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Old Feb 14, 2013, 07:14 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Quote:
Originally Posted by Erik v. Schaik View Post

btw, what reasonable airframe would be good for such a small fan and such a big batteriepack? only thing that comes in my mind is a K&A v1

best regards,
Erik
I guess you know about this thing that I`ve just about finished. I`m just trying to nail down the power system, and waiting for ESCs to arrive.
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Old Feb 14, 2013, 07:16 PM
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With the likelihood that 4kW fans will be running rotors with large hubs designed for 36-40mm motors anyway, it makes sense to have a fan whose housing accommodates that size motor. 28mm motors on 40mm fan hubs have the step behind the rotor hub to create nasty turbulence. A 36mm motor in a 36mm housing with a 36mm rotor hub is very appealing.

Our max power just went up.
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Old Feb 14, 2013, 07:20 PM
efflux RC's Avatar
United States, CA, Santa Clarita
Joined Aug 2009
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Quote:
Originally Posted by Knife Liddle View Post
Sounds great Gary. I say it`s about time someone did it. It may render my high rpm outrunner experiments obsolete, but there are always more than one way to skin a cat. I like the high powered 70mm for it`s ability to generate super high efflux speeds. Then if you put two of them on something like a Victory, and you`ve got 15lbs of thrust at over 300mph. That should make for a pretty impressive EDF for sure.
Thanks Lee.
Here'a a pic of it as it sits on the shelve. (it needs a different kv motor)
The motor is JB welded to the stators so getting it out is gonna be some work.
Dam I gotta find some time to get to all this stuff (or some help. )

Hey, your airframe looks awesome. Good luck!

..........................

Murd,
I think 36mm is plenty big enough. I considered 39mm, since there's also ton's of available kvs. Even though the work is mostly done at the outter portions of the blade, I don't want to take up ALL the FSA.
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Old Feb 14, 2013, 07:27 PM
Lee Liddle
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Carrollton, Tx
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Thanks Gary. I fly it`s little brother out behind the apt, once or twice after work when the weather`s nice. I bought some 3s 950mah Nanotechs so now I get a nice 4 min flight with plenty of full power time. Two min wasn`t long enough. I find that after 4 min I`m ready for a break. At 90mph on 3s it will keep ya busy.
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Old Feb 15, 2013, 04:10 PM
My project: FAIREY DELTA 1
Erik v. Schaik's Avatar
Uden Volkel, Netherlands
Joined Dec 2003
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Quote:
Originally Posted by Knife Liddle View Post
I guess you know about this thing that I`ve just about finished. I`m just trying to nail down the power system, and waiting for ESCs to arrive.
Woah, totally forgotten about that project

On my designs i tend to maiden them on a 350-500w setup to dial them in before going full power. This might be a great route for you as well to get comfortable with your plane.

good luck!

Erik
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Old Feb 15, 2013, 05:40 PM
Lee Liddle
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Carrollton, Tx
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Quote:
Originally Posted by Erik v. Schaik View Post
Woah, totally forgotten about that project

On my designs i tend to maiden them on a 350-500w setup to dial them in before going full power. This might be a great route for you as well to get comfortable with your plane.

good luck!

Erik
Yes you are right. I've thought about doing that. Maybe I'll fly it with a low powered, 2kw, set up first.
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Old Feb 15, 2013, 06:02 PM
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United States, CA, SF
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Quote:
Originally Posted by murdnunoc View Post

Our max power just went up.


And % KV through the roof.
....roof of a sky scraper.



Gryphon
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Old Feb 25, 2013, 02:01 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Just got in two new ESCs today, and I have a new stock 1600kv (aprox a 10 to 12s motor) also a promising rewound motor at 1350kv (slated for 12 to 14s at 90 to 100 amps)

I think I've got the bugs out of the system, so stay tuned for video of a 70mm fan that pushes 5kw. I wonder if I'll see thrust north of 8lbs.
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Old Feb 27, 2013, 12:46 AM
Lee Liddle
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Carrollton, Tx
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Well, I guess the YEP/Sunrise HV 120 esc just can`t do the job. I did everything right, made sure that PWM was set at 16Khz and the timing was set at 30 degrees. Still, the esc won`t hold sync with a 6 pole motor above 48k rpm. According to the specs, it should be good for 70k on a 6 pole motor, but it`s not.

I can`t think of anything I might be doing wrong, but if anyone has any ideas, please post up and let me know what you think.

