Wind Power B/C

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Alex-RCHS
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Re: Wind Power B/C

Post by Alex-RCHS » February 27th, 2017, 4:59 pm

You should keep testing variables! For example, you could make the same blade design at 20, 17, 14, and 11 cm and see which does best.
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Re: Wind Power B/C

Post by ashmmohan » February 28th, 2017, 5:02 pm

tyasasvi wrote:I got 600mV on high speed with no resistance. However, we are only using 14 cm blades. Whenever we increase the blade length, it becomes slower. We are thinking it is because of the added weight longer blades bring to us, but I am hearing from other teams that the longer the blade the better. Can someone tell me if I should try longer blades or just keep it around 14 cm?
Although we are division C and can only go to 14cm max, I find that having longer blades generates higher results than shorter blades for sure.
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Re: Wind Power B/C

Post by Xuax » February 28th, 2017, 5:42 pm

ashmmohan wrote:
tyasasvi wrote:I got 600mV on high speed with no resistance. However, we are only using 14 cm blades. Whenever we increase the blade length, it becomes slower. We are thinking it is because of the added weight longer blades bring to us, but I am hearing from other teams that the longer the blade the better. Can someone tell me if I should try longer blades or just keep it around 14 cm?
Although we are division C and can only go to 14cm max, I find that having longer blades generates higher results than shorter blades for sure.
Cp=0.5 rho * av^3

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Re: Wind Power B/C

Post by Tesel » March 1st, 2017, 11:05 am

Xuax wrote:
ashmmohan wrote:
tyasasvi wrote:I got 600mV on high speed with no resistance. However, we are only using 14 cm blades. Whenever we increase the blade length, it becomes slower. We are thinking it is because of the added weight longer blades bring to us, but I am hearing from other teams that the longer the blade the better. Can someone tell me if I should try longer blades or just keep it around 14 cm?
Although we are division C and can only go to 14cm max, I find that having longer blades generates higher results than shorter blades for sure.
Cp=0.5 rho * av^3
Yes, the easiest way to max out your speed would be to do longer blades due to the equation above.
However, that equation is mostly useless once you realize that almost everyone is testing on the same setup with same air density, velocity, and sweep area. You didn't include the efficiency, which is what Wind Power is all about. You are trying to find the most efficient blade design since everyone has the same theoretical limit.
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Re: Wind Power B/C

Post by Xuax » March 1st, 2017, 11:17 am

Tesel wrote:
Xuax wrote:
ashmmohan wrote: Although we are division C and can only go to 14cm max, I find that having longer blades generates higher results than shorter blades for sure.
Cp=0.5 rho * av^3
Yes, the easiest way to max out your speed would be to do longer blades due to the equation above.
However, that equation is mostly useless once you realize that almost everyone is testing on the same setup with same air density, velocity, and sweep area. You didn't include the efficiency, which is what Wind Power is all about. You are trying to find the most efficient blade design since everyone has the same theoretical limit.
I know, I'm just saying why making blades longer would increase power.

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Re: Wind Power B/C

Post by freed2003 » March 1st, 2017, 1:48 pm

Hey does anyone know how to calculate the solidity of the wind blade?
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Re: Wind Power B/C

Post by Xuax » March 1st, 2017, 2:07 pm

freed2003 wrote:Hey does anyone know how to calculate the solidity of the wind blade?
What do you mean? When I look up solidity, all I find is a programming language.

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Re: Wind Power B/C

Post by freed2003 » March 1st, 2017, 3:04 pm

I mean of a rotor
also can someone help me with this question?
A power plant in Chicago is generating 900 MW on a 700 KV line. Assuming the line
is 100 kilometers long, with a resistance along the line of 0.2 ohms, what is the current along the lines

When I use I=V/R I get 3500kA but when I use I=P/V I get 1286 A
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Re: Wind Power B/C

Post by Alex-RCHS » March 1st, 2017, 3:44 pm

freed2003 wrote:I mean of a rotor
also can someone help me with this question?
A power plant in Chicago is generating 900 MW on a 700 KV line. Assuming the line
is 100 kilometers long, with a resistance along the line of 0.2 ohms, what is the current along the lines

When I use I=V/R I get 3500kA but when I use I=P/V I get 1286 A
I've never heard of that term, but this might help:
https://en.m.wikipedia.org/wiki/Blade_solidity

As for that question, I don't understand either. It seems like a poorly worded question to me. I've also seen other questions on the test that was from that had incorrect answers on the answer key.
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Re: Wind Power B/C

Post by P2P » March 1st, 2017, 3:52 pm

Unsure. But Ohm's law (V = IR) is talking about voltage drop through a resistor of resistance R. Since the values you were given never mention the drop in voltage, but rather voltage generated, you can't use it.

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