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emrys
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PostSubject: Hello   Wed Feb 18, 2015 8:53 pm

Hello All

Just joined the forum and thought I should introduce myself.

I am not a highly skilled modeller by any means but enjoy playing with model boats. Most of the models I make are small (sub 20 inches) because it makes them a lot easier to carry to the lake.

Have just ordered a Chwannen Ddwr hull from Chris Brown model boats and am looking forward to making a start when it arrives.
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nhp651
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PostSubject: Re: Hello   Wed Feb 18, 2015 9:14 pm

you are most welcome to the site Emrys..........we are a friendly bunch and love nothing more than helping others with any problems they have with their building, and more so love to look at other members progress in their builds.

I am sure that our members would love to see your progress on the Chris Brown model once started.

I part built his Cariad Pilot cutter many years ago before a member of a local club made me an offer I couldn't refuse.............they are nice models.
Hope to see your posts soon.

neil and the crew.
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emrys
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PostSubject: Re: Hello   Fri Feb 20, 2015 2:51 pm

The hull and drawings arrived this morning. Very good value for money and a very prompt service from Chris Brown. Being a small (16 inch) model of a canal boat I cannot imagine it will need much by way of power. I am going to take a look at some small brushless motors and see if I can find anything appropriate. The amps will supplied by a 6v 4.5Ah gel cell.
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barriew
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PostSubject: Re: Hello   Fri Feb 20, 2015 5:17 pm

Hi Emrys and welcome!

I wouldn't recommend a brushless motor and SLA combination. Also brushless aren't to my mind suited to slow scale boats. A 385 size brushed motor with an Mtroniks 10 amp speed control would be my solution for a boat that size.

Hope this helps,

Barrie
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emrys
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PostSubject: Re: Hello   Fri Feb 20, 2015 5:35 pm

Thanks Barrie

Your advice is much appreciated.
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barriew
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PostSubject: Re: Hello   Fri Feb 20, 2015 5:41 pm

Emrys

I actually built the work boat version many years ago. I'm trying to remember what I used to power it, but can't. Sad It may be that Chris sold it complete with a motor in those days.

Barrie
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emrys
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PostSubject: Re: Hello   Sun Feb 22, 2015 12:38 pm

Thanks Barrie

I now have an Mtroniks 15 amp ESC and a 385 motor is on its way.
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barriew
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PostSubject: Re: Hello   Sun Feb 22, 2015 1:03 pm

Emrys

When I bought the work boat it came with a bucket, mop and boat hook. I am pretty certain I still have these if you would like them for the Flea.

Barrie
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Roadrunner
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PostSubject: Re: Hello   Sun Feb 22, 2015 3:11 pm

Did u buy the mfa 385 motor?  if you did i would seriously suggest returning it i used one originally on the classic build and it was utter useless, i ended up swapping to  GRAPHNER 400 althought i do understand they are near impossible to get hold of now, that said i would recoment one of the JP power 400's ... [You must be registered and logged in to see this link.] they are actually better with the RPM then the graphners were and will run off a 10-15 amp esc super easy.

as for brushless motors, you can not run a brushless motor from a lead acid battery, the motors and ESC's for them draw far to many amps and lead acids can not discharge quick enough to power them.

If you opt to look at brushless motors first off don't rush into it, because for boating applications ( other then the super fast electrics racing ones ) there are limited dedicated motors available to forfil your needs,(more so for much smaller boats)
So shopping around would be best, then you have to locate suitable esc's & then consider if your going to run NHMI batterys or Lipos, if your running a 30amp brushless motor and esc u can run quite a few nhim batteryts, but for anything over 30-50amp you need the nhmi  high discharge rated ones, anything upwards of 50 amp's then your into lipo battery's by no choice as lipos were designed to match these systems.
other options to consider when going brushless is the ability to go backwards. you'll find many brushless esc dont offer that ability, the ones that do tend to not work or have limited ability, so u may have face off against this lack of feature on your model. Brushless motors were designed with one purpose to go really fast one way and mostly for the aviation models.

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emrys
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PostSubject: Re: Hello   Sun Feb 22, 2015 6:36 pm

Hi Roadrunner

I have a 'spare' 400 size 6v MIG motor in my parts box and did think of using it in the boat until I checked and found that the MIG motor is quoted as running at 15000 revs at 7.2 volts. In an ideal world I would like a motor that runs at 5000 to 7000 revs max so abandoned the idea of using the MIG motor for this build. I have no way of checking but would guess that the MIG would run at around 10000+ rpm on 6v so a tad too high.
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barriew
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PostSubject: Re: Hello   Sun Feb 22, 2015 8:17 pm

I tend to disagree about the 385 - maybe it depends on the brand. I have an MFA version in my Pilot Boat II and it works very well. This is a larger model than the Flea and think it will have plenty of power. I run mine on a 10 amp Mtroniks Viper from a 7.4 volt LiPo - the latter to save weight in the bows. As a canal boat I guess you are looking for a scale 4 mph.

