In its simplest incantation, work, or energy, equals force multiplied by distance.
Distance travelled: d = 0. W = F*d. Even lim(W, F->infinity) = 0 if distance travelled, d = 0. You can get energy out of the magnet only by moving it. Oh, sure - let's hold the magnet away from the fridge a centimeter, and let go. It moved - non-zero work! Except we had to expend energy to move the magnet that first centimeter.
And since I'm at it already:
- I won't mention the thermodynamics arguements many have already posted about
- It doesn't matter how many newtons of force a motor statically exerts - 1N or 1000000N - it's not linked to efficiency.
- The best way to measure efficiency is by a dynamometer. Versions I've worked with basically are generators which you directly hook up your test motor to. Knowing the properties of the generator (efficiency model, etc) you can figure out how much energy your motor is outputting versus how much energy you're putting into running the motor. You can find efficiency curves for any motor design you wish by spending some time with google. Why doesn't Flynn's website provide these? Don't give me any bull about patents; novel motor configurations are common.
- Despite its flaws, the peer-review journal system is still the most rigorous method of testing science. I don't need to search Science's website to tell you that "parallel path technology" will return 0 results.
- While racing solar cars, I've encountered motors running anywhere between 80 to 98% efficiency. That's efficiency defined in the traditional sense: mechanical power out divided by electrical power in. I found it funny that Flynn is trying to convince solar car teams to try out his motor design.
Give me some steel tubing, enough calculator solar cells, an electric lawnmower and my Swiss Army knife, and I'm sure I get farther in WSC2007 than Flynn. (Interestingly, the parallel path wiki says it can reduce solar cell surface area by 50%! Tell that to anyone who's raced a solar car and see how quickly they laugh)
Interestingly, the crash/fatality ratio of solar cars is less than that of the crash/fatality ratio of the space shuttle.
Solar car racing became known in the early 80's, and since then hundreds of solar cars have been built. This is the first fatality involving a solar car ever. Although Andrew, Blue Sky, and the many others affected by the crash may not feel this way right now, that's a hell of a record; not even NASA, with its amazing force of experienced engineers has managed that. (2 fatal errors in just over 100 flights for NASA, compared to 1 fatal error in much more than 100 (even probably much more than 1000) long-distance drives for solar cars)
Let's stop speculating; an investigation is under way so you'll hear about why it happened soon enough. It's disrepectful to everyone involved in the crash, as well as to all the engineers and engineering students involved in projects such as this.
Statistically, solar car teams are safer than your average driver. It's a tragedy what has happened, and let's just leave it at that. Besides, from the comments I've read, most people here don't even have adequate knowledge to make even the smallest judgement call regarding solar cars and their safety.
Just to further my comments, I'm not saying that it _wasn't_ crosswinds, I just don't think that we should speculate until an investigation has determined the cause of the crash.
This is actually false. Crosswinds are a big problem that we have to deal with. I seem to recall at least one solar car being restricted to slower speeds during the American Solar Challenge in 2003 (which, U of T / Blue Sky completed the 3600 km just fine) due to bad performance in crosswinds.
Again, I cannot speak for the U of T team but on our solar car, performance in crosswinds was taken into consideration during the design and in Australia, we drove past many "willy nillies" (dust storms resembing small tornadoes) with no problem. The U of T team did race ASC 2003 using the solar car which was involved in the accident without serious crosswinds problems, though a different situation may have happened Thursday. I don't know. I don't have enough information to make an educated conclusion. In fact, I think that applies to almost everyone here. And as a further hint, I think I may have more information than the typical masses here. (Though it does look like a lot of solar car racers are reading this - hello!)
From the side, well designed solar cars are much more aerodynamic than bricks. (Even the worst-designed solar car is probably more aerodynamic than the holes in some of the people's heads here who have posted blatantly wrong information, while trying to be the expert.)
Although it may not look like it to someone not versed in aerodynamics, a well designed solar car handles crosswinds fairly well - you might not be able to jump straight into the driver's seat of a solar car without training, but our trained drivers had little problem.
