As I said in another reply, one of the limits is the speed rating of the airplane's tires. At a constant weight, as density altitude increases (due to being high above sea level, or at a high temperature) the speed at which the airplane has to roll before it can rotate increases. At some high temperature, the V rating of the tire is exceeded, so that even with an infinitely long runway you wouldn't be able to take off.
In that case you might be able to reduce the weight of the airplane, or simply wait for the temperature to drop...
I can just picture United dragging people out of the airplane and throwing them onto the tarmac until the airplane is light enough to take off.;-)
You may be right, but I would think that a modern car with a mass flow sensor will simply adjust the fuel to maintain the correct air/fuel mixture, so I actually wouldn't expect any difference in engine efficiency.. Not sure about that, though.
I'm sure you're right about the fuel mix, but drag also goes up because of denser cold air (quick calculation says it changes about 10% between summer and winter), and probably the tires have more rolling resistance even if you keep them at the proper pressure (but that's just a guess).
I'm seeing Bolts advertised for $32,200 in my area. Take the $7,500 federal incentive = $24,700. In my state (MA) another $2,500 state incentive and it's $22,200.
I've never been in an i3, but lots of YouTube videos have people saying they're small on the outside, big on the inside (i.e. they make efficient use of space... still, it is certainly what you would consider a city car).
The Volt is a medium size car... 4 people fit very comfortably. I haven't tried loading a bunch of luggage in the trunk yet, so I can't really comment on that.
I couldn't imagine risking running out of juice if I needed to take a family member to the hospital at midnight and the car wasn't charged enough yet
That's my point about a big enough battery. Restate your comment: "I can't imagine running out of gas if I needed to take a family member to the hospital at midnight" and the obvious thing you do now is you don't run your gas tank down to empty and park overnight that way. You make sure you always have at least enough for the quick emergency trip.
So, the BEV way of thinking of that is that you should have a big enough battery that when you get home and plug in, you still have enough charge for a quick emergency trip if you need to...
(or, as I mentioned, you buy a Rex like an i3 or a Volt so that you can always fall back on the gas engine if you need to).
I agree that Gas to Electric by itself isn't a big thing.
Now fossil fuel -> renewables is a BIG deal in my book, and a car that runs on the power source that Solar + Wind + Hydro produce... I think that's also a big thing.
Gonna take a couple decades to make a dent, but I think we're seeing the beginning of the revolution that is humankind's switch to renewable energy. It's about goddam time!
I don't think this is a fair posting. It would be like one person saying "I like my ICE car because I can go as far as I want without having to worry about range" and someone countering that isn't true because their ICE car lost oil pressure and wouldn't work, despite there being gas in the tank. Or maybe stopped running because of a check-engine condition.
I can understand your frustration with the situation your wife found herself in (twice) but that's an argument against unreliable cars, not against range extended vehicles (except maybe that a Rex is more complicated so more chance of something going wrong).
I kind of felt like that with my first electric vehicle (Honda Fit EV). I really didn't like the idea of hauling around an engine and a gas tank that I would never use.
On the other hand, for some people a pure BEV won't work. Or, they just don't want to have to plan every trip. So, for them, a range extended electric probably makes a lot of sense.
We have a Volt now and my daughters really like the fact that they can go on trips longer than the range of the Honda Fit EV. Ultimately, I think pure BEV will be the way to go for passenger cars, but while the battery and charging is still being improved, Rex vehicles make sense for some people.
Electric cars don't look odd just to annoy you, they look the way they do because engineers are trying to compensate for limited energy in today's batteries with reduced weight and lower coefficient of drag. If your electric car were to look more like a Chevy Corvette and less like a Tesla model S, then you wouldn't be passing many pumps, or charging stations, as a Corvette Cd is probably better in reverse, and a Tesla Model S has an excellent Cd, as did the Chevy EV1.
There are a couple reasons EV look the way they do. One is certainly Cd as you mention. But another is that a lot of companies feel the car has to look unique/different/futuristic. They believe that the early adopters won't buy it unless it's different enough to attract attention. The Prius is an example of this way of thinking (both Cd and looking unique).
I personally think we're past the early adopter phase and we need to make sure the BEV looks like any other "normal" car.
Some people like the way the Leaf looks. I can't stand it. Some people hate the way the Bolt looks. I think it looks pretty good.
Consider a Rex like an i3 or a Volt. Around the city, 99% of your driving can be electric only, but if you want to do a road trip you're still getting 40 mpg or better.
BMW claims that some huge percentage of the people that order the i3 with the Rex almost never use it.
Some of this depends on the range of a car. With 110 miles of range (in the summer) with my Honda Fit EV, I was finding that I needed my ICE car about once a month. I figure with a Bolt or Tesla it would be once or twice a year. I'd be willing to rent a car once or twice a year to have an electric vehicle the rest of the time.
Depends on the car. My Honda Fit EV took almost 50% hit on cold weather days here in Boston. That car used resistive heating, having a heat pump like in a Leaf helps somewhat, but there's still lots of range lost. I also notice my ICE car loses range on a tank of gas in the cold weather...
The used market for electric cars is really low, i.e. the original purchaser takes quite a bath when they sell (except for Tesla - they seem to hold their value). If you don't mind buying a used electric to give it a try, the pricing is very affordable.
I bought a 3 year old Chevy Volt with 40,000 miles on it for $11,000. My daughters do 98% of their driving on the battery (about 38 miles worth on a charge) and only buy gas when they want to go on a long trip. So far it's working out very well...
That's a good point. With my Honda Fit EV I would typically have only used 1/2 the charge, so it would only take 90 minutes @ 220v to charge. With 110v that would have probably been 4-5 hours... not nearly as good as 90 minutes, but it would probably work for a lot of situations.
I'm reading all these and I'm really surprised. When I got my Honda Fit EV it came with a 220v charger. I paid my electrician a couple hundred bucks to put a dryer outlet next to my panel, plugged the 220v charger into the dryer outlet and I was done. No environmental study, no hassle. Granted, my panel is in my garage so I didn't have to run a cable the length of my house, so it might be more of a hassle if your panel isn't in the garage, but still...
Do you really have to get an environmental study in Washington State to install a dryer?
I'm also a little surprised to hear people saying their service isn't sufficient to run the extra circuit. I've got an electric dryer, electric oven, well pump, septic pump, AND the circuit for the car in a house built in 1975 (i.e. the service isn't THAT new) and I've never had a problem.
We now have a Chevy Volt (daughter crashed the BEV) and my only complaint is that the Volt takes longer than it should to charge @ 220v... Would love it if GM would sell an upgraded charging system in the Volt that would use more current.
I guess it depends on why you say a step back for consumers.
I much prefer driving a BEV over a gas car. The low amount of noise, the quick acceleration, no lurching as it shifts, and the one pedal driving.
Disadvantage: having to plan refueling. With a big enough battery, that won't be the case for most people. It's pretty rare for the average guy to drive more than 300 miles a day, so most people could just plug in at night and not really worry about it. For those who do drive a lot of miles a day, or end up in places without a charging infrastructure, a Rex like the i3 or Chevy Volt gives you 99% of the advantages of a BEV without having to worry about running out of charge.
I think they're definitely a step ahead for consumers, and will continue to be even better.
We had a pure BEV which my daughter crashed. I replaced it with a low mileage 2013 Volt for $11,000. For 98% of what my two daughters need, they can do it all on the battery. But, when they want to drive to New Hampshire to the beaches, they can put a few gallons in it and use the gas engine. It gets about 40 mpg which isn't as good as say a Prius, but 98% of the time they're not burning any gas at all (and thus no teenage fights about who needs to fill the tank).
That brings up another point. I like sports cars. I would not consider any of the BEVs out there a sports car. The Model S is a luxury sedan. I'm hoping that the Model 3 will handle well. If not, perhaps BMW will come out with a good handling BEV.
I don't need to scream out at the world I have an electric car, I want something that looks nice, drives well and I can smile smugly to myself when I pass the pumps.
I totally agree with this. I had a Honda Fit EV which was almost indistinguishable from the regular Fit. We now have a Volt which looks just like a Cruze, i.e. nobody realizes these are electric cars.
On the other hand, the Leaf is too fugly for me to want to own one (we'll see what they do with V2), and the i3 is also pretty darn ugly.
Early adopters (which I guess I am) typically want to make a statement, so you end up with something like a Prius that screams "I'm so green!!!".
I think we're past early adopters - it's time for mainstream looks for BEVs that aren't converted gas cars.
I actually like the Chevy Bolt and the Model S and Model 3. I didn't like the nose of the Model 3 when it was first shown, but I guess it's grown on me.
Um, towards the bottom of the article it mentions "10 times faster" which is probably achievable and probably what they actually are looking for. They even mention that rewriting an inner loop, shaving a few milliseconds off will give a substantial speed increase.
Way back I worked at Alliant Computer Systems (https://en.wikipedia.org/wiki/Alliant_Computer_Systems) which was a hardware/software system that would automatically unroll loops in Fortran code and run them in parallel on up to 8 processors at a time (and each of the 8 also had vector hardware). It was very fast on the right Fortran code... Hardware support for concurrency control when one iteration of the loop depended on a computation from another iteration. All done in custom hardware which was killed (like many supercomputer companies) by the advent of high performance microprocessors.
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As I said in another reply, one of the limits is the speed rating of the airplane's tires. At a constant weight, as density altitude increases (due to being high above sea level, or at a high temperature) the speed at which the airplane has to roll before it can rotate increases. At some high temperature, the V rating of the tire is exceeded, so that even with an infinitely long runway you wouldn't be able to take off.
In that case you might be able to reduce the weight of the airplane, or simply wait for the temperature to drop...
I can just picture United dragging people out of the airplane and throwing them onto the tarmac until the airplane is light enough to take off. ;-)
It's not the length of the runway, it's the speed rating of the tires.
The hotter it is, the faster the plane has to roll before it can rotate. At some temperature, that speed exceeds the speed rating of the tires.
You may be right, but I would think that a modern car with a mass flow sensor will simply adjust the fuel to maintain the correct air/fuel mixture, so I actually wouldn't expect any difference in engine efficiency.. Not sure about that, though.
I'm sure you're right about the fuel mix, but drag also goes up because of denser cold air (quick calculation says it changes about 10% between summer and winter), and probably the tires have more rolling resistance even if you keep them at the proper pressure (but that's just a guess).
I'm seeing Bolts advertised for $32,200 in my area. Take the $7,500 federal incentive = $24,700. In my state (MA) another $2,500 state incentive and it's $22,200.
Both the i3 and the Volt are 4 seat vehicles.
I've never been in an i3, but lots of YouTube videos have people saying they're small on the outside, big on the inside (i.e. they make efficient use of space... still, it is certainly what you would consider a city car).
The Volt is a medium size car... 4 people fit very comfortably. I haven't tried loading a bunch of luggage in the trunk yet, so I can't really comment on that.
Just curious - I drive about 12,000 miles a year here in Boston... How many miles a year do you drive?
I couldn't imagine risking running out of juice if I needed to take a family member to the hospital at midnight and the car wasn't charged enough yet
That's my point about a big enough battery. Restate your comment: "I can't imagine running out of gas if I needed to take a family member to the hospital at midnight" and the obvious thing you do now is you don't run your gas tank down to empty and park overnight that way. You make sure you always have at least enough for the quick emergency trip.
So, the BEV way of thinking of that is that you should have a big enough battery that when you get home and plug in, you still have enough charge for a quick emergency trip if you need to...
(or, as I mentioned, you buy a Rex like an i3 or a Volt so that you can always fall back on the gas engine if you need to).
I agree that Gas to Electric by itself isn't a big thing.
Now fossil fuel -> renewables is a BIG deal in my book, and a car that runs on the power source that Solar + Wind + Hydro produce... I think that's also a big thing.
Gonna take a couple decades to make a dent, but I think we're seeing the beginning of the revolution that is humankind's switch to renewable energy. It's about goddam time!
I don't think this is a fair posting. It would be like one person saying "I like my ICE car because I can go as far as I want without having to worry about range" and someone countering that isn't true because their ICE car lost oil pressure and wouldn't work, despite there being gas in the tank. Or maybe stopped running because of a check-engine condition.
I can understand your frustration with the situation your wife found herself in (twice) but that's an argument against unreliable cars, not against range extended vehicles (except maybe that a Rex is more complicated so more chance of something going wrong).
I kind of felt like that with my first electric vehicle (Honda Fit EV). I really didn't like the idea of hauling around an engine and a gas tank that I would never use.
On the other hand, for some people a pure BEV won't work. Or, they just don't want to have to plan every trip. So, for them, a range extended electric probably makes a lot of sense.
We have a Volt now and my daughters really like the fact that they can go on trips longer than the range of the Honda Fit EV. Ultimately, I think pure BEV will be the way to go for passenger cars, but while the battery and charging is still being improved, Rex vehicles make sense for some people.
Electric cars don't look odd just to annoy you, they look the way they do because engineers are trying to compensate for limited energy in today's batteries with reduced weight and lower coefficient of drag. If your electric car were to look more like a Chevy Corvette and less like a Tesla model S, then you wouldn't be passing many pumps, or charging stations, as a Corvette Cd is probably better in reverse, and a Tesla Model S has an excellent Cd, as did the Chevy EV1.
There are a couple reasons EV look the way they do. One is certainly Cd as you mention. But another is that a lot of companies feel the car has to look unique/different/futuristic. They believe that the early adopters won't buy it unless it's different enough to attract attention. The Prius is an example of this way of thinking (both Cd and looking unique).
I personally think we're past the early adopter phase and we need to make sure the BEV looks like any other "normal" car.
Some people like the way the Leaf looks. I can't stand it. Some people hate the way the Bolt looks. I think it looks pretty good.
Consider a Rex like an i3 or a Volt. Around the city, 99% of your driving can be electric only, but if you want to do a road trip you're still getting 40 mpg or better.
BMW claims that some huge percentage of the people that order the i3 with the Rex almost never use it.
Some of this depends on the range of a car. With 110 miles of range (in the summer) with my Honda Fit EV, I was finding that I needed my ICE car about once a month. I figure with a Bolt or Tesla it would be once or twice a year. I'd be willing to rent a car once or twice a year to have an electric vehicle the rest of the time.
Depends on the car. My Honda Fit EV took almost 50% hit on cold weather days here in Boston. That car used resistive heating, having a heat pump like in a Leaf helps somewhat, but there's still lots of range lost. I also notice my ICE car loses range on a tank of gas in the cold weather...
The used market for electric cars is really low, i.e. the original purchaser takes quite a bath when they sell (except for Tesla - they seem to hold their value). If you don't mind buying a used electric to give it a try, the pricing is very affordable.
I bought a 3 year old Chevy Volt with 40,000 miles on it for $11,000. My daughters do 98% of their driving on the battery (about 38 miles worth on a charge) and only buy gas when they want to go on a long trip. So far it's working out very well...
That's a good point. With my Honda Fit EV I would typically have only used 1/2 the charge, so it would only take 90 minutes @ 220v to charge. With 110v that would have probably been 4-5 hours... not nearly as good as 90 minutes, but it would probably work for a lot of situations.
I'm reading all these and I'm really surprised. When I got my Honda Fit EV it came with a 220v charger. I paid my electrician a couple hundred bucks to put a dryer outlet next to my panel, plugged the 220v charger into the dryer outlet and I was done. No environmental study, no hassle. Granted, my panel is in my garage so I didn't have to run a cable the length of my house, so it might be more of a hassle if your panel isn't in the garage, but still...
Do you really have to get an environmental study in Washington State to install a dryer?
I'm also a little surprised to hear people saying their service isn't sufficient to run the extra circuit. I've got an electric dryer, electric oven, well pump, septic pump, AND the circuit for the car in a house built in 1975 (i.e. the service isn't THAT new) and I've never had a problem.
We now have a Chevy Volt (daughter crashed the BEV) and my only complaint is that the Volt takes longer than it should to charge @ 220v... Would love it if GM would sell an upgraded charging system in the Volt that would use more current.
I guess it depends on why you say a step back for consumers.
I much prefer driving a BEV over a gas car. The low amount of noise, the quick acceleration, no lurching as it shifts, and the one pedal driving.
Disadvantage: having to plan refueling. With a big enough battery, that won't be the case for most people. It's pretty rare for the average guy to drive more than 300 miles a day, so most people could just plug in at night and not really worry about it. For those who do drive a lot of miles a day, or end up in places without a charging infrastructure, a Rex like the i3 or Chevy Volt gives you 99% of the advantages of a BEV without having to worry about running out of charge.
I think they're definitely a step ahead for consumers, and will continue to be even better.
There are 3 or 4 companies working on BEV pickups right now, so you shouldn't have to wait too long...
We had a pure BEV which my daughter crashed. I replaced it with a low mileage 2013 Volt for $11,000. For 98% of what my two daughters need, they can do it all on the battery. But, when they want to drive to New Hampshire to the beaches, they can put a few gallons in it and use the gas engine. It gets about 40 mpg which isn't as good as say a Prius, but 98% of the time they're not burning any gas at all (and thus no teenage fights about who needs to fill the tank).
So far I'm very happy with the Volt...
That brings up another point. I like sports cars. I would not consider any of the BEVs out there a sports car. The Model S is a luxury sedan. I'm hoping that the Model 3 will handle well. If not, perhaps BMW will come out with a good handling BEV.
I don't need to scream out at the world I have an electric car, I want something that looks nice, drives well and I can smile smugly to myself when I pass the pumps.
I totally agree with this. I had a Honda Fit EV which was almost indistinguishable from the regular Fit. We now have a Volt which looks just like a Cruze, i.e. nobody realizes these are electric cars.
On the other hand, the Leaf is too fugly for me to want to own one (we'll see what they do with V2), and the i3 is also pretty darn ugly.
Early adopters (which I guess I am) typically want to make a statement, so you end up with something like a Prius that screams "I'm so green!!!".
I think we're past early adopters - it's time for mainstream looks for BEVs that aren't converted gas cars.
I actually like the Chevy Bolt and the Model S and Model 3. I didn't like the nose of the Model 3 when it was first shown, but I guess it's grown on me.
I've always thought we should separate the production of medicines from the discovery of medicines.
Give a bounty for cures. First company/university to create a drug/treatment gets the bounty.
Then license that for production by any/all, i.e. make it dirt cheap to make that available to everybody.
It's immoral to have a cure that could help people, but withhold it from them because they can't afford it.
Um, towards the bottom of the article it mentions "10 times faster" which is probably achievable and probably what they actually are looking for. They even mention that rewriting an inner loop, shaving a few milliseconds off will give a substantial speed increase.
Way back I worked at Alliant Computer Systems (https://en.wikipedia.org/wiki/Alliant_Computer_Systems) which was a hardware/software system that would automatically unroll loops in Fortran code and run them in parallel on up to 8 processors at a time (and each of the 8 also had vector hardware). It was very fast on the right Fortran code... Hardware support for concurrency control when one iteration of the loop depended on a computation from another iteration. All done in custom hardware which was killed (like many supercomputer companies) by the advent of high performance microprocessors.
Why is this such news when Terrafugia has been working on a real flying car for a while now.
Now, how sure am I that it'll ever actually ship. Um, not all that sure. But at least it's a real flying car, compared to this stupid device.
https://www.terrafugia.com/the...