Student-designed solar car smashes world speed record | Hacker News Reader

Student-designed solar car smashes world speed record

inhabitat.com

38 pointskia27 comments

The best part is "the car is entirely powered by silicon solar cells and produces about 1200 watts — the same amount of power required to run a toaster." That's really cool!

Indeed. That's actually the depressing part.

As in, you need that many of the best solar cells we can make these days just to power a toaster. It makes real solar powered anything seem a long way off.

the depressing part it highlights is how much energy we waste.

I can build you a solar-powered toaster with a piece of foil for few bucks. Yet you'd rather use chinese toaster that uses as much energy as can propel you and a vehicle at 100+ kph...

Nice, how about a hybrid of solar/human power for a more practical looking/working car?

My battery powered mountain bike can do 25mph for a couple hours on 48v 20ah, so if made into a three wheeler with that array in parallel maybe it could go longer, faster.

But part of their secret is being so low to the ground to cheat wind resistance which is the real problem above 25mph.

Yes, it is indeed all about aerodynamics. (And to some extent tire rolling resistance.) You will find that world-speed-record human powered vehicles are also low to the ground and have carefully designed aerodynamic bodies, rather than being open-frame like a mountain bike.

http://reviews.cnet.com/8301-13746_7-20007977-48.html

In the submitted article they are talking about officially registered record.

I do know that in the races these cars are designed to compete in, the top teams regularly run at the speed limits: 130 km/h in the (Australia) World Solar Challenge, 65 mph in the (USA) American Solar Challenge; not sure about the South African or Japanese races. If for some reason Guinness doesn't have that recorded, then perhaps one of the competitors in those races should invite them?

e.g. http://en.wikipedia.org/wiki/Tokai_Challenger or http://en.wikipedia.org/wiki/Nuna_5

Might be special restrictions on the speed record, like flat road and certain wind conditions.

You have to go twice in opposite directions on the same road and take the worst time

I think that this is a record for a car using silicon based solar cells. The car came first in the silicon section of the 2009 world solar challenge, and fourth overall.

To summarize that article, The University of Michigan Solar Car Team reached 105 mph at Ford's Proving Ground in 2010.

It looks like they never officially called Guinness, so that's why their record isn't in the books.

(I used to be the project manager of the team back in the late 90's... you can see our car at Boston's Museum of Science.) :)

Did they follow all the rules? Or were they assisted by wind in one direction? It's not just the act of not calling the record keepers - it is following the rules, and having people make sure that there is no funny business going on.

It's a solar only record without any battery assist. Also, they don't control for weather somifnthere was more sun one day that's justntoo bad..

BTW Jed, I heard they're pulling the car from the Bos MOS display and sending back to A2. :-(

Seriously? Any info as to when?

For those of us in the US, 88 km/h is roughly 55 mph. (54.68 to be more precise)

EDIT: Also, later on, 103 km/h is mentioned, which is 64 mph.

Still, this is extremely cool for a solar car to get that fast.

For those people not in the US, the US school system has been teaching the metric system since at least since the late 70's. We do know the conversions (eg .62, 2.2, and 1.8). It might take another decade but we will get to the metric system.

Funny, I'm in the US, and I moved around a ton in primary school days (I went to 6 schools from K-5). I managed to never get instruction on the 'US' system of measure. I have no idea how many feet are in a mile, how many quarts in a gallon, cups in a quart, etc.

I did manage to hit each school districts 'metric' year...6 times in a row. So I know the SI system like the back of my hand - it's kind of awkward really.

Also, for those of us who think in terms of horsepower, 1200 watts is about 1.6 hp. A blender might be a more useful kitchen appliance comparison than a toaster to grasp the amount of mechanical power that this car produces.

Now, all they need to do is make the horizontal plane wider, add rudder and ailerons and propeller and they are good to fly (without wasting all that energy to overcome roll friction)!

All of which would induce so much drag making take of impossible. I have no sense of humor.

interesting. I'm not quite sure right now that this is true. Theoretically you can make infinitely long wing that will not induce any drag:

http://en.wikipedia.org/wiki/Lift-induced_drag#Reducing_indu...

An infinite wing would not have induced drag but it would have infinite parasitic drag. There are two kinds of drag at play. As one is reduced the other becomes more dominant.

Overcoming gravity might be a bigger problem than rolling friction.

I don't want them to fly at 35000ft!

Currently they have this wing shaped in such a way as to keep it from flying off the road anyway, and this inevitably creates rolling friction. But why should they waste energy on this?

Solar car aero shells are designed for zero lift, not to press the car into the ground or take off. This is the minimum energy usage.

It's true that you could reduce your rolling resistance by making a car with positive aerodynamic lift, but doing so would make you dissipate more energy in the air than you would save.

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