Planet Rugby Forum

...
Anderson: So what have all your creative people come up with, then? What’s different in your basic technology versus 50 years ago?

Musk: I can’t tell you much. We have essentially no patents in SpaceX. Our primary long-term competition is in China—if we published patents, it would be farcical, because the Chinese would just use them as a recipe book. But I can give you one example.

Anderson: What is it?

Musk: It involves the design of the airframe. If you think about it, a rocket is really just a container for the liquid oxygen and fuel—it’s a combination propellant tank and primary airframe. Traditionally, a rocket airframe is made by taking an aluminum plate perhaps a couple of inches thick and machining deep pockets into it. Then you’ll roll or form what’s left into the shape you want—usually sections of a cylinder, since rockets tend to be primarily cylindrical in shape. That’s how Boeing and Lockheed’s rockets are made, and most other rockets too. But it’s a pretty expensive way to do it, because you’re left with a tiny fraction of the plate’s original mass. You’re starting with a huge slab of material and then milling off what isn’t needed, so you get a huge loss of material. Plus, machining away all that metal takes a lot of time, and it’s very expensive.

Anderson: What’s the alternative?

Musk: It’s similar to the way that most airplanes are made: The stiffness is provided by ribs and hoops that are added on.

Anderson: It’s basically aluminum origami—you’re cutting very precise grooves into it so it folds together into a stiff shape.

Musk: But there’s a catch, because you can’t rivet a rocket like you can an airplane. The pressure differential of an airplane—the difference between the internal and external pressure during flight—is perhaps 7 to 10 psi. But in the case of a rocket, it’s likely to be 80 psi. It’s a lot harder for rivets to withstand that pressure with no leaks.

Anderson: Right.

Musk: So the approach used for aircraft is not exactly feasible for rockets. But there’s another way to do it, which is to use an advanced welding technology called stir welding. Instead of riveting the ribs and hoops, you use a special machine that softens the metal on both sides of the joint without penetrating it or melting it. Unlike traditional welding, which melts and potentially compromises some metals, this process works well with high-strength aluminum alloys. You wind up with a stiffer, lighter structure than was possible before. And your material loss is maybe 10 percent, just for trimming the edges. Instead of a ratio of purchased to flown material—what they call the “buy to fly” ratio—of maybe 10 to 20, you have a ratio of 1.1, 1.2 tops.

Anderson: Wow. Why can you tell us about that?

Musk: The reason I can talk about it is that nobody else knows how to build a rocket this way. [Laughs.]
...

DOB wrote:FA, 100-110 years ago, the same graph would have shown Horse-powered vehicles in the place of cars, and cars in the place of EVs.

bimboman wrote:

DOB wrote:FA, 100-110 years ago, the same graph would have shown Horse-powered vehicles in the place of cars, and cars in the place of EVs.

Except the analogy would make more sense if the Horse drawn vehicle was replaced by one drawn by Donkeys....

The Man Without Fear wrote:

bimboman wrote:

DOB wrote:FA, 100-110 years ago, the same graph would have shown Horse-powered vehicles in the place of cars, and cars in the place of EVs.

Except the analogy would make more sense if the Horse drawn vehicle was replaced by one drawn by Donkeys....

Although the donkeys were about a thousand times more reliable, luxurious and just as fast as early motor cars, which made Heath Robinson look like a paragon of efficient design.

Motor Trend Magazine wrote:It may very well be the most important new car since the Model T

TheBouncer wrote:Bloomberg did a great doc on Musk a while ago, part of a series on serial entrepreneurs...


Phenomenal talent.

slow wing wrote:Opportune timing to be having this discussion now on the historical importance of electric cars, as Motor Trend Magazine has just offered this opinion on the Tesla Model S...

Motor Trend Magazine wrote:It may very well be the most important new car since the Model T

Here's the video that quote is from...
2013 Tesla Model S - The Quickest Sedan Built in America - Ignition Episode 38 - YouTube, 7m55s

merlin the happy pig wrote:See here for wireless charging.

http://news.bbc.co.uk/2/hi/programmes/c ... 708468.stm

Though the video doesn't state it explicitly, using a little imagination you could install these at traffic lights.
As you approach an electronic handshake could tell the charger your details so that you can be debited while charging.
Efficiency of 90% which is as good as plugging a battery into the mains

Another possibility is for motorways and main trunk roads to include inductive charging while moving,
The induction efficiency is lower for a moving vehicle but a mitigating factor is that it can directly power the motor avoiding the losses in the charge/discharge cycle.

