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標題: Paula 3 brushless question [打印本頁]

作者: bobpinpin 時間: 2008-5-13 00:22
標題: Paula 3 brushless question
Any brother knows which model or brand of brushless motor and ESC is good for the Robbe ship Paula 3? I plan to use 7.4V 4400mah lipo as the powersource for this boat.

Waiting for help.

Bob

作者: bobpinpin 時間: 2008-5-14 08:39
Can any brother help?

作者: 夜遊神 時間: 2008-5-14 21:21
Motor:
A brushless no smaller than 540-size should work fine on Paula 3. In-runner should have a proper reduction gearbox for higher torque output and power efficiency.

Battery & ESC:
You can use NiCd, NiHM or lead-acid battery to power brushless motor. Li-po is not the best choice for heavy duty application because its discharge rate is usually lower than NiHM or lead-acid. For instance, 4400mah implies the battery can discharge at the rate of 4.4A for an hour. If it is a 15C battery, the maximum discharge rate would be 4.4 x 15 = 66A for 4 minutes (60/15=4). 20C would be 4.4 x 20 = 88A for 3 minutes. If your motor (brush or brushless) drains more current than the Li-po can handle, the battery would be cooked. In the worst case, it would burst into fire and toast your boat. Therefore, the choice of Li-po and ESC is highly dependent to your choice of motor.

Besides, Li-po would be permanently damaged once they're shorted (the risk is high in case of boating). Since Paula 3 is not such a tiny boat, it should not have weight problem that requires the use of Li-po.

Although I'm a Li-po supporter, I must admit that the use of Li-po requires extra caution.

作者: bobpinpin 時間: 2008-5-14 22:06
Brother

Thank you so much and since I am not good at Physics. I would study your suggestions carefully. Btw, I only have lipo at home and unless I really have to buy NiHM .Otherwise, I would stick to lipo.

Bob

作者: bobpinpin 時間: 2008-5-23 13:47
Hey brother

If I use Tamiya Spot Tuned motor and original Tamiya ESC (bundled with cars) , is it okay for this boat?
Will it be too fast or slow? Can the ESC survive?

What T of motor will be suitable for my Paula. Thanks...still waiting for powerset to get start.

bob

作者: jpmontoya2 時間: 2008-5-23 18:06

原帖由 bobpinpin 於 2008-5-23 13:47 發表

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Hey brother

If I use Tamiya Spot Tuned motor and original Tamiya ESC (bundled with cars) , is it okay for this boat?
Will it be too fast or slow? Can the ESC survive?

What T of motor will be su ...

Perhaps you can try some 550 size motors or the Graupner 600 series which deliver more torque than a 540.

The Paula 3 is not a boat designed to go fast, so i guess selecting a motor with torque is the key. If 540 is your choice, then you may prefer to add a 2:1 reduction gearbox to slow down the boat as well as to strengthen the torque of a 540~

Whether the original Tamiya ESC can survive or not depends on your pitch and size of the prop, so its hard to say at this moment. However i would advise you to get an ESC that is capable of withstanding lower T motors, that can gurantee your boat returning to you safely rather than on fire~~~

~.....

[ 本帖最後由 jpmontoya2 於 2008-5-23 18:08 編輯 ]

作者: 夜遊神 時間: 2008-5-23 23:59
Better believe in brother jpmontoya2

By the way, you can check the current rate at stall of the Speed motor series at Graupner's web site. Here is the link:
https://shop.graupner.de/webuerp/servlet/AA?wgr=821

Take the 7.2V Speed 500 for instance, it drains 59A when its output shaft is fully stopped by means of external force, which implies the motor drains less than 59A as long as it is revolving. The exact current drainage, just as brother jpmontoya2 said, depends on the pitch and size of the prop.

[ 本帖最後由夜遊神於 2008-5-24 23:18 編輯 ]

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