Power and control

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Power and control

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10 April 2020 at 03:30 #86660
Jay Harris 1
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@jayharris1
I am SUPER new to this hobby, like less than 2 weeks really. This lock down finally gave me the time and excuse I needed to dive in… and dive in I did, into the deep end. I am currently working on a scratch built model from a set of plans called The Black Rose… this is a wooden tall ship a little over 2 feel long, about 1/48th scale. I have no idea how to sail, but I know that if I have a small slow motor and prop in it, I can putter around the local ponds without much trouble.

With that being said, I know NOTHING about the power train of model boats and all the ins and outs that go along with that. I have been watching a lot of videos, digging around a lot of websites, but man there is a lot of info out there. With so much information, I am getting overloaded. Can anyone point me in the right direction to get some simple info about what basic things I need to get this ship in the water, and moving around at a sailing pace? Here in the states its all about speed boats and racing and thats not really my thing. any help is appreciated, thank you all!
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10 April 2020 at 03:30 #2912
Jay Harris 1
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@jayharris1
prop, shaft, motor, controller, etc
10 April 2020 at 07:18 #86661
Ray Wood 3
Participant
@raywood3
Hi Jay,

You clearly know more than nothing as your thread description lists what you need to propel your boat, you will need to make provision for a stern tube and shaft in the keel with some means of steering? Maybe a photo of the drawing of the stern would help us to advise you 😀

Regards Ray
10 April 2020 at 07:40 #86662
Jay Harris 1
Participant
@jayharris1
Thanks Ray!

There are some great photos of the same build in another thread called "black rose", but here is an image of the PDF plans that I have, I am just now starting on the keel and the bulkheads (waiting for a bit more wood to arrive this week to finish that up, but now is the time to plan for such things!
10 April 2020 at 07:45 #86663
Jay Harris 1
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@jayharris1
my biggest issues right now are figuring out the right size of motor, type of prop, the drive shaft (no idea how that works with keeping things water tight) and a basic RC controller, battery and types of servos, etc.

My assumption is that battery will go near the middle just in front of the center mast, and the motor somewhere underneath the second deck in the back, just before the poop deck. I can only guess that my best bet here is to notch out the inner lower bit of the rudder and have the prop come out at the bottom of the keel at the rear? are there other, more viable, options?
10 April 2020 at 08:50 #86664
ashley needham
Participant
@ashleyneedham69188
Jay. For a starter, if you go to the home page and scroll down just a bit, in the centre is an article by Dave M concerning boat electrics. Should make it crystal clear for you. A low power 540 motor would likely do for you (MFA 540/1)

In addition, the features section with hints and tips contains a good few articles on all sorts of stuff including pictures of motor/coupling/shaft/prop layout. Waterproofing…basically the propshaft stops water getting in, as long as there is sufficient glue around it sealing the prop shaft to the hull.

Hoverer, inserting a propshaft in your model may be tricky as ideally it needs to come out centrally in line with the rudder. It would mean some artistic cutting and reinforcing internally and then making a larger rudder with a cutout.

It would be possible to have a small prop protruding from the side but not recommended.

I think several persons have built this vessel but not sure if any have motorised it?

Ashley

Edited By ashley needham on 10/04/2020 08:58:11
10 April 2020 at 09:03 #86666
Ray Wood 3
Participant
@raywood3
Hi Jay,

This is slightly different arrangement for a Friendship sloop from Maine, but the principal is the same as Ashley is describing. The stern tube is built into the keel and the external planking seals the hull, I think you main issue will ballast in the hull low down, or an external keel to keep the boat up the right way 😀

When I build this boat I will move the prop forward into a recess in the keel, to make the rudder easier to build .

Regards Ray

Edited By Ray Wood 2 on 10/04/2020 09:07:11
10 April 2020 at 09:20 #86667
ashley needham
Participant
@ashleyneedham69188
Like Ray said! His illustration is the sort of thing you need, the different style of boat means you will need to keep your shaft lower, that’s all.

I would also think about a thin (sheet brass) rudder…don’t know what the plan says, but without a prop therudder is likely to be quite fat which won’t help the motoring at all.

Ashley. (Snaps please)
10 April 2020 at 11:23 #86671
Malcolm Frary
Participant
@malcolmfrary95515
If it is to be fitted with sails, any moving air will cause it to be a sailboat, and might well overpower the efforts of the prop.