There are two types of three wheeled designs. Single wheel forward and single wheel back. 3 wheeled ATVs had a single wheel forward, unless I am mistaken. Single wheel forward designs are less stable than the design employed by the University of Toronto, and many other solar car teams: 1 rear wheel, and 2 forward wheels which steer. I wasn't the mechanical manager of my solar car team, but my understanding is that this is a stable design and much different than the single wheel forward design. There are some solar cars which do use the single wheel forward design, and have, handling-wise, performed exceedingly well. Aurora 101 of Australia is the chief example. More design & test work is required to ensure the safety of a difficult design such as theirs, but it is possible.
Anyways, my point is, the University of Toronto team is not using what you would consider the three wheeled design that ATVs used to use.
On the contrary, solar car teams try their utmost to ensure the safety of the driver. Here's a list of some of the things we did to ensure the safety of the Queen's car:
- Finite element analysis is used to model the structure of the solar car with forces similar to those experienced in crashs. (Structural reports are mandatory for the American Solar Challenge)
- Destructive testing of mechanical and structural elements is performed
- Battery ventiliation was incorporated, and the batteries sealed, to prevent release of HF
(hydrogen-floride, you won't see much lithium gas around) gas from our Li-ion-poly batteries
- Battery shutdown circuitry
- Emergency-stop switches, operable from the exterior and interior of the vehicle, to disable all sources of electricity
- Roll-cage for rollover protection
- Modelling of winds experienced using computation fluid dynamics software as well as wind-tunnel testing
The engineering students involved in these solar vehicles use every tool available to them to ensure the safety of their vehicles. Remember that these are vehicles that their team members, and often themselves, are going to to be driving in.
In the end though, as hard as you try, accidents are inevitable. Like our faculty advisor pointed out numerous times, it's a matter of probability, and the law of large numbers. Even though the probability is small, if solar cars are driven for enough hours, then something is bound to happen.
Here's a thought --
"For my assured failures and derelictions, I ask pardon beforehand of my betters and my equals in my Calling here assembled; praying that in the hour of my temptations, weakness and weariness, the memory of this my Obligation and of the company before whom it was entered into, may return to me to aid, comfort and restrain."
Let's stop bashing the solar car and their designers for a second, and as all the engineers who are reading this (especially the Canadian ones, who will recognize the above quote) most likely are doing now, let's aid and comfort those who were involved instead of telling second-hand stories on how unsafe these vehicles are. True, they're not as safe as your family sedan, but they're driving under different conditions too.
As for the other posts, if you want to talk about the pros and cons of Hummers and bikes, start a new thread. Let's respect what happened yesterday. I for one will be mourning someone who I didn't know well, but it could have been anyone - either in a solar car or on a bike, or even in a car.
Ben Esposito was speaking for the UWO solar car.
I have seen solar cars use 'traditional' steering similar to a gas automobile, tank steering, paddle steering, etc. Most of these methods actually don't differ by much - you are still converting an applied force into a change of steering angle. It doesn't matter if it's a stick, two sticks, steering wheel, or some other contraption.
Each solar car is designed by a different team who choose their steering mechanisms for different reasons, though safety is always ranked first. I know of no engineer who would design a solar car with an intrinsically unsafe steering system and then put their team-mates (and often themselves) into the car.
Let's keep a handle on the accusations on what caused the crash - I've read speculation on the fact that it was crosswinds, to sun in the driver's eyes, to driver error, to design error, to mechanical problems - until an investigation has been completed into what caused the accident, I think it's best not to make immature conclusions. Speculation has a habit of quickly turning into "a reliable source says..."
Experimental licenses, like the ones we use to drive our solar cars, do not allow us on 400 series highways. If I understand correctly, the accident was on Highway 7 west of Waterloo, which is similar to many city roads that you drive on daily.
And again, as for street legality, I will repeat the motorcycle argument as not only has it appeared here, but it has been used in considering safety during the design of many solar cars. I would posit that in most crash situations, a solar car is safer than a motorcycle.
Please note that at this point, a detailed investigation into the causes of the crash has not been completed yet. To say that "the design of the car was bad..." is out of line. Many, or one, different cause(s) may have contributed to the crash. As with all solar car teams, the University of Toronto engineering students involved in the building of their solar car did their best to design the car and protect the driver from as many situations as possible.
Unfortunately, as many engineers realize, despite the fact that you put all your effort into ensuring the safety of your design, something may invevitably go wrong.
My sympathy goes out to the U of T team, families, and all those involved in the crash.
