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Sep 20, 2015, 11:59 AM
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Help!

Newbie with head about to implode needs help ...


Guys, I am but a poor aeromodeller trying to make some kind of sense of things nautical, so have pity on me please ... I have this hankering after making myself a Springer tugboat, but just in case I get a bad dose of the boating bug and start really getting into it, I want to make sure that I'm on the right track from the start.

First off, as I understand it there are two ways I could use my Spektrum DX61 for boats: either I have rudder on the stick with the centre detent and throttle on the free-moving stick (with "off" at mid-travel), or I have them the other way round. Is which is best down to personal preference, or is there some greater concern?

And I want to make the right choice of motor and battery type from the start. I'm used to brushless motors and ESC's, and I have 2S LiPo's about the place. Given that
(a) any model boating I do will be small models on a small pond (maybe 100ft x 50ft)
(b) I'm mainly attracted to tugboat-type boats (power and maneuverability rather than speed)
(c) An hour or so duration will do me just fine
(d) Cost is an issue
would you advise me to stick with brushless motors and my Lipo's for boats, or to start thinking now in terms of brushed motors and 6v batteries?
Last edited by Roger Andout; Sep 20, 2015 at 12:10 PM. Reason: Clarity
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Sep 20, 2015, 12:37 PM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
You can stick with the Brushless and Lipo, but if you use your existing motors, you may
have to gear them down to get lower rpm. For scale models like tugs, people are looking
to brushless motors that have around 460-900 kv at 6-12 volts.

Your DX will be fine for controlling the model.
It is personal preferance as to how you run the throttle.
I like the free stick with center stop, but others prefer the spring center and a positive stop position that the spring provides.

A springer tug would be a simple start to boat modeling.
The plans are free online, and there are cheap simple kits available.
Zippkits is a good example of an affordable springer kit.

Sep 20, 2015, 01:25 PM
Registered User
CaptCB's Avatar
Since you only have small ponds, you might consider a smaller boat, than the standard 18'' x 8'' Springer. We have built some boats that use an almost identically shaped hull, but, are only 12'' long, by 5.5'' wide. They weigh less than 4 pounds. Just a thought.
Sep 21, 2015, 01:17 AM
Registered User
Thread OP
Umi, in that case I'll try 7.2v and the 880Kv motor I have sitting here on the shelf and see what happens!

CaptCB, my wife just looked over my shoulder, so I now have a mini-Springer to build right after the Springer which I'm still at the head-scratching stage with.

Oh boy. What am I getting into ...
Sep 21, 2015, 08:11 AM
Registered User
You Do Not need a brushless motor! A brushed motor is preferred and best of all you can use big batteries for ballest....
Sep 21, 2015, 11:46 AM
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Thread OP
Quote:
Originally Posted by Old Wood Boats
You Do Not need a brushless motor! A brushed motor is preferred and best of all you can use big batteries for ballest....
Why is a brushed motor preferred?
Sep 21, 2015, 12:47 PM
Big Boats Rule!
boater_dave's Avatar
The original argument against converting to brushless and Lipo was that all of the existing equipment, like chargers, esc's, motors, etc would become obsolete and that the new stuff would require a big $$ investment. Nowadays, especially for flyers getting into boats, that just isn't the case.
Brushed motors do work just fine in scale boats, as the advantages of brushless aren't required, but there is no reason why brushless won't work. One big advantage that brushless motors have over brushed is that there are far more to choose from, and the specs are well published. Believing the specs is another story (for example, the 300 amp esc with Tamiya connector).

Dave
Sep 21, 2015, 01:22 PM
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CaptCB's Avatar

Why a brushed motor ?


For a small tug, it is "simpler" and usually, "way cheaper"! Also, works much better at SLOW speeds.
For our 12'' boats, we are using an "Electrifly" Speed 400, with a 3:1 gearbox. Part #GPMG0415, gives you that system. Our gearbox's are almost identical, but came from a different source. Our speed controls are M-Tronics 10 amp (UK), and our props are a 4-bld, 1.5'' dia x M-4 shaft. They come from the Prop Shop (UK). Here is a picture of the running gear layout. These photo's should give you some idea of the layout. Yes, we are using fiberglass hulls, as that is what's in the kit we mfg. But, Aircraft Ply, with some bracing, would work also.
Sep 21, 2015, 02:00 PM
Registered User
Thread OP
Thank you gentlemen. That's really helpful!

If I wasn't coming to this from aircraft modelling and if the money wasn't so tight, I'd probably go with brushed motors. But I have a couple of 850 - 880kV brushless kicking around here, also the 7.2V LiPo batteries and corresponding charger, so it makes sense to me to see if I can get away with those for this first attempt.

It's all a bit of a leap into the unknown for me, but I'm much obliged to all you guys for making it a bit less of an unkown ...
Sep 21, 2015, 02:10 PM
Registered User
CaptCB's Avatar
Currently, the ElectriFly motor/gearbox system, sells for $22.00 US, on the web, and, you can probably find the speed control (it HAS reverse, your airplane ones don't), on the web for about $40.00 US, maybe less.
Last edited by CaptCB; Sep 21, 2015 at 05:10 PM. Reason: Spelling / grammar.
Sep 21, 2015, 07:54 PM
Registered User
Quote:
Originally Posted by Roger Andout
Thank you gentlemen. That's really helpful!


It's all a bit of a leap into the unknown for me, but I'm much obliged to all you guys for making it a bit less of an unkown ...
I'm an airplane guy myself.
Slow, low powered small boats should not be much of a challenge for you. The only thing new is learning how to keep the water out, and ballasting it so it doesn't tip over when the wind starts blowing, or a frog jumps into the water nearby.
Have fun.
Sep 22, 2015, 05:28 AM
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Thread OP
Thanks guys


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