Since it is only 2 feet long, and not intended to be fast, I would consider a 5 pole 385 motor intended for a max of 15 volts, but run on about 6 volts. The smaller motor (smaller than a 540) gives more choice of where to fit it. It also weighs less, and a boat like this will need as much ballast as possible as low as possible. Even more so if sails are fitted.

Adding a motor to a sailboat always raises the center of gravity, and this is never a wanted thing on a sailboat.
10 April 2020 at 16:19 #86677
Jay Harris 1
Participant
@jayharris1
Posted by ashley needham on 10/04/2020 09:20:14:

Like Ray said! His illustration is the sort of thing you need, the different style of boat means you will need to keep your shaft lower, that’s all.

I would also think about a thin (sheet brass) rudder…don’t know what the plan says, but without a prop therudder is likely to be quite fat which won’t help the motoring at all.

Ashley. (Snaps please)

It calls for 3 mm balsa… my plan was to taper the balsa to a thinner edge on the front end to make it more like a wedge
10 April 2020 at 16:53 #86680
ashley needham
Participant
@ashleyneedham69188
3mm is ok. Would use thin ply personally, especially as it is in the propwash. (or will be)

Malcolm has a point, however you could consider using muslin for the sails, as I did with the London, to minimise wind resistance?

Ashley

Edited By ashley needham on 10/04/2020 16:58:08
10 April 2020 at 17:05 #86681
Jay Harris 1
Participant
@jayharris1
Posted by ashley needham on 10/04/2020 16:53:17:

3mm is ok. Would use thin ply personally, especially as it is in the propwash. (or will be)

Malcolm has a point, however you could consider using muslin for the sails, as I did with the London, to minimise wind resistance?

Ashley

Edited By ashley needham on 10/04/2020 16:58:08

absolutely, I was trying to figure out what I was going to use for the sails, and this seems like an excellent solution!
10 April 2020 at 18:09 #86683
Jay Harris 1
Participant
@jayharris1
I will convert the rudder from 3 mm balsa to a ply… would a solid bit of basswood work as well? (UK= Lime)
11 April 2020 at 09:04 #86695
ashley needham
Participant
@ashleyneedham69188
Jay. Don’t get hung up too much on materials.

Anything can be used for making boats, any material can be made waterproof and/of stiff enough with the right treatment, be that resin or varnish etc. Captain Bob is currently using corrugated card to build a speed boat, and I have used hardboard in the past very successfully although these, materials are not to everyone’s taste!

I only suggested ply for the rudder as small bits of balsa are not very strong and the rudder is likely to be blasted by bits of debris/mud/fish parts via the relatively high speed jet of water from the prop.

Lolly sticks are a good source of small wood….

Ashley Snap….hardboard battleship
19 April 2020 at 02:05 #86981
Jay Harris 1
Participant
@jayharris1
Well I am at the point where electronics need to be ordered. So, I would like recommendations on a transmitter, servo (just for the rudder), battery, motor, prop and shaft (model and makes would be appreciated) and any websites you would recommend would be super helpful…

Also, I would like to fit the captains cabin with an LED light, as well as possibly some lights on the deck. I already have the proper candle flicker style LEDs, I just need some kind of way to turn them on and off from the radio.. not really sure how that works yet…

any input would be greatly appreciated!
19 April 2020 at 02:22 #86982
Jay Harris 1
Participant
@jayharris1
also, for the shaft, i think I may use a flex shaft so I can mount the motor just off center and still have the prop come out exactly where I need it
19 April 2020 at 09:11 #86983
ashley needham
Participant
@ashleyneedham69188
Jay. A new Planet 2+2 set would be good as they have the normal go/turn sticks, but also two simple on/of types great for just turning stuff on and off.

Wouldnt recommend a flexishaft, they take a lot of maintenance and the prop-end skeg needs substantial fixing.

I would rather try and fit a slimline shaft (6mm diameter) just to one side of the keel, if you can’t drill through the keel. This will put the thrust line slightly off centre but should not make much difference for pottering about.

Muslin sails will lessen wind pressure on the masts and thus heeling movement.

Ashley
19 April 2020 at 09:20 #86985
Malcolm Frary
Participant
@malcolmfrary95515
Lots of low cost 2G4 radio outfits out there, starter line is usually 4 channels these days. Just don't plug anything into the unused channels. A 6 channel version with switched channels might be better here.

Servo. More or less any standard size servo will do the job. A smaller size will be easier to fit, but the rudder is not a balanced type.

Motor. It isn't a speedboat, and it is a 2 foot long model. A 15 volt 385 run on 6 volts (or 7.4 if using lithium batteries) will be plenty.

