Don't know which epoxy Aptera is using for their body. But when I searched for ignition temperature of epoxies, all I found was melting, or more accurately, softening temperatures. In high heat, epoxies get soft, more like rubber, losing their strength. These are heats like 300 to 600 degrees F --- warm to very hot oven temperatures. Being thermally insulating, it would take quite a while for an extenal fire's heat to reach inside. I found no mention of ignition. Gasoline burns at 495 degrees F, so it would soften but not ignite the Aptera body. The vinyl wrap doesn't ignite until it gets over 700 degrees. So you'll just be roasted well done if you can't escape and no one puts out the fire. Don't worry --- you'll expire from the hemp smoke long before that happens. Don't let that happen.
Hi Harry. I live in a Marina with quite a few pleasure and commercial boats. We have had a number of fires over the last 15 years. You may have read about the pleasure diving boat accident where 34 people died in the nearby Santa Cruz Island. I have witness a half dozen boat fires personally. I can tell you that fiberglass/epoxy boats burn, and burn fast. They don't get soft and rubbery. There is a strong toxic black smoke that is emitted which can incapacitate you if you don't get out fast enough. There is plenty of video on YT, just search MV Conception. This one reason why many of the commercial boats are steel. One of our club members is a Coast Guard Captain and he has many stories to tell. Most fires are electrical with gas/diesel being second.
The problem with the completely enclose fiberglass composite shell filled with high tension wires (350 volts) and any number of components that could fail, overheat, or short out combined with flammable lithium ion batteries, could be a disaster with a bad accident. As I had pointed out earlier, if the car flips over during an accident, one could become trapped since the upward swinging doors would be blocked from opening. Once the black smoke happens, you have about one breath before succumbing to the fumes. I don't mean to sound gory, but one has to realize the potential problems dealing with all the accelerants within the same cabin areas. This is the same problem with the Corvette.
When discussing fires, one has to understand the uniqueness of lithium ion battery fires. LiPo cells are susceptible to the same troubles of other lithium-ion cells; overcharge, over-discharge, over-temperature, short circuit, crush and nail penetration can all result in thermal run away and catastrophic failure leading to explosion and fire. The electrolyte itself acts as an oxidizer making the fire almost impossible to put out. Water is not the way to put out a lithium ion battery fire. Our RC (radio controlled) club flies planes, boats and cars. We often charge and transport the higher amperage batteries in special metal boxes or insulated bags. This is because many RC batteries are pouch cells just like in cell phones. Samsung had a rash of fires in their Note 7 series. The Boeing 787 had early issues with the new replacement lithium batteries in 2013 causing spontaneous fires.
This is one reason I mainly use lithium Fe (iron) cell technology to avoid some of these issues. They tend to have a better lifespan, 50% more recharges and less chance of fire. The only drawback is less storage capacity per weight.
OK enough doom and gloom, lets see what safety factors Aptera comes up with. I am hoping that the windshield could easily be kicked out in case of being overturned and trapped.
I can't imagine this landing upside down then catching on fire is likely to happen at all. First, the Aptera is so bottom heavy and rounded that like a rolly-polly toy, even if it landed on it's top somehow, it would almost always roll back over onto its feet. Certainly it would if it was floating on water.
Has a single Tesla out of the 1/2 million sold, with its much less rounded body, ever landed upside down in any extreme accident? I remember seeing one amazing video where a Tesla was launched into the air in a collision, did a half roll in midair, landed on its roof and then kept rolling back onto its feet (and nobody died)! Wish I could find that one now
@Harry Parker Hello Harry. Of course this is all design speculation since we have not seen any crash testing. I understand your bottom heavy, rounded theory, but most cars are also bottom heavy. Even though the Aptera is probably the most rounded car body I can think of, it also has two large pontoons that stick out further than most cars are wide. This will block complete roll over back to the normal side up stance. One normally doesn't choose where they hit or lose control and may land against a wall, tree or dense vegetation. With the 70:30 weight distribution of the Aptera (front-heavy) and the shape of the rear underbelly of the car, it will be prone to somersaulting forward if hit in the rear by another vehicle especially while braking. The high rear light panel sits about at the height of most cars hoods especially when they are braking. This will wedge the impacting car under the Aptera and actually lift the rear end as it plows forward, potentially flipping the rear of the car upwards if the speed and circumstances are ideal. This will be even more augmented if the main impact was to one side of the rear trailing arm. Of course this is only speculation, but because of Aptera's shape and unique front suspension it is more possible than with a more conventional car shape which encloses the front wheels such as a Tesla. Tesla's are inherently more stable because it is a four wheeled, heavy automobile, not an ultralight weight three wheeled cycle. Just my opinion, thanks for listening.
