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Aussie Team Smashes Land Speed Record For Solar-Powered Cars
snowdon writes "A record which has stood since 1987, set by General Motors, has been broken (YouTube video) by a university team. The land speed record for a solar powered car was 78km/h, and now stands at 88km/h despite the cloudy conditions... If only Doc Brown had used the metric system!"
The car in TFA didn't have a battery. The solar panels are connected directly to the drive train/motor(s).
The difference is the WSC cars are allowed to use a battery - the rules for the Guinness World Record specify solar power only.
In the 2009 WSC the UNSW car reached 103km/h with a LiPol battery, but that was removed for this attempt to comply with the Guinness rules.
What part of "a well regulated militia" do you not understand?
Both vehicles have about 25kG of batteries. The difference: Sunswift 4 was operating only off solar power, whereas Nuna was in a race where batteries were not only allowed, but required (the race was over several days.) Nuna had both solar and battery power for acceleration.
Please help metamoderate.
I can tell you the World Solar Challenge rules. (The SunSwift car depicted looks like it follows WSC Challenge class rules.) There are safety requirements for roll cage, braking, steering, wiring, circuit breakers. The driver's eye-line must be at least 70cm above the road. There's a maximum angle the driver is allowed to lay back at. There's a max of 6 square meters of solar cells. The battery is a max of 5kW.h. (This is a trivial amount of energy compared to the energy budget over the whole challenge, but is tactically useful for hill climbing, clouds, etc.)
It looks like the only change they made for this Guinness challenge was to remove the battery pack.
Yes, it looks like the 2003, 2005, 2009 WSC challenge winners (Nuna, Nuna, Tokai) could have knocked this record over, just by removing the battery pack and getting Guinness certification. Doing some rough maths, UNSW's pace is still pretty competitive: the speeds you see listed for WSC course competition do not figure in the time the cars spent charging their batteries each dawn and dusk, after racing ends at 5pm for the day and before it begins at 8am the next day.
It would be awesome if we could have made it thinner -- the wing is there as the lowest-drag shape that we can put around the other components in the car -- suspension, steering, driver, etc. Its designed to be a lifting body because of the ground effect which would otherwise result in a negative lift. The cambered wing counters the negative lift generated by the ground effect.
At the time the movie was made, the giga prefix wasn't in popular use except in certain scientific fields, and scientists disagreed whether it should be pronounced with a hard g or a j-sound. Jiggawatt was a perfectly correct pronunciation which simply went out of fashion.
Finally! A year of moderation! Ready for 2019?
Power is proportional to velocity cubed for air resistance actually (and velocity for rolling resistance). On 200 watts the car will go 50km/h (we did this on the day when the sun went away), at the 1100 we got we hit 88, over 5 times the power for less than double the speed. Likewise between 88 and 100 you get ~ 1.4x as much aero drag.