So, at this point, I have two options for a HV esc that should work. The Turnigy/Hobbywing 120HV shows to have the 24KHz option and then there`s the CC 120HV which also has it. I have some CC esc at the factory now, so I may just wait on them. Or while waiting, I could try the Turnigy 120.

I know the motor can work with the CC esc because I ran an 8 pole at 55k with an Ice 100 on 8s with a full load. But the amps were too high (in the 140 range) for the esc to survive. But at least I know it worked.

So it will be several more weeks until I can fully test this motor, but it is looking pretty good. From what I could see tonight it is holding 1200kv while loaded with roughly 3.5kw power. That works out to about 87% of the unloaded KV which isn`t bad. My guess is that it will still be at 85% with 4kw running thru it.
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Old Feb 27, 2013, 12:55 AM
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That's weird.
I turned my 6 pole Mega at 60k with the HiModel 120HV.

You know I'd be a fan of running the Castle on the experimental motor, just so there's not two things experimenting on each other, creating some demonic third experiment stepchild!

An ICE 120HV would surely have more amp capacity than the Sunrise/YEP.
ICE 160HV for even more headroom.
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Old Feb 27, 2013, 01:47 AM
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But if its not in sync it will not achieve the right rpm. If these motors run like synchronize motors then this formula should work Speed = (Freq x 120)/Poles.
So is this a power factor issue?
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Old Feb 27, 2013, 07:05 AM
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Australia
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PWM frequency should not really have that much of a bearing on things other than making the ESC run hotter, it may help a little with reading the back EMF but outrunners are all iron core motors, increasing PWM is usually only done when you are running an ironless motor as they are low inductance motors. Have you tried running it at a low timing setting? I seem to recall when winding VL motors with 6 poles I used low timing, RPM was pretty high in the old Vasa fans.
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Old Feb 27, 2013, 11:53 AM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Quote:
Originally Posted by murdnunoc View Post
That's weird.
I turned my 6 pole Mega at 60k with the HiModel 120HV.

An ICE 120HV would surely have more amp capacity than the Sunrise/YEP.
ICE 160HV for even more headroom.

That`s good to know about the 6 pole motor. D you know what your timing setting was?

I don`t think that the amps are a problem. Ay 48k on 12s I`m only hitting about 80 amps. The esc isn`t getting hot. I think is blowing the esc is that when it`s spinning at 48k and then suddenly hits the sync issue and the esc shuts down, the motor keeps spinning and starts creating electricity. That feeds back to the esc and blows the fets. I think???
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Old Feb 27, 2013, 11:54 AM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Quote:
Originally Posted by p901P901 View Post
But if its not in sync it will not achieve the right rpm. If these motors run like synchronize motors then this formula should work Speed = (Freq x 120)/Poles.
So is this a power factor issue?
So what determines the value of the Freq variable?
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Old Feb 27, 2013, 12:15 PM
Lee Liddle
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Carrollton, Tx
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Quote:
Originally Posted by Extreme_RC View Post
PWM frequency should not really have that much of a bearing on things other than making the ESC run hotter, it may help a little with reading the back EMF but outrunners are all iron core motors, increasing PWM is usually only done when you are running an ironless motor as they are low inductance motors. Have you tried running it at a low timing setting? I seem to recall when winding VL motors with 6 poles I used low timing, RPM was pretty high in the old Vasa fans.
OK, that makes sense. I have very limited knowledge (maybe no knowledge) when it comes to PWM. I thought you needed higher PWM capability to handle the high rpms and high pole count.

So, I should go back to 8KHz I guess. Then start at zero timing and work up from there to try to get the smoothest run.


Well, I have one more new Hi Models Ice 120HV. I guess I could risk one more. In the last 6 months I`ve burned up 5 of these things trying to get them to work with these outrunners at 4.5kw or so. At $100 each inc shipping, these inexpensive esc are starting to get expensive as they add up.

If anyone wants to make a small donation to help me with esc costs, I`m not too proud to accept any gifts as long as they are small (say a max of $10). That could be done thru PP as a gift. leeliddle628@verizon.net

This motor and rotor are going to work at 4.5kw+. I just have the hope of making this esc work, so that the total package can be put together for less than $150 inc shipping for the fan/rotor/motor/esc.

Right now it`s good for 47.5k rpm. With this rotor, that puts it in the 3.5kw power range and the motor can deal with that non stop. That`s twice what most guys are doing with 70mm fans. You just have to watch the rpms.
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