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Old Mar 10, 2005, 06:39 PM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
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One hour CD ROM construction part 7

It is over 1k posts in One hour CD ROM construction part 6

The previous parts are:

One Hour CD ROM Construction Part 5

One hour CD ROM motor construction PART 4!!

One hour CD ROM motor construction PART3

One hour CD ROM motor construction PART2

One hour CD_ROM motor construction

Enjoy

RysiuM
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Old Mar 10, 2005, 07:09 PM
AKA Don
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United States, MI, Houghton Lake
Joined Dec 2002
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From part 6
Quote:
That is GREAT... I think the 12Turn 24 in delta would be about the same as a 7 turn wye... So I may just rewire using the same motor in delta... Or would you recommend, just 7 Turns in 22awg, wye?

I'm putting this on a 28" wing.. Right now the pitch speed on my 4.5x4.1 is around 60mph.. So this should will really cook... Plus, the thrust will be up apropriately to handle a bit larger battery, to keep the CG right and power the motor.

90mph == Fun
12 T Delta = 12/1.73 T Y = 6.93 Yep, very much the same. Great idea to save rewinding. Is your wire sizeed so the twelve turns fills the space? If so you would gain nothing by rewinding, just reconnect.
Don
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Old Mar 10, 2005, 08:15 PM
Fidler & twidler
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2 RysiuM

thanx
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Old Mar 10, 2005, 11:05 PM
Our Daddy and Heli Junkie
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Man, you guys are good with several K posts!!!
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Old Mar 10, 2005, 11:43 PM
fix-it-up chappie
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Just don't take our motor info source away Fred, and we'll do what ever you say.
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Old Mar 11, 2005, 12:12 AM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
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Quote:
Originally Posted by tolladay
Just don't take our motor info source away Fred, and we'll do what ever you say.
Sometimes I find myself not remembering data of the motors I made and the only place to find it is just here as I posted it in RC-Groups. In example making another motor for Hummingbird I didn't remember, wire, turns nor connection. However I new I posted my motor here a year ago or so. So I just searched for my post

Yes, Frank. Keep us happy and we will do the same for you

RysiuM
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Old Mar 11, 2005, 12:58 AM
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Don..

I ended up rewinding.. So I ended up winding 7 turns of 22awg...
Here are the results...

10.7 amps... 9.6v and 16100 rpm... using an apc 5x5 prop in pusher config.. My battery was a 3s 1800... funny thing is, it jumps from like 8 amps to 10 amps on the last 2 cliks of the throttle... Its strange, This motor should handle 100W... and at only 103 watts I noticed some heat build up. Now I'm curious why the single can handle 70 watts and not get hot, on a 24awg 12 turn and slightly smaller prop... 4.5x4.1 apc..
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Old Mar 11, 2005, 08:16 AM
Why not Delta?
rysium's Avatar
Sacramento, CA
Joined Jun 2003
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Quote:
Originally Posted by klong66
10.7 amps... 9.6v and 16100 rpm... using an apc 5x5 prop in pusher config.. My battery was a 3s 1800... funny thing is, it jumps from like 8 amps to 10 amps on the last 2 cliks of the throttle
My guess is you are overloading the motor. I mean to much torque. These numbers are static, right? I guess you should be OK in the air. First of all the wind will cool down the motor. While prop unloads with the speed it should reduce current.


Other than that all looks fine to me.

RysiuM
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Old Mar 11, 2005, 10:10 AM
AKA Don
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United States, MI, Houghton Lake
Joined Dec 2002
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Quote:
Originally Posted by klong66
Don..

I ended up rewinding.. So I ended up winding 7 turns of 22awg...
Here are the results...

10.7 amps... 9.6v and 16100 rpm... using an apc 5x5 prop in pusher config.. My battery was a 3s 1800... funny thing is, it jumps from like 8 amps to 10 amps on the last 2 cliks of the throttle... Its strange, This motor should handle 100W... and at only 103 watts I noticed some heat build up. Now I'm curious why the single can handle 70 watts and not get hot, on a 24awg 12 turn and slightly smaller prop... 4.5x4.1 apc..
The numbers overall look about right. I mean I call the MotoCalc "predictions" or "estimates" for a reason.

The change in current with the last 2 throttle clicks does not sound right, unless you have some exponential programed in. Assuming not, I would look and listen for signs the controller is loosing sync. Watch out for long wires between the motor and ESC. Also check that you are not getting a can/winding rub. On a pusher at high thrust the can will move if not restrained. I had a pusher I flew about ten times before I finally figured out that a can rub at near full throttle was causing a significant loss of performance. It ran fine at normal flight loads, but started loosing sync at high thrust. Get out the marking pen and color the inside of the can. Or just add a STRONG thrust washer to move the can about .030 inch away. That's all I think of to check, but something is not right.

