Mike SVOR

My Feedback: (1)

Well, here's the story: http://www.rcuniverse.com/forum/m_81...tm.htm#8182393

I put the 4900KV motor on the 7 blade fan with a 11 volt 2100 lipo, 60 amp esc.
It pulled 80 amps at 3/4 throttle and would not go higher. The rpm actually went down after 3/4 throttle. It put out ~500 watts.
esc was hot after a brief run.
Obviously, I have no idea what i'm doing when it comes to brushless motors.

I really want to power this 7 blade fan. I need max power and would go as high as an 18 volt lipo to power it.
Could anyone please tell me what motor (and esc if needed) I need to buy to power this fan?
I could really use some help.

Thanks!
Mike

tIANci

Dude ... you got it all wrong. Hence, the problems. That is a huge fan unit for a 3S lipo set up. You are best off using at the least a 4S set up. Look for a motor of 28mm in diameter like the HET 2W-25. That is a good start.

Also, you are killing your batt, your batt is good for prob 60A max and you are pulling 80A out of it.

p/s why don't you follow the reviews at Hobby City? There are specs there as to what motor they used and what lipo?

Mike SVOR

My Feedback: (1)

I know nothing about what motor needs to power this fan.
The requirements said: 28-35 8 Turn
I went with a 28-47-8 turn. I figured that the extra length of the motor would provide more power, and that the extra kv would put me in the rpm range of the fan with my 11 volts.
But I was completely wrong. I'm a newb at electric brushless edf.

Does this fan require an outrunner motor for power? Or should I stick with inrunner?

Like I said, I can go up to 18 volts and buy a different esc or whatever is needed. But I would like to power this fan to it's maximum performance. (as cheap as possible of course. lol)

Me ->

tIANci

Mike ... the motor size is ok but its not the right KV and number of cells. Read the reviews and follow them. That is real life data and its a great help. The motor you have may be good for a geared system later on. I prefer inrunners for EDF, makes life simpler.

Don't worry, when I started out with EP I was at a complete blur. After a few years and getting assistance on the forums I now can feel my way around EP. Everyone is here to assist in forums.

Here is a simple guide:

64mm EDF 3S - 20mm/24mm motor - 4,200KV to 5,300 KV
70mm EDF 3S/4S - 28mm motor - 2,600KV to 3,300 KV
90mm EDF 5S/6S - 36mm motor - 1,600 to 1,800KV

Have fun ok!

rcflyer48

My Feedback: (1)

Do you have a link for the Hobby City reviews? Thanks your answer was great. I have just ordered a 70mm edf jet and have basically no clue what to get for it. I live at 5000 altitude in Colorado so I need power with not too much weight.
Any thoughts would be helpful.
Thanks again.

Mike SVOR

My Feedback: (1)

thank you very much for the reply and guide!

I don't mean to question your recommendation, but the website says the fan requires a 3900Kv motor. You are recommending a 1800-2600Kv motor (since the fan is ~80mm). People that have left comments about that fan say they ran it up to ~30,000 rpm.
So what should I buy for a motor? Should I get a 2500Kv motor (14.8v) so it spins up to 37,000 rpm? Should I get a 3900Kv motor that would 'TRY' to spin the fan to 57,720 rpm?
Is the recommendation on the site wrong about the fan needing a 3900Kv motor?

Mike SVOR

My Feedback: (1)

I ended up choosing this motor: http://www.hobbycity.com/hobbycity/s...trunner_2350kv

I'm waiting for it to be delivered and will post results and maybe movie of it running.
I hope the 4mm shaft will hold the fan better, and the ability to balance the entire assembly including outrunner bell, will aid in performance.

asmund

You are pulling 80 amps through a 60 amp regulator, even at only 3/4 of full throttle. You might consider a bigger regulator too