The Lordstown Endurance is the only other vehicle that I know of current using the Elaphe hub motors on a production basis. This is a photo of the truck. The incident happened on January 2021 and was released to the public a month later, not through Lordstown but from police reports. These are photos from the Farmington Hills Fire Dept. The EV was not involved in a collision but caught fire during a normal drive. I would guess that it occurred in the battery pack since it started from underneath the truck. I do not have anything against Lordstown, and am totally understanding that fires could occur in any pre-production vehicle. I am only pointing out that with the high energy these battery packs contain, they should be respected whether it is in a cell phone, hoverboard, e-bike, or airline battery. Some drag strips are not allowing EV's to participate because their fire departments are not trained to handle their potential fires.
The N Fork of the Payette River near where I live is notorious for car crashes leading to drownings. Enough so that locals carry a hammer in their vehicle to smash windows in case of submersion. Plus I remember getting pushed off a snowy BC highway by a drunk driver and ending up upside down in the ditch with my pregnant wife, both of us hanging from the seat belts in my Tercel SW. With both these scenarios, gull wing doors pose a hazard. What work arounds can mitigate that threat? Otherwise, I'm looking forward to the gull wing doors.
1) A hammer won't break polycarbonate, the way it will for any other car's tempered non-windshield glass. I do wonder whether it would even break that though, when submerged with water pressing inward while you're trying to break the glass outward. That's why I suggested a manual safety release like on bus windows.
2) What happens electrically with a BEV when an accident submerges it in fresh or salt water?
This what happened today in a steel bodied Tesla. Disregard the auto-pilot but focus on the difficulties of putting out a battery fire. The photos explain it all.
Apparently fires occur in less than less than 0.5% of auto accidents, & EVs are even less likely to catch fire than gas cars.
My BEV battery is in a steel case very much like a gas tank, & in a similar location. Anything that would puncture it would likely puncture a gas tank, & based on the above plus gut instinct I'd rather take my chances with a battery.
So what I meant to imply was that for fire, driving an Aptera is likely better than driving a Corvette (or even getting hit by one in any other car) with its similar composite outer body PLUS all that flammable liquid gasoline.
Most cars (including the Corvette) have quite a bit of exterior plastic in the form of bumper covers, airdams, SUV wheelwell cladding, rocker covers, spoilers, fender liners, etc. I wonder how that is for burning/melting.
Without the approximately 80% waste heat of combustion, EV coolant doesn't get "scalding" like a gas car's does. "Body temperature" is more like it: I monitored my BEV's coolant temperature for a while, including in mid-90s Fahrenheit weather, & it never even reached 100F, & even that would still be safe. My EV battery is only rated to 125F, so when necessary, the A/C actually chills the coolant to keep it cooler than that.
What if a gasoline-powered fiberglass Corvette has a crash with a tree that bursts into flames. Would that be sufficient ignition? Does the shell material melt or ignite before or after all the interior materials?
@dhapp I think your question is a valid one. Any composite resin structure can burn quite easily once the ignition temperature has been reached. I am also concerned that scalding hot coolant might be circulating in the body shell to dissipate the heat of the batteries, motor, and inverters can be breached and spray into the cabin. One big source of ignition of the car in any distortion or breaking of the lithium cells; it is a horrible fire, once that gets started. https://www.motor1.com/news/359360/chevy-corvette-catches-fire-video/
There are several common risks for first responders associated with electric vehicle fires:
Electrical shock (up to 400 volts).
Extremely high temperatures and thermal runaway.
Toxic fumes.
Lithium burns (respiratory and skin reactions).
Toxic runoff.
Reignition up to 24 hours after initial extinguishment.
I was planning to keep some marshmallows in the motorcycle, just in case.
Now that you had brought up your concern, I may as well place my own here. I am worried about being trapped in the car when a fire breaks out. I once hit a foot long piece of rebar steel which was kicked up by the car in front of me. It badly dented the steel door sill. If that were to puncture the battery, you will have a spontaneous fire. If you look at the design of the car, if it were to flip and land in rocks or bushes it would be sit there on its roof. While the roof structure of the car may support the weight of the car and avoid crushing the occupants, it will also prevent the up-flipping doors from opening. Not a scene that I like imagining.
The fiberglass fibers themselves do not burn. The hemp fibers would. The epoxy resin would do a mix of melting and burning, depending on which one they use. The aerospace composites I have used have a flame retardant mixed in, so they mostly melt. You would need a crack in the shell with a jagged edge to really get them burning. The batteries, seats, carpets, and interior plastics would be a much bigger fire concern than the composite frame.