-- Ron Yeung (Queen's University Solar Vehicle Team Alumni)
Slashdot Mirror
To elaborate on the magnet on the fridge analogy:
In its simplest incantation, work, or energy, equals force multiplied by distance.
Distance travelled: d = 0. W = F*d. Even lim(W, F->infinity) = 0 if distance travelled, d = 0. You can get energy out of the magnet only by moving it. Oh, sure - let's hold the magnet away from the fridge a centimeter, and let go. It moved - non-zero work! Except we had to expend energy to move the magnet that first centimeter.
And since I'm at it already:
- I won't mention the thermodynamics arguements many have already posted about
- It doesn't matter how many newtons of force a motor statically exerts - 1N or 1000000N - it's not linked to efficiency.
- The best way to measure efficiency is by a dynamometer. Versions I've worked with basically are generators which you directly hook up your test motor to. Knowing the properties of the generator (efficiency model, etc) you can figure out how much energy your motor is outputting versus how much energy you're putting into running the motor. You can find efficiency curves for any motor design you wish by spending some time with google. Why doesn't Flynn's website provide these? Don't give me any bull about patents; novel motor configurations are common.
- Despite its flaws, the peer-review journal system is still the most rigorous method of testing science. I don't need to search Science's website to tell you that "parallel path technology" will return 0 results.
- While racing solar cars, I've encountered motors running anywhere between 80 to 98% efficiency. That's efficiency defined in the traditional sense: mechanical power out divided by electrical power in. I found it funny that Flynn is trying to convince solar car teams to try out his motor design.
Give me some steel tubing, enough calculator solar cells, an electric lawnmower and my Swiss Army knife, and I'm sure I get farther in WSC2007 than Flynn. (Interestingly, the parallel path wiki says it can reduce solar cell surface area by 50%! Tell that to anyone who's raced a solar car and see how quickly they laugh)
Interestingly, the crash/fatality ratio of solar cars is less than that of the crash/fatality ratio of the space shuttle. Solar car racing became known in the early 80's, and since then hundreds of solar cars have been built. This is the first fatality involving a solar car ever. Although Andrew, Blue Sky, and the many others affected by the crash may not feel this way right now, that's a hell of a record; not even NASA, with its amazing force of experienced engineers has managed that. (2 fatal errors in just over 100 flights for NASA, compared to 1 fatal error in much more than 100 (even probably much more than 1000) long-distance drives for solar cars) Let's stop speculating; an investigation is under way so you'll hear about why it happened soon enough. It's disrepectful to everyone involved in the crash, as well as to all the engineers and engineering students involved in projects such as this. Statistically, solar car teams are safer than your average driver. It's a tragedy what has happened, and let's just leave it at that. Besides, from the comments I've read, most people here don't even have adequate knowledge to make even the smallest judgement call regarding solar cars and their safety.
Just to further my comments, I'm not saying that it _wasn't_ crosswinds, I just don't think that we should speculate until an investigation has determined the cause of the crash.
This is actually false. Crosswinds are a big problem that we have to deal with. I seem to recall at least one solar car being restricted to slower speeds during the American Solar Challenge in 2003 (which, U of T / Blue Sky completed the 3600 km just fine) due to bad performance in crosswinds.
Again, I cannot speak for the U of T team but on our solar car, performance in crosswinds was taken into consideration during the design and in Australia, we drove past many "willy nillies" (dust storms resembing small tornadoes) with no problem. The U of T team did race ASC 2003 using the solar car which was involved in the accident without serious crosswinds problems, though a different situation may have happened Thursday. I don't know. I don't have enough information to make an educated conclusion. In fact, I think that applies to almost everyone here. And as a further hint, I think I may have more information than the typical masses here. (Though it does look like a lot of solar car racers are reading this - hello!)
From the side, well designed solar cars are much more aerodynamic than bricks. (Even the worst-designed solar car is probably more aerodynamic than the holes in some of the people's heads here who have posted blatantly wrong information, while trying to be the expert.)
Although it may not look like it to someone not versed in aerodynamics, a well designed solar car handles crosswinds fairly well - you might not be able to jump straight into the driver's seat of a solar car without training, but our trained drivers had little problem.
There are two types of three wheeled designs. Single wheel forward and single wheel back. 3 wheeled ATVs had a single wheel forward, unless I am mistaken. Single wheel forward designs are less stable than the design employed by the University of Toronto, and many other solar car teams: 1 rear wheel, and 2 forward wheels which steer. I wasn't the mechanical manager of my solar car team, but my understanding is that this is a stable design and much different than the single wheel forward design. There are some solar cars which do use the single wheel forward design, and have, handling-wise, performed exceedingly well. Aurora 101 of Australia is the chief example. More design & test work is required to ensure the safety of a difficult design such as theirs, but it is possible.
Anyways, my point is, the University of Toronto team is not using what you would consider the three wheeled design that ATVs used to use.
On the contrary, solar car teams try their utmost to ensure the safety of the driver. Here's a list of some of the things we did to ensure the safety of the Queen's car: - Finite element analysis is used to model the structure of the solar car with forces similar to those experienced in crashs. (Structural reports are mandatory for the American Solar Challenge) - Destructive testing of mechanical and structural elements is performed - Battery ventiliation was incorporated, and the batteries sealed, to prevent release of HF (hydrogen-floride, you won't see much lithium gas around) gas from our Li-ion-poly batteries - Battery shutdown circuitry - Emergency-stop switches, operable from the exterior and interior of the vehicle, to disable all sources of electricity - Roll-cage for rollover protection - Modelling of winds experienced using computation fluid dynamics software as well as wind-tunnel testing The engineering students involved in these solar vehicles use every tool available to them to ensure the safety of their vehicles. Remember that these are vehicles that their team members, and often themselves, are going to to be driving in. In the end though, as hard as you try, accidents are inevitable. Like our faculty advisor pointed out numerous times, it's a matter of probability, and the law of large numbers. Even though the probability is small, if solar cars are driven for enough hours, then something is bound to happen. Here's a thought -- "For my assured failures and derelictions, I ask pardon beforehand of my betters and my equals in my Calling here assembled; praying that in the hour of my temptations, weakness and weariness, the memory of this my Obligation and of the company before whom it was entered into, may return to me to aid, comfort and restrain." Let's stop bashing the solar car and their designers for a second, and as all the engineers who are reading this (especially the Canadian ones, who will recognize the above quote) most likely are doing now, let's aid and comfort those who were involved instead of telling second-hand stories on how unsafe these vehicles are. True, they're not as safe as your family sedan, but they're driving under different conditions too. As for the other posts, if you want to talk about the pros and cons of Hummers and bikes, start a new thread. Let's respect what happened yesterday. I for one will be mourning someone who I didn't know well, but it could have been anyone - either in a solar car or on a bike, or even in a car.
Ben Esposito was speaking for the UWO solar car. I have seen solar cars use 'traditional' steering similar to a gas automobile, tank steering, paddle steering, etc. Most of these methods actually don't differ by much - you are still converting an applied force into a change of steering angle. It doesn't matter if it's a stick, two sticks, steering wheel, or some other contraption. Each solar car is designed by a different team who choose their steering mechanisms for different reasons, though safety is always ranked first. I know of no engineer who would design a solar car with an intrinsically unsafe steering system and then put their team-mates (and often themselves) into the car. Let's keep a handle on the accusations on what caused the crash - I've read speculation on the fact that it was crosswinds, to sun in the driver's eyes, to driver error, to design error, to mechanical problems - until an investigation has been completed into what caused the accident, I think it's best not to make immature conclusions. Speculation has a habit of quickly turning into "a reliable source says..."
Experimental licenses, like the ones we use to drive our solar cars, do not allow us on 400 series highways. If I understand correctly, the accident was on Highway 7 west of Waterloo, which is similar to many city roads that you drive on daily. And again, as for street legality, I will repeat the motorcycle argument as not only has it appeared here, but it has been used in considering safety during the design of many solar cars. I would posit that in most crash situations, a solar car is safer than a motorcycle.
Please note that at this point, a detailed investigation into the causes of the crash has not been completed yet. To say that "the design of the car was bad..." is out of line. Many, or one, different cause(s) may have contributed to the crash. As with all solar car teams, the University of Toronto engineering students involved in the building of their solar car did their best to design the car and protect the driver from as many situations as possible. Unfortunately, as many engineers realize, despite the fact that you put all your effort into ensuring the safety of your design, something may invevitably go wrong. My sympathy goes out to the U of T team, families, and all those involved in the crash. -- Ron Yeung (Queen's University Solar Vehicle Team Alumni)