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Old Feb 14, 2007, 12:02 PM
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fly4fun's Avatar
Gilbert AZ
Joined Jun 2001
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Brushless Outrunners and united hobbies

I'm looking at united Hobbies outrunners for their great prices and cannot find what I need. https://www.unitedhobbies.com/UNITED...rsus_index.asp

I would like an outrunner that can do 600Watts on 3s Lipos max 60amps.

Help Needed. Thanks.

David
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Old Feb 14, 2007, 12:27 PM
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fly4fun's Avatar
Gilbert AZ
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Or please recommend other low cost BL outrunners that can do 600watts on 3s. Thanks.
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Old Feb 14, 2007, 01:22 PM
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Dr Kiwi's Avatar
Chattanooga, Tennessee, United States
Joined May 2003
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The hard part is finding a big motor which has a high enough Kv to draw 60A on 3s - most need at least 4s, many need 10s! Most of those big UH motors are only ~280Kv.

Here is one which is in the right power range, and 840Kv, but even it is recommended for 4s:

http://2dogrc.com/ecommerce/os/catal...ze-p-2012.html

This E-flite Power 46 might do it (670Kv) but it definitely needs 4s.

http://www.e-fliterc.com/Products/De...odID=EFLM4046A
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Old Feb 14, 2007, 01:48 PM
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fly4fun's Avatar
Gilbert AZ
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Dr KIWI after lots of research I see what you mean. Thanks for the reply.
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Old Feb 14, 2007, 03:03 PM
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LBMiller5's Avatar
San Marcos, CA
Joined Jan 2005
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fly4fun,

Running motors is always a balance of current and voltage. What you want out of the motor is Watts, which is Voltage X Current, and you can get in many different ways. High voltage-Low Current setups are generally more efficeint than Low Voltage-High Current setups because a large portion of the losses in our motors is in the form of heat, and the heat generated is proportional to the current draw.

In typical applications of electric power systems, you will see the current value be 2 or 3 times the voltage value. For example, if you are running a 2-cell Li-Po pack (7.4 volts), you typically see current draws in the 10 to 20 amp range. For 3-cell Li-Po packs (11.1 volts), you normally see current draws in the 20-30 amp range. For 4-cell packs (14.8 volts), you will typically see current draws in the 30-45 amp range and so on.

Now granted, there are cases, such as ducted fan applications, where you will pull more current than this, and other applications where you will draw less current, but these are the normal operating ranges that you will find in the majority of the aircraft out there. This is due to the fact that there is a maximum current level for every motor, and that is based on the size of the wire used to wind the stator. Whether you have 3 volts or 30 volts through the winding, the same current restriction applies, so the higher the voltage used, the more power you can get out of a motor.

In your application, where you are wanting 60 amps from a 3 cell pack, you are running almost 6 times as much current as voltage, 60 amps at 11.1 volts. In order to do this you would need a motor that was normally rated for 5-6 cell operation, and has a 60 amp rating, but then only run it on 3 cells and have to put a HUGE prop on it to get the amp draw up where you want it. This goes along with what Dr. Kiwi said earlier.

I would assume that you are placing two 3-cell packs in parallel to get this current handling ability. In my opinion, you would be better suited putting the packs in series and running 22.2 volts at 30 amps to get your 600 watt requirement. That is basically what I am doing in my larger ParkJets. I am running 6-cell A123 battery packs, and pulling 36 amps from them. Since the A123 Cells have a slightly lower voltage than the Li-Po batteries, this combination gives me 17.22 volts under load at 36 amps, for a little over 600 watts.

One of my ParkJet motors has a Kv of 950, and turns a 9x7 prop at around 14,000 RPM pulling 615 watts. The other one has a motor with a Kv of 670, and turns an 11x8.5 prop at around 9,000 RPM, pulling the same 615 watts. It all depends on the application, but I think you get the idea.

Hopefully this will be of some help to you.

Lucien
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Old Feb 14, 2007, 04:03 PM
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wolw's Avatar
Gustafs, Sweden
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Listen to Lucien

If you do insist on going on 3S there is an inrunner Quannum 36-70that I've had my eyes on my self for Hotliner use, kv1000 rated for 70A.

//Peter
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Old Feb 14, 2007, 04:25 PM
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Gilbert AZ
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Yes Im trying to stay with 3S and really like Himax Motors.

http://www.allerc.com/product_info.p...oducts_id=1812.

So If I have a 3S Pack that can Handle 60amps I should be good to go with this motor.

Thanks for all the info.

David
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Old Feb 14, 2007, 04:29 PM
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fly4fun's Avatar
Gilbert AZ
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Quote:
Originally Posted by wolw
Listen to Lucien

If you do insist on going on 3S there is an inrunner Quannum 36-70that I've had my eyes on my self for Hotliner use, kv1000 rated for 70A.

//Peter
I believe that Inrunner would require a Gear Box.

I'm a newbee to running large motors and batteries. Thanks for helping me out.
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Old Feb 14, 2007, 05:43 PM
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San Marcos, CA
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That motor is designed for direct drive. One thing that you never mentioned is what size prop you intend on using and the plane that it is going to go on. That plays a HUGE role in determining the best motor to fit the job at hand. If you could provide that information it would be a big help.

For example, saying I need 600 watts on 3S batteries does not really say much. You could use 3S packs with a 6000Kv motor to turn a 4" ducted fan at 50,000 RPM for a jet, or you could use the same 600 watts to turn a 16x8 prop with a 600Kv motor at 5000 RPM. Both are 600 watts, but they are 2 completely different situations that require 2 completely different motors.

If you tell us the appliction, you will get much more useful feedback from the forum.

Lucien
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Old Feb 14, 2007, 06:35 PM
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Chattanooga, Tennessee, United States
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Quote:
Originally Posted by fly4fun
Yes Im trying to stay with 3S and really like Himax Motors.

http://www.allerc.com/product_info.p...oducts_id=1812.

So If I have a 3S Pack that can Handle 60amps I should be good to go with this motor.

Thanks for all the info.

David
The biggest of those in your link (the HC 3528 1000Kv) is only 450W max? - so how do you get 600W into it?
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Old Feb 14, 2007, 06:50 PM
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bildo baggins's Avatar
Warner Robins, GA
Joined Aug 2003
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Checking in to see what transpires. Agree with LB, need prop sizes and application.
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Old Feb 14, 2007, 07:15 PM
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fly4fun's Avatar
Gilbert AZ
Joined Jun 2001
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[QUOTE=Dr Kiwi]The biggest of those in your link (the HC 3528 1000Kv) is only 450W max? - so how do you get 600W into it?[/QUOT

Ok sorry for the lack of info.

Ok here is my project.

Dazzler from Tower Hobbies.

Target Weight 4-5lbs
Watts 100 Watts per pound.
Prop 12x6apc
Desire batteries Parallel 3s Lipros packs.
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Old Feb 14, 2007, 07:32 PM
There are four lights!
kcar's Avatar
Santa Cruz, C.A.
Joined Jan 2005
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How about a Axi 2826 /08?
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Old Feb 14, 2007, 07:43 PM
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fly4fun's Avatar
Gilbert AZ
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Kcar that has possiblities. Thanks a bunch
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Old Feb 14, 2007, 08:19 PM
There are four lights!
kcar's Avatar
Santa Cruz, C.A.
Joined Jan 2005
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My /10 draws 50a with a 14x7 apc on tp 3s4200 (two 3s2100pl packs)
500+watts wot.

I figure the /08 with a 13x6.5 would be around 600W, but don't take
my word for it.

Kcar
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