Barrie

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Roadrunner
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PostSubject: Re: Hello   Sun Feb 22, 2015 8:37 pm

To be honest 5000rpm sounds a lot, but when your running a boat, with some weight its not enough at all you need to be looking at the 15-20,000 rpm range to get the boat up to any such speed, now i'm not saying that you need 15,000 rpm for shear speed, in fact you need need the rpm to push the boats mass either through the water if its a displacement, or a planing type vessel, once you add nearly 1kg of dead weight (lead acid battery then the boats overall weight) even the smaller boats can weigh in around 1.5-2kg,

This is turn is also subject to the prop size, that prop makes the world of difference,
say for example u are making a planing type boat at 500mm long running on a m2 prop shaft with a 30mm 3 bladed prop ( that the largest prop u can buy for a M2 shaft) at 5000 rpm that boat will barely move, any water chop or wind will over power the boat.
On a displacement type boat running the same setup, that boats as good as a stick.

Now on a much larger boat... say a 1m model running an M4 shaft, with a much larger prop upwards from 40mm even to a 60mm ( providing the motor is able to shift such a prop) 5000rpm is more the enough to push that model up to power, as the prop size is much larger so that surface area is now using 5000rpm's worth or torque to push the boat. through the water.

i'll show u a video to demonstrate...



This video is of my Classic, its running a Graphner 400 motor, at 7.2v on an M2 prop shaft with a 3 bladed prop and what you see is top speed. Now in scale that's fine and she looks the part however she is a very light boat. and a planing type hull. she should be faster for a motor that can output 16,000 RPM, and even then that motor was red hot upon a 20min run, which indicated that the prop was far to much for the boat!,
cold and warm to the touch motors = good use of power & correct load.
Hot motors = over loaded motors!

Now even with my 1200 KV brusless motor i couldn't get her much faster than that due to the prop size.( but the motor remained cool) which i ended up changing out to an M4 shaft to be able to start taking the X35 props and 40 planing types to give her that speed she requires.

Like i said prop size is everything, if you want slow and steady you need a low rpm motor on a big prop, with a matching motor and esc that can handle the load, (and big props over 30mm will only fit on M4 & M5 shafts.
If you want a fast moving boat then you need high RPM motors and the again the right type prop.

Have faith i won't steer you wrong

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barriew
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PostSubject: Re: Hello   Sun Feb 22, 2015 8:44 pm

RR

That's all true, BUT this is the model he's building

[You must be registered and logged in to see this link.]

Its 16 inches long. A 140 motor would drive it at over scale speed. I know, I built the Bantam Tug on the same hull.

Barrie
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PostSubject: Re: Hello   Sun Feb 22, 2015 9:00 pm

Right.. did'nt know it was that tiny lol! ( is that a kingston moulding? [You must be registered and logged in to see this link.] )

I did build the mobile marine canal boats (1:24th scale) and used a T4 motor M4 6" prop shaft, a 45mm 3 blade 'standard rh prop, on 6v LA i think that T4 runs at 6400 rpm, honestly tho i've run the boat once since building it, it just isn't a boat i was happy to sail, 3" wide 36" long, even in a light breeze i was always worried it would keel over.

The 385 might work for you, just keep in mind that prop size, thats going to make the diffrence between a working model or a static.

(sorry i'm sounding really blunt tonight, ex issues, need i say more)

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emrys
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PostSubject: Re: Hello   Sun Feb 22, 2015 9:53 pm

Hi Roadrunner

It is a Chris Brown hull: [You must be registered and logged in to see this link.]

I have a soft spot for canal boats - probably because of my childhood. I used to love operating locks and being around boats on the canal.
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PostSubject: Re: Hello   Sun Feb 22, 2015 10:43 pm

Looks like a good little model to make, i'm sure i speak for everyone here we look forward to the build log on the forum

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nhp651
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PostSubject: Re: Hello   Sun Feb 22, 2015 11:29 pm

magnificent boat handling on that video......the guy should work for REA towing co., lol
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PostSubject: Re: Hello   Mon Feb 23, 2015 12:43 am

Thats one of our club members who's nothing but a Tug boat nutcase, which is kinda handy for rescues! i belive thats one of of his voith tugs

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emrys
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PostSubject: Re: Hello   Mon Feb 23, 2015 3:13 pm

barriew wrote:
Emrys

When I bought the work boat it came with a bucket, mop and boat hook. I am pretty certain I still have these if you would like them for the Flea.

Barrie

Yes please Barrie.

Please let me know how much you want for them
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