Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: Geoff C on April 12, 2014, 11:41:01 am
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Hi Guys, I've started building a 36" model of the Cervia tug which would be driven by a 540 type motor through a gearbox and a 60mm Graupner nylon 3 blade prop, which I already have. Electronize make a 543 motor that's been rewound to give more torque. Do I need a gearbox? and if so, whats best, gears or belt drive? Cheers, Geoff C.
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Geoff
I reckon you'd be better off with one of these. More torque and less expense. I shall be fitting one to my new Maine Lobsterboat.
http://www.componentshop.co.uk/mabuchi-555-dc-motor-mounting-bracket.html (http://www.componentshop.co.uk/mabuchi-555-dc-motor-mounting-bracket.html)
DM
(and you can collect from Llanllechid from where you are and save the postage, too!)
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Inertia, Many thanks for that. It looks like I won't need a g/box with that motor, thanks. Geoff C.
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hi there Geoff
Are you building the Cervia from a kit or is it a readymade hull; or are you making the Cervia from scratch - as in the masterclass build. The reason I ask, is that 36 inches overall seems an oddball length as a 1:35 scale should work out at 38 inches roughly. I think 1:24 scale works out at about 28 inches - but that is just a thought.
As a 60 mm prop does seem on the large size for the hull. I seem to recall when I built the Cervia it was either a 45 or 50 mm brass prop that I used. To drive this, I used the MFA belt driven gear box but sadly MFA dont produce these gearboxes any longer. You can still get them though if you shop or hunt around Ebay and such good places.
The motor I used was a 540 pretty high revving one on 6 volts. As another side note O0 the motor Dave is mentioning on the thread above, if its the same one or the same style as Dave supplied to me when he owned ACTion - it will do the job fine cos I have this type of motor (direct drive) in the Archer Tug which I built - it drives a 50 mm 4 blade prop using a 7.2 NiCad battery.
Food for thought my mate.
aye
John
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Hi it looks as though the scale has been worked out at 1/35th ok but somebody has used the length B P which is a tad over 105ft instead of her overall length which is 113ft at 1/35th the BP for the hull would be 35.9 inches and at her O A length it would be 38.5 inches.
the length BP is measured between the two vertical points where the bow and normally the rudder stock touches the water, and the O A length is just that from tip to tip. hope this helps Geo.
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I bought a couple of 555's from Dave at the Leamington Spa Show 18 months ago (last 2 left - special price!) and have one fitted to my 33" Mountfleet Models 'Highlander' Puffer driving a 4 Blade 70mm prop. Goes beautifully.
John
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Thanks for the info guys. I just thought 36" would be a handy size to handle. Most of my models have been between 30" and 36" loa. I'm building it from the hobbies store plans and scaled the loa of 28" up to 36". It will be scratch built with plank on frame hull as per Bluebird's excellent masterclass. Best regards, Geoff C.