Geek wrote:Maybe there's been a dramatic breakthrough in inductive charging in the last year but I doubt it. I saw some presentations from researchers working at the cutting edge of this technology in late 2010 and the efficiencies they were discussing for charging over these kinds of distances were certainly not in the 90% range. I wonder what power per unit area is being transfered at those efficiencies and how small the transmitter is relative to the receiver.

Magne Charge is a largely obsolete inductive charging system, also known as J1773, used to charge battery electric vehicles (BEV) formerly made by General Motors, for vehicles such as the EV1, Chevy S10 EV, and other electric vehicles.[citation needed] It was produced by the General Motors subsidiary Delco Electronics.[1] It is still used by a few hundred first generation Toyota RAV4 EV electric vehicles. ...

Researchers in Korea reportedly are already working on an electric bus powered by a continuous inductive connection with a cable buried in the road.

The scenario of induction highways that allow EVs to make intercity journeys without stopping to recharge may no longer be the stuff of science fiction.

slow wing wrote:P.S. that last item looks dodgy to me. A buried cable isn't going to do the trick with any sort of efficiency, unless I am missing something.

slow wing wrote:Bobby Bobson, so what would you use for highway charging? How much power could it transfer and at what efficiency?


The trouble with a 2-dimensional transmitter is that it is only going to be aligned for a small fraction of a second. Insurmountable?

bobbybobson wrote:

merlin the happy pig wrote:See here for wireless charging.

http://news.bbc.co.uk/2/hi/programmes/c ... 708468.stm

Though the video doesn't state it explicitly, using a little imagination you could install these at traffic lights.
As you approach an electronic handshake could tell the charger your details so that you can be debited while charging.
Efficiency of 90% which is as good as plugging a battery into the mains

Another possibility is for motorways and main trunk roads to include inductive charging while moving,
The induction efficiency is lower for a moving vehicle but a mitigating factor is that it can directly power the motor avoiding the losses in the charge/discharge cycle.

Not quite, a wireless charging system will have all of the losses of a system with a physical connection as well as the magnetic losses associated with transferring power across the air gap between the primary and secondary coils (basically like a transformer without a core). But the magnetic losses are not particularly substantial so the difference isn't all that great. I certainly think that wireless charging is something which will become a commercial reality in residential settings (i.e. instead of plugging your car into the mains, you park it over a charging pad), although roadway powered IPT systems are probably a lot further off for a number of reasons.

merlin the happy pig wrote:

bobbybobson wrote:

merlin the happy pig wrote:See here for wireless charging.

http://news.bbc.co.uk/2/hi/programmes/c ... 708468.stm

Though the video doesn't state it explicitly, using a little imagination you could install these at traffic lights.
As you approach an electronic handshake could tell the charger your details so that you can be debited while charging.
Efficiency of 90% which is as good as plugging a battery into the mains

Another possibility is for motorways and main trunk roads to include inductive charging while moving,
The induction efficiency is lower for a moving vehicle but a mitigating factor is that it can directly power the motor avoiding the losses in the charge/discharge cycle.

Not quite, a wireless charging system will have all of the losses of a system with a physical connection as well as the magnetic losses associated with transferring power across the air gap between the primary and secondary coils (basically like a transformer without a core). But the magnetic losses are not particularly substantial so the difference isn't all that great. I certainly think that wireless charging is something which will become a commercial reality in residential settings (i.e. instead of plugging your car into the mains, you park it over a charging pad), although roadway powered IPT systems are probably a lot further off for a number of reasons.

My apology, near as good as.

As for mobile recharging, there has been quite a bit of research into powered roads in Korea.
http://www.reuters.com/article/2009/05/ ... 7U20090517

This is the only one I could find at short notice.
The efficiency doesn't approach that of stationary charging at this point (I heard 75%) and I'm not sure what the theoretical limits would be.
However as I stated before, one advantage of drawing power directly from the road is that you don't have to charge/recharge the battery which itself is maybe 90% efficient resulting in .9 x .9 = .81 for charge/discharge.