Prop. Something small, two or three blades, or go look for "towboatjoe" website. There is a section on there that tells how to knok up you own from brass sheet, which lets you choose your preferred size. towboatjoe.tripod.com/hulls.htm

Shaft, again, the towboatjoe (sorry, no link, this forums paste arrangements just don't play nice for me) site tells how to make your own from brass rod and tube. Or, for a commercial shaft, SHG do some nice short slimline ones. Flexi shafts are for forward only, they unwind in reverse. This is going to be a boat with very limited steering, its going to get into positions where reverse is needed. Coupling motor to shaft was not mentioned, but at these power levels, close fitting silicone sleeving will do the job.

Battery. While a model like this will need ballast weight, SLA is best avoided. You need the weight, but it needs to be as low as possible to counter the heeling that the masts and sails (even very leaky ones) will induce. A 2S lithium of about 3000mAH would do the job, and allow for (hopefully) enough lead in the bottom of the hull.

Switching items. Decide how many functions, switchers are available that plug into the channels corresponding to the switches on the transmitter.

Not mentioned was the ESC. Not the cheapest, but usually you only need to buy a marine Viper once. The 15A one shoud be overkill here. Also has a built in BEC so the power for the radio, servo and switcger is sorted.

Edited By Malcolm Frary on 19/04/2020 09:21:44

Edited By Malcolm Frary on 19/04/2020 09:24:32
19 April 2020 at 10:19 #86990
Dave Milbourn
Participant
@davemilbourn48782
A new Planet 2+2 set would be good as they have the normal go/turn sticks, but also two simple on/of types great for just turning stuff on and off.

Point of order. Mr Speaker. Planet 2+2 has THREE proportional channel and one 2-way switched one. The auxiliary proportional one is operated via a rotary knob and so can be used with a servo or speed controller, if required.

Dave M
19 April 2020 at 12:49 #86994
ashley needham
Participant
@ashleyneedham69188
Just keeping it simple Mr speaker for someone getting to grips with it all.

Ashley
23 April 2020 at 13:53 #87118
Dave Cooper 6
Participant
@davecooper6
Radio on rudder only ?

If it were me (and not wanting to risk being 'stranded' mid-lake), I would go for some form of motor control as well. Simple on/off perhaps, but definitely forward /reverse – to get out of reed banks etc.

I think Ashley carries a RC landing craft for such retrievals !!

Good luck,

Dave C
23 April 2020 at 14:10 #87119
ashley needham
Participant
@ashleyneedham69188
Oh yes, handy, always take one! Ashley
23 April 2020 at 14:35 #87122
Ray Wood 3
Participant
@raywood3
Hi Dave,

Am I missing something ? Who was suggesting rudder only ??

Some of my smaller boats just have On & Off with a servo & micro switch for motor control.

I just bought the Planet 2+2 it's an ideal choice 😀

Regards Ray

Edited By Ray Wood 2 on 23/04/2020 14:36:40
23 April 2020 at 19:05 #87127
Dave Cooper 6
Participant
@davecooper6
Posted by Jay Harris 1 on 19/04/2020 02:05:51:

Well I am at the point where electronics need to be ordered. So, I would like recommendations on a transmitter, servo (just for the rudder), battery, motor, prop and shaft (model and makes would be appreciated) and any websites you would recommend would be super helpful…

Also, I would like to fit the captains cabin with an LED light, as well as possibly some lights on the deck. I already have the proper candle flicker style LEDs, I just need some kind of way to turn them on and off from the radio.. not really sure how that works yet…

any input would be greatly appreciated!

Open to interpretation I suppose Ray – no real mention of motor control here…

Dave
23 April 2020 at 19:18 #87128
Jay Harris 1
Participant
@jayharris1
As expected, this forum is a wealth of information, and you have all been extremely helpful in this task. I have taken the suggestions, and with additional research on what is easily available in the states, I think I have ordered pretty much everything I need except for the prop shaft and prop. I want to wait until everything arrives and see how it can fit into the hull before I make a final decision on the shaft/motor/prop positions and layout

the build is coming along with only minor problems here and there, and while things are drying on my primary project I have started a secondary boat… a 38 ft Wheeler Express (SS Minnow from Gilligan's Island). I even spoke to the grandson of the man who started the Wheeler company and he was kind enough to send me some historical photographs of the boat so I can better see some of the details of the ship. I think I may be ears deep into this hobby, guess there is no turning back now… and I have all of you to thank for it!
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