what I think are reasonable numbers for the rolling coefficient, the calculations seem to suggest a DOD of around 50-60%, similar to what GM plans to use with the Volt. In some ways that's comforting but it does change a lot of other calculations such as those involving hill climbs.

This is hardly my field and I can fat finger the calculator but I think the numbers are good.

[garygid]

In the pictures of the body mold, and the pictures of the body parts,
partially or fully assembled, with the door mounted or just open, I see
some evidence of a rubber gasket that would be effective when the door
is closed, but nothing that looks like a gutter for when the door is open.
Of course, these pictures are not of the production Aptera.

Also, it seems that the rain can come straight down through the upper,
rear, inboard part of the door opening and fall into the body and
land directly on the left part of the driver seat.
No gutter will catch that, since it never hits the Aptera body.

But, you are right, it does not rain much here.

[garygid]

DOD = Depth of Discharge
If an 12 kWh battery can only be discharged so that 10 kWh is useable,
then maybe it is called a 10 kWh battery, not a 12 kWH battery?

[Rat]

Also, it seems that the rain can come straight down through the upper,
rear, inboard part of the door opening and fall into the body and
land directly on the left part of the driver seat.
No gutter will catch that, since it never hits the Aptera body.
I put this in the "good catch" department. I hadn't thought about it before, but I think it could be a non-trivial problem. Maybe there could be a fold-out flap on the top of the door, or on the headliner. Of course, I park my regular car outside now and when it rains, I get wet getting in or out. To prevent this , in rainy weather I carry a low-tech solution called an umbrella, so I don't see this as insurmountable. It might just take some practice opening the umbrella as you open the door and holding it just right to protect the exposed part of the seat/interior (and yourself) until you can close the door.
:(

[DonC]

DOD = Depth of Discharge
If an 12 kWh battery can only be discharged so that 10 kWh is useable,
then maybe it is called a 10 kWh battery, not a 12 kWH battery?

It would still be a 12 kWh battery pack. You could treat the pack more harshly by using a higher DOD, and you couls also use the full 12 kWh in an emergency. GM plans to use 8 kWh out of 16 kWh but I'm assuming if the ICE dies you'll be able to use the last 30% of the battery below the desired SOC to get home or to a station.

It's really a trade-off between DOD and life.

Moreover I don't think the kWh in the battery pack interests anyone save a few nerds. People want to know what the range is. If an Aptera has a range of 120 miles at 55 mph I doubt few if any care whether it uses 10 kWh or 5 kWh to obtain that range.

Sort of similar to the watts rating on solar panels. (I use this because I believe you've interested in the rating). The panels are rated in DC watts but most people are concerned with AC watts. The 30% conversion loss turns out not to be a big deal because people just want to know how much their monthly bill will go down.

[n_dawg]

It would still be a 12 kWh battery pack. You could treat the pack more harshly by using a higher DOD, and you couls also use the full 12 kWh in an emergency. GM plans to use 8 kWh out of 16 kWh but I'm assuming if the ICE dies you'll be able to use the last 30% of the battery below the desired SOC to get home or to a station.

I wish there were some sort of over-ride that at least let me *know* I'm trading off battery life for additional range, sort of like the 'emergency tank' on motorcycles that moves the fuel intake.

Moreover I don't think the kWh in the battery pack interests anyone save a few nerds. People want to know what the range is. If an Aptera has a range of 120 miles at 55 mph I doubt few if any care whether it uses 10 kWh or 5 kWh to obtain that range.

Completely agree, and I'm one of the nerds.

Sort of similar to the watts rating on solar panels. (I use this because I believe you've interested in the rating). The panels are rated in DC watts but most people are concerned with AC watts. The 30% conversion loss turns out not to be a big deal because people just want to know how much their monthly bill will go down.

30% losses? Which inverter are you looking at? The Sunny Boy 3000/4000 (http://www.partsonsale.com/SB3000US-4000US-042007%5B1%5D.pdf) is between 89% and 97% efficient.

[DonC]

I wish there were some sort of over-ride that at least let me *know* I'm trading off battery life for additional range, sort of like the 'emergency tank' on motorcycles that moves the fuel intake.

