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Author Topic: Which motors for a 1:12 Tyne lifeboat.  (Read 1800 times)

Mark47

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Which motors for a 1:12 Tyne lifeboat.
« on: January 22, 2009, 07:42:42 PM »

As the caption says, I thought of 550s, then I came across a pair of 545s I have spare. Would it be OK to run the 545s on 12 volts?

Does anyone have any experience with that?

Thanks for helping.

Mark
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stallspeed

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #1 on: January 22, 2009, 09:13:15 PM »

You can run them on 24 volts if you like.It's all down to the load you put on the motor and whether that keeps the internal power loss and temperature within limit.
You'll see MFA list a higher nominal voltage for the same motor when it is supplied with a gear assembly.

If the immersed prop is so big that it causes the motor to slow down below half the motor no-load speed then a reduction gear is needed no matter what the supply voltage is.

http://www.mabuchi-motor.co.jp/en_US/technic/t_0201.html shows a prop exerting the load torque on the motor should not be so big or coarsely pitched that the point of diminishing returns is passed (to the right of the maximum power).
A 550 motor peaks out with a larger prop than a 545 but a 1/12 scale Arun prop ,for example, cannot be driven directly by either of those motors.
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Mark47

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #2 on: January 22, 2009, 10:31:45 PM »

You can run them on 24 volts if you like.It's all down to the load you put on the motor and whether that keeps the internal power loss and temperature within limit.
You'll see MFA list a higher nominal voltage for the same motor when it is supplied with a gear assembly.

If the immersed prop is so big that it causes the motor to slow down below half the motor no-load speed then a reduction gear is needed no matter what the supply voltage is.

http://www.mabuchi-motor.co.jp/en_US/technic/t_0201.html shows a prop exerting the load torque on the motor should not be so big or coarsely pitched that the point of diminishing returns is passed (to the right of the maximum power).
A 550 motor peaks out with a larger prop than a 545 but a 1/12 scale Arun prop ,for example, cannot be driven directly by either of those motors.



Hmmm, I've got some thinking to do O0

What would you recommend?


Mark
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Mark47

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #3 on: January 22, 2009, 10:32:52 PM »

If using 545s on 12 volts, which gear ratio?

Mark
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Shipmate60

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #4 on: January 22, 2009, 10:33:57 PM »

Mark,
What size and type of prop are you running?

Bob
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stallspeed

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #5 on: January 22, 2009, 11:10:21 PM »

Hmmm, I've got some thinking to do O0

What would you recommend?


Mark
No thinking is required.
The starting point is what prop do you want to drive.




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Mark47

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #6 on: January 22, 2009, 11:33:47 PM »

Mark,
What size and type of prop are you running?

Bob

Too be honest. I don't know what the true scale size is. On a 1:20 scale it's a 4 blade 30mm.

I'm wanting to Know what the true scale size is?

What electric motor will run this with decent running time, direct drive or geared?


Mark

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Garabaldy

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #7 on: January 23, 2009, 01:02:59 AM »

if 1:20 scale is a 30mm then a 1:12 scale would be a 50mm prop.  I hope im right!!

i have this size of prop, 4 blades too on one of my tugs.  I use an MFA torpedo 800 on direct drive.  Ive yet to run out of battery when sailing.  They are more expensive than your bog standard 545/550 motors though
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Mark47

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Re: Which motors for a 1:12 Tyne lifeboat.
« Reply #8 on: January 23, 2009, 01:12:04 AM »

if 1:20 scale is a 30mm then a 1:12 scale would be a 50mm prop.  I hope im right!!

i have this size of prop, 4 blades too on one of my tugs.  I use an MFA torpedo 800 on direct drive.  Ive yet to run out of battery when sailing.  They are more expensive than your bog standard 545/550 motors though

I'll look into them, thanks for the info.

Trying to work out costs. I want to see if 1:20 or 1:12 will be my best option for costs.

Mark
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