new to model making hi to all

[andrew jollyParticipant @andrewjolly45059]

just ordered a 49 inch torpedo boat woodedn kit so here goes lol

[andrew jollyParticipant @andrewjolly45059]

made models in my youth lol

[Kev.WParticipant @kev-w]

Hi & welcome to the hobby.

One piece of advice, first thing to take out of the box, is the instruction sheet, read it through at least twice, then read it again, just to make sure.

Edited By Kip Woods on 07/11/2014 17:06:26

[andrew jollyParticipant @andrewjolly45059]

thanks kip lol

[andrew jollyParticipant @andrewjolly45059]

could anyone tell me the best brushsless motor to buy for this model thanks

[Paul TParticipant @pault84577]

Hello Andy and welcome to our little group.

Before answering the question about brushless motors we would need to know a little bit more about the model so if you could tell us which kit it is (so that we can estimate the weight), how many motors you intend to install (for example the Perkasa had three) do you want a reverse facility on your motors (quite a few brushless motors are intended for model aircraft and aren't designed to reverse)

Sorry to be asking so many basic questions but the answers will enable us to give you the best advice.

All the best

Paul

[andrew jollyParticipant @andrewjolly45059]

its the 49.5 inch wooden perkasa torpedo boat ,yes going to put reverse on it.can it run one one motor tar paul

[ashley needhamParticipant @ashleyneedham69188]

Andrew. Yes it can run quite adequately on one prop and this is by far the simplest way to go.

I would allow a generous prop clearance, to fit a prop up to at least 60mm to give you lee-way in prop choice (not suggesting a 60mm prop is whats wanted, but leave your options open)

Likewise, a 5mm diameter propshaft is my suggestion, especially as likely your propshaft will be quite long, and I am wary that 4mm diameter long shafts may flex and vibrate. usually the motor is fitted well forward, to give a shallow propshaft angle, unless the drawings give or suggest a position.

Do some surfing regarding brushless motor choice, as this is a right minefield, assuming there are no suggestions forthcoming on this forum.

Probably a large 800-900Kv outrunner will be required, running on a 12V Nimh Battery pack. Off the top of my head, something in excess of at least 150W will be needed and more likely 200+W…so look for motors needing a 30-50A ESC. No doubt someone who has built something similar and fitted a brushless motor will put me straight.

Ashley

[andrew jollyParticipant @andrewjolly45059]

thanks for info ash so a 900 kv motor what does outrunner meam

[ashley needhamParticipant @ashleyneedham69188]

Kv describes the revolutions per volt of battery….so a 10v battery on a 900Kv motor will produce 9000 RPM.

An outrunner motor is one where the OUTER CASING of the motor revolves, and this has the output shaft on it…bit like an old Bentley Rotary engine on a Sopwith Camel.

An inrunner is like a normal can motor…the can stay still and the rotor inside goes round.

Ashley

[Paul TParticipant @pault84577]

Bentley Rotary engine?

Will one fit in my not a project

Edited By Paul T on 08/11/2014 19:00:51

[andrew jollyParticipant @andrewjolly45059]

Posted by ashley needham on 08/11/2014 18:45:10:

Kv describes the revolutions per volt of battery….so a 10v battery on a 900Kv motor will produce 9000 RPM.

An outrunner motor is one where the OUTER CASING of the motor revolves, and this has the output shaft on it…bit like an old Bentley Rotary engine on a Sopwith Camel.

An inrunner is like a normal can motor…the can stay still and the rotor inside goes round.

Ashley

Ship by E-Express Mystery D2830 4000kv Outrunner RC Brushless Motor + ESC 30A

( 231056549636 ) would this be ok ash

[ashley needhamParticipant @ashleyneedham69188]

Andrew. Not likely. Too many revs, something more like….as below, but I would wait and see if someone posts. I have only built one "boat" with a brushless motor, and this is a 3000Kv item. however it is a sort of hydroplane and so you need the revs and it uses a small prop. A large boat like yours needs a large prop to bite the water

EMAX XA2212 980KV Brushless Motor +Simonk 20A ESC+Prop Adapter for RC Quadcopter

or….

RC Turnigy D2836/9 950KV Brushless Outrunner Motor

 

 

 

Edited By ashley needham on 08/11/2014 21:16:08

[andrew jollyParticipant @andrewjolly45059]

thanks for info ash

[CookieOldParticipant @cookieold]

Hi Andrew , I am also building a 49 inch Perkasa , Surly as you are building a scale boat you should go with the correct drive train E.G 3 props , 2 rudders.

Regards Dave

[andrew jollyParticipant @andrewjolly45059]

does the esc need to be water cooled tar

[andrew jollyParticipant @andrewjolly45059]

were you from david

[Charles OatesParticipant @charlesoates31738]

Hi Andrew, I built this model many years ago, here’s my thoughts on your build.
It’s a good model but not true scale, one motor is fine, at least to start with, you can change that later if you want to. Get it running and learn as you go, we’ll all help you.
Build it as light as you can, weight is the enemy of a planing boat.
I used a long gone motor ( I think) a Graupner 850. It was adequate, no more. Get advice from others on here and use a brushless motor. Most of all, enjoy it. We do this for fun!

[ashley needhamParticipant @ashleyneedham69188]

Andrew. As a thought, if you put the one shaft in with an eye to fitting outer shafts later then you can always convert. I would think that the real thing has exposed external shafting on "A" frames… three of these takes some tricky setting up, and is more expensive than just installing one fully sleeved shaft.

ESC watercooling….well, if there is some ventilation in the boat, to allow a flow of air across the ESC, this should not be a problem. Can be helped by a small computer fan wafting air across. If you are not fussed about reverse, as many of the chaps on the pond with fast boats are not fussed, then get a watercooled ESC, Fit and forget. If the motor is not man enough and you fit something more powerful, the ESC will cope at its max due to being properly cooled,

Obviously a water pickup will have to be fitted but this is very easy. Get the main stuff in first!

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Andrew. Check out the Mtronics website..they do some matched sets of brushless motors and ESC, just as a thought.

Ashley

[andrew jollyParticipant @andrewjolly45059]

Posted by ashley needham on 10/11/2014 14:53:15:

Andrew. Check out the Mtronics website..they do some matched sets of brushless motors and ESC, just as a thought.

Ashley

thanks ash what sort off tools are best to buy for planning and sanding

[ashley needhamParticipant @ashleyneedham69188]

A ordinary cork sanding block and a selection of med/course, medium and fine aluminium oxide paper should be all you need …say 100, 120 and 180 or 200 grit. possibly something a bit finer for finishing off for painting.. I use an 18mm snap-off blade type knife for trimming and so on, but its amazing how much material a reasonabley course paper willremove. You have a big boat so easy to get good long sweeps on.

For glues, try **LINK** an aliphatic wood glue is best and the Eze-cote resin is good stuff for sealing the wood up prior to painting.

Ashley

[andrew jollyParticipant @andrewjolly45059]

thanks ash

[andrew jollyParticipant @andrewjolly45059]

hi ash whats best to coat the inside off the hull to water tight it thanks

[Kev.WParticipant @kev-w]

Hi Andrew, the other members of my club were unanimous in recommending a coating of resin (as used for fibreglass) to seal my Billings 'plank on frame' hull.

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