Completely agree, and I'm one of the nerds.

30% losses? Which inverter are you looking at? The Sunny Boy 3000/4000 (http://www.partsonsale.com/SB3000US-4000US-042007%5B1%5D.pdf) is between 89% and 97% efficient.
No worries on knowing the trade off between aggressive driving and battery use. The gauges we've seen on the dash panel will instantly let you know the trade-offs, and the Prius has more or less established how drivers change their driving habits when the energy use information is readily available.

I'm with you on the nerd part. :love0014:

It's not efficiency it's just that DC watts and AC watts are not the same. The efficiency losses are on top of that. If you look at solar system proposals or solar energy rebate forms you'll see an entry that says something like "Average Power Output (Wac per Wdc)". The number is usually .7X. That is the DC to AC conversion number and it's what I'm talking about.

[n_dawg]

It's not efficiency it's just that DC watts and AC watts are not the same.

Please explain this to me. A watt is just a joule per second, right? Assuming a resistive load, DC and AC should be indistinguishable in this area.

[DonC]

Please explain this to me. A watt is just a joule per second, right? Assuming a resistive load, DC and AC should be indistinguishable in this area.
The sad truth is that this is one of those things that I know to be true (from putting in a solar system) but really don't know why it's true.

If I had to guess I'd say it's because of a mismatch between the voltage of the grid or the battery and the voltage of the panel. The panel is rated at 16-17 volts but the grid/battery will probably handle 12 or 120 volts. The panel can't be designed for 12 volts because in many circumstances -- when it gets hot under the summer sun for example -- performance degrades and you might not be able to output at 12 volts. Or the inverter inefficiencies might cause the volts to drop. Consequently the panel has to be over sized by 30% and you end up losing the "cushion".

Just a guess. Maybe someone else knows.

[garygid]

Solar panel DC to DC which is then used to charge batteries is most of the loss (maybe 20%), then low voltage DC to high voltage AC conversion could easily lose another 10%.

[futura]

With a resistive (as opposed to reactive) load, AC, DC Watts are the same.
I suspect your 30% "loss" is just the cosine effect from PV panels at a fixed angle instead of tracking the sun.

[airboy]

When exiting in the rain, will water pour off the door and roof right onto the driver and seat?

Gary,

The Aptera doors seem quite similar to those in our Cirrus SR20 airplane. I can attest that water does get into the cabin when the doors are open in the rain --- but it's not too bad, since most of the cabin is protected by the roof. An umbrella helps!

Cheers,
Roger

[DonC]

With a resistive (as opposed to reactive) load, AC, DC Watts are the same.
I suspect your 30% "loss" is just the cosine effect from PV panels at a fixed angle instead of tracking the sun.
The conversion comes after the output is calculated and not before. Likewise it's also not related to the inverter because the loss attributable to that conversion is applied after the DC->AC conversion loss. I'm still thinking a mismatch between the voltages. However, in all honesty, my thinking may be unduly influenced by the fact that if you output 7 amps at 17 volts and it gets converted to 7 amps at 12 volts that's a loss of 30% which is the number I'm looking for. (The numerology approach?)

A few other people have solar systems so maybe one of those folk will know. It's part of the basic calculation. When I saw it I wasn't surprised because from researching I knew there was a 30% difference between the PV's rated DC and AC output. The AC number is important because that's the number you get paid on.

[KarenRei]

Here's how to calculate a PV system's derate factor -- the difference between what ostensibly should come out of the panels and what you get at the plug after AC conversion:

http://rredc.nrel.gov/solar/codes_algs/PVWATTS/version1/derate.cgi

PVWatts uses a default derate factor of 0.77. Their losses:

PV module nameplate DC rating: 0.95 (0.80 - 1.05)
Inverter and Transformer: 0.92 (0.88 - 0.96)
Mismatch: 0.98 (0.97 - 0.995)
Diodes and connections: 0.995 (0.99 - 0.997)
DC wiring: 0.98 (0.97 - 0.99)
AC wiring: 0.99 (0.98 - 0.993)
Soiling: 0.95 (0.30 - 0.995)
System availability: 0.98 (0.00 - 0.995)
Shading: 1.00 (0.00 - 1.00)
Sun-tracking: 1.00 (0.95 - 1.00)
Age: 1.00 (0.70-1.00)

[n_dawg]

Yeah, the losses I know about are PV temperature (hotter is less output), voltage mismatch (though some chargers will transform it), non-tracking losses, eclipse losses, and inverter losses.

