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CVMSAvalacheStudent wrote:Is balsa wood a good material to use for the blades?

Yes, balsa will work fine as long as you have a way to angle it so it actually "catches" the wind. I believe mine was about 3/32" thick, although I've seen a few with thicker designs (they were discussing pros and cons of heavier blades above).

ashmmohan wrote:

Alex-RCHS wrote:

ashmmohan wrote: Ehh depends. At Cornell, I saw plenty of teams with heavy designs, too heavy in my opinion. I go with a lighter design, and with higher resistance I just give it a tap at competition, within the 3 minute modification period of course.

By "a tap" do you mean to get it to start spinning?

Do you know if those heavy designs did well?

What I read was that a heavier design might generate a larger voltage against higher resistance than a lighter design would. That seems weird to me -- I kind of doubt that the resistance would have that much of an effect.

Well, we use a lighter design and placed 1st at the Cornell invitational. For me, the higher resistance just impacts the beginning of the spin. Then you would have to tap it, or as you said, get it to start spinning.

That makes sense, thank you.

1st at Cornell is impressive! Congrats!

dragon_fruit35 wrote:

CVMSAvalacheStudent wrote:Is balsa wood a good material to use for the blades?

Yes, balsa will work fine as long as you have a way to angle it so it actually "catches" the wind. I believe mine was about 3/32" thick, although I've seen a few with thicker designs (they were discussing pros and cons of heavier blades above).

So by catching wind, does that mean curving the wood or placing it at a slant? This season, I have been angling my blades at 10 degrees, but have not had much success.

Chameleon02 wrote:

dragon_fruit35 wrote:

CVMSAvalacheStudent wrote:Is balsa wood a good material to use for the blades?

Yes, balsa will work fine as long as you have a way to angle it so it actually "catches" the wind. I believe mine was about 3/32" thick, although I've seen a few with thicker designs (they were discussing pros and cons of heavier blades above).

So by catching wind, does that mean curving the wood or placing it at a slant? This season, I have been angling my blades at 10 degrees, but have not had much success.

I curved my blade.

CVMSAvalacheStudent wrote:

Chameleon02 wrote:

dragon_fruit35 wrote:
Yes, balsa will work fine as long as you have a way to angle it so it actually "catches" the wind. I believe mine was about 3/32" thick, although I've seen a few with thicker designs (they were discussing pros and cons of heavier blades above).

So by catching wind, does that mean curving the wood or placing it at a slant? This season, I have been angling my blades at 10 degrees, but have not had much success.

I curved my blade.

Did you curve it convex to the oncoming wind, or concave?

I was taking a test and the answer key said the first electricity producing wind turbine was created in 1821. Wasn't it James Blyth in 1887 who created the first electricity producing wind turbine? I did some searching online and found that in 1821 Michael Farady discovered the principle of electromagnetic induction, and that the first natural gas well was drilled in the U.S., but I don't see anything about a wind turbine. Was the test just wrong or am I missing something?

I think the test was wrong as well. I can't find a single source that says anything before Blythe in 1887.

I made my first ever design using curved balsa wood and at the invitational, I got 181 low speed and 340 high speed. I wanted to know how good these scores would be on average.

highbuilder wrote:I made my first ever design using curved balsa wood and at the invitational, I got 181 low speed and 340 high speed. I wanted to know how good these scores would be on average.

Unfortunately, because of the way this event is run, it's kinda hard to compare scores. The fans and the test rigs can give very different results depending on what brand they are, etc. I think last year the highest mine got on high speed was around 600ish (don't quite remember, whoops), assuming you're speaking in mV.

Also, chameleon, I actually angled my blades, which worked pretty well. I believe you would want the blades to be concave looking straight on at them if you were to curve them. At least, last year we tested curved blades and that's how they were .

highbuilder wrote:I made my first ever design using curved balsa wood and at the invitational, I got 181 low speed and 340 high speed. I wanted to know how good these scores would be on average.

Like DragonFruit said, it's really hard to compare. You could try asking the proctor what the highest score was at the tournament, although they don't always tell you.

The only thing you can compare it to is previous designs. As long as you keep getting better, you can't go wrong!

For comparison purposes, my team and I have been testing at 670 mV HS and 400 mV LS without any resistor wired in. At regionals we got 360 mV HS and 210 mV LS, with 6.7 ohms of resistance. We think the difference is due to the fan being different, not the resistance, but we aren't sure.