Physics Lab B/C

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georgexu316
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Re: Physics Lab B/C

Post by georgexu316 » January 2nd, 2010, 8:54 am

I hastily built a prototype wind turbine with cardboard just to test it out. I think the shape is excellent, just a little to heavy. Foam would probably work better.
Max diameter: 27.2 cm
I didn't cut the CD down yet because I haven't thought of the best way to cut it.
Here's a video:
http://www.youtube.com/watch?v=NnetzWzkgL4

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Last edited by georgexu316 on January 22nd, 2010, 4:36 pm, edited 1 time in total.
Physics lab wind turbine videos:
http://www.youtube.com/user/georgexu316

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Re: Physics Lab B/C

Post by andrewwski » January 2nd, 2010, 3:47 pm

Looking at the blades, I'd go with something narrower that tapers as you go toward the tip.

A soldering iron (preferably an old one) is the easiest way to cut a CD. Essentially melt right through it.

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Re: Physics Lab B/C

Post by Glacierguy1 » January 3rd, 2010, 3:16 pm

Is it bad to use scissors to cut a CD or is it just inefficient?
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Re: Physics Lab B/C

Post by andrewwski » January 3rd, 2010, 8:21 pm

Doubt it'll work very well. CD's are very difficult to cut.

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Re: Physics Lab B/C

Post by Flavorflav » January 4th, 2010, 2:48 am

andrewwski wrote:Looking at the blades, I'd go with something narrower that tapers as you go toward the tip.

A soldering iron (preferably an old one) is the easiest way to cut a CD. Essentially melt right through it.
I think the shape is probably good for this wind speed. Airplane propellers are narrower because they move faster.

Did you get a voltage reading on that setup?

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Re: Physics Lab B/C

Post by georgexu316 » January 4th, 2010, 7:58 am

andrewwski wrote:Looking at the blades, I'd go with something narrower that tapers as you go toward the tip.
Narrower blades are for slower wind speed. At slower wind speed, the extra mass just adds to the moment of inertia. At high speeds, however, it captures wind energy efficiently, while adding relatively few moments of inertia.
That’s why if you look at a normal windmill, it will have narrow blades because wind speed isn’t very high. But in this competition, the fan produces enormous amount of wind speed (relatively), thus a big fat blade works much better.

I’ll probably cannibalize my old CD player to get a motor to measure voltage this week.
I’m also trying foam blades. I’ll post up the voltage measurement results.
Physics lab wind turbine videos:
http://www.youtube.com/user/georgexu316

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Re: Physics Lab B/C

Post by Glacierguy1 » January 4th, 2010, 1:00 pm

andrewwski wrote:Doubt it'll work very well. CD's are very difficult to cut.
I've already cut 5 or 6 using scissors. Does it damage the structural integrity of the remaining part or is it just tough on the scissors and hands?
SAVE OUR GLACIERS.

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Re: Physics Lab B/C

Post by georgexu316 » January 5th, 2010, 11:41 am

Glacierguy1 wrote:
andrewwski wrote:Doubt it'll work very well. CD's are very difficult to cut.
I've already cut 5 or 6 using scissors. Does it damage the structural integrity of the remaining part or is it just tough on the scissors and hands?
No it doesn't damage anything. The CD realy doesn't do much anyways; its just there to standarize the hole.
Physics lab wind turbine videos:
http://www.youtube.com/user/georgexu316

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Re: Physics Lab B/C

Post by Glacierguy1 » January 6th, 2010, 5:08 pm

How much variation is there in CD player motors? Also, what is a good voltage?
SAVE OUR GLACIERS.

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Re: Physics Lab B/C

Post by TwoplusTwoEqualsFive » January 6th, 2010, 8:18 pm

As we approach closer to the competition, I just want to get a rougher estimate in how I was doing. I know it varies from fan to fan but I'm pulling roughly a 875mV on high and 550 mV on low. Anybody bold enough to give me a comparison? - Haha
D.A.H.S. SCI OLY 08 - 09

STATES 2009 EVENTS
Chem Lab - 1st
Electric Vehicle - 2nd
Elevated Bridge - 5th
Experimental Design - We'll work on it haha

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