[jstdadd]

Garygid;

Steve and company have said a little about using airplane design technology in the Aptera design. The small, curved-fuselage airplanes I have flown and flown in absolutely dumped water into the cabin during rainstorms. So much so, that you would see a whole bunch of people sitting in the planes outside an airport restaurant waiting for the rain to stop.

It generally doesn't help much to open an umbrella out the doors, either - the rain on the upper fuselage just rolls right down and through the door opening.

Imaginative use of 'guttering-gaskets' could help, but I imagine that this could be one of the quirky side-effects of the rounded vehicle body - the water-dump effect.

If they could even put small gutters into the body shape, they could divert away maybe 80% of the water coming in off the upper body toward the doors.

[DonC]

Here's how to calculate a PV system's derate factor -- the difference between what ostensibly should come out of the panels and what you get at the plug after AC conversion:
Nice cite Karen. You nailed it. However, it turns out you get to 70% pretty quickly because the actual output as tested tends to fall short of the rated output. Some panels are better than others but the best seem to lose 10% rather than 5%.

http://gosolarcalifornia.org/equipment/pvmodule.php

[Carbon Saver II]

Bring a towel. If you get caught in the rain in the Cobra, the water comes up from the ground and follows the hips over the doors into the cabin. Oh, and depending on speed some might get past the windshield..... :) Be parpared and enjoy the ride.

Besides "It doesn't rain in California...."

[RainCaster]

I believe the actual quote is "it never rains in Southern California". ;)

[paddler13]

A watt is a watt is a watt. There is no difference in power based on whether the electricity is AC or DC, it is the same. What you may be confusing the "not the same" comment with is the conversion between the output of the DC pv panels and the output of the AC power equipment used in the system. Plus, the output of a PV panel is rated at peak voltage, roughly 17 volts for a 12 volt nominal panel, so the watts = volts x amps calculation produces an artificially high rating. The loss is either in systems that never peak out above 15 volts (equalizing charge) for a non-mppt controlled system (thus losing the extra 2 volts in the above equation) or that use mppt control to convert some voltage to amperage (with efficiency losses) and lose some efficiency that way.

That is also in addition to battery efficiencies, inverter efficiencies and wiring efficiencies (though anyone that doesn't overbuild in that area is nuts, wire is relatively cheap).

(btw, I'm definitely a solar nerd)

But for electric drive cars I really do think it is about range rather than battery capacity and remember too that all batteries will get back some small amount of capacity if they've been rested. That's a good trick to know if your ICE vehicle starting battery dies. Just let it rest for a time with no load (30 minutes or so) and then try to start the vehicle again. You might just regain enough power to get the job done and in an electric vehicle you might get enough power to get yourself at least out of a trouble spot and into a safe place to park it (or even some place to charge it up enough to get home).:aptera:

I'm very curious as to how they solve the window issue. Maybe a fold down flap like a sun visor on the driver and passenger ceilings that could be flipped out to direct any rain out the open door would be enough to allow passengers to get in and out and close the door in the rain.

[n_dawg]

split window

[aptera1213]

well it seems VW doesn't think split windows will deter customers...

http://www.blogcdn.com/www.autoblog.com/media/2011/01/046-volkswagen-formula-xl1-concept.jpg


sigh, the 2e at the top of the page here at aptera forum could be in mass production already...

Gavin

[SEGsby]

Mmm, pretty.

[NeilBlanchard]

To think this is the car (the first VW 1L anyway) was part of the inspiration for the Aptera, right?

This one (nearly) has the side by side seating that the earlier two designs do not.

