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Old 08-02-2012, 12:23 AM
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vxquizit1
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Default noob in boats with an electric plane question.

hi peep.
Do you plane people run your electric motor in reverse for reverse thrust ?
Or only use vp props ?
If so. How ?
I want to run my boat motors 4ward/reverse.
Equip.
FS 6c tx. Copy of futba.
2x Bec's to suit.
3x 6ch rx's to suit.
3x brushless inrunners.
;-) Cause I,m a noob, I thought inrunners were needed because they were going IN the boat,
as against OUT on the wing.
Might have to send that one into the funny forum :-)

vxq.
Old 08-02-2012, 03:57 AM
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CGRetired
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Default RE: noob in boats with an electric plane question.

No, we do not run our brushless motors in reverse. We have pusher props to do reverse thrust. I don't even know if you can reverse a brushless ESC.

The direction of rotation comes from the phase and step of the three inputs to a motor.

In runners mean that the armature rotates with the shell or stator remain stationary. The magnet is part of the armature and the armature rotates.

In outrunners, the magnets are part of the shell and the shell rotates while the armature has the windings and remains stationary.

In runners tend to have more RPM or a higher KV rating (KV = # 1000 rpm per applied volt) with less power, but can be geared down for better power output to the driven prop, where the outrunners tend to have a lower KV rating but higher torque at the lower RPM and can drive props directly.

For our aircraft, as I said, we use pusher props when we mount the motors pointing to the rear. For boats, I presume a bit of ignorance, but I would think that if you are using a propellor under water (versus an air driven prop such as an air boat) and points to the rear and would be a pusher type prop. Reverse??? I don't know.. a reversing gear box would be something interesting to see.. would be pretty small and probably to intricate to be practical.

Yeah, probably better to post the question in a boat forum.

CGr.
Old 08-02-2012, 05:44 AM
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KW_Counter
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Default RE: noob in boats with an electric plane question.

The car people have reverse and use brushless motors.
Based on that I will assume you can run them in reverse.
(Yes, I know what assume spells.)

I have also read that if a brushless motor is running in reverse then reverse any 2 wire to remedy it.

Exactly how it is all done you will have to do some research on.

Good Luck,
KW_Counter
Old 08-02-2012, 05:48 AM
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Villa
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Default RE: noob in boats with an electric plane question.

The out runner brush-less motor is reversed by switching any two of the three wires between the ESC and the motor. I have a pusher plane and I then mount the prop "backward" so that the prop correctly pushes the air to the rear of the plane.
Old 08-02-2012, 07:27 AM
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CGRetired
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Default RE: noob in boats with an electric plane question.


ORIGINAL: KW_Counter

The car people have reverse and use brushless motors.
Based on that I will assume you can run them in reverse.
(Yes, I know what assume spells.)

I have also read that if a brushless motor is running in reverse then reverse any 2 wire to remedy it.

Exactly how it is all done you will have to do some research on.

Good Luck,
KW_Counter
That's right, isn't it. I forgot about that.. ha.. my mistake - and I do it all the time. Age, I guess.. So, I guess some sort of arrangement with an electronic switch built in the ESC can probably do just that.

CGr.
Old 08-02-2012, 10:55 AM
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jester_s1
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Default RE: noob in boats with an electric plane question.

No switch needed. All you do, as stated above, is switch any two wires and the motor will run the other way. It makes no difference in efficiency or power when you do that. He'd need something fancier than plane ESC's if he wanted to have a forward drive and a reverse in his boat, but just for forward movement a direct setup will work fine.
Old 08-02-2012, 04:43 PM
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vxquizit1
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Default RE: noob in boats with an electric plane question.

I know about swapping the wires to reverse but I want to be able to do it from the tx.
The only way I can see would be to run to esc`s into a y cable.
Would want a bit of lag in the middle to prevent overlap.  Otherwise the smoke might escape.
Old 08-02-2012, 06:39 PM
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cfircav8r
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Default RE: noob in boats with an electric plane question.

Here is just one of many options for a boat speed controller that can be set up as a forward only or a forward/reverse ESC.
http://www.nitrorcx.com/rcboatesc.html and they are water cooled. You would need one for each motor.


P.S. Most fast boats and cars run inrunners as they turn higher RPM's. If you want to turn a larger prop slower, as in a scale fishing trawler then an out runner may work well. If you have a speed boat then an in runner will be better, and may need a gear box depending on the prop size.
Old 08-02-2012, 08:07 PM
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jester_s1
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Default RE: noob in boats with an electric plane question.

Yep, get a reversible ESC to do it right. I've never heard of a switching mechanism that didn't include a reversible ESC. You have to remember those wires have to carry a lot of current, and any connection adds to the resistance and the heat.

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