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Author Topic: My First Rebuild – Vintage Cabin Cruiser  (Read 15676 times)

Jon

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Re: My First Rebuild – Vintage Cabin Cruiser
« Reply #50 on: May 31, 2014, 03:03:02 PM »

Hi Jon,

See if you can get your hands on an 'industrial' motor like this Bühler:
http://www.rc-point.nl/index.php?item=buhler-6-18-vdc-motor--12v-3030-toeren-1_7a--pakket&action=article&group_id=20000271&aid=69112&lang=nl#.U4m9CyhC1dw

Last year I used 14 of these motors in 140 cm long models and they run all day on a 12V 7Ah battery turning a Ø55 mm prop.

Regards, Jan.

I mentioned in an earlier post that I had a large industrial motor that I was thinking of using, but I thought it was slightly too large, and at 48V inconvenient.
It just so happens it's one of the motors you mentioned, albeit a 48V one.

The choice of motors I have that will likely work, it either the Bühler, or the Marx GT300 (Taken next to a stock 540 for comparison)



The Bühler needs 28V to make 3500 RPM, while the GT300/10 only needs 5V to do 3500 RPM, my gut feeling is neither of these is ideal, bit I may fit the GT300 and take it to the pool tomorrow to test anyway.
I know the GT300 is totally excessive, hell 4 of these will power a 1:6 scale C-130 Hercules apparently.
Other option is to knock up a belt reduction for a 540, as I think a 500 can operating at the designed RPM will have adequate power.
The hectoperm was only drawing 30 odd watts, so a 500 should be more than capable, and much lighter than a low RPM direct drive larger motor.
Rgds
Jon
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Jon

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Re: My First Rebuild – Vintage Cabin Cruiser
« Reply #51 on: May 31, 2014, 05:22:46 PM »

Just had a better look at the Bühler link, and my Bühler motor is considerably larger.

Mine is 54x107mm

I do have another Bühler motor I've just located, appears to be a 600 can size (36.6mm can), and gives ~4K RPM with 14V,
I believe it to be a 48V motor also, so it would be well out of it's nominal operating range.
So IF this was powerful enough it may be an option.



I struggled to stop the pinion with a pair of pliers at 14V, and it was drawing ~2.5A during that.
Just a pain it's going to have to be 4S lipo, or a pair of racepacks to try it out, and my current ESC is only rated to 12V, so that's a pain too.
Guess I could try it on 10 cell (max stated by ESC) to see how it goes.
All of these motors were out of a Xerox Phaser Wax printer.

Rgds
Jon
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pompebled

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Re: My First Rebuild – Vintage Cabin Cruiser
« Reply #52 on: May 31, 2014, 05:33:08 PM »

Hi Jon,

Yes, those Bühler motors are generally torque monsters.

If you have 3S Lipo's at hand, give those a try first, you won't exceed the ESC limits.

When the GT series came out, they were a sensation, really large commutors with large brushes which could handle the 300W all day long without overheating (in a plane).

The have also been used in boats, but the limited cooling proved to be an issue in competition boats.

If you would run the GT300/10 (730Kv) on 3S and used a belt reduction 1:2, you'd have about 3300 rpm under load and the motor wouldn't even get warm...
On 4S, the 4000 rpm  would make it a very fast cruiser.

Regards, Jan.
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Jon

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Re: My First Rebuild – Vintage Cabin Cruiser
« Reply #53 on: June 08, 2014, 02:25:41 PM »

Well I just got back from the boating pool (Worcester Country Hall), and I believe I have a successful combination on the Tarpon.
The 600 can Bühler motor appears to be just right, running on 4S, pulling 2.75A peak (so ~45W) and giving a good scale speed in near silence.
After 10 minutes or so of running the motor was slightly warm to the touch, so no over heating problems which is great.
I may try 5S (21v Charged) just to see if it has any benefit, but 4S (16.8V Charged) was perfectly acceptable.
5S may just give me a better speed when the batteries are down at their nominal voltage, as 5S nominal is only a bit above the peak charge of 4S, so Thinking about it5S may be better, and just not throttle it full when the batteries are fresh.



After I blew up the second MTronics 'Marine 20' when running on 12V, I moved to my Electronize ESC to test the boat.
These are rated to 24V, so no issues with voltage, and I've replaced the FET with a very low RDSon so should it shouldn't heat up much either.



On the subject of the MTronics 'Marine 20' this second unit was a warranty replacement for the 1st unit, I ran the 1st unit on 3S LiPo, and the unit failed very quickly.
This one I was bench testing the Bühler motor on a lead acid battery (12V), and it lasted less than five minutes. Not impressed. I was not overloading the ESC in either case (<1A on the second time), so I can only assume they are just rubbish.

Ive also got a first coat of paint on the cabin, and the mast is erect for the 1st time in a few decades I would think.
Just need to order some acrylic for the windows, a new searchlight, and some brass NAVlights I can put LEDs in.




I'll try to get another video done soon, to show the improvement over the Hectoperm.

Jon
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pompebled

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Re: My First Rebuild – Vintage Cabin Cruiser
« Reply #54 on: June 08, 2014, 06:11:30 PM »

Nice!

Looking forward to the video.

Regards, Jan.
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Jon

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Re: My First Rebuild – Vintage Cabin Cruiser
« Reply #55 on: June 29, 2014, 11:29:52 AM »

Well I was going to put up a video today of the new motor BUT.....

I lost my prop after a full astern collision avoidance event this morning.  >:-o
I'd locknutt'ed it up, but obviously not enough for the high torque motor now running on 5Cell LiPo.
Bit it was great before the event, bow was lifting nicely, stern was not digging in too deep, and the speed was great at 3/4 throttle.

Same really as it was a 1950/60's cast prop that looked really well built.
Looks like I now need to find a suitable replacement.
So I likely need a 55mm 3 blade brass.

Oh well these things happen....
Jon
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