VW's press release, including full specs:

---

Conceptually, the XL1 represents the third evolutionary stage of Volkswagen’s 1-litre car strategy. When the new millennium was ushered in, Prof. Dr. Ferdinand Piëch, who is today Chairman of the Supervisory Board of Volkswagen AG, formulated the visionary goal of bringing to the market a production car that was practical for everyday use with a fuel consumption of 1.0 litre per 100 km. In the Volkswagen XL1, Volkswagen is demonstrating that this goal is now within reach.

The new Volkswagen XL1 attains a CO2 emissions value of 24 g/km, thanks to a combination of lightweight construction (monocoque and add-on parts made of carbon fibre), very low aerodynamic drag (Cd 0.186) and a plug-in hybrid system - consisting of a two cylinder TDI engine (35 kW / 48 PS), E-motor (20 kW / 27 PS), 7-speed dual-clutch transmission (DSG) and lithium-ion battery. The results: with fuel consumption of 0.9 l/100 km, the new Volkswagen XL1 only emits 24 g/km CO2. Since it is designed as a plug-in hybrid, the XL1 prototype can also be driven for up to 35 kilometres in pure electric mode, i.e. with zero emissions at point of use. The battery can be charged from a conventional household electric outlet. Naturally, battery regeneration is also employed to recover energy while slowing down and store as much of it as possible in the battery for re-use. In this case, the electric motor acts as an electric generator.

Despite the very high levels of efficiency, developers were able to design a body layout that offers greater everyday practicality, incorporating side by side seating rather than the tandem arrangement seen in both the first 1-litre car presented in 2002 and the L1 presented in 2009. In the Volkswagen XL1, wing doors make it easier to enter and exit the car. Further progress has been made by manufacturing body parts from carbon fibre reinforced polymer parts (CFRP), a technique used in Formula 1 car construction. Once again, Volkswagen has successfully achieved significant reductions in production costs– an important step forward to make viable a limited production run of the XL1. Background: together with suppliers, Volkswagen has developed and patented a new system for CFRP production in what is known as the aRTM process (advanced Resin Transfer Moulding).

Most efficient car in the world

The Volkswagen XL1 shows the way forward for extreme economy vehicles and clean technologies. It also demonstrates that such cars can also be fun. The feeling when driving the XL1 is truly dynamic - not based on pure power, rather on its pure efficiency. Two examples: 1) To travel at a constant speed of 100 km/h, the prototype only needs 6.2 kW / 8.4 PS – a fraction of the performance of today’s cars (Golf 1.6 TDI with 77 kW and 7-speed DSG: 13.2 kW / 17.9 PS). 2) In electric mode, the XL1 needs less than 0.1 kWh (82 Wh/km) to complete a one kilometre driving course. These are record values.

When the full power of the hybrid system is engaged, the Volkswagen prototype accelerates from 0 to 100 km/h in just 11.9 seconds; its top speed is 160 km/h (electronically limited). Yet these numbers alone do not tell the whole story: Since the XL1 weighs just 795 kg, the drive system has an easy job of propelling the car. When full power is needed, the electric motor, which can deliver 100 Newton metres of torque from a standstill, works as a booster to support the TDI engine (120 Newton metres torque). Together, the TDI and E-motor deliver a maximum torque of 140 Newton metres in boosting mode.

Plug-in hybrid concept

With the Volkswagen XL1, Volkswagen is implementing a plug-in hybrid concept, which utilises the fuel efficient technology of the common rail turbodiesel (TDI) and the dual clutch transmission (DSG). The TDI generates its stated maximum power of 35 kW / 48 PS from just 0.8 litre displacement. The entire hybrid unit is housed above the vehicle’s driven rear axle. The actual hybrid module with electric motor and clutch is positioned between the TDI and the 7-speed DSG; this module was integrated in the DSG transmission case in place of the usual flywheel. The integrated lithium-ion battery supplies the E-motor with energy. The high voltage energy flow from and to the battery or E-motor is managed by the power electronics, which operates at 220 Volts. The XL1’s body electrical system is supplied with the necessary 12 Volts through a DC/DC converter.