A double cannot dissipate twice the heat of a single. A double has only 50% more wire surface exposed to the air for cooling. Think of a single as having four sides on each stator arm (front, back, and two sides). Each arm of the double has only six such areas front, back, and 2 on each side (the sides are twice as long) = six. 6/4 is only 150% or 50% more. Also the heat generated in the iron has farther to go to get out. Bottom line a double will not be happy at twice the power that makes a single warm.

Finally, as rysium says the current in the air is usually lower. But, in your case, with a 5-5 prop at high speed, the prop ia severely stalled in the static condition. That means the current will actually go up when the prop gets a "bite" on the air in flight. Racers are well aware of this higher current in flight, most sport and 3d flyers are used to lower currents when flying. A severly stalled prop is the reason some high speed planes need a catapult launce. The thrust is so low the plane will not accelerarte to flying speed on it's own. Yet, once the prop gets a bite they fly at very high speeds which require more thrust than would be needed for takeoff.

STRONG Thrust Washers
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Old Mar 11, 2005, 11:06 AM
crashin with a smile
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Los Angeles Industry, California, United States
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wow I was planning on reading this when I started winding my brushless motors but for a 1hour cd thread it would have taken me 24hrs just to catch up on where the thread is now.
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Old Mar 11, 2005, 12:21 PM
Fidler & twidler
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Quote:
Originally Posted by sirdirk007
wow I was planning on reading this when I started winding my brushless motors but for a 1hour cd thread it would have taken me 24hrs just to catch up on where the thread is now.
You read FAST - took me 3 weeks of eye strain to read all the parts

Mike
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Old Mar 11, 2005, 03:37 PM
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Thanks for the great info!!! to both Don And Rysium....

Don, I am using a strong, thrust washer... They help out tremendously. This strange amp jump happens on all of the motors I run, not just the GB's but the factory ones as well.. I've asked about this in the radio forum, but nobody seems to have a good explenation for this behaviour.

The tests were done static. Maybe a bit different prop would be advised.. down again to the 4.5x4.1 prop... just faster, rpms.. I was hoping the double would get me a bit bigger prop and more rpms.. But more rpms will be ok too on the same prop.. I'll test and get some new numbers for the 4.5 x4.1 prop.. I also need to get a 4.75x4.75 prop as well.

The stator was not completely full with the 7 turns of 22awg.. So maybe yet another rewind of 12T, 24awg and delta connection might just be the ticket.

As for the prop being stalled and higher amps... I've been having lots of troupble with the GBx, 12t 24awg, Wye.. with an apc 4.5x4.1 prop.. I'm guessing this prop is stalled as well. So static wot, is running about 7 amps and about 75-80w... WOW.. so this means that the amps will actually be higher in flight? How does one go about finding out? This plane has been glitching on me severly, I wonder if I've been over amping the poor cc-10 esc?
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Old Mar 11, 2005, 04:47 PM
AKA Don
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United States, MI, Houghton Lake
Joined Dec 2002
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Yes, with a 4.5x4.1 prop the flight amps could be higher than static also. Maybe, AirMover or one of the other Go Fast Guys can tell us about how much it might go up. Go from 7 to 10 amps is more than I would guess. But, I am guessing.
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Old Mar 13, 2005, 08:36 AM
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Chiba, Japan
Joined Jan 2002
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APC 5x5 GoBrushless Double

Hi klong66.

Trying to spin APC 5x5 for a wing? I have been flying GoBrushless double, two strands of 0.35 mm 9T Delta since last fall. The motor uses GoBrushless double can, 12 10x5x2 N45 magnets. It spins APC 5x5 about 18,000 rpm+ static with old flat PolyQuest 1800 3S. Sorry detailed figure is in my dead PC and I cannot retrieve it now but I remember input was about 140W. (about 14A). I use CC-25 or MTM-18 for ESC. I built stator holder/motor mount with thin skin aluminum pipes. AUW is 295g.

The motor will never get hot. It flies with good ballance of thrust and pitch speed. It is fast but not as fast as pylon racer. SpeedWing with my configuration is rather draggy. When it makes a large loop, I observe dive speed is not much faster than climb speed.

Satoru
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Old Mar 15, 2005, 03:08 AM
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Satoru,
Thats exactly what I'm doing... I've got a single that runs great on a 3s 880PQ pack. with a 4.5x4.1 apc prop... I'll probably play around with the props a bit to see If I Can't get those amps down a bit... to use maybe only an 1100 3s pack...
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