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Author Topic: Workboat motor  (Read 2987 times)

AlanP

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Workboat motor
« on: December 02, 2008, 07:47:48 PM »

I am about to build the work boat Sea Helper from plans that where in MMI July 2008.  A chap in our club has just built the boat, fitting a 555 motor on 12v driving what I think is a 45mm 3 bladed prop (no measuring stick with me). It's first outing was a windy day and the boat was blown all over the place, only went OK with a tail wind, this Sunday I borrowed the boat to extract my Springer from an ice pack  :embarrassed: and found the boat to be really under powered.

I would prefer direct drive and looking at the drawing think I could squeeze a 50mm 3 bladed prop in.
So I am asking the experts what they think would be a better motor.

Regards Alan
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Sandy Calder

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Re: Workboat motor
« Reply #1 on: December 02, 2008, 08:09:10 PM »

Hi Alan.
The 45 mm prop is probably a touch too big and although it may have been sold as a 12 volt motor the exact part number may indicate it it is 12 volts in the broadest of definition.
Going down a prop size might give more speed.
If you can supply any data like the stall current,the vendor or the full part number it may reveal that it is more like 36 volts if you do a like-for-like comparison with the model boat trade motors.

Sandy Calder
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Stavros

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Re: Workboat motor
« Reply #2 on: December 02, 2008, 09:55:49 PM »

Ah ha another Model Motors direct Motor,the best thing your M8 can do is to take the motor out and throw it into the bin as what they are selling are not the old 555 as we used to know them.I had a pair in a Yorkshireman what did I do throw them!!!!!!!!!!! I personally use Graupener motors,But I personally would use something along the lines of a Graupener 600BB on 12v.
Take your pick of what everyone will suggest.


Stavros
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gingyer

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Re: Workboat motor
« Reply #3 on: December 02, 2008, 10:01:44 PM »

what type of ESC's are you using with the 555's?
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AlanP

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Re: Workboat motor
« Reply #4 on: December 02, 2008, 11:03:37 PM »

Sandy, think you are right about the motor, looking it up, seems as though it would run much better on 30volts. I will suggest to him that he tries a smaller prop.

Stavros, why did I know you where going to say that  {-)     , unfortunately my mate does not read Mayhem hence fitting a 555. I will have a look at what you suggest for mine.

Gingyer, it is not my boat but I think he had a Viper marine 15 fitted.

What I was looking for was suggestions for a motor so that I didn't end up with an under powered boat

Regards Alan
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gingyer

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Re: Workboat motor
« Reply #5 on: December 02, 2008, 11:29:54 PM »

Hi there,
I have some ESC's that don't work properly with 555's or 777's
the viper is ok and will work with it  :-))

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Sandy Calder

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Re: Workboat motor
« Reply #6 on: December 02, 2008, 11:40:32 PM »

Hi Alan.
If you have been to "shows" you may have seen these motors which are 48 mm dia and are marked
"LOW VOLTAGE MOTORS LTD"
 
The one with holes in the front cap are ideal for 12 volts and on 12 volts......
stall torque = 1.6 kg cm ( on a par with a servo )
stall current = 6.2 amp
If the figures still don't mean anything it will drive a 50 - 70 mm prop direct.
It is possible to get equivalent 540/550 sized motors but they usually cost a packet.
The only local source I have seen for such higher torque 540/550s lately is Deans.

Sandy Calder
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AlanP

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Re: Workboat motor
« Reply #7 on: December 03, 2008, 06:28:27 PM »

Hi Sandy, will keep an eye open for those motors at the next show. Deans motors did not make a lot of sense to me, wouldn't know which ones to buy  :embarrassed:

Been having a look around at motors, Howes do a 550 for 5.99.  After what Davros said about the 555s and seeing the performance of one in my mates work boat I will have to throw the two out of my partly built Graemsey while I can still get at them, so buying 3 of these motors, one for the work boat and two for the Graemsey would not put too big a hole in the pocket.
Your thoughts on this would be appreciated

Regards Alan
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Sandy Calder

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Re: Workboat motor
« Reply #8 on: December 03, 2008, 07:16:53 PM »

Hi Alan.
I'm pretty sure a standard 550 is up to the job although 45 mm is as much as it can handle.

The mention of " low voltage" motor is purely because it is in a class of motors like the torpedo 800 or a 900 motor which are suited to props on the large side.
Deans had a 550 motor with stronger magnets which put it in the same class.

There is nothing wrong with a 555.It's just a case a case of applying the correct voltage and load.
The particular 555 you have has too many turns.You might get more output power with a 30 or 35mm prop.This link explains why.http://www.mabuchi-motor.co.jp/en_US/technic/t_0201.html

The price you pay for the 550 is the higher stall current and greater radio interference.

550
http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_550pcvc
555s
http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_555pcvc
http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_555pxvx
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AlanP

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Re: Workboat motor
« Reply #9 on: December 04, 2008, 05:57:08 PM »

Thanks for all the information, just have to make a decision now.

Regards Alan
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Sandy Calder

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Re: Workboat motor
« Reply #10 on: December 04, 2008, 07:23:46 PM »

I think you may be surprised what a difference is made by changing the prop.
Regards
Sandy Calder
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