Interplay of E-motor and TDI engine: The E-motor supports the TDI in acceleration (boosting), but as described it can also power the XL1 prototype on its own for a distance of up to 35 km. In this mode, the TDI is decoupled from the drivetrain by disengaging a clutch, and it is shut down. Meanwhile, the clutch on the gearbox side remains closed, so the DSG is fully engaged with the electric motor. Important: The driver can choose to drive the XL1 in pure electric mode (provided that the battery is sufficiently charged). As soon as the electric mode button on the instrument panel is pressed, the car is propelled exclusively by electrical power. Restarting of the TDI is a very smooth and comfortable process: In what is known as "pulse starting" of the TDI engine while driving, the electric motor’s rotor is sped up and is very quickly coupled to the engine clutch. This accelerates the TDI to the required speed and starts it. The entire process takes place without any jolts, so the driver hardly notices the TDI engine restarting.

When the XL1 is braked, the E-motor operates as a generator that utilises the braking energy to charge the battery (battery regeneration). In certain operating conditions the load shared between the TDI engine and the electric motor can be shifted so that the turbodiesel is operating at its most favourable efficiency level. The gears of the automatically shifting 7-speed DSG are also always selected with the aim of minimising energy usage. The engine controller regulates all energy flow and drive management tasks, taking into account the power demanded at any given moment by the driver. Some of the parameters used to realise the optimum propulsion mode for the given conditions are: accelerator pedal position and engine load, as well as the energy supply and mix of kinetic and electrical energy at any given time.


Two-cylinder TDI uses mass production technology: The 0.8 litre TDI (35 kW / 48 PS) was derived from the 1.6 litre TDI, which drives such cars as the Golf and Passat. The 0.8 TDI exhibits the same data as the 1.6-litre TDI common rail engine in terms of cylinder spacing (88 mm), cylinder bore (79.5 mm) and stroke (80.5 mm). In addition, the XL1’s two-cylinder and the mass produced four cylinder share key internal engine features for reducing emissions. They include special piston recesses for multiple injection and individual orientation of the individual injection jets.

The excellent, smooth running properties of the common rail engines were transferred to the two cylinder engine. within addition, a balancer shaft that is driven by the crankshaft turning at the same speed optimises smooth engine running.

Meanwhile, the TDI’s aluminium crankcase was constructed to achieve high rigidity and precision, which in turn leads to very low friction losses. With the goal of reducing emissions, exhaust gas recirculation and an oxidation catalytic converter as well as a diesel particulate filter are used. Equipped in this way, the 0.8 TDI already fulfils the limits of the Euro-6 emissions standard.

Also designed for efficiency is the vehicle’s cooling system. Engine management only cools the TDI by activating an externally driven electric water pump when engine operating conditions require it. This cooling system includes an automatically controlled air intake system at the front of the vehicle to reduce cooling system drag. This thermal management strategy also contributes towards reduced fuel consumption. A second electric water pump, which is also used only as needed, circulates a separate lower temperature coolant loop to cool the starter generator and power electronics.

[NeilBlanchard]

Specs continued:
CFRP body is a technical masterpiece

The development team made extraordinary strides in designing the CFRP body - in terms of its lightweight construction as well as its aerodynamics. A comparison to the Golf illustrates just how innovative the body concept of the Volkswagen XL1 is:

The drag coefficient of the highly successful Golf is very good for the compact class: Cd (0.312) x A (frontal area 2.22 m2) equals a total drag figure of 0.693 m2 (Cd.A) providing this car with benchmark aerodynamic credentials in its class. Meanwhile, the XL1 exceeds this performance with a Cd value of 0.186 and a frontal area of 1.50 m2. The product of these two parameters yields a total drag, or Cd.A value of 0.277 m2 which is 2.5 times lower than that of the Golf.

Design for a new era: The Volkswagen XL1 is 3,888 mm long, 1,665 mm wide and just 1,156 mm tall. These are extreme dimensions. The Polo has a similar length (3,970 mm) and width (1,682 m), but it is significantly taller (1,462 mm). The height of the Volkswagen XL1 is about the same as that of a Lamborghini Gallardo Spyder (1,184 mm). So, it is easy to visualise just how spectacular such a Volkswagen would appear on the road – as long and wide as a Polo, but with a low profile like a Lamborghini.

