Wind Power B/C

[GoofyFoofer]

So to clarify, the resistors are just there so we can calculate power, then? My testing device doesn't show a decrease in RPM when resistors are attached....so there doesn't seem to be a braking effect with the load.

Yes, resistors are simply for calculating power. You don't really have to worry about that.

[fl0w]

Thanks . also, is there a way to not get wild readings...? Even with resistors on, the voltage peaks right after I turn the fan on, and then quickly drops .

[dragonfruit35]

Thanks . also, is there a way to not get wild readings...? Even with resistors on, the voltage peaks right after I turn the fan on, and then quickly drops .

That's a little weird... you do have your blades attached, correct?

[fl0w]

Yep. Possibly unbalanced? Or maybe not sturdy enough material?

I also tried a different box fan. Readings are still dropping by a significant margin.

[OHscioly]

Several factor that will affect your blade score, and they all are determined at the actual event/trial competition.
1. Motor and box fan are different in each event
2. Resistance Load
3. Your placement among other competitors

Ideally you want to score high enough from everyone else so that it doesn't matter what written test score you get, you still come out a head. Look at the score sheet from soinc it will show you the combine score on what if scenarios.

Having said all this, of course, my top observed score at invitational events are 300-400 mV. I don't know what value would consider competitive or 1st place score, but 400 mV blow all other competitors to dust.

Now if you are getting 2V, chance are your motor is a different class. not the CD motor. Be prepare for reality check in the competitive event when the actual CD motor will be used. Voltage are normally in the mV.

Our blade design gets 400 low power and well over 600 on high and we were 1/4 the speed of the fastest team at Solon. We are having a very hard time figuring out what a good score would be. We got a .267 on high power and .171 for low on our score report. This was at Solon-does this mean we were 1/4 of the speed of the best team? Our blade spins so fast- I can't imagine something spinning 4 times faster at high speed.

[fl0w]

How do you know you were 1/4 of their speed? You should be able to calculate where you are relative to the highest team, as your blade assembly score is just 50*(your total power score/highest team power score)

[0ddrenaline]

Those are probably your raw voltages. They don't really mean much unless you know the other teams' voltage scores.

[fl0w]

So when you guys test, do your blades get up to a certain cruise speed/voltage, and then the voltage stabilizes? or does it kind of fluctuate around everywhere

[soyuppy]

the original motor that I pry out of a CD player did have this voltage fluctuate. Then I order this motor from Amazon, and haven not seen this problem again.
http://www.amazon.com/gp/product/B00OTC ... ge_o09_s00

Another possibility, if the voltage variance is small, could be attributed to imbalance of blade. If you see the stand that hold the blade rattle or shaken, then voltage will fluctuate.

[soyuppy]

Several factor that will affect your blade score, and they all are determined at the actual event/trial competition.
1. Motor and box fan are different in each event
2. Resistance Load
3. Your placement among other competitors

Ideally you want to score high enough from everyone else so that it doesn't matter what written test score you get, you still come out a head. Look at the score sheet from soinc it will show you the combine score on what if scenarios.

Having said all this, of course, my top observed score at invitational events are 300-400 mV. I don't know what value would consider competitive or 1st place score, but 400 mV blow all other competitors to dust.

Now if you are getting 2V, chance are your motor is a different class. not the CD motor. Be prepare for reality check in the competitive event when the actual CD motor will be used. Voltage are normally in the mV.

Our blade design gets 400 low power and well over 600 on high and we were 1/4 the speed of the fastest team at Solon. We are having a very hard time figuring out what a good score would be. We got a .267 on high power and .171 for low on our score report. This was at Solon-does this mean we were 1/4 of the speed of the best team? Our blade spins so fast- I can't imagine something spinning 4 times faster at high speed.

so that means, the fastest team got 1.6V low and 2.4V on high ? WOW. That's amazing.