The shell is fiber-reinforced-epoxy, which does not melt. When we find the ignition temperature, let's see how that compares to our current cars' dashboard, seats, carpet, door panels...
The answer is yes, if the temperature is high enough. The good news is that it would be rather unlikely to encounter an ignition source sufficient to start it burning.
What if the Aptera has a crash with a gasoline-powered vehicle that burst into flames. Would that be sufficient ignition? Does the shell material melt or ignite?
Don't know which epoxy Aptera is using for their body. But when I searched for ignition temperature of epoxies, all I found was melting, or more accurately, softening temperatures. In high heat, epoxies get soft, more like rubber, losing their strength. These are heats like 300 to 600 degrees F --- warm to very hot oven temperatures. Being thermally insulating, it would take quite a while for an extenal fire's heat to reach inside. I found no mention of ignition. Gasoline burns at 495 degrees F, so it would soften but not ignite the Aptera body. The vinyl wrap doesn't ignite until it gets over 700 degrees. So you'll just be roasted well done if you can't escape and no one puts out the fire. Don't worry --- you'll expire from the hemp smoke long before that happens. Don't let that happen.
Being upside down and the butterfly doors not opening is scary. It is also scary to think of being in water and unable to craw out the small windows.
The Lordstown Endurance is the only other vehicle that I know of current using the Elaphe hub motors on a production basis. This is a photo of the truck. The incident happened on January 2021 and was released to the public a month later, not through Lordstown but from police reports. These are photos from the Farmington Hills Fire Dept. The EV was not involved in a collision but caught fire during a normal drive. I would guess that it occurred in the battery pack since it started from underneath the truck. I do not have anything against Lordstown, and am totally understanding that fires could occur in any pre-production vehicle. I am only pointing out that with the high energy these battery packs contain, they should be respected whether it is in a cell phone, hoverboard, e-bike, or airline battery. Some drag strips are not allowing EV's to participate because their fire departments are not trained to handle their potential fires.
The N Fork of the Payette River near where I live is notorious for car crashes leading to drownings. Enough so that locals carry a hammer in their vehicle to smash windows in case of submersion. Plus I remember getting pushed off a snowy BC highway by a drunk driver and ending up upside down in the ditch with my pregnant wife, both of us hanging from the seat belts in my Tercel SW. With both these scenarios, gull wing doors pose a hazard. What work arounds can mitigate that threat? Otherwise, I'm looking forward to the gull wing doors.
This what happened today in a steel bodied Tesla. Disregard the auto-pilot but focus on the difficulties of putting out a battery fire. The photos explain it all.
https://www.theverge.com/2021/4/18/22390612/two-people-killed-fiery-tesla-crash-no-driver
Apparently fires occur in less than less than 0.5% of auto accidents, & EVs are even less likely to catch fire than gas cars.
My BEV battery is in a steel case very much like a gas tank, & in a similar location. Anything that would puncture it would likely puncture a gas tank, & based on the above plus gut instinct I'd rather take my chances with a battery.
So what I meant to imply was that for fire, driving an Aptera is likely better than driving a Corvette (or even getting hit by one in any other car) with its similar composite outer body PLUS all that flammable liquid gasoline.
Most cars (including the Corvette) have quite a bit of exterior plastic in the form of bumper covers, airdams, SUV wheelwell cladding, rocker covers, spoilers, fender liners, etc. I wonder how that is for burning/melting.
Without the approximately 80% waste heat of combustion, EV coolant doesn't get "scalding" like a gas car's does. "Body temperature" is more like it: I monitored my BEV's coolant temperature for a while, including in mid-90s Fahrenheit weather, & it never even reached 100F, & even that would still be safe. My EV battery is only rated to 125F, so when necessary, the A/C actually chills the coolant to keep it cooler than that.
What if a gasoline-powered fiberglass Corvette has a crash with a tree that bursts into flames. Would that be sufficient ignition? Does the shell material melt or ignite before or after all the interior materials?
The fiberglass fibers themselves do not burn. The hemp fibers would. The epoxy resin would do a mix of melting and burning, depending on which one they use. The aerospace composites I have used have a flame retardant mixed in, so they mostly melt. You would need a crack in the shell with a jagged edge to really get them burning. The batteries, seats, carpets, and interior plastics would be a much bigger fire concern than the composite frame.
The shell is fiber-reinforced-epoxy, which does not melt. When we find the ignition temperature, let's see how that compares to our current cars' dashboard, seats, carpet, door panels...
The answer is yes, if the temperature is high enough. The good news is that it would be rather unlikely to encounter an ignition source sufficient to start it burning.