The wing doors of the Volkswagen XL1 are also reminiscent of a high-end sports car. They are hinged at two points: low on the A-pillars and just above the windscreen in the roof frame, so they do not just swivel upwards, but slightly forwards as well. The doors also extend far into the roof. When they are opened, they free up an exceptionally large amount of entry and exit space.

Visually, the Volkswagen XL1 also adopts the styling lines of the L1 presented in 2009; however, the new prototype has a more dynamic appearance thanks to its greater width. The design of the entire body was uncompromisingly subjected to the laws of aerodynamics. In front, the Volkswagen XL1 exhibits the greatest width; the car then narrows towards the rear. Viewed from above, the form of the XL1 resembles that of a dolphin; especially at the rear, where the lines optimally conform to the air flow over the car body to reduce the Volkswagen’s aerodynamic drag.

In side profile, the roofline reflects styling lines that trace an arc from the A-pillar back to the rear. The rear wheels are fully covered to prevent air turbulence; the air flows here are also optimised by small spoilers in front of and behind the wheels. Observers will look for door mirrors in vain; replacing them on the wing doors are small cameras which take on the role of digital outside mirrors that send images of the surroundings behind the car to two displays inside the vehicle.

The front end of the Volkswagen XL1 no longer exhibits the typical radiator grille; however, it still reflects the styling of the current Volkswagen "design DNA" with a predominance of horizontal lines. Specifically, there is a black cross-stripe (in the area where there is no longer a radiator grille) that combines with the energy-efficient dual LED headlights to form a continuous band. The actual air intake for cooling the TDI engine, battery and interior is located in the lower front end section and has electrically controlled louvres. The narrow turn indicators are also designed in LED technology; these form an "L" shape which vertically follows the wheel housing and horizontally a line beneath the headlights. This creates a front end, which – although it is completely redesigned and extreme in its dimensions – can immediately be recognised as a Volkswagen design by its clean lines.

At the rear, the design takes an entirely new path, reinterpreting the brand values of precision and quality. A new dimension of Volkswagen styling was created here. Four characteristics are discernible:

1. Once again, the dolphin body form that narrows towards the rear with very precise trailing edges for perfect aerodynamics.

2. The coupé-shaped roofline without rear windscreen. Merging into the roofline is the large rear boot lid that covers the drive unit and 100 litre luggage space.

3. A strip of red LEDs that frames the rear section at the top and on the sides. Integrated in this LED strip are the reversing lights, rear lights, rear fog lights and brake lights.

4. A black diffuser, which exhibits nearly seamless transitions to the completely covered underbody.

Lightweight construction: more systematic than ever: Large sections of the Volkswagen XL1’s body consist of carbon fibre reinforced polymer (CFRP) - which is as lightweight as it is strong. Specifically, the monocoque with its slightly offset seats for driver and passenger and all exterior body parts are made of CFRP. The layers of carbon fibre, which are aligned with the directions of forces, are formed into parts with an epoxy resin system in the aRTM process. This material mix produces an extremely durable and lightweight composite. For a long time, it was considered impossible to manufacture a body of CFRP, like that of the Volkswagen XL1, to industrial standards. Nonetheless, Volkswagen successfully found a cost-effective way to mass produce CFRP parts in sufficient volumes as early as 2009 – in the framework of the XL1 development project. Now this process has been further perfected.

CFRP is the ideal material for the body of the Volkswagen XL1 because of its light weight. The XL1 prototype weighs only 795 kg. Of this figure, 227 kg represents the entire drive unit, 153 kg the running gear, 80 kg the equipment (including the two bucket seats) and 105 kg the electrical system. That leaves 230 kg, which is precisely the weight of the body – produced largely of CFRP - including wing doors, front windscreen in thin-glass technology as in motorsport and the highly safe monocoque. A total of 21.3 percent of the Volkswagen XL1, or 169 kg, consists of CFRP. In addition, Volkswagen uses lightweight metals for 22.5 percent of all parts (179 kg). Only 23.2 percent (184 kg) of the Volkswagen XL1 is constructed from steel and iron materials. The rest of its weight is distributed among various other polymers (e.g. polycarbonate side windows), metals, natural fibres, process materials and electronics.

Lightweight construction: safer than ever: The Volkswagen XL1 is not only lightweight, but very safe as well. As mentioned, this is due in part to the use of CFRP as a material. In the style of Formula 1 race cars, the Volkswagen has a high-strength monocoque. In contrast to Formula 1, however, this safety capsule is enclosed on top – for safety. Depending on the type of collision, the load path may be directed through the A- and B-pillars, cant rails and sills, all of which absorb the impact energy. Additional side members and crossmembers in the front and rear perfect the car’s passive safety.

Running gear with ESP utilises high-tech materials

The running gear is equipped with anti-roll bars at the front and rear and is characterised by lightweight construction with maximum safety. In front, a double wishbone suspension is used, while a semi-trailing link system is employed at the rear. The front and rear suspension are both very compact in construction and offer a high level of driving comfort. The running gear components mount directly to the CFRP monocoque in key areas.

Running gear weight has been reduced by the use of aluminium parts (including suspension components, brake calipers, dampers, steering gear housing), CFRP (anti-roll bars), ceramics (brake discs) magnesium (wheels) and plastics (steering wheel body). Friction-optimised wheel bearings and drive shafts, as well as an entirely new generation of optimised low rolling resistance tyres from MICHELIN (front: 115/80 R 15; rear: 145/55 R 16), contribute to the low energy consumption of the Volkswagen XL1. Safety gains are realised by an anti-lock braking system (ABS) and electronic stabilisation programme (ESP). That is because sustainability without maximum safety would not really be a step forward. The Volkswagen XL1 shows how these two parameters can be brought into harmony.

Technical data

Body

Construction method
CFR monocoque and add-on parts

Length / width / height
3,888 mm / 1,665 mm / 1,156 mm

Wheelbase
2,224 mm


Drive system

Type
Plug-in hybrid, rear wheel drive

Internal combustion engine
TDI, two cylinder, 800 cm3,
35 kW / 48 PS, 120 Nm

Electric motor
20 kW / 27 PS, 100 Nm

Gearbox
7-speed DSG

Battery
Lithium-ion

Emissions class
Euro 6


Weight data

Kerb weight
795 kg


Performance / fuel economy

V/max
160 km/h (electronically limited)

0-100 km/h
11.9 s

Fuel consump. (Ø NEDC)
0.9 l/100 km

CO2 emissions ((Ø NEDC)
24 g/km

Range: E-drive
35 km

Range: TDI + E-drive
approx. 550 km (10 litre fuel tank)

[NeilBlanchard]

last part of specs:
The new Volkswagen XL1 Super Efficient Vehicle (SEV) has been unveiled at the Qatar Motor Show. Pioneering construction techniques, an advanced plug-in hybrid drivetrain and innovative packaging all play a part in allowing the Volkswagen XL1 to return 313 mpg on the combined cycle while emitting 24 g/km of CO2to set a new benchmark for vehicle efficiency.

Powering the Volkswagen XL1 is a compact 800 cc TDI two-cylinder common rail diesel engine developing 48 PS. It’s linked to an electric motor producing 27 PS, resulting in a total of 75 PS – a modest output yet more than enough when the low kerb weight (795 kg) of the vehicle is taken into account.

The TDI engine is linked to an electric motor and a seven-speed DSG gearbox with an automatic clutch mounted between each unit. The electric motor can either work independently of the TDI engine or in tandem when accelerating. In pure electric mode the Volkswagen XL1 can travel up to 35 km before the diesel engine cuts in. Accelerating from rest to 62 mph can be achieved in 11.9 seconds; the electronically limited top speed is 99 mph.

In both its styling and packaging the Volkswagen XL1 draws on lessons learned from the 1-Litre car (2002) and the L1 concept (2009). The Volkswagen XL1 has evolved to feature staggered seating with the driver and passenger placed next to each other in a body structure made from advanced new materials providing immense strength yet weighing just 230 kg.

To make such weight savings possible, and yet viable for series production, Volkswagen developed and patented a new system for the manufacture of the Carbon Fibre Reinforced Polymer (CFRP) parts on the car called the Resin Transfer Moulding (RTM) process.

In total the Volkswagen XL1 weighs 795 kg. In addition to the body structure, the weight is accounted for by the drivetrain (227 kg), the running gear (153 kg), the interior including a pair of bucket seats (80 kg) and the electrical system (105 kg). In total just 23.2 per cent of the car (184 kg) is made out of either steel or iron.

Further savings are made through the extensive use of lightweight materials including magnesium (wheels), ceramics (brake discs) and aluminium (dampers, steering system, brake calipers).

The styling of the Volkswagen XL1 is borne out of functional requirements – easy access to the interior is granted via a pair of elegant scissor doors that hinge on the A-pillar while the profile of the car has been honed in the wind tunnel, the result being a remarkable coefficient of drag figure of 0.186. The Volkswagen XL1’s overall length (3,970 mm) and width (1,682 mm) are similar to those of a Volkswagen Polo yet its height (1,184 mm) is more akin to that of a Lamborghini Gallardo Spyder.

Although the Volkswagen XL1 is still very much a concept, its unveiling marks the next step towards the birth of a new class of Super Efficient Vehicles, while the advent of a process such as RTM is a significant milestone.

[PatQ562]

"So Hurry Up and Make One For a Customer!" (Couldn't resist).

It is indeed very interesting to see what a world-class company can bring to the game. Weight, at 795Kg (almost 1800 lbs) is hardly featherlight, outweighing an old Beetle for example, but this is a very sophisticated machine, and it claims to get about EIGHT TIMES the mpg of the old Bug. The Cd at 0.186, similar to the EV1, also indicates that it is really hard to better this number even with an all-out effort and access to serious test facilities. This is of course a 4-wheel vehicle, and taps into highly refined TDi technology as well as advanced electrics (although one wonders if the Ecomotor would be even better).

Pat Q

[NeilBlanchard]

Right Pat -- it is impressive they got a Cd better than the EV1 without narrowing the rear wheel track. My working theory is that if you have a single chassis "mass", then you can't go lower drag than this car without narrowing the rear wheel track.

The Edison2 beats this (0.165 if I recall correctly?) by virtue of the outboard wheel pods -- the rear of the main chassis tapers almost to nothing.

My hope is that my CarBEN EV design will be as low as the Edison2, or lower.

[randyd]

"So Hurry Up and Make One For a Customer!" (Couldn't resist).
Amen!

It is indeed very interesting to see what a world-class company can bring to the game. Weight, at 795Kg (almost 1800 lbs) is hardly featherlight, outweighing an old Beetle for example, but this is a very sophisticated machine, and it claims to get about EIGHT TIMES the mpg of the old Bug. The Cd at 0.186, similar to the EV1, also indicates that it is really hard to better this number even with an all-out effort and access to serious test facilities. This is of course a 4-wheel vehicle, and taps into highly refined TDi technology as well as advanced electrics (although one wonders if the Ecomotor would be even better).

Pat Q

I am not getting my hopes up about Cd numbers. This IS a concept car, after all. And I don't really expect the CFRP body to be a part of the production car without the price being un-sellably high.

[NeilBlanchard]

The Cd is 0.186 and the A is 1.50 sq m so CdA is 0.277 sq m.

[plainar]

I like the 1L.

Ah, the ol' split windows that PBW said would never sell. This was the beginning of a long string of poor decisions made by PBW, but we already know that. This thread brought me back for a few moments.

[SlowSRT4]

well it seems VW doesn't think split windows will deter customers...
I agree that Aptera should have gone ahead and produced with the split window. But I wouldn't give VW credit for proving anything yet. I would like to see this car sold to the public with split windows and still be successful in the marketplace, but I am doubtful that scenario will occur. If you can't fit a bag of fast food and a couple extra large sodas through the window, it won't pass muster in the US. :fighting0027:

[Grendal]

If you can't fit a bag of fast food and a couple extra large sodas through the window, it won't pass muster in the US. :fighting0027:

An extra large soda WILL fit, IF you bring it through sideways... ;-)

:tongue0015: