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  • the Stanford solar car

    Every entry always thinks they have the fastest solar-powered car, before the race. My friend Dennis, who directed the solar car entry from Texas A&M when he taught there ten years ago, says "this time it looks like Stanford is right."

    Here are photos of the car, taken (perhaps) on a street near Frank Ford's house.

    http://news.cnet.com/2300-11386_3-10...tag=topStories
    Last edited by aostling; 08-14-2011, 09:56 PM.
    Allan Ostling

    Phoenix, Arizona

  • #2
    That's pretty cool. Seems all the solar cars are stuck using a broad horizontal deck in general to mount the solar cells. Two or three square meters of sunlight would be enough to generate the 1500 watt level they talked about, and that's allowing for 'only' 50 % efficiency. I'd like to see them come up with something other than solar cells to generate the electricity. It's unlikely that the cells they're using are even 25% efficient- couldn't they use say a long parabolic trough, or even a pair of them, with tilting to track the sun, and garner more of the energy of the sun- or also, how about arranging the cells in a corrugated manner and shining the sunlight into the 'pleats'. This would require a special refractive coating on the cells, but could minimize the rejected sun energy as a bonus. Maybe there's another, more efficient way of generating an electron when you 'knock' photons sideways-

    i want to see heat into electricity, not just light into electricity. While we're at it, why not heat into axle rotation, operating in parallel with the electric motor, not just electric propulsion.

    Ah, you got me going a little bit there-
    Last edited by darryl; 08-14-2011, 11:20 PM.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      The amount of engineering that goes into these Solar Challenge cars is amazing, and the competition is fierce. We hired the team lead of the University of Kentucky solar car, which did really well at the Indy Brickyard Race.

      You'll notice the University of Michigan team is dominant in many of the Solar Challenges, including the World Solar Challenge that Allan posted - they have a massive budget sponsored by Detroit. Over a million dollars/year, and a team of over 100 students (!)

      The Indy race coverage, including so closeups of the chassis designs, start at 8:00 in this Discovery Channel article:

      http://watch.discoverychannel.ca/#clip472968
      "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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      • #4
        Using concentrators doesn't make it possible to "garner more energy". It just allows you to use many fewer solar cells although much more expensive ones. You are still limited to the max insolation of about 1000 watts per sq metre.

        For that reason solar cars will never be practical. They are a good test bed for solar energy systems. Much more interesting that a few panels on the roof of the engineering college.
        Free software for calculating bolt circles and similar: Click Here

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        • #5
          There have been teams using fresnel lenses and tilting panels, but I think the rules have changed to disallow them.
          My old university Delft was always using triple junction GaAs solar panels, the last one with an efficiency of 34%. But the rules have also penalised that by allowing less area for GaAs panels.
          So everybody is now back to silicon with something like 22% efficiency......
          It is a lot cheaper though

          Igor

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          • #6
            There is a lot to be gained by having the panels aimed at the sun at the right tilt. I wonder if anyone has considered building a car that can drive in any direction via pivoting wheels with perhaps a saucer shaped body? That wouldn't violate the no tilting rule.
            Free software for calculating bolt circles and similar: Click Here

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            • #7
              Aerodynamics are king in this competition, if your vehicle body is tilted front to back air drag will be enormous.

              This is an example of the lenses + tilting. We donated the actuation system for this car


              Igor

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              • #8
                When are they going to build a practical car, these are of no use what so ever. The rules should be changed to a vehicle that can seat 5 + some cargo and then start developing new usable cars.

                Isn't that what solar car development is suppose to be about.
                The shortest distance between two points is a circle of infinite diameter.

                Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

                Southwestern Ontario. Canada

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                • #9
                  Photo #12 shows the sophistication of the steering. All three wheels must be steerable, else they could not fit within the narrow confines of the cowlings. The rear wheel has two modes, dynamic (for turning) and sailing, in which it can put the vehicle in a crabbed posture to face into angled headwinds.

                  As Evan mentions, solar cannot supply the bulk of the energy needed for a car. The competitions are teaching aids, rather fun I think.
                  Allan Ostling

                  Phoenix, Arizona

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                  • #10
                    Originally posted by loose nut
                    When are they going to build a practical car, these are of no use what so ever. The rules should be changed to a vehicle that can seat 5 + some cargo and then start developing new usable cars.
                    They've tried that, Google had a high efficiency gasoline car competition, but it was boring, and they didn't get many participants.

                    These Solar Challenges are projects for mechanical engineering students, and a solar car has a great combination of engineering and system integration challenges.
                    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                    • #11
                      BTW, this looks like an ideal application for supercaps, if they are allowed. It sure would help with getting up the next hill and keeping the speed up through the shadows.
                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        LOL!! - loose nut - (I don't think they are going to invite you to the party.) Here they are having millions(!) of dollars of fun and you go and get all practical.

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                        • #13
                          while i appreciate the engineering & design that goes into this stuff I must say I think it a major waste of time energy & resources that could be put to better use designing "the next generation" real world transport rather than reinventing the wheel..... which is all this is.

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                          • #14
                            Originally posted by Abner
                            LOL!! - loose nut - (I don't think they are going to invite you to the party.) Here they are having millions(!) of dollars of fun and you go and get all practical.
                            Sorry to be such a downer but in this day and age of the so called "greens" and faced with rapidly dwindling resources, I just think that it is time to start getting something useful from all this experimentation. Redoing the same type of race with basically the same type of cars over and over doesn't do much good. If this is done for training then they need to push the envelope a little more and get something useful out of it.
                            The shortest distance between two points is a circle of infinite diameter.

                            Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

                            Southwestern Ontario. Canada

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                            • #15
                              Originally posted by loose nut
                              Redoing the same type of race with basically the same type of cars over and over doesn't do much good. If this is done for training then they need to push the envelope a little more and get something useful out of it.
                              How is that any different than the MIT mechanical engineering class where they build sumo robots, or robots that climb ropes?

                              Making incremental enhancements to existing products is not a good educational exercise. You have plenty of time to do mindless work when you enter the real world
                              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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