Glow to Electric Conversions Discuss glow/gas conversion to electric here.

TO: GREG COVEY (...OR anyone else who knows)

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Old 01-03-2005, 01:26 PM
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kf6gub
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Default TO: GREG COVEY (...OR anyone else who knows)

I"ve gained a lot in terms of understanding this electronics business, but I do get puzzled once in a while. I ran across the Actro series of brushless motors. I had the idea that a lipol series of three cells at 3.7 amps (10c=37amps) x 2p would provide 830 watts approx. The Actro 40-6 is supposed to run in the 730-1220 watt range. Are not the six cells enough to run it? I know the Actro literature calls for 24-32 cells for the 40-6. Is the 24-32 cells referring to lipols? I have gaps in my knowledge. I guess I'm missing something simple. Thanx. Jim
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Old 01-03-2005, 03:16 PM
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Greg Covey
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Hi Jim,

Don't worry about being frustrated. The learning curve starts out looking huge but you can cover plenty of ground in a short period of time.

The reference to 24-32 cells is for NiCd or NiMH. Simply divide by 3.5 for a close estimate of Lithium cells or use a general reference of 10 cells NiCd is equal to 3 cells Lithium.

Example: 30 cells NiCd is about 10 cells Lithium or a 10s configuration for about 36 volts under load. Most folks use 3.6v per Lithium cell under load.

Power is measured in watts which is voltage times the current. (i.e. P=IE)

I think that in your post above, you mixed 3.7 volts with 3.7 amps.

For your Actro 40-6 motor using a 6s Lithium pack,

1000 watts = (6x3.6v) / current needed
1000 watts = 21.6v / 46.3amps

So you need a Lithium pack with a 6s configuration that can deliver 46amps continuous.
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Old 01-03-2005, 04:31 PM
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kf6gub
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Greg: Are we talking about one pack of 6 cells connected in a series to provide a 1000 watts? Or do we have to hitch in parallel several sets of 6 cells in a series to get the 1000 watts? Thanx. Jim
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Old 01-03-2005, 08:33 PM
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Wazmo
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

If you've got LiPo cells that support a 46 amp continuous discharge rate (e.g., a 2300mAh rated for 20C) you could use a 6S1P pack. More likely you'll need to build a 6S2P or higher parallel pack.
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Old 01-04-2005, 12:45 AM
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

To simplify things I have started dropping the 'P' nomeclature. It's just not important if all the cells are in one pack. A 6S 5,000 mAh pack can deliver 50A at 20V these days. That rounds out to 1,000W. It really doesn't matter how many cells (paralelled) that are necessary to get the 5,000mAh.
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Old 01-04-2005, 07:00 AM
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Henke Torphammar
 
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

a motor this big needs 8-10s.

for 6s look for a smaller motor.
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Old 01-04-2005, 08:05 AM
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Hannu Vuorinen
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Hi,

yes, Henket is right, Actro 40-6 is very long wind motor, it runs best on 9 or 10s lipos
at max 40A region. I have flown it with it closer 30 flight hours on 10s pack.
Roughly specs like below:

Menz STD 19x8 5700rpm 38A
APC Thin E 19x11 5400rpm 41A
Menz STD 20x11 5300rpm 43A

Going down in voltage better options would be then morelikely Actro 40-4 or 40-5.
6series lipo on Actro 40-6 needs very big prop on low rpms.

Regards,
Hannu
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Old 03-23-2005, 09:07 PM
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Dear Greg Covey,

I have a Hangar 9 Corsair converted over to the AXi 4130/16, based on your conversion of same. I also now have a Duane Habets Air Tractor, which I am doing the same conversion on. My question is about motor cooling. We all know the Corsair has all the cooling it would ever need, since the air flows through the dummy radial cutout, past the motor and out through the cowling gaps.

However, my Air Tractor is different. The nose comes to a point which gets totally covered up by a 3 inch yellow plastic spinner which is used on the glow or gas motors. If I use the spinner (it looks best to use it), it blocks off all air to the AXi motor. To get around this, I mounted the AXi motor out to where the cooling holes of the motor are out in front of the end of the fuselage, left off the spinner and put a 16x10 3-blade Master Airscrew prop on it with a black spinner nut. I also ground out an air escape hatch on the bottom of the fuselage, so the air coming into the motor compartment has a place to go out.

I need to know if I am doing this like you would or if I should do it differently. If you can e-mail me at www.tango@ida.net , I can send you some photos to show you what it looks like. I don't know how to post photos on the forum. Sorry.

Have you ever done it or heard of anyone using the AXi 4130/16 without airflow to the motor?

It doesn't look too bad without the 3 inch yellow plastic spinner, but I think it would look better if I was able to use it. Oh yeah, one more thing. I noticed on the radial mount of the AXi 41xx series that the prop hub isn't long enough for the thick Master Airscrew prop to be used with a spinner anyway. Is there another 16x10, 3-blade prop out there with a thinner hub? I could use an APC electric 17x10, 2-blade and use a 2-blade spinner and it would still stay at 54 amps for full throttle.

Any help you can give would sure be greatly appreciated.

Thanks,

Flyin' Tango
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Old 03-24-2005, 07:02 AM
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Joacim
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Also keep in mind that Actro always esimate and specify there motors with OUTPUT power, there recomended maximum output power with best eff is abaout 1300watts continuos on 40-6 with Nicd/nimh, the motor has a low kv so you need 10s Lipo and the motor still turns props araound 20" with high %. A Actro motor equal to a Axi 4130 is the 32-x serie.

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Old 03-25-2005, 12:04 PM
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Matt Kirsch
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

FlyinTango,

You can use the spinner if you make alternate means for the air to get in. For example, you could put one or more air scoops on the sides or underneath the motor. With a little creativity and careful prep work you could make them look like they were meant to be there.

Running 54 Amps to the motor, I would not recommend flying with no airflow to ANY motor.
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Old 03-30-2005, 11:24 AM
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Darrell B.
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Also remember to allow plenty of air out. This will encourage the air to move past your motor quickly and keep the temps down. My rule of thumb is to have 4 times the area for air out, as for air in. This has never let me down yet.
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Old 03-30-2005, 03:55 PM
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FlyinTango
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Hey Guys,

Big thanks to Matt Kirsch for the tips on the scoops. I actually have some of those little scoops from Hobby-Lobby. If I go that route, I will put them up on top in the black paint, making them harder to see and with the air exit on the bottom and to the rear, I think it would do the best airflow job. However, before I do that, I will fly it to make sure it flies at least like scale. Then, if all goes well, I will put the modifications to it.

Also, big thanks to Darrel B. for the air exit tip. The AXi manual says twice as much air exit as incoming air, but I am sure four times as much would only do a better job.

Thanks Guys!

FlyinTango
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Old 03-30-2005, 04:03 PM
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FlyinTango
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Default RE: TO: GREG COVEY (...OR anyone else who knows)

Darrel B.,

I really like your yellow and purple jet! She looks great! I'd like to see more of that jet.

When I said I would fly my Air Tractor first, I meant to say without the spinner on it, so there will be plenty of airflow to the motor/esc. I need to fly my Hangar 9 Corsair a lot of times before I try to fly my Air Tractor. Just waitin' on some good flyin' weather to get the Corsair out.

If you e-mail me at www.tango@ida.net I can send you some photos of my Air Tractor. Also, I would like to see some more photos of that yellow and purple jet you have under your name here.

Thanks,

FlyinTango
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