The other upside of course would be smaller batteries, lighter cars.

Agree with your comment, this is a lot further in the future and may not occur at all.

bobbybobson wrote:

slow wing wrote:Bobby Bobson, so what would you use for highway charging? How much power could it transfer and at what efficiency?


The trouble with a 2-dimensional transmitter is that it is only going to be aligned for a small fraction of a second. Insurmountable?

I know that inductive power transfer systems have been developed for operation at ~100 kW, however that is with a significantly smaller airgap than for EVs. I believe that the systems currently being developed (for both stationary battery charging and roadway powered EVs) are in the range of 10s of kW. Because most of the losses occur in the power conversion rather than the power transfer I (roughly estimate) that efficiencies of 80 - 90% are realistic. Rather than using a 'cable', the systems being developed at the moment are based on a series of transmitter 'pads' in the roadway, which offer a far more even flux distribution (and one which can be better directed towards a similarly desinged receiver pad) than that of a cable. Moreover, they seem to show reasonable resilience to misalignment which is inevitable in a roadway setting.

Edit: Turns out that the systems I am thinking of (based on pads) are in the range of < 10 kW..

bobbybobson wrote:

merlin the happy pig wrote:

bobbybobson wrote:

merlin the happy pig wrote:See here for wireless charging.

http://news.bbc.co.uk/2/hi/programmes/c ... 708468.stm

Though the video doesn't state it explicitly, using a little imagination you could install these at traffic lights.
As you approach an electronic handshake could tell the charger your details so that you can be debited while charging.
Efficiency of 90% which is as good as plugging a battery into the mains

Another possibility is for motorways and main trunk roads to include inductive charging while moving,
The induction efficiency is lower for a moving vehicle but a mitigating factor is that it can directly power the motor avoiding the losses in the charge/discharge cycle.

Not quite, a wireless charging system will have all of the losses of a system with a physical connection as well as the magnetic losses associated with transferring power across the air gap between the primary and secondary coils (basically like a transformer without a core). But the magnetic losses are not particularly substantial so the difference isn't all that great. I certainly think that wireless charging is something which will become a commercial reality in residential settings (i.e. instead of plugging your car into the mains, you park it over a charging pad), although roadway powered IPT systems are probably a lot further off for a number of reasons.

My apology, near as good as.

As for mobile recharging, there has been quite a bit of research into powered roads in Korea.
http://www.reuters.com/article/2009/05/ ... 7U20090517

This is the only one I could find at short notice.
The efficiency doesn't approach that of stationary charging at this point (I heard 75%) and I'm not sure what the theoretical limits would be.
However as I stated before, one advantage of drawing power directly from the road is that you don't have to charge/recharge the battery which itself is maybe 90% efficient resulting in .9 x .9 = .81 for charge/discharge.

The other upside of course would be smaller batteries, lighter cars.

Agree with your comment, this is a lot further in the future and may not occur at all.

There is actually a lot of research happening in NZ with regard to wireless power transfer for both EV and industrial applications - http://www.qualcommhalo.com/ - a spin-off company from the Univeristy of Auckland, was recently acquired by Qualcomm. I think they are looking into both stationary charging and roadway charged/powered vehicles..

merlin the happy pig wrote:

bobbybobson wrote:

slow wing wrote:Bobby Bobson, so what would you use for highway charging? How much power could it transfer and at what efficiency?


The trouble with a 2-dimensional transmitter is that it is only going to be aligned for a small fraction of a second. Insurmountable?

I know that inductive power transfer systems have been developed for operation at ~100 kW, however that is with a significantly smaller airgap than for EVs. I believe that the systems currently being developed (for both stationary battery charging and roadway powered EVs) are in the range of 10s of kW. Because most of the losses occur in the power conversion rather than the power transfer I (roughly estimate) that efficiencies of 80 - 90% are realistic. Rather than using a 'cable', the systems being developed at the moment are based on a series of transmitter 'pads' in the roadway, which offer a far more even flux distribution (and one which can be better directed towards a similarly desinged receiver pad) than that of a cable. Moreover, they seem to show reasonable resilience to misalignment which is inevitable in a roadway setting.

Edit: Turns out that the systems I am thinking of (based on pads) are in the range of < 10 kW..

For a pertol vehicle at a steady 100km/hr doing 10L/100km this means assuming 20% efficiency and 35 Mj/L in petrol the such a car uses a steady 20kw.
A smaller vehicle like a leaf would do 6L/100km or so and would need just over 10kw.

Haven't got time to check my maths, may come back to general derision if I got it wrong.

merlin the happy pig wrote:

bobbybobson wrote:

merlin the happy pig wrote:

bobbybobson wrote:

merlin the happy pig wrote:See here for wireless charging.

http://news.bbc.co.uk/2/hi/programmes/c ... 708468.stm

Though the video doesn't state it explicitly, using a little imagination you could install these at traffic lights.
As you approach an electronic handshake could tell the charger your details so that you can be debited while charging.
Efficiency of 90% which is as good as plugging a battery into the mains

Another possibility is for motorways and main trunk roads to include inductive charging while moving,
The induction efficiency is lower for a moving vehicle but a mitigating factor is that it can directly power the motor avoiding the losses in the charge/discharge cycle.

Not quite, a wireless charging system will have all of the losses of a system with a physical connection as well as the magnetic losses associated with transferring power across the air gap between the primary and secondary coils (basically like a transformer without a core). But the magnetic losses are not particularly substantial so the difference isn't all that great. I certainly think that wireless charging is something which will become a commercial reality in residential settings (i.e. instead of plugging your car into the mains, you park it over a charging pad), although roadway powered IPT systems are probably a lot further off for a number of reasons.

My apology, near as good as.

As for mobile recharging, there has been quite a bit of research into powered roads in Korea.
http://www.reuters.com/article/2009/05/ ... 7U20090517

This is the only one I could find at short notice.
The efficiency doesn't approach that of stationary charging at this point (I heard 75%) and I'm not sure what the theoretical limits would be.
However as I stated before, one advantage of drawing power directly from the road is that you don't have to charge/recharge the battery which itself is maybe 90% efficient resulting in .9 x .9 = .81 for charge/discharge.

The other upside of course would be smaller batteries, lighter cars.

Agree with your comment, this is a lot further in the future and may not occur at all.

There is actually a lot of research happening in NZ with regard to wireless power transfer for both EV and industrial applications - http://www.qualcommhalo.com/ - a spin-off company from the Univeristy of Auckland, was recently acquired by Qualcomm. I think they are looking into both stationary charging and roadway charged/powered vehicles..

Thanks for the linky

bobbybobson wrote:

Geek wrote:Maybe there's been a dramatic breakthrough in inductive charging in the last year but I doubt it. I saw some presentations from researchers working at the cutting edge of this technology in late 2010 and the efficiencies they were discussing for charging over these kinds of distances were certainly not in the 90% range. I wonder what power per unit area is being transfered at those efficiencies and how small the transmitter is relative to the receiver.

The problem is not efficiency but the fact that the power which can be transferred across an air-gap (especially a relatively wide one as is the case with EVs) is relatively low. The challenge is not to improve efficiency (wireless charging systems are actually very efficient) but to improve coupling between the primary and secondary.

merlin the happy pig wrote:

Geek wrote: It would be nice to believe you are right but I don't think you are. The ability to automatically drive a car and avoid randomly moving objects is extremely difficult to accomplish. There are various robotics programs aimed precisely in this area and they are currently limited to very slow speeds and very small operating distances. It is certainly not ready for primetime and won't be for many years yet.

The google driverless car use only LIDAR and hs driven 300,000km in normal traffic with no incidents.
(except the crash when the human occupant was in charge)
The environment is far from random, especially as it will become less so once most vehicles are automated. In the interim they can run automated on bus lanes and manual elsewhere unil they prove their reliability.

The task is not anywhere near requiring general intelligence, avoiding pedestrians and other vehicles is not really that hard.
They will also have access to information that humans don't. Other cars can transmit hazard data almost instantly, including pedestrians, potholes, crashes, snow an ice.

But don't take my word for it, read the article.

It also doesn't need to be perfect, only a lot better than human drivers which in truth isn't asking a lot.

The only downside I can see is an end to autodarwination of a few westies.

Geek wrote:

merlin the happy pig wrote:

Geek wrote: It would be nice to believe you are right but I don't think you are. The ability to automatically drive a car and avoid randomly moving objects is extremely difficult to accomplish. There are various robotics programs aimed precisely in this area and they are currently limited to very slow speeds and very small operating distances. It is certainly not ready for primetime and won't be for many years yet.

The google driverless car use only LIDAR and hs driven 300,000km in normal traffic with no incidents.
(except the crash when the human occupant was in charge)
The environment is far from random, especially as it will become less so once most vehicles are automated. In the interim they can run automated on bus lanes and manual elsewhere unil they prove their reliability.

The task is not anywhere near requiring general intelligence, avoiding pedestrians and other vehicles is not really that hard.
They will also have access to information that humans don't. Other cars can transmit hazard data almost instantly, including pedestrians, potholes, crashes, snow an ice.

But don't take my word for it, read the article.

It also doesn't need to be perfect, only a lot better than human drivers which in truth isn't asking a lot.

The only downside I can see is an end to autodarwination of a few westies.

Just remembered this discussion.

The Google car does not just use LIDAR, it uses a variety of sensors and then compares the outputs. The "autonomous" driving of these cars has not been logged in traffic in inner cities as far as I know but on quiet roads in the middle of nowhere. Even the KPMG report you seem to love doesn't back up your suggestions - look at pages 12 and 13 in particular. As for hard science we are some way off having a system which can respond to randomly moving pedestrians (and more importantly predict them) in the same manner as a human mind. People massively underestimate the complexity of the human mind and the extraordinary job it does when planning automated systems to replace human thinking. Driving on a motorway is certainly far more achievable for these driver assist aids, but not inner city driving. Not for quite some time.

Geek wrote:

bobbybobson wrote:

Geek wrote:Maybe there's been a dramatic breakthrough in inductive charging in the last year but I doubt it. I saw some presentations from researchers working at the cutting edge of this technology in late 2010 and the efficiencies they were discussing for charging over these kinds of distances were certainly not in the 90% range. I wonder what power per unit area is being transfered at those efficiencies and how small the transmitter is relative to the receiver.

The problem is not efficiency but the fact that the power which can be transferred across an air-gap (especially a relatively wide one as is the case with EVs) is relatively low. The challenge is not to improve efficiency (wireless charging systems are actually very efficient) but to improve coupling between the primary and secondary.

Sorry are you talking about inductive or radiative charging? For inductive coupling is precisely the problem across an air gap of any significance, particularly as you increase the power per unit area - the efficiency of transfer plummets. Basically more of the magnetic field generated in the transmission coil will miss the receiver coil as the gap is increased. Has the University of Auckland published any papers which propose a solution to this problem?

2013 Automobile of the Year: Tesla Model S
From our January, 2013 issue / By David Zenlea / Photos by A. J. Mueller

...this year's field was the strongest in recent memory. We weren't expecting much from the Tesla other than some interesting dinner conversation as we considered "real" candidates like the Subaru BRZ and the Porsche Boxster. In fact, the Tesla blew them, and us, away. ...

Tesla reaches ‘turning point,’ promises mass production for 2013


November 5, 2012 6:56 PM
Dylan Tweney
...

2013 Motor Trend Car of the Year: Tesla Model S
Shocking Winner: Proof Positive that America Can Still Make (Great) Things
By Angus MacKenzie | Photos By Andrew Yeadon, Motor Trend Staff | January, 2013 |

The 2013 Motor Trend Car of the Year is one of the quickest American four-doors ever built. It drives like a sports car, eager and agile and instantly responsive. But it's also as smoothly effortless as a Rolls-Royce, can carry almost as much stuff as a Chevy Equinox, and is more efficient than a Toyota Prius. Oh, and it'll sashay up to the valet at a luxury hotel like a supermodel working a Paris catwalk. By any measure, the Tesla Model S is a truly remarkable automobile, perhaps the most accomplished all-new luxury car since the original Lexus LS 400. That's why it's our 